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Two-dimensional transition metal carbides and nitrides (MXenes) based biosensing and molecular imaging

  • Huiyu Liu , Xiaotong Xing , Yan Tan EMAIL logo and Haifeng Dong ORCID logo EMAIL logo
Published/Copyright: November 14, 2022
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Nanophotonics
From the journal Nanophotonics Volume 11 Issue 22

Abstract

As a “star material”, 2D transition metal carbides and/or nitrides (MXenes) have tremendous potential applications in biosensor development and molecular imaging. MXenes have a lot of advantages due to their large specific surface, excellent electrical conductivity, adjustable band gap, and easy modification. MXenes that immobilized with DNA strands, proteins, enzymes, or other bioluminescent materials on the surface, have been used to measure small molecules with extraordinary sensitivity and remarkable limit of detection. This review provides an overview of most recent development in the synthesis, fundamental properties, biosensing, and molecular imaging applications of MXenes. We focused on molecular detection through MXene-based electrochemical properties their challenges and novel opportunities of MXenes in biological applications. This article will provide a guide for researchers who are interested in the application of MXenes biosensors.

Keywords: biosensors; microRNA detection; molecular imaging; MXenes; two-dimensional nanomaterials

1 Introduction

Since the two-dimensional (2D) graphene nanosheets were magnificently exfoliated from bulk graphite in 2004 [1, 2], 2D nanomaterials have attracted extensive interest and become one of the most dynamic research areas in nanotechnology. Etching the A element from the MAX phase of layered ceramic yielded 2D transition metal carbonitrides, generating a new class of nanomaterials termed MXene materials. The chemical formula of MXene is M n+1X n T x [3, 4], wherein M represents an early transition metal element (Sc, Ti, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W, etc.), X represents C or N, and n = 1 to 4. T represents a surface end group (–OH, –O, –F, etc.) (Figure 1A).

Figure 1: The elements and structures of MXenes. (A) Chemical formula of MXenes. Wherein M represents an early transition metal element (Sc, Ti, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W, etc.), A means a group element including Al, Si, P, S, Fe, Cu, Zn, Ga, Ge, As, Cd, In, Sn, Sb, Ir, Au, Tl, Pb, Bi, etc. X represents C or N. T represents a surface end group (–OH, –O, –F, etc.). (B) Etching processes from MAX to MXenes phases.
Figure 1:

The elements and structures of MXenes. (A) Chemical formula of MXenes. Wherein M represents an early transition metal element (Sc, Ti, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W, etc.), A means a group element including Al, Si, P, S, Fe, Cu, Zn, Ga, Ge, As, Cd, In, Sn, Sb, Ir, Au, Tl, Pb, Bi, etc. X represents C or N. T represents a surface end group (–OH, –O, –F, etc.). (B) Etching processes from MAX to MXenes phases.

MXene materials derived from MAX have become the most prominent family of 2D materials due to the diversity of MAX phase compositions and structures [5]. Gogotsi group successfully prepared Ti3C2 nanosheets by etching Ti3AlC2 with hydrofluoric acid (HF) at room temperature in 2011, which promoted progress in the synthesis and characterization of MXenes [6]. The structure and preparation of M2X, M3X2, and M4X3 are shown in Figure 1B [7].

Considering the research on MXene materials in our group, the goal of this review mainly focused on the summary of the latest progress in the field of biosensing using MXenes. We provide an overview of MXenes and describe the synthesis, properties, and surface modifications. Furthermore, we elucidate the MXenes-based detection of microRNA and other small molecules and biomedical imaging applications. Finally, we illustrate the challenges for MXenes-based analysis. This review will outline the significant developments of MXenes in molecular detection and bioimaging applications. It will also serve as a reference for researchers by highlighting notable instances of their application in microRNA detection (Scheme 1).

Scheme 1: Overview of MXenes in this review.
Scheme 1:

Overview of MXenes in this review.

2 Properties of MXenes

MXenes have a lamellar structure with weak interlayer bonds and strong in-plane covalent bonds. Almost all of the atoms of MXenes are exposed after exfoliation (ultrathin form). The increased surface area of these MXenes materials considerably improves their chemical and physical reactivity, enabling drug loading and functional modification, and generating unique photonic, catalytic, magnetic, and electronic characteristics not found in bulk materials. MXenes are employed to construct innovative nanoplatforms with intriguing functions for optical imaging, photothermal imaging, biosensing, and targeted drug delivery. Thus, MXenes have great potential in biomedical applications [8, 9].

2.1 Electronic property

MXenes have either conductor or semiconductor properties due to their ordered arrangement of metal atoms. The various coating groups of MXenes produce distinct electron attraction capabilities, which profoundly influence their electrical properties. A significant influence on the metal layer’s electrical properties would occur from the imbalanced distribution of electron density caused by the increase in surface defects created during the synthesis of MXenes, which hinders the free flow of electrons [10]. MXenes have the capacity to produce active electrons and vacancies in response to specific stimuli (such as light excitation), and the interaction between MXene and surrounding environment is able to cause oxidative stress. The electrical conductivity can be accurately determined by measuring the current changing between the electrodes after binding to the testing species. A change in the local charge field initiates the signal accumulation which is reflected by material’s conductivity. The main advantage of MXenes as electronic biosensors is that the cross-sectional area is on the same spatial scale as the charge field of the nearby biomolecules, which serve as the smallest spatially limited target to sense electrical changes as a function of the measured conductivity [11]. Moreover, MXenes can produce active electrons under external stimuli such as heat or light.

2.2 Optical property

According to “first-principles density functional theory,” the calculations show that the optical band gap of MXenes can be changed by modifying the surface group compositions and contents. The linear optical properties (e.g., absorption, photoluminescence) and nonlinear optical properties (e.g., saturable absorption, nonlinear refractive index) highly depended on the structure [12]. Compared to the MXenes with the same thickness, the MAX phase absorbs more light and is transparent under visible light irradiation. Halim group established that MXenes films with larger intercalants were more transparent and less conductive [13]. The optoelectronic properties of the films may be modified by the electrochemical intercalation of the cations, exhibiting reversible transmission in the UV–Vis range, indicating the potential of MXenes to act as transparent conductors [14]. The UV–Vis spectrum shows a clear difference between MAX and MXene that MXene has significant absorption near 300 nm and a broad absorption near 800 nm, while the MAX showed weak absorption of at the range of 200–1000 nm [15, 16].

Nonlinear optics relate to the interplay between light and matter interactions in the nonlinear response of materials to electromagnetic fields. This phenomenon is crucial for laser optics, photonic devices, and optical communications applications. The unique photoluminescence lifetime of MXene nanomaterials can be directly used as a valuable probe for sensing and enabling live cell imaging [17]. Additionally, MXenes have potential to generate reactive oxygen species (ROS) under light irradiation, which can be designed as a platform for simultaneous photoacoustic imaging (PAI) and photodynamic therapy (PDT) [18]. However, the photothermal conversion mechanism of MXenes has not yet fully developed. Dong et al. speculated that MXenes like Ti3C2 have a localized surface plasmon resonance (LSPR) effect that similar to the gold nanoparticles [19]. It has the ability of photothermal conversion in the near-infrared (NIR) light region. Similarly, Wang’s group demonstrated that MXenes have photothermal conversion ability in NIR because of their excellent electromagnetic interference shielding and LSPR effect [20]. The Mo2Ti2C3T x MXene material reported by Guo et al. exhibited excellent saturable absorption properties, with an enhanced 40% modulation depth observed within the double transition carbide compared to previously reported MXenes, and can be used as a passively Q-switched mid-infrared fiber laser for SAM [21].

3 Synthesis and surface modification of MXenes

3.1 Synthesis methods

The efficient synthesis of MXene is the basis for expanding the materials’ range of applications. MAX has a crystal structure, and “M” atoms form an octahedral-like structure. “X” atoms are filled in the gaps of the octahedron. “A” intercalated into the lamellae formed with M and X and finally obtained an M n+1AX n structure. Primarily, the M–X bond belongs to the covalent bond and ionic bond. M–A and A–A belong to metallic bonds, and their bond energy is lower than that of the M–X bond, so the “A” atom is more active and easily stripped. The method for synthesizing MXenes is mainly a chemical etching method. Generally, MXenes materials are fabricated using two different methods: a top-down approach based on multilayer bulk flake exfoliation and a bottom-up approach to growing 2D flakes from their precursor salts. These synthesis methods endow various physical, surface, chemical, and electronic properties that can be used to perceive the connection between structural and functional properties [22]. In a top-down approach, thin layers of MXene films are exfoliated from their MAX phase precursors, primarily by mechanical exfoliation [23, 24]. Moreover, this is a liquid strip method with lower production costs and extended production capacity. The bottom-up approach depends on combining appropriate “metal-organic molecules” to make MXene films, mostly by metal-organic decomposition, chemical vapor deposition (CVD), wet chemistry, and other methods. Large areas of two-dimensional defect-free monolayer crystals can also be synthesized [25].

3.1.1 Top-down method

The top-down method for MXenes preparation is selectively etching the A layer in MAX material. It is mainly divided into HF etching, fluoride etching, molten salt, alkali-assisted hydrothermal, and other methods. Because the bond between the M layer and the A layer of the MAX phase is a solid covalent or metallic bond, MXenes was synthesized from the MAX phase by selective etching of the A layer by temperature processing [26]. The smaller the force constant contributed by adjacent atoms to the A atom, the smaller the exfoliation energy and the more manageable the exfoliation. Electrons injected into the MAX phase lead to the elongation of the M–A bond, which further induces the MAX phase’s swelling and the layer’s exfoliation [27].

3.1.2 HF etching

HF selectively etches metal layers, mainly adopting the following equation of reaction to complete the preparation of MXenes (Figure 2A). The first non-MAX phase precursor synthesized Mo2CT x was Mo2Ga2C by HF etching of Ga [28]. HF etching method has the advantages of simple operation and low reaction temperature and is suitable for etching the MAX phase containing Al and part of non-MAX phases. However, it suffers from the disadvantages of high corrosivity, toxicity, operational risk, and poor energy storage [25].

(1) M n + 1 A l X n + 3 H F → M n + 1 + A l F 3 + 1.5 H 2

(2) M n + 1 X n + 2 H 2 O → M n + 1 X n ( O H ) 2 + H 2

(3) M n + 1 X n + 2 H F → M n + 1 X n F 2 + 1.5 H 2

Figure 2: Preparing of MXenes. “Top–down” method: (A) HF selectively etches metal layers. (B) Acid/fluoride etching. (C) Carbide-derived carbon is formed by the electrochemical etching method. (D) Al atomic layer was etched by molten fluoride salt under argon at 550 °C. (E) Iodine-assisted strategy for etching Ti3AlC2 in anhydrous acetonitrile. (F) Ar/H2 thermal reduction strategy to produce TiC MXenes. (G) The algae extract to etch V2AlC crystals in an aqueous solution. “Bottom–up” method: (H) Mo2C crystals on the liquid copper surface by ambient pressure CVD. (I) synthesize N-doped Mo2C nanosheets based on the MoO2 template. Figures are adapted from references [6, 29–36].
Figure 2:

Preparing of MXenes. “Top–down” method: (A) HF selectively etches metal layers. (B) Acid/fluoride etching. (C) Carbide-derived carbon is formed by the electrochemical etching method. (D) Al atomic layer was etched by molten fluoride salt under argon at 550 °C. (E) Iodine-assisted strategy for etching Ti3AlC2 in anhydrous acetonitrile. (F) Ar/H2 thermal reduction strategy to produce TiC MXenes. (G) The algae extract to etch V2AlC crystals in an aqueous solution. “Bottom–up” method: (H) Mo2C crystals on the liquid copper surface by ambient pressure CVD. (I) synthesize N-doped Mo2C nanosheets based on the MoO2 template. Figures are adapted from references [6, 29–36].

3.1.3 Acid/fluoride etching

Halim et al. made the first hydrogen fluoride salt etching application using NH4HF2 sputter-deposited epitaxial Ti3AlC2 films [13]. Owing to the change of fluoride salt can adjust the interlayer spacing of MXenes, Ghidiu et al. conducted an etching process with HCl/LiF solution at 40 °C (Figure 2B) [29]. Additionally, this synthesis strategy can etch Ti3AlC2 without water and apply to water-sensitive MXenes materials. Difluoride salts are solid at room temperature and much safer than HF, and more attention should be paid for their application to exfoliate MAX phases. Multilayer Ti3C2T x MXenes material reported by Wu et al. was etched by a hydrothermal process using oxalic acid and NH4F at different temperatures of 100–180 °C for 24 h (Figure 2C) [30]. The kinetic of this method depended on the acidity of the dissociated organic anion and its interaction with the dissociated F of the ionic liquid.

3.1.4 Electrochemical etching method

The metal-carbon atoms are selectively extracted from the ternary layered carbides in an electrochemical manner. The carbide was added in a NaCl, HCl, or HF solution, and an anodic potential was applied so that carbide-derived carbon (CDC) is formed (Figure 2D), and a carbon film with a very narrow pore size distribution was formed [31]. The critical points of this method were the voltage, etching time, and electrolyte concentration. However, this method was unsuitable for large-scale preparation due to its low yield.

3.1.5 Molten salt method and other methods

Carbide MXenes can be easily and successfully prepared by HF or fluoride etching, but nitride MXenes cannot be prepared. The Ti–Al bond in Ti n+1AlN n is stronger than that in Ti n+1AlC n , so the preparation of Ti n+1AlN n requires higher energy. Meanwhile, Ti n+1AlN n is less stable and easy to degrade in HF. The molten salt method uses low melting point salt as flux with improved ion diffusion rate. Urbankowski et al. reported the first Ti4N3-based MXenes, using the molten fluoride salt for etching an Al atomic layer at 550 °C under argon conditions [37]. Recently, other new synthetic methods have also been explored. For example, halogen can also be used as an etchant to de-etch the MAX phase. Shi et al. designed an iodine-assisted way for etching Ti3AlC2 in anhydrous acetonitrile (Figure 2E) [32]. Mei et al. reported a new Ar/H2 thermal reduction strategy to produce TiC MXenes from the sulfur Ti2SC MAX phase (Figure 2F) [33]. Zada et al. used algae extract to etch bulk V2AlC crystals in an aqueous solution (Figure 2G) [34]. It has also been reported using UV-induced etching [38] and surface acoustic waves for ultrafast one-step synthesis of MXenes [39].

3.1.6 Bottom-up

The bottom-up method for preparing MXenes is a chemical synthesis that includes CVD, atomic layer deposition (ALD), plasma-enhanced pulsed laser deposition (PEPLD), template methods, etc. Xu et al. produced ultrathin α-Mo2C crystals of several nanometers by using methane as a carbon source, copper foil on Mo foil as substrate, and a temperature higher than 1085 °C [40]. Geng et al. reported the growth of Mo2C crystals with controllable thickness and morphology on a liquid copper surface by ambient pressure CVD (Figure 2H) [35]. ALD, a variant of CVD, is a gas-phase method based on two successive self-limiting surface reactions. However, the rate of final products is usually low and requires special equipment. Zhang et al. demonstrated a type of Mo2C thin films with controlled crystal structure growth on sapphire substrates by PLD at a temperature of 700 °C [41]. Jia et al. used MoO2 as a template that was also a highly active electrocatalyst to synthesize N-doped Mo2C nanosheets (Figure 2I) [36]. Compared with the top–down method, the bottom-up approach saves raw materials and accurately controls the element composition, size, and surface groups. However, it is a challenge to prepare large-size MXenes. Most of the reported MXenes are prepared by the top-down method, with few reports on the bottom–up approach.

3.2 Surface modification

By altering the surface and interlayer spacing of MXenes, the proton transport efficiency will be enhanced, which will be beneficial to the electrochemical properties of MXenes. MXenes can be doped with various elements, nanoparticles, ligands, drugs, and other surface modifications to obtain desired characteristics. Doping with Fe3+, Co2+, Ni2+, Mn2+, and other metal ions is helpful to promote intrinsic performance. Zhang et al. replaced a Cu layer electrodeposited thereon by a Pt current using Pt-modified SnO2C (Pt/SnO2C) nanofibers. Thus, SnO2C nanofibers exhibited competitive oxygen reduction reaction catalytic activity, enhanced methanol tolerance, and superior durability [42]. Cao et al. utilized Au nanocrystals to selectively grow on the edges of TiO2 nanosheets with highly exposed (001) facets to fabricate Au-TiO2 NSs as an acoustic sensitizer [43]. Polymers such as dextran, cellulose, chitosan, polyethylene glycol (PEG) [44–46], polyethyleneimine (PEI) [47], polyvinylpyrrolidone (PVP) [48], polyacrylic acid, and polyvinyl alcohol [49], which are used to improve the stability, hydrophilicity, degradability, and biocompatibility of the MXenes. Pan et al. prepared Gd3+-doped MoSe2 nanosheets by a simple liquid phase method with a PEG modification on the surface for better PAI [50]. Cao et al. used vanadium carbide quantum dots (V2C QDs) with an engineered exosome (Ex) carrier to accomplish effective tumor therapy via bio-membrane modification [51]. MXenes decorated with metal nanoparticles can exhibit a strong plasmon-photothermal effect. By modifying with biomolecular such as folic acid [52], HA, arginyl glycyl aspartic acid, and chlorophyll [45], endowing MXene materials with excellent biocompatibility, strong physiological stability, and high clinical transformation potential. Radioisotope-based modified MXenes such as131I, and 64Cu can be adapted for imaging-guided cancer treatment [53, 54]. Overall, MXenes can be adjusted by different compositions, sizes, thicknesses, controlled surface functional groups, and surface terminals, confer different characteristics, and can be applied in biomedical fields [55].

4 Biosensing application

4.1 MicroRNA detection

As the Mxenes materials process unique metallic conductivity and hydrophilic properties which are fit for microRNA (miRNA) analysis, they are able to adsorb the single-stranded DNA (ssDNA) through weak Van Der Waals force. The biosensor based with fluorescent signals (FL), surface-enhanced Raman spectroscopy (SERS), photoelectrochemical (PEC) and electrochemical (EC) have been exploited [56] (Table 1).

Table 1:

2D MXenes applied for microRNA detection.

MicroRNA Samples Detection method Limit of detection Reference
MXene/MoS2@AuNPs miRNA-182 Human serum SERS 6.61 am [57]
Ti3AlC2-Au miR-377 Human serum EC 1.35 aM [58]
Ti3C2T x QDs/(001) TiO2/FTO miR-155 / PEC 25 fM [59]
Ti3C2@ReS2 miRNA-141 Human serum PEC 2.4 aM [60]
FWNs miR-21/miR-210 H1299 FL 0.75 nM [61]
AuNP@MXene/Au miR-141/miR-21 Human plasma EC 204 aM/138 aM [62]
Mo2C miR-21 / EC 0.34 fM [63]
Mo2C QDs miR-21 B16-F10/A549/MDA-MB-231 FL / [64]
Ti3C2 miR-141 / EC 0.26 pM [65]
Co-MOF-ABEI/Ti3C2T x miR-21 / EC 3.7 fM [66]
Luminol-Au NPs-Ti3C2 miR-155 Human plasma EC 0.15 fM [67]
GSH-MQDs miRNA-221 / EC 10 fM [68]

In the presence of miRNA, the duplex DNA will be formed and dissociated from the surface of the Mxene materials. The fluorescence will be recovered that realized rapid, simple, and selective recognition [69]. In Wang’s work, a synergistic calibrated SERS strategy based on MXene/MoS2@AuNPs with controllable morphology has been presented for detecting miRNA-182. The system has three characteristic Raman peaks (at 382 cm−1 and 402 cm−1 corresponding to MoS2 and at 611 cm−1 corresponding to MXene) as a benchmark instead of additional beacon molecules. Specifically, the LOD was 6.61 am for miRNA-182 in human serum samples [57]. Various studies focused on signal amplification methods to enlarge the detection sensitivity and accuracy. For example, Wang et al. fabricated novel in situ reductions of gold nanoparticles (AuNPs)-decorated Ti3C2 MXene electrochemical biosensor combined with a cascaded signal amplification strategy for the detection of miRNA-21, MXene served as both the reductant and stabilizer. By cascaded signal amplification, the assessment indicated that this electrochemical biosensor has a detection limit of 50 aM (S/N = 3) (Figure 3A) [70]. Li’s group also constructed a Ti3AlC2-Au nanocomposite and G-quadruplex nano-amplification-based electrochemical biosensor for miRNA-377 measurement in human serum samples. Specifically, the designed biosensor displayed excellent sensing performance with a limitation of detection (LOD) as low as 1.35 aM (Figure 3B) [58]. For microRNA-155 detection, a Ti3C2T x QDs/(001) TiO2/FTO platform was constructed. Detailed, the structure was composed of TiO2 and Ti3C2T x QDs by a type II heterojunction and the LOD was 25 fM [59]. Xu’s group presented a Ti3C2@ReS2 via the vertical anchoring flaky ReS2 on the Ti3C2 backbone for miRNA-141 detection. According to the assessment, the Ti3C2@ReS2 sample containing 45 wt% of ReS2 showed a 2.48-time promotion in the photocurrent compared to ReS2 owing to the synergistic effects of its photoactive and conductive counterparts. In essence, the estimated LOD was 2.4 aM (Figure 3C) [60].

Figure 3: Application of MXenes in microRNA detection. (A) Gold nanoparticles (AuNPs)-decorated Ti3C2 MXenes served as an electrochemical biosensor. By combining with a cascaded signal amplification strategy, miRNA-21was sensitivity detected. (B) Ti3AlC2-Au nanocomposites and G-quadruplex nano-amplification based electrochemical biosensor. (C) Ti3C2@ReS2 based biosensor. Figures are adapted from references [58, 60, 70].
Figure 3:

Application of MXenes in microRNA detection. (A) Gold nanoparticles (AuNPs)-decorated Ti3C2 MXenes served as an electrochemical biosensor. By combining with a cascaded signal amplification strategy, miRNA-21was sensitivity detected. (B) Ti3AlC2-Au nanocomposites and G-quadruplex nano-amplification based electrochemical biosensor. (C) Ti3C2@ReS2 based biosensor. Figures are adapted from references [58, 60, 70].

There are also numerous examples of the detection of multiple intracellular miRNAs. Liao et al. used folate-adsorbed carbon nitride to create a multipurpose probe for in-situ monitoring of various miRNAs [71]. Lee et al. synthesized AuNP@MXene/Au to modify with vast numbers of DNA probes for miRNA-21 and miRNA-141 detection, and LOD was determined as 204 aM and 138 aM, respectively. Moreover, this device successfully indicated three cancer plasma samples [62]. Tian et al. reported a simple amplification strategy of enzyme-free miRNA target-triggered strand displacement reaction to fabricate a molybdenum carbide (Mo2C) biosensor with ferrocene to detect miR-21 [63]. Additionally, Dai et al. also synthesized a class of monolayer Mo2C QDs with biocompatibility and water solubility by liquid exfoliation method to deliver the optimized molecular beacons MB into cells for accurate quantitative detection of mature miRNAs [64]. Wang et al. reported a stable luminol-Au NPs-Ti3C2 as an ECL biosensor for miRNA-155 detection. The immobilization of ECL emitters is a versatile strategy that not only decreases the electron transmission distance, but significantly improves the ECL signal of luminol. The LOD was 0.15 fM in human serum samples (Figure 4A). Ma et al. constructed a GSH-MQDs biosensor for the detection of miRNA-221 and magnetic biomimic vesicles. Glutathione is used as a precursor to improving the oxidation resistance of MXene effectively. Both the metal atoms of the MXene and the sulfhydryl group of GSH could reduce the defects in the MXene-derived QDs. Furthermore, on the cyclic amplification with a T7 exonuclease, the biosensor can detect miRNA-221 in the triple-negative breast tumor tissues (Figure 4B). Du et al. used CdS: W nanocrystals modified Ti3C2 MXenes as an ECL signal emitter to detect miRNA-141 [65]. Jiang et al. reported a hybrid luminescent Co-MOF-ABEI/Ti3C2T x composite used to estimate miRNA-21 with a detection limit of 3.7 fM [66]. Overall, compared with FL output signals, the biosensor with EC and PEC exhibited much higher sensitive performance.

Figure 4: Mxenes material-based ECL biosensor. (A) Luminol-Au NPs-Ti3C2 as an ECL biosensor for miRNA-155 detection (B) GSH-MQDs biosensor for the detection of miRNA-221 and magnetic biomimic vesicles. Figures are adapted from references [67, 68].
Figure 4:

Mxenes material-based ECL biosensor. (A) Luminol-Au NPs-Ti3C2 as an ECL biosensor for miRNA-155 detection (B) GSH-MQDs biosensor for the detection of miRNA-221 and magnetic biomimic vesicles. Figures are adapted from references [67, 68].

4.2 Gas detection

MXenes have good sensitivity to many small molecules and can be used for gas sensing [72]. Wu et al. reported a Ti3C2 MXene based gas sensor for NH3 detection with high selectivity (Figure 5A) [73]. Many other MXenes such as SnO [74], CuO [75], NiO [76], In2O3 [77], WO3 [78], and Co3O4 [79] exhibit good characteristics for gas analysis. Cho et al. designed a MoS2 based on CVD for detecting NO2 and NH3 (Figure 5B) [80]. In addition to MoS2, other metal disulfides such as MoSe2, SnS2, and WS2 also have applications in gas detection [81–83]. Yu et al. studied the adsorption of NH3, H2, CH4, CO, CO2, N2, NO2, and O2 by monolayer Ti2CO2; only NH3 could be chemisorbed on Ti2CO2 (Figure 5C) [84]. Xiao et al. considered the interaction between NH3 and O-terminated semiconductor MXenes (M2CO2, M = Sc, Ti, Zr, Hf) with different charge states by using first-principles simulations. NH3 can strongly adsorb on M2CO2 with obvious charge transfer. O-terminated semiconductor MXenes are excellent materials for NH3 sensors with the advantage of highly reversible release and capture (Figure 5D) [85].

Figure 5: Application of MXenes in gas small molecule detection. (A) Ti3C2 MXene based gas sensor for NH3 detection. (B) Gas sensor based on MoS2 synthesized by CVD for detecting NO2 and NH3. (C) Porous DPSNs@X% TiO2-X composite photocatalyst was used for the detection of NH3. (D) O-terminated semiconducting MXenes are excellent materials for NH3 sensors or capture. Figures are adapted from references [73, 80, 84, 85].
Figure 5:

Application of MXenes in gas small molecule detection. (A) Ti3C2 MXene based gas sensor for NH3 detection. (B) Gas sensor based on MoS2 synthesized by CVD for detecting NO2 and NH3. (C) Porous DPSNs@X% TiO2-X composite photocatalyst was used for the detection of NH3. (D) O-terminated semiconducting MXenes are excellent materials for NH3 sensors or capture. Figures are adapted from references [73, 80, 84, 85].

4.3 Detection of other small molecules

The qualitative and quantitative analysis of metabolites is a crucial indicator of physiological and pathological alterations. H2O2 is an essential molecule in many signal transduction processes in vivo and is involved in cellular metabolism. MXene-Ti3C2 nanosheet was designed as a colorimetric strip that reacted with H2O2 and has good performance for free radical scavenging (Figure 6A) [86]. Ti3C2T x /PtNP sensor can detect small redox molecules such as ascorbic acid, dopamine, uric acid, and acetaminophen [87]. MoS2 nanosheets and lactate oxidase biosensors can selectively detect lactate (Figure 6B) [88]. Moreover, MXenes materials can detect glucose, GSH, proteins, dengue DNA and RNA, circulating tumor DNA, and T4 polynucleotide kinase (T4 PNK) [89–95]. For example, MoS2 could specifically detect a minimal amount of target DNA molecules (Figure 6C) [96]. Very recently, Wang et al. reported Ti3C2T x as an ultra-efficient hemoperfusion absorber for eliminating the cytokine storm syndrome which induced by COVID-19. The molecular-level investigations demonstrated that Mxenes has strong chemisorption for immobilizing cytokine interleukin-6 and good blood compatibility (Figure 6D) [97].

Figure 6: Application of MXenes in the detection of small molecules. (A) MXene-Ti3C2 nanosheet as a colorimetric strip for reactive oxygen species (ROS) and reactive nitrogen species (RNS) detection and scavenging. (B) Lactate detection sensor. (C) MXenes sensor detects specific hybridization with probe DNA molecules based on molybdenum disulfide nanosheets and lactate oxidase. (D) Ti3C2T x is an ultra-efficient hemoperfusion absorber for eliminating cytokines. Figures are adapted from references [86, 88, 96, 97].
Figure 6:

Application of MXenes in the detection of small molecules. (A) MXene-Ti3C2 nanosheet as a colorimetric strip for reactive oxygen species (ROS) and reactive nitrogen species (RNS) detection and scavenging. (B) Lactate detection sensor. (C) MXenes sensor detects specific hybridization with probe DNA molecules based on molybdenum disulfide nanosheets and lactate oxidase. (D) Ti3C2T x is an ultra-efficient hemoperfusion absorber for eliminating cytokines. Figures are adapted from references [86, 88, 96, 97].

5 Biological imaging and disease diagnosis

MXenes have great potential for the non-invasive imaging, including MRI, positron emission tomography (PET), X-ray computed tomography, FL, PAI, etc. [98–105]. Nanoscale MXenes are also suitable for bioimaging and disease diagnosis [106, 107]. First, the nanoscale size enables them to exist in the organism for a longer time, effectively avoiding the self-clearing function of the blood circulation, enabling intermolecular interactions, and inducing luminescence. Secondly, certain hydrophilic functional groups on the surface of MXenes could improve water solubility and have promising biological. Especially, recent studies have shown that MXenes can be degraded and eliminated in organisms. In addition, the near-infrared absorption of MXenes makes them a suitable contrast agent for PAI.

5.1 Photoacoustic imaging

As a new diagnostic imaging technique, PAI induces optical imaging by irradiating the tissue with excitation light. Because of its low tissue attenuation coefficient, PAI can achieve the purpose of real-time detection of biological lesions. The spectrum of MXenes extends from ultraviolet-visible to NIR, and MXenes have good photothermal conversion capability, which enables them to be effective PAI contrast agents. The photothermal effect has been demonstrated in various MXene compositions such as Ti3C2, Nb2C, and Ta4C3 [36, 108, 109]. The strong absorption spectrum is the NIR region, facilitating for deep tissue PAI. For example, Chen et al. fabricated niobium carbide (Nb2C) MXene via a simple and scalable two-step liquid exfoliation method for efficient in vivo photothermal ablation of NIR-II windows in mouse tumor xenografts with good PAI ability [36]. Dai et al. developed Mo2C QDs by a simple ultrasound-assisted liquid phase exfoliation method showing excellent performance in PAI [110]. The Mo2C QDs have high stability, biocompatibility and low cytotoxicity.

5.2 SERS and fluorescence imaging

The LSPR effect of MXene nanosheets with semi-metallic properties can enhance the Raman scattering signal and serve as a good building block for SERS. Emitting MXene QDs are reported by fabricating small-size dot phase MXenes. Strong emissions were realized under specific wavelength excitation, which resulted from the quantum confinement caused by size effect and luminescence resulting in induced defects [111, 112]. Based on this, many researchers used MXene SERS imaging for sensitive detection applications. For instant, the Yury Gogotsi group reported titanium carbide MXene Ti3C2T x that can enhance Raman signal from organic dyes on a substrate and in solution (Figure 7A) [113]. Due to the synergistic effect of the charge transfer resonance and electromagnetic enhancement, Nb2C and Ta2C MXenes were shown as remarkable SERS enhancement probes for sensitively detecting the SARS-CoV-2 spike protein (Figure 7B). The results indicated that the detection limit is as low as 5 × 10−9 M, which is suitable for achieving real-time monitoring and early warning of novel coronavirus [114].

Figure 7: Application of MXenes in bioimaging. (A) Ti3C2T x has enhanced the Raman signal. (B) Nb2C and Ta2C MXenes are remarkable SERS enhancement probes. (C) MQD showed excitation-dependent photoluminescence spectra with high quantum yields. (D) Photoluminescence Ti3C2 MXene quantum dots for multicolor cell imaging. Figures are adapted from references [113–116].
Figure 7:

Application of MXenes in bioimaging. (A) Ti3C2T x has enhanced the Raman signal. (B) Nb2C and Ta2C MXenes are remarkable SERS enhancement probes. (C) MQD showed excitation-dependent photoluminescence spectra with high quantum yields. (D) Photoluminescence Ti3C2 MXene quantum dots for multicolor cell imaging. Figures are adapted from references [113–116].

With the recently developed luminescent MXene QDs, MXenes have been applied to luminescent cell imaging. Similar to graphene and carbon dots, MXene QDs exhibited luminescence properties, and their emission is related to excitation. For example, Zhi et al. developed photoluminescent Ti3C2 MXene QDs (MQD) for multicolor cell imaging. Due to the strong quantum confinement, the as-prepared MQD showed excitation-dependent photoluminescence spectra with high quantum yields. The application of MQD as a biocompatible multicolor cell imaging probe and zinc ion sensor was demonstrated in (Figure 7C) [115]. Wang et al. synthesized amphiphilic carbide-derived GQDs combined with layered Ti3C2X MXene to apply in cellular imaging due to their excellent properties, such as bright and tunable photoluminescence, low cytotoxicity, good photostability, and chemical inertness (Figure 7D) [116].

5.3 Multifunctional MXenes theranositic platform

MXenes-based MXenes theranositic platform could be used for imaging localized tumors, tracking drug delivery, and monitoring cancer treatment. Owing to their large surface area, MXenes can adsorb different imaging molecules and nanoparticles, such as fluorophores, gadolinium, radioactive elements, IONP, and other NPs [19, 109, 117], [118], [119]. For example, Ti3C2T flakes were covalent functionalized with a chelating agent diethylenetriaminepentaacetic acid (DTPA), and then complexed with Gd3+ ions for T 1 MR imaging [120]. Wu’s group constructed the tantalum carbide (Ta4C3) Mxene functionalized with manganese oxide nanoparticles (MnO x ) component for multiple imaging-guided photothermal tumor ablations. The MnO x /Ta4C3 has achieved high-performance contrast agents for contrast-enhanced computed tomography, T 1-weighted MRI, and contrast-enhanced PAI (Figure 8A) [121]. Various biocompatible nanoplatforms formed from Ti3C2, Ta4C3, and Nb2C nanosheets are suitable for diagnosis/imaging. However, compared to the carbide- and carbonitride-based MXenes, nitride-based MXenes have been rarely explored, especially for biological and biomedical appliances [122, 123]. Actually, these nitride-based MXenes exhibited better biodegradability in the physiological environment. According to a facile top-down method, Prof. Huang’s group synthesized titanium nitride quantum dots (Ti2N QDs) in solution. The Ti2N QDs exhibited good performance on PAI-guided PTT in both NIR-I/II biowindows for precision cancer treatment [124]. Interestingly, MXenes with enzymatic labels were used to fabricate a versatile multiplexed label-free single-cell detection strategy with high-dimensional imaging. Generally, a set of MXenes is selected to ensure mass detection within the cytometry range while avoiding overlap with more than 70 currently available tags and able to survey multiple biological parameters at the single-cell level or in different organs (Figure 8B) [125].

Figure 8: MXenes for therapeutic and diagnostic multimodal imaging applications. (A) MnOx/Ta4C3 were the high-performance contrast agents for CT, T1-weighted MRI, and PAI. (B) New biomedical application based on Nb4C3, Mo2Ti2C3, and Ta4C3 for detecting cells and tissues using three mass-cytometry-based methods (single-cell mass cytometry, imaging mass cytometry, and ion-beam imaging). Figures are adapted from references [121, 125].
Figure 8:

MXenes for therapeutic and diagnostic multimodal imaging applications. (A) MnOx/Ta4C3 were the high-performance contrast agents for CT, T1-weighted MRI, and PAI. (B) New biomedical application based on Nb4C3, Mo2Ti2C3, and Ta4C3 for detecting cells and tissues using three mass-cytometry-based methods (single-cell mass cytometry, imaging mass cytometry, and ion-beam imaging). Figures are adapted from references [121, 125].

6 Conclusion and outlook

MXenes offer unique properties and enormous potential in biological applications. However, the clinical translation of these compounds still confronts several obstacles. Most of MXenes are prepared by the top–down method, lacking an approach to precisely control the size, layer number distribution, and surface groups of the final products. Large-scale preparation is essential for further commercial applications. However, the current synthesis of MXenes is only in the laboratory stage. There are few bottom–up approaches, developing an effective bottom–up method for MXene synthesis is extremely desirable. In addition to nanosheets, it’s also important to construct MXenes with various morphologies such as nanotubes and nanocages. Furthermore, the combination of MXenes with other functional materials to form hybrid materials with attractive properties is also highly needed. Finally, the biosafety remains a key challenging issue. Scientists have conducted short-term toxicity and organ residue distribution studies to confirm that MXenes have excellent ideal short-term biosafety. However, long-term biosafety including genotoxicity, immunotoxicity, and reproductive toxicity are required. We believed that the development of chemical materials science, biology, and medicine and the collaboration among various disciplines would accelerate the bioanalytical and imaging applications of MXenes in the future.

Corresponding authors: Yan Tan and Haifeng Dong, Marshall Laboratory of Biomedical Engineering, Research Center for Biosensor and Nanotheranostic, School of Biomedical Engineering, Health Science Center, Shenzhen University, Shenzhen 518060, China, E-mail: (Y. Tan), (H. Dong) (H. Dong)

Huiyu Liu and Xiaotong Xing contributed equally.

Funding source: The Excellent Young Scientists Fund

Award Identifier / Grant number: 22022407

Funding source: National Natural Science Foundation of China

Award Identifier / Grant number: 21874008

Funding source: Major Program of National Natural Science Foundation of China

Award Identifier / Grant number: 21890740

  1. Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

  2. Research funding: The work was supported by the Excellent Young Scientists Fund (22022407), National Natural Science Foundation of China (21874008, 22004006), the work was also supported by Major Program of National Natural Science Foundation of China (21890740 and 21890742) and The Special Foundation for State Major Research Program of China (Grant No.2019YFC1606603), SZU Top Ranking Project (860000002100165) and 2021 Stability support plan of Shenzhen University (8940206/0200). We would like to thank SHAH ZADA in Guangdong Laboratory of Artificial Intelligence and Digital Economy (SZ) for helping polish the manuscript.

  3. Conflict of interest statement: The authors declare no conflicts of interest regarding this article.

References

[1] C. N. Rao, A. K. Sood, K. S. Subrahmanyam, and A. Govindaraj, “Graphene: the new two-dimensional nanomaterial,” Angew. Chem. Int. Ed. Engl., vol. 48, no. 42, pp. 7752–7777, 2009. https://doi.org/10.1002/anie.200901678.Search in Google Scholar PubMed

[2] A. K. Geim and K. S. Novoselov, The Rise of Graphene, UK, Nanoscience and Technology, Co-Published with Macmillan Publishers Ltd, 2009, pp. 11–19.10.1142/9789814287005_0002Search in Google Scholar

[3] L. Fu and W. Xia, “MAX phases as nanolaminate materials: chemical composition, microstructure, synthesis, properties, and applications,” Adv. Eng. Mater., vol. 23, no. 4, p. 2001191, 2021. https://doi.org/10.1002/adem.202001191.Search in Google Scholar

[4] M. W. Barsoum and M. Radovic, “Elastic and mechanical properties of the MAX phases,” Annu. Rev. Mater. Res., vol. 41, no. 1, pp. 195–227, 2011. https://doi.org/10.1146/annurev-matsci-062910-100448.Search in Google Scholar

[5] Y. Wei, P. Zhang, R. A. Soomro, Q. Zhu, and B. Xu, “Advances in the synthesis of 2D MXenes,” Adv. Mater., vol. 33, no. 39, p. e2103148, 2021. https://doi.org/10.1002/adma.202103148.Search in Google Scholar PubMed

[6] M. Naguib, M. Kurtoglu, V. Presser, et al.., “Two-dimensional nanocrystals produced by exfoliation of Ti3 AlC2,” Adv. Mater., vol. 23, no. 37, pp. 4248–4253, 2011. https://doi.org/10.1002/adma.201102306.Search in Google Scholar PubMed

[7] M. Naguib, O. Mashtalir, J. Carle, et al.., “Two-dimensional transition metal carbides,” ACS Nano, vol. 6, no. 2, pp. 1322–1331, 2012. https://doi.org/10.1021/nn204153h.Search in Google Scholar PubMed

[8] W. Tao, N. Kong, X. Ji, et al.., “Emerging two-dimensional monoelemental materials (Xenes) for biomedical applications,” Chem. Soc. Rev., vol. 48, no. 11, pp. 2891–2912, 2019. https://doi.org/10.1039/c8cs00823j.Search in Google Scholar PubMed

[9] M. Qiu, W. X. Ren, T. Jeong, et al.., “Omnipotent phosphorene: a next-generation, two-dimensional nanoplatform for multidisciplinary biomedical applications,” Chem. Soc. Rev., vol. 47, no. 15, pp. 5588–5601, 2018. https://doi.org/10.1039/c8cs00342d.Search in Google Scholar PubMed

[10] H. Jing, H. Yeo, B. Lyu, et al.., “Modulation of the electronic properties of MXene (Ti3C2Tx) via surface-covalent functionalization with diazonium,” ACS Nano, vol. 15, no. 1, pp. 1388–1396, 2021. https://doi.org/10.1021/acsnano.0c08664.Search in Google Scholar PubMed

[11] K. Hantanasirisakul and Y. Gogotsi, “Electronic and optical properties of 2D transition metal carbides and nitrides (MXenes),” Adv. Mater., vol. 30, no. 52, p. e1804779, 2018. https://doi.org/10.1002/adma.201804779.Search in Google Scholar PubMed

[12] X. Jiang, A. V. Kuklin, A. Baev, et al.., “Two-dimensional MXenes: from morphological to optical, electric, and magnetic properties and applications,” Phys. Rep., vol. 848, pp. 1–58, 2020. https://doi.org/10.1016/j.physrep.2019.12.006.Search in Google Scholar

[13] J. Halim, M. R. Lukatskaya, K. M. Cook, et al.., “Transparent conductive two-dimensional titanium carbide epitaxial thin films,” Chem. Mater., vol. 26, no. 7, pp. 2374–2381, 2014. https://doi.org/10.1021/cm500641a.Search in Google Scholar PubMed PubMed Central

[14] K. Hantanasirisakul, M.-Q. Zhao, P. Urbankowski, et al.., “Fabrication of Ti3C2Tx MXene transparent thin films with tunable optoelectronic properties,” Adv. Electron. Mater., vol. 2, no. 6, p. 1600050, 2016. https://doi.org/10.1002/aelm.201600050.Search in Google Scholar

[15] W. Tao, X. Ji, X. Zhu, et al.., “Two-dimensional antimonene-based photonic nanomedicine for cancer theranostics,” Adv. Mater., vol. 30, no. 38, p. e1802061, 2018. https://doi.org/10.1002/adma.201870283.Search in Google Scholar

[16] X. Ji, N. Kong, J. Wang, et al.., “A novel top-down synthesis of ultrathin 2D boron nanosheets for multimodal imaging-guided cancer therapy,” Adv. Mater., vol. 30, no. 36, p. 1803031, 2018. https://doi.org/10.1002/adma.201803031.Search in Google Scholar PubMed PubMed Central

[17] X. Meng, X. Wang, Z. Cheng, et al.., “Photoluminescence lifetime of black phosphorus nanoparticles and their applications in live cell imaging,” ACS Appl. Mater. Interfaces, vol. 10, no. 37, pp. 31136–31145, 2018. https://doi.org/10.1021/acsami.8b11648.Search in Google Scholar PubMed

[18] Y. Lin, Y. Wu, R. Wang, et al.., “Two-dimensional tellurium nanosheets for photoacoustic imaging-guided photodynamic therapy,” Chem. Commun, vol. 54, no. 62, pp. 8579–8582, 2018. https://doi.org/10.1039/c8cc04653k.Search in Google Scholar PubMed

[19] G. Liu, J. Zou, Q. Tang, et al.., “Surface modified Ti3C2 MXene nanosheets for tumor targeting photothermal/photodynamic/chemo synergistic therapy,” ACS Appl. Mater. Interfaces, vol. 9, no. 46, pp. 40077–40086, 2017. https://doi.org/10.1021/acsami.7b13421.Search in Google Scholar PubMed

[20] D. Xu, Z. Li, L. Li, and J. Wang, “Insights into the photothermal conversion of 2D MXene nanomaterials: synthesis, mechanism, and applications,” Adv. Funct. Mater., vol. 30, no. 47, p. 2000712, 2020. https://doi.org/10.1002/adfm.202070314.Search in Google Scholar

[21] X. Guo, S. Wang, P. Yan, et al.., “High modulation depth enabled by Mo2Ti2C3Tx MXene for Q-switched pulse generation in a mid-infrared fiber laser,” Nanomaterials, vol. 12, no. 8, pp. 1343–1352, 2022. https://doi.org/10.3390/nano12081343.Search in Google Scholar PubMed PubMed Central

[22] C. Murugan, V. Sharma, R. K. Murugan, G. Malaimegu, and A. Sundaramurthy, “Two-dimensional cancer theranostic nanomaterials: synthesis, surface functionalization and applications in photothermal therapy,” J. Controlled Release, vol. 299, pp. 1–20, 2019. https://doi.org/10.1016/j.jconrel.2019.02.015.Search in Google Scholar PubMed

[23] J. R. Brent, N. Savjani, and P. O’Brien, “Synthetic approaches to two-dimensional transition metal dichalcogenide nanosheets,” Prog. Mater. Sci., vol. 89, pp. 411–478, 2017. https://doi.org/10.1016/j.pmatsci.2017.06.002.Search in Google Scholar

[24] B. Jayasena and S. Subbiah, “A novel mechanical cleavage method for synthesizing few-layer graphenes,” Nanoscale Res. Lett., vol. 6, no. 1, pp. 95–102, 2011. https://doi.org/10.1186/1556-276x-6-95.Search in Google Scholar

[25] S. Panda, K. Deshmukh, S. K. Khadheer Pasha, J. Theerthagiri, S. Manickam, and M. Y. Choi, “MXene based emerging materials for supercapacitor applications: recent advances, challenges, and future perspectives,” Coord. Chem. Rev., vol. 462, p. 214518, 2022. https://doi.org/10.1016/j.ccr.2022.214518.Search in Google Scholar

[26] Y. Li, X. Yin, and W. Wu, “Preparation of few-layer MoS2 nanosheets via an efficient shearing exfoliation method,” Ind. Eng. Chem. Res., vol. 57, no. 8, pp. 2838–2846, 2018. https://doi.org/10.1021/acs.iecr.7b04087.Search in Google Scholar

[27] K. Zhang, J. Tang, J. Yuan, et al.., “Production of few-layer graphene via enhanced high-pressure shear exfoliation in liquid for supercapacitor applications,” ACS Appl. Nano Mater., vol. 1, no. 6, pp. 2877–2884, 2018. https://doi.org/10.1021/acsanm.8b00515.Search in Google Scholar

[28] R. Meshkian, L. Å. Näslund, J. Halim, J. Lu, M. W. Barsoum, and J. Rosen, “Synthesis of two-dimensional molybdenum carbide, Mo2C, from the gallium based atomic laminate Mo2Ga2C,” Scr. Mater., vol. 108, pp. 147–150, 2015. https://doi.org/10.1016/j.scriptamat.2015.07.003.Search in Google Scholar

[29] M. Ghidiu, M. R. Lukatskaya, M. Q. Zhao, Y. Gogotsi, and M. W. Barsoum, “Conductive two-dimensional titanium carbide ‘clay’ with high volumetric capacitance,” Nature, vol. 516, no. 7529, pp. 78–81, 2014. https://doi.org/10.1038/nature13970.Search in Google Scholar PubMed

[30] H. Wu, J. Gu, Z. Li, et al.., “Characterization of phonon thermal transport of Ti3C2TxMXene thin film,” J. Phys.: Condens. Matter, vol. 34, no. 15, p. 155704, 2022. https://doi.org/10.1088/1361-648x/ac4f1c.Search in Google Scholar

[31] M. R. Lukatskaya, J. Halim, B. Dyatkin, et al.., “Room-temperature carbide-derived carbon synthesis by electrochemical etching of MAX phases,” Angew. Chem. Int. Ed. Engl., vol. 53, no. 19, pp. 4877–4880, 2014. https://doi.org/10.1002/anie.201402513.Search in Google Scholar PubMed

[32] H. Shi, P. Zhang, Z. Liu, et al.., “Ambient-stable two-dimensional titanium carbide (MXene) enabled by iodine etching,” Angew. Chem. Int. Ed. Engl., vol. 60, no. 16, pp. 8689–8693, 2021. https://doi.org/10.1002/ange.202015627.Search in Google Scholar

[33] J. Mei, G. A. Ayoko, C. Hu, and Z. Sun, “Thermal reduction of sulfur-containing MAX phase for MXene production,” Chem. Eng. J., vol. 395, p. 125111, 2020. https://doi.org/10.1016/j.cej.2020.125111.Search in Google Scholar

[34] S. Zada, W. Dai, Z. Kai, et al.., “Algae extraction controllable delamination of vanadium carbide nanosheets with enhanced near-infrared photothermal performance,” Angew. Chem. Int. Ed. Engl., vol. 59, no. 16, pp. 6601–6606, 2020. https://doi.org/10.1002/ange.201916748.Search in Google Scholar

[35] D. C. Geng, X. X. Zhao, L. J. Li, et al.., “Controlled growth of ultrathin Mo2C superconducting crystals on liquid Cu surface,” 2D Mater., vol. 4, no. 1, p. 011012, 2017. https://doi.org/10.1088/2053-1583/aa51b7.Search in Google Scholar

[36] H. Lin, S. Gao, C. Dai, Y. Chen, and J. Shi, “A two-dimensional biodegradable niobium carbide (MXene) for photothermal tumor eradication in NIR-I and NIR-II biowindows,” J. Am. Chem. Soc., vol. 139, no. 45, pp. 16235–16247, 2017. https://doi.org/10.1021/jacs.7b07818.Search in Google Scholar PubMed

[37] P. Urbankowski, B. Anasori, T. Makaryan, et al.., “Synthesis of two-dimensional titanium nitride Ti4N3 (MXene),” Nanoscale, vol. 8, no. 22, pp. 11385–11391, 2016. https://doi.org/10.1039/c6nr02253g.Search in Google Scholar PubMed

[38] J. Mei, G. A. Ayoko, C. Hu, J. M. Bell, and Z. Sun, “Two-dimensional fluorine-free mesoporous Mo2C MXene via UV-induced selective etching of Mo2Ga2C for energy storage,” Sustainable Mater. Technol., vol. 25, p. e00156, 2020. https://doi.org/10.1016/j.susmat.2020.e00156.Search in Google Scholar

[39] A. E. Ghazaly, H. Ahmed, A. R. Rezk, et al.., “Ultrafast, one-step, salt-solution-based acoustic synthesis of Ti3C2 MXene,” ACS Nano, vol. 15, no. 3, pp. 4287–4293, 2021. https://doi.org/10.1021/acsnano.0c07242.Search in Google Scholar PubMed PubMed Central

[40] C. Xu, L. Wang, Z. Liu, et al.., “Large-area high-quality 2D ultrathin Mo2C superconducting crystals,” Nat. Mater., vol. 14, no. 11, pp. 1135–1141, 2015. https://doi.org/10.1038/nmat4374.Search in Google Scholar PubMed

[41] Z. Zhang, F. Zhang, H. C. Wang, C. H. Chan, W. Lu, and J. Y. Dai, “Substrate orientation-induced epitaxial growth of face centered cubic Mo2C superconductive thin film,” J. Mater. Chem. C, vol. 5, no. 41, pp. 10822–10827, 2017. https://doi.org/10.1039/c7tc03652c.Search in Google Scholar

[42] K. Zhang, C. Feng, B. He, et al.., “An advanced electrocatalyst of Pt decorated SnO2/C nanofibers for oxygen reduction reaction,” J. Electroanal. Chem., vol. 781, pp. 198–203, 2016. https://doi.org/10.1016/j.jelechem.2016.11.002.Search in Google Scholar

[43] Y. Cao, T. Wu, W. Dai, H. Dong, and X. Zhang, “TiO2 nanosheets with the Au nanocrystal-decorated edge for mitochondria-targeting enhanced sonodynamic therapy,” Chem. Mater., vol. 31, no. 21, pp. 9105–9114, 2019. https://doi.org/10.1021/acs.chemmater.9b03430.Search in Google Scholar

[44] L. Cheng, J. Liu, X. Gu, et al.., “PEGylated WS(2) nanosheets as a multifunctional theranostic agent for in vivo dual-modal CT/photoacoustic imaging guided photothermal therapy,” Adv. Mater., vol. 26, no. 12, pp. 1886–1893, 2014. https://doi.org/10.1002/adma.201304497.Search in Google Scholar PubMed

[45] H. Lu, S. Zada, S. Tang, et al.., “Artificial photoactive chlorophyll conjugated vanadium carbide nanostructure for synergistic photothermal/photodynamic therapy of cancer,” J. Nanobiotechnol., vol. 20, no. 1, p. 121, 2022. https://doi.org/10.1186/s12951-022-01331-x.Search in Google Scholar PubMed PubMed Central

[46] X. Meng, Z. Liu, Y. Cao, et al.., “Fabricating aptamer-conjugated PEGylated-MoS2/Cu1.8S theranostic nanoplatform for multiplexed imaging diagnosis and chemo-photothermal therapy of cancer,” Adv. Funct. Mater., vol. 27, no. 16, p. 1605592, 2017. https://doi.org/10.1002/adfm.201605592.Search in Google Scholar

[47] F. Zhi, H. Dong, X. Jia, et al.., “Functionalized graphene oxide mediated adriamycin delivery and miR-21 gene silencing to overcome tumor multidrug resistance in vitro,” PLoS One, vol. 8, no. 3, p. e60034, 2013. https://doi.org/10.1371/journal.pone.0060034.Search in Google Scholar PubMed PubMed Central

[48] Z. Lei, W. Zhu, S. Xu, J. Ding, J. Wan, and P. Wu, “Hydrophilic MoSe2 nanosheets as effective photothermal therapy agents and their application in smart devices,” ACS Appl. Mater. Interfaces, vol. 8, no. 32, pp. 20900–20908, 2016. https://doi.org/10.1021/acsami.6b07326.Search in Google Scholar PubMed

[49] H. Dong, W. Dai, H. Ju, et al.., “Multifunctional poly(L-lactide)-polyethylene glycol-grafted graphene quantum dots for intracellular MicroRNA imaging and combined specific-gene-targeting agents delivery for improved therapeutics,” ACS Appl. Mater. Interfaces, vol. 7, no. 20, pp. 11015–11023, 2015. https://doi.org/10.1021/acsami.5b02803.Search in Google Scholar PubMed

[50] J. Pan, X. Zhu, X. Chen, Y. Zhao, and J. Liu, “Gd(3+)-Doped MoSe2 nanosheets used as a theranostic agent for bimodal imaging and highly efficient photothermal cancer therapy,” Biomater. Sci., vol. 6, no. 2, pp. 372–387, 2018. https://doi.org/10.1039/c7bm00894e.Search in Google Scholar PubMed

[51] Y. Cao, T. Wu, K. Zhang, et al.., “Engineered exosome-mediated near-infrared-II region V2C quantum dot delivery for nucleus-target low-temperature photothermal therapy,” ACS Nano, vol. 13, no. 2, pp. 1499–1510, 2019. https://doi.org/10.1021/acsnano.8b07224.Search in Google Scholar PubMed

[52] X. C. Qin, Z. Y. Guo, Z. M. Liu, W. Zhang, M. M. Wan, and B. W. Yang, “Folic acid-conjugated graphene oxide for cancer targeted chemo-photothermal therapy,” J. Photochem. Photobiol. B, vol. 120, pp. 156–162, 2013. https://doi.org/10.1016/j.jphotobiol.2012.12.005.Search in Google Scholar PubMed

[53] L. Chen, X. Zhong, X. Yi, et al.., “Radionuclide (131)I labeled reduced graphene oxide for nuclear imaging guided combined radio- and photothermal therapy of cancer,” Biomaterials, vol. 66, pp. 21–28, 2015. https://doi.org/10.1016/j.biomaterials.2015.06.043.Search in Google Scholar PubMed

[54] L. Cheng, S. Shen, S. Shi, et al.., “FeSe2-Decorated Bi2Se3 nanosheets fabricated via cation exchange for chelator-free (64)Cu-labeling and multimodal image-guided photothermal-radiation therapy,” Adv. Funct. Mater., vol. 26, no. 13, pp. 2185–2197, 2016. https://doi.org/10.1002/adfm.201504810.Search in Google Scholar PubMed PubMed Central

[55] K. Huang, Z. Li, J. Lin, G. Han, and P. Huang, “Two-dimensional transition metal carbides and nitrides (MXenes) for biomedical applications,” Chem. Soc. Rev., vol. 47, no. 14, pp. 5109–5124, 2018. https://doi.org/10.1039/c7cs00838d.Search in Google Scholar PubMed

[56] D. Lu, H. Zhao, X. Zhang, Y. Chen, and L. Feng, “New horizons for MXenes in biosensing applications,” Biosensors, vol. 12, no. 10, p. 820, 2022.10.3390/bios12100820Search in Google Scholar PubMed PubMed Central

[57] L. Liu, C. Shangguan, J. Guo, et al.., “Ultrasensitive SERS detection of cancer-related miRNA-182 by MXene/MoS2@AuNPs with controllable morphology and optimized self-internal standards,” Adv. Opt. Mater., vol. 8, no. 23, p. 2001214, 2020. https://doi.org/10.1002/adom.202001214.Search in Google Scholar

[58] Q. Wu, Z. Li, Q. Liang, et al.., “Ultrasensitive electrochemical biosensor for microRNA-377 detection based on MXene-Au nanocomposite and G-quadruplex nano-amplification strategy,” Electrochim. Acta, vol. 428, p. 140945, 2022. https://doi.org/10.1016/j.electacta.2022.140945.Search in Google Scholar

[59] B. Yan, Z. Cheng, C. Lai, et al.., “Boosting the photocatalytic ability of TiO2 nanosheet arrays for MicroRNA-155 photoelectrochemical biosensing by titanium carbide MXene quantum dots,” Nanomaterials, vol. 12, no. 20, p. 3557, 2022.10.3390/nano12203557Search in Google Scholar PubMed PubMed Central

[60] L. Liu, Y. Yao, K. J. Ma, et al.., “Ultrasensitive photoelectrochemical detection of cancer-related miRNA-141 by carrier recombination inhibition in hierarchical Ti3C2@ReS2,” Sens. Actuators, B, vol. 331, p. 129470, 2021. https://doi.org/10.1016/j.snb.2021.129470.Search in Google Scholar

[61] Y. Song, X. Yan, G. Ostermeyer, et al.., “Direct cytosolic MicroRNA detection using single-layer perfluorinated tungsten diselenide nanoplatform,” Anal. Chem., vol. 90, no. 17, pp. 10369–10376, 2018. https://doi.org/10.1021/acs.analchem.8b02193.Search in Google Scholar PubMed

[62] M. Mohammadniaei, A. Koyappayil, Y. Sun, J. Min, and M. H. Lee, “Gold nanoparticle/MXene for multiple and sensitive detection of oncomiRs based on synergetic signal amplification,” Biosens. Bioelectron., vol. 159, p. 112208, 2020. https://doi.org/10.1016/j.bios.2020.112208.Search in Google Scholar PubMed

[63] L. Tian, J. Qi, X. Ma, et al.., “A facile DNA strand displacement reaction sensing strategy of electrochemical biosensor based on N-carboxymethyl chitosan/molybdenum carbide nanocomposite for microRNA-21 detection,” Biosens. Bioelectron., vol. 122, pp. 43–50, 2018. https://doi.org/10.1016/j.bios.2018.09.037.Search in Google Scholar PubMed

[64] W. Dai, H. Lu, F. Yang, H. Dong, and X. Zhang, “Accurate detection of intracellular microRNAs using functional Mo2C quantum dots nanoprobe,” Chem. Commun., vol. 55, no. 71, pp. 10615–10618, 2019. https://doi.org/10.1039/c9cc04261j.Search in Google Scholar PubMed

[65] J. F. Du, J. S. Chen, X. P. Liu, C. J. Mao, and B. K. Jin, “Coupled electrochemiluminescent and resonance energy transfer determination of microRNA-141 using functionalized Mxene composite,” Mikrochim. Acta, vol. 189, no. 7, p. 264, 2022. https://doi.org/10.1007/s00604-022-05359-6.Search in Google Scholar PubMed

[66] Y. Jiang, R. Li, W. He, et al.., “MicroRNA-21 electrochemiluminescence biosensor based on Co-MOF-N-(4-aminobutyl)-N-ethylisoluminol/Ti3C2Tx composite and duplex-specific nuclease-assisted signal amplification,” Mikrochim. Acta, vol. 189, no. 3, p. 129, 2022. https://doi.org/10.1007/s00604-022-05246-0.Search in Google Scholar PubMed

[67] T. T. Zhuang, H. X. Zhang, L. Wang, L. H. Yu, and Z. H. Wang, “Anchoring luminol based on Ti3C2-mediated in situ formation of Au NPs for construction of an efficient probe for miRNA electrogenerated chemiluminescence detection,” Anal. Bioanal. Chem., vol. 413, no. 28, pp. 6963–6971, 2021. https://doi.org/10.1007/s00216-021-03651-7.Search in Google Scholar PubMed

[68] Z. Li, Z. Wang, Y. Nie, P. Wang, and Q. Ma, “A novel GSH-capping MXene QD-based ECL biosensor for the detection of miRNA221 in triple-negative breast cancer tumor,” Chem. Eng. J., vol. 448, p. 137636, 2022. https://doi.org/10.1016/j.cej.2022.137636.Search in Google Scholar

[69] H. I. Kim, D. Yim, S. J. Jeon, et al.., “Modulation of oligonucleotide-binding dynamics on WS2 nanosheet interfaces for detection of Alzheimer’s disease biomarkers,” Biosens. Bioelectron., vol. 165, p. 112401, 2020. https://doi.org/10.1016/j.bios.2020.112401.Search in Google Scholar PubMed

[70] X. Yang, L. L. Zhao, L. Lu, et al.., “In situ reduction of gold nanoparticle-decorated Ti3C2 MXene for ultrasensitive electrochemical detection of MicroRNA-21 with a cascaded signal amplification strategy,” J. Electrochem. Soc., vol. 169, no. 5, p. 057505, 2022. https://doi.org/10.1149/1945-7111/ac6a7f.Search in Google Scholar

[71] X. Liao, Q. Wang, and H. Ju, “Simultaneous sensing of intracellular microRNAs with a multi-functionalized carbon nitride nanosheet probe,” Chem. Commun., vol. 50, no. 88, pp. 13604–13607, 2014. https://doi.org/10.1039/c4cc05768f.Search in Google Scholar PubMed

[72] X. H. Liu, T. T. Ma, N. Pinna, and J. Zhang, “Two-dimensional nanostructured materials for gas sensing,” Adv. Funct. Mater., vol. 27, no. 37, p. 1702168, 2017. https://doi.org/10.1002/adfm.201702168.Search in Google Scholar

[73] M. Wu, M. He, Q. Hu, et al.., “Ti3C2 MXene-based sensors with high selectivity for NH3 detection at room temperature,” ACS Sens., vol. 4, no. 10, pp. 2763–2770, 2019.10.1021/acssensors.9b01308Search in Google Scholar PubMed

[74] P. Sun, W. Zhao, Y. Cao, Y. Guan, Y. F. Sun, and G. Y. Lu, “Porous SnO2 hierarchical nanosheets: hydrothermal preparation, growth mechanism, and gas sensing properties,” CrystEngComm, vol. 13, no. 11, pp. 3718–3724, 2011. https://doi.org/10.1039/c1ce05073g.Search in Google Scholar

[75] C. Yang, F. Xiao, J. Wang, and X. Su, “3D flower- and 2D sheet-like CuO nanostructures: microwave-assisted synthesis and application in gas sensors,” Sens. Actuators, B, vol. 207, pp. 177–185, 2015. https://doi.org/10.1016/j.snb.2014.10.063.Search in Google Scholar

[76] J. Wang, W. Zeng, and Z. Wang, “Assembly of 2D nanosheets into 3D flower-like NiO: synthesis and the influence of petal thickness on gas-sensing properties,” Ceram. Int., vol. 42, no. 3, pp. 4567–4573, 2016. https://doi.org/10.1016/j.ceramint.2015.11.150.Search in Google Scholar

[77] L. Gao, Z. Cheng, Q. Xiang, Y. Zhang, and J. Xu, “Porous corundum-type In2O3 nanosheets: synthesis and NO2 sensing properties,” Sens. Actuators, B, vol. 208, pp. 436–443, 2015. https://doi.org/10.1016/j.snb.2014.11.053.Search in Google Scholar

[78] B. X. Xiao, Q. Zhao, C. H. Xiao, et al.., “Low-temperature solvothermal synthesis of hierarchical flower-like WO3 nanostructures and their sensing properties for H2S,” CrystEngComm, vol. 17, no. 30, pp. 5710–5716, 2015. https://doi.org/10.1039/c5ce00870k.Search in Google Scholar

[79] Z. Y. Zhang, Z. Wen, Z. Z. Ye, and L. P. Zhu, “Gas sensors based on ultrathin porous Co3O4 nanosheets to detect acetone at low temperature,” RSC Adv., vol. 5, no. 74, pp. 59976–59982, 2015. https://doi.org/10.1039/c5ra08536e.Search in Google Scholar

[80] B. Cho, M. G. Hahm, M. Choi, et al.., “Charge-transfer-based gas sensing using atomic-layer MoS2,” Sci. Rep., vol. 5, p. 8052, 2015. https://doi.org/10.1038/srep08052.Search in Google Scholar PubMed PubMed Central

[81] S. Y. Choi, Y. Kim, H. S. Chung, et al.., “Effect of Nb doping on chemical sensing performance of two-dimensional layered MoSe2,” ACS Appl. Mater. Interfaces, vol. 9, no. 4, pp. 3817–3823, 2017. https://doi.org/10.1021/acsami.6b14551.Search in Google Scholar PubMed

[82] J. Z. Ou, W. Ge, B. Carey, et al.., “Physisorption-based charge transfer in two-dimensional SnS2 for selective and reversible NO2 gas sensing,” ACS Nano, vol. 9, no. 10, pp. 10313–10323, 2015. https://doi.org/10.1021/acsnano.5b04343.Search in Google Scholar PubMed

[83] K. Y. Ko, J. G. Song, Y. Kim, et al.., “Improvement of gas-sensing performance of large-area tungsten disulfide nanosheets by surface functionalization,” ACS Nano, vol. 10, no. 10, pp. 9287–9296, 2016. https://doi.org/10.1021/acsnano.6b03631.Search in Google Scholar PubMed

[84] X. F. Yu, Y. C. Li, J. B. Cheng, et al.., “Monolayer Ti(2)CO(2): a promising candidate for NH(3) sensor or capturer with high sensitivity and selectivity,” ACS Appl. Mater. Interfaces, vol. 7, no. 24, pp. 13707–13713, 2015. https://doi.org/10.1021/acsami.5b03737.Search in Google Scholar PubMed

[85] B. Xiao, Y. C. Li, X. F. Yu, and J. B. Cheng, “MXenes: reusable materials for NH3 sensor or capturer by controlling the charge injection,” Sens. Actuators, B, vol. 235, pp. 103–109, 2016. https://doi.org/10.1016/j.snb.2016.05.062.Search in Google Scholar

[86] J. Liu, W. Lu, X. Lu, L. Zhang, H. Dong, and Y. Li, “Versatile Ti3C2T x MXene for free-radical scavenging,” Nano Res., vol. 15, no. 3, pp. 2558–2566, 2022. https://doi.org/10.1007/s12274-021-3751-y.Search in Google Scholar PubMed PubMed Central

[87] L. Lorencova, T. Bertok, J. Filip, et al.., “Highly stable Ti3C2Tx (MXene)/Pt nanoparticles-modified glassy carbon electrode for H2O2 and small molecules sensing applications,” Sens. Actuators, B, vol. 263, pp. 360–368, 2018. https://doi.org/10.1016/j.snb.2018.02.124.Search in Google Scholar

[88] A. M. Parra-Alfambra, E. Casero, L. Vázquez, C. Quintana, M. del Pozo, and M. D. Petit-Domínguez, “MoS2 nanosheets for improving analytical performance of lactate biosensors,” Sens. Actuators, B, vol. 274, pp. 310–317, 2018. https://doi.org/10.1016/j.snb.2018.07.124.Search in Google Scholar

[89] N. Rohaizad, C. C. Mayorga-Martinez, Z. Sofer, R. D. Webster, and M. Pumera, “Niobium-doped TiS2: formation of TiS3 nanobelts and their effects in enzymatic biosensors,” Biosens. Bioelectron., vol. 155, p. 112114, 2020. https://doi.org/10.1016/j.bios.2020.112114.Search in Google Scholar PubMed

[90] X. Yan, Y. Song, C. Zhu, et al.., “Graphene quantum dot-MnO2 nanosheet based optical sensing platform: a sensitive fluorescence “turn off-on” nanosensor for glutathione detection and intracellular imaging,” ACS Appl. Mater. Interfaces, vol. 8, no. 34, pp. 21990–21996, 2016. https://doi.org/10.1021/acsami.6b05465.Search in Google Scholar PubMed

[91] F. Chekin, K. Bagga, P. Subramanian, et al.., “Nucleic aptamer modified porous reduced graphene oxide/MoS2 based electrodes for viral detection: application to human papillomavirus (HPV),” Sens. Actuators, B, vol. 262, pp. 991–1000, 2018. https://doi.org/10.1016/j.snb.2018.02.065.Search in Google Scholar

[92] S. A. Jin, S. Poudyal, E. E. Marinero, R. J. Kuhn, and L. A. Stanciu, “Impedimetric dengue biosensor based on functionalized graphene oxide wrapped silica particles,” Electrochim. Acta, vol. 194, pp. 422–430, 2016. https://doi.org/10.1016/j.electacta.2016.02.116.Search in Google Scholar

[93] W. Zhang, Z. Dai, X. Liu, and J. Yang, “High-performance electrochemical sensing of circulating tumor DNA in peripheral blood based on poly-xanthurenic acid functionalized MoS2 nanosheets,” Biosens. Bioelectron., vol. 105, pp. 116–120, 2018. https://doi.org/10.1016/j.bios.2018.01.038.Search in Google Scholar PubMed

[94] H. L. Shuai, K. J. Huang, and Y. X. Chen, “A layered tungsten disulfide/acetylene black composite based DNA biosensing platform coupled with hybridization chain reaction for signal amplification,” J. Mater. Chem. B, vol. 4, no. 6, pp. 1186–1196, 2016. https://doi.org/10.1039/c5tb02214b.Search in Google Scholar PubMed

[95] J. Ge, L. J. Tang, Q. Xi, et al.., “A WS2 nanosheet based sensing platform for highly sensitive detection of T4 polynucleotide kinase and its inhibitors,” Nanoscale, vol. 6, no. 12, pp. 6866–6872, 2014. https://doi.org/10.1039/c4nr00944d.Search in Google Scholar PubMed

[96] D. W. Lee, J. Lee, I. Y. Sohn, et al.., “Field-effect transistor with a chemically synthesized MoS2 sensing channel for label-free and highly sensitive electrical detection of DNA hybridization,” Nano Res., vol. 8, no. 7, pp. 2340–2350, 2015. https://doi.org/10.1007/s12274-015-0744-8.Search in Google Scholar

[97] T. Y. Wang, X. Y. Sun, X. Guo, et al.., “Ultraefficiently calming cytokine storm using Ti3C2Tx MXene,” Small Methods, vol. 5, no. 5, p. 2001108, 2021. https://doi.org/10.1002/smtd.202001108.Search in Google Scholar PubMed PubMed Central

[98] Y. Wu, W. Xiong, Z. Wang, et al.., “Self-assembled MXene-based Schottky-junction upon Transition metal oxide for regulated tumor microenvironment and enhanced CDT/PTT/MRI activated by NIR irradiation,” Chem. Eng. J., vol. 427, p. 131925, 2022. https://doi.org/10.1016/j.cej.2021.131925.Search in Google Scholar

[99] Y. Wu, X. Song, W. Xu, et al.., “NIR-activated multimodal photothermal/chemodynamic/magnetic resonance imaging nanoplatform for anticancer therapy by Fe(II) ions doped MXenes (Fe-Ti3C2),” Small, vol. 17, no. 33, p. 2101705, 2021. https://doi.org/10.1002/smll.202101705.Search in Google Scholar PubMed

[100] D. An, X. Wu, Y. Gong, et al.., “Manganese-functionalized MXene theranostic nanoplatform for MRI-guided synergetic photothermal/chemodynamic therapy of cancer,” Nanophotonics, vol. 11, no. 22, pp. 5177–5188, 2022.10.1515/nanoph-2022-0533Search in Google Scholar

[101] Z. Liu, M. Zhao, L. Yu, W. Peng, Y. Chen, and S. Zhang, “Redox chemistry-enabled stepwise surface dual nanoparticle engineering of 2D MXenes for tumor-sensitive T1 and T2 MRI-guided photonic breast-cancer hyperthermia in the NIR-II biowindow,” Biomater. Sci., vol. 10, no. 6, pp. 1562–1574, 2022. https://doi.org/10.1039/d1bm01957k.Search in Google Scholar PubMed

[102] J. Pan, M. Zhang, G. Fu, et al.., “Ti3C2 MXene nanosheets functionalized with NaErF4:0.5%Tm@NaLuF4 nanoparticles for dual-modal near-infrared IIb/magnetic resonance imaging-guided tumor hyperthermia,” ACS Appl. Nano Mater., vol. 5, no. 6, pp. 8142–8153, 2022. https://doi.org/10.1021/acsanm.2c01251.Search in Google Scholar

[103] W. Chen, W. Pan, J. Wang, et al.., “Emerging two-dimensional monoelemental materials (Xenes): fabrication, modification, and applications thereof in the field of bioimaging as nanocarriers,” WIREs Nanomed. Nanobiotechnol., vol. 14, no. 2, p. e1750, 2022. https://doi.org/10.1002/wnan.1750.Search in Google Scholar PubMed

[104] A. Molkenova, T. S. Atabaev, S. W. Hong, C. Mao, D. W. Han, and K. S. Kim, “Designing inorganic nanoparticles into computed tomography and magnetic resonance (CT/MR) imaging-guidable photomedicines,” Mater. Today Nano, vol. 18, p. 100187, 2022. https://doi.org/10.1016/j.mtnano.2022.100187.Search in Google Scholar

[105] B. Lu, S. Hu, D. Wu, et al.., “Ionic liquid exfoliated Ti3C2Tx MXene nanosheets for photoacoustic imaging and synergistic photothermal/chemotherapy of cancer,” J. Mater. Chem. B, vol. 10, no. 8, pp. 1226–1235, 2022. https://doi.org/10.1039/d1tb01938d.Search in Google Scholar PubMed

[106] A. Zamhuri, G. P. Lim, N. L. Ma, K. S. Tee, and C. F. Soon, “MXene in the lens of biomedical engineering: synthesis, applications and future outlook,” Biomed. Eng. Online, vol. 20, no. 1, p. 33, 2021. https://doi.org/10.1186/s12938-021-00873-9.Search in Google Scholar PubMed PubMed Central

[107] X. Lin, Z. Li, J. Qiu, et al.., “Fascinating MXene nanomaterials: emerging opportunities in the biomedical field,” Biomater. Sci., vol. 9, no. 16, pp. 5437–5471, 2021. https://doi.org/10.1039/d1bm00526j.Search in Google Scholar PubMed

[108] S. L. Zhang and W. Q. Han, “Recent advances in MXenes and their composites in lithium/sodium batteries from the viewpoints of components and interlayer engineering,” Phys. Chem. Chem. Phys., vol. 22, no. 29, pp. 16482–16526, 2020. https://doi.org/10.1039/d0cp02275f.Search in Google Scholar PubMed

[109] C. Dai, H. Lin, G. Xu, Z. Liu, R. Wu, and Y. Chen, “Biocompatible 2D titanium carbide (MXenes) composite nanosheets for pH-responsive MRI-guided tumor hyperthermia,” Chem. Mater., vol. 29, no. 20, pp. 8637–8652, 2017. https://doi.org/10.1021/acs.chemmater.7b02441.Search in Google Scholar

[110] W. Dai, H. Dong, and X. Zhang, “A semimetal-like molybdenum carbide quantum dots photoacoustic imaging and photothermal agent with high photothermal conversion efficiency,” Materials, vol. 11, no. 9, pp. 1776–1787, 2018. https://doi.org/10.3390/ma11091776.Search in Google Scholar PubMed PubMed Central

[111] C. Peng, T. Zhou, P. Wei, et al.., “Photocatalysis over MXene-based hybrids: synthesis, surface chemistry, and interfacial charge kinetics,” APL Mater., vol. 9, no. 7, p. 070703, 2021, https://doi.org/10.1063/5.0055711.Search in Google Scholar

[112] Z. Wang, J. Xuan, Z. Zhao, Q. Li, and F. Geng, “Versatile cutting method for producing fluorescent ultrasmall MXene sheets,” ACS Nano, vol. 11, no. 11, pp. 11559–11565, 2017. https://doi.org/10.1021/acsnano.7b06476.Search in Google Scholar PubMed

[113] A. Sarycheva, T. Makaryan, K. Maleski, et al.., “Two-dimensional titanium carbide (MXene) as surface-enhanced Raman scattering substrate,” J. Phys. Chem. C, vol. 121, no. 36, pp. 19983–19988, 2017. https://doi.org/10.1021/acs.jpcc.7b08180.Search in Google Scholar

[114] Y. Peng, C. Lin, L. Long, et al.., “Charge-transfer resonance and electromagnetic enhancement synergistically enabling MXenes with excellent SERS sensitivity for SARS-CoV-2 S protein detection,” Nanomicro Lett., vol. 13, p. 52, 2021. https://doi.org/10.1007/s40820-020-00565-4.Search in Google Scholar PubMed PubMed Central

[115] Q. Xue, H. J. Zhang, M. S. Zhu, et al.., “Photoluminescent Ti3C2 MXene quantum dots for multicolor cellular imaging,” Adv. Mater., vol. 29, no. 15, p. 1604847, 2017. https://doi.org/10.1002/adma.201604847.Search in Google Scholar PubMed

[116] L. Zhou, F. Wu, J. Yu, Q. Deng, F. Zhang, and G. Wang, “Titanium carbide (Ti3C2Tx) MXene: a novel precursor to amphiphilic carbide-derived graphene quantum dots for fluorescent ink, light-emitting composite and bioimaging,” Carbon, vol. 118, pp. 50–57, 2017. https://doi.org/10.1016/j.carbon.2017.03.023.Search in Google Scholar

[117] H. Lin, Y. Chen, and J. L. Shi, “Insights into 2D MXenes for versatile biomedical applications: current advances and challenges ahead,” Adv. Sci., vol. 5, no. 10, p. 1800518, 2018. https://doi.org/10.1002/advs.201800518.Search in Google Scholar PubMed PubMed Central

[118] G. H. Yang, J. L. Zhao, S. Z. Yi, X. J. Wan, and J. N. Tang, “Biodegradable and photostable Nb2C MXene quantum dots as promising nanofluorophores for metal ions sensing and fluorescence imaging,” Sens. Actuators, B, vol. 309, p. 127735, 2020. https://doi.org/10.1016/j.snb.2020.127735.Search in Google Scholar

[119] M. Soleymaniha, M. A. Shahbazi, A. R. Rafieerad, A. Maleki, and A. Amiri, “Promoting role of MXene nanosheets in biomedical sciences: therapeutic and biosensing innovations,” Adv. Healthcare Mater., vol. 8, no. 1, p. 1801137, 2019. https://doi.org/10.1002/adhm.201801137.Search in Google Scholar PubMed

[120] V. Neubertova, O. Guselnikova, Y. Yamauchi, et al.., “Covalent functionalization of Ti3C2T MXene flakes with Gd-DTPA complex for stable and biocompatible MRI contrast agent,” Chem. Eng. J., vol. 446, p. 136939, 2022. https://doi.org/10.1016/j.cej.2022.136939.Search in Google Scholar

[121] C. Dai, Y. Chen, X. Jing, et al.., “Two-dimensional tantalum carbide (MXenes) composite nanosheets for multiple imaging-guided photothermal tumor ablation,” ACS Nano, vol. 11, no. 12, pp. 12696–12712, 2017. https://doi.org/10.1021/acsnano.7b07241.Search in Google Scholar PubMed

[122] G. J. Soufi, P. Iravani, A. Hekmatnia, E. Mostafavi, M. Khatami, and S. Iravani, “MXenes and MXene-based materials with cancer diagnostic applications: challenges and opportunities,” Comments Inorg. Chem., vol. 42, no. 3, pp. 174–207, 2022. https://doi.org/10.1080/02603594.2021.1990890.Search in Google Scholar

[123] S. Iravani and R. S. Varma, “MXenes in photomedicine: advances and prospects,” Chem. Commun., vol. 58, no. 53, pp. 7336–7350, 2022. https://doi.org/10.1039/d2cc01694j.Search in Google Scholar PubMed

[124] J. Shao, J. Zhang, C. Jiang, J. Lin, and P. Huang, “Biodegradable titanium nitride MXene quantum dots for cancer phototheranostics in NIR-I/II biowindows,” Chem. Eng. J., vol. 400, p. 126009, 2020. https://doi.org/10.1016/j.cej.2020.126009.Search in Google Scholar

[125] L. Fusco, A. Gazzi, C. E. Shuck, et al.., “Immune profiling and multiplexed label-free detection of 2D MXenes by mass cytometry and high-dimensional imaging,” Adv. Mater., vol. 34, no. 45, p. 2205154, 2022. https://doi.org/10.1002/adma.202205154.Search in Google Scholar PubMed

Received: 2022-09-08
Accepted: 2022-10-28
Published Online: 2022-11-14

© 2022 the author(s), published by De Gruyter, Berlin/Boston

This work is licensed under the Creative Commons Attribution 4.0 International License.

Articles in the same Issue

  1. Frontmatter
  2. Editorial
  3. Novel two-dimensional materials based bio-nanophotonics
  4. Reviews
  5. Carbon nanomaterials for phototherapy
  6. Two-dimensional transition metal carbides and nitrides (MXenes) based biosensing and molecular imaging
  7. Two-dimensional photonic MXene nanomedicine
  8. Two-dimensional nanostructures based ‘-onics’ and ‘-omics’ in personalized medicine
  9. Emerging nanophotonic biosensor technologies for virus detection
  10. Research Articles
  11. Three birds with one stone: oxygen self-supply engineering palladium nanocluster/titanium carbide hybrid for single-NIR laser-triggered synergistic photodynamic-photothermal therapy
  12. Oxygen-supplied electrotherapy for enhanced photodynamic synergistic therapy overcomes hypoxia tumor microenvironment
  13. NIR-II light-activated two-photon squaric acid dye with Type I photodynamics for antitumor therapy
  14. Highly active selenium nanotherapeutics combined with metformin to achieve synergistic sensitizing effect on NK cells for osteosarcoma therapy
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  16. Fluorescein-derived carbon dots with chitin-targeting for ultrafast and superstable fluorescent imaging of fungi
  17. A pH-sensitive liposomal co-delivery of fingolimod and ammonia borane for treatment of intracerebral hemorrhage
  18. Exploring magneto-optic properties of colloidal two-dimensional copper-doped CdSe nanoplatelets
  19. Nanoparticle-on-mirror pairs: building blocks for remote spectroscopies
  20. Mesoporous biophotonic carbon spheres with tunable curvature for intelligent drug delivery
  21. Manganese-functionalized MXene theranostic nanoplatform for MRI-guided synergetic photothermal/chemodynamic therapy of cancer
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https://doi.org/10.1515/nanoph-2022-0550
Keywords for this article
biosensors; microRNA detection; molecular imaging; MXenes; two-dimensional nanomaterials
Creative Commons
BY 4.0

Articles in the same Issue

  1. Frontmatter
  2. Editorial
  3. Novel two-dimensional materials based bio-nanophotonics
  4. Reviews
  5. Carbon nanomaterials for phototherapy
  6. Two-dimensional transition metal carbides and nitrides (MXenes) based biosensing and molecular imaging
  7. Two-dimensional photonic MXene nanomedicine
  8. Two-dimensional nanostructures based ‘-onics’ and ‘-omics’ in personalized medicine
  9. Emerging nanophotonic biosensor technologies for virus detection
  10. Research Articles
  11. Three birds with one stone: oxygen self-supply engineering palladium nanocluster/titanium carbide hybrid for single-NIR laser-triggered synergistic photodynamic-photothermal therapy
  12. Oxygen-supplied electrotherapy for enhanced photodynamic synergistic therapy overcomes hypoxia tumor microenvironment
  13. NIR-II light-activated two-photon squaric acid dye with Type I photodynamics for antitumor therapy
  14. Highly active selenium nanotherapeutics combined with metformin to achieve synergistic sensitizing effect on NK cells for osteosarcoma therapy
  15. Self-powered broadband photodetector based on MoS2/Sb2Te3 heterojunctions: a promising approach for highly sensitive detection
  16. Fluorescein-derived carbon dots with chitin-targeting for ultrafast and superstable fluorescent imaging of fungi
  17. A pH-sensitive liposomal co-delivery of fingolimod and ammonia borane for treatment of intracerebral hemorrhage
  18. Exploring magneto-optic properties of colloidal two-dimensional copper-doped CdSe nanoplatelets
  19. Nanoparticle-on-mirror pairs: building blocks for remote spectroscopies
  20. Mesoporous biophotonic carbon spheres with tunable curvature for intelligent drug delivery
  21. Manganese-functionalized MXene theranostic nanoplatform for MRI-guided synergetic photothermal/chemodynamic therapy of cancer
  22. Copper decorated Ti3C2 nanosystem with NIR-II-induced GSH-depletion and reactive oxygen species generation for efficient nanodynamic therapy
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