Volume 5, Issue 5

Gold nanoparticles (AuNPs) can be suitably engineered for applications in gene delivery, and as carriers of peptides and proteins. They present innovative strategies in gene therapy for the treatment of genetic as well as acquired diseases. Optimisation of AuNPs in binding and the eventual release of the therapeutic agent in a controlled manner are crucial steps in the pathway to effective drug or gene therapy. In this study, we propose the formulation of cationic polymer [chitosan (Chit) and poly- l -lysine (PLL)] and cysteine (Cys)-coated AuNPs. These cationic AuNPs displayed good stability and resistance to aggregation under physiological conditions. All functionalised formulations remained in the size range 15.7–186 nm with narrow particle distributions and low polydispersity index (<0.9). Band shift and ethidium bromide intercalation assays determined the complexation of pDNA to the functionalised AuNP (FAuNP). Au-Chit/pDNA exhibited a significant 126% (p<0.01) cell viability in HepG2 cells, followed by Au-PLL/pDNA at 104% in HeLa cells and Au-cysteine/pDNA at 91.8% (p<0.001) in Caco-2 cells. Significant transgene activities in all cell lines were noted with enhanced gene expression for the FAuNP complexes over the cationic complexes on their own. The results of this study suggest that the low cytotoxicity and promising transgene activity of these FAuNPs, coupled with the ability to parametrically control particle size and surface properties, make these formulations suitable nanocarriers for drugs and genes.

The present investigation strives to formulate nanoparticles of poly-ε-caprolactone (PCL), containing celecoxib (CXB), a non-steroidal anti-inflammatory agent. The CXB-PCL nanoparticles were formulated by solvent displacement method and optimized based on formulation variables like drug-to-polymer ratio and surfactant concentration. The formulations were characterized for particle dimensions, surface morphology, physicochemical features, percentage drug incorporation efficiency, in vitro drug release, in vitro trans-corneal permeation, in vivo efficacy against arachidonic acid-induced ocular inflammation, and stability study. The prepared nanoparticles were nearly spherical having particle sizes ranging from 89.16±8.2 nm to 191.27±12.1 nm with maximum entrapment efficiency of 97.03±0.20%. The drug release was in sustained fashion (<75% drug released after 8 h) and obeyed zero-order release kinetics. The trans -corneal permeation was significantly higher than the aqueous suspension of CXB (p=0.05). Further, % hydration level was observed within permissible ranges suggesting ocular tolerability. The anti-inflammatory activity was found better as there was observed an improvement in parameters like lid closure score, PMN counts, and protein content against CXB aqueous suspension. The formulations were stable as evident from accelerated stability testing results. Thus, the CXB-PCL nanoparticles may prove a viable alternative to conventional dosage forms offering enhanced ocular bioavailability and compatibility with ocular milieu.

Chitosan-dextran sulfate nanoparticles of acetazolamide were formulated by using the ionic gelation technique, and evaluated for different attributes like particle size, ζ potential, drug entrapment, particle morphology, in vitro drug release, and in vivo efficacy. Particle size was observed to be changed with the increment of the drug/polymer ratio. Sustained in vitro drug release was exhibited by the particulate formulation that followed the Korsmeyer-Peppas kinetic model. Drug release from nanoparticles was found to occur, as shown by the results, through a combination of dissolution and diffusion. The optimized formulation had a particle size of 172.3 nm and ζ potential of 36.46 mV. The particles had a spherical shape and polydispersity index of 0.257. Decrease in crystallinity of the drug was indicated by powder X-ray diffraction and differential scanning calorimetry studies, in the optimized nanoparticle formulation. Approximately 2.5 times higher transcorneal permeation of drug was observed across the excised goat cornea, in comparison to the aqueous solution of drug, without any corneal damage, during ex vivo transcorneal studies. In vitro mucoadhesion studies showed 91.59% mucoadhesion. The in vivo studies involving ocular hypotensive activity in rabbits revealed significantly higher hypotensive activity with a p-value of <0.05, in contrast to a plain drug solution, with no signs of ocular irritation. The stability studies showed that the formulation was rather stable.

Phase-change probe memory has been extensively regarded as one of the most prospective candidates to satisfy the recording density requirement from the incoming age of big data. However, in spite of recent advances, the energy consumption of phase-change probe memory still remains fairly high due to the use of the diamond-like carbon bottom electrode usually having a relatively high electric resistivity. In this case, the possibility of using titanium nitride to replace the diamond-like carbon as the electrode materials is investigated in this paper. The thickness and time-dependent resistivity of titanium nitride film is measured, allowing for a more conductive characteristic and a better stability than diamond-like carbon film at the same condition. Consequently, the writing of crystalline bit using the previously designed phase-change probe memory architecture but with titanium nitride bottom electrode is performed experimentally, and results show that using titanium nitride as bottom electrode would enable an achievement of ultra-high recording density with lower energy consumption than the phase-change stack with diamond-like carbon electrode.

Today, the total amount of global data has been increasing at a phenomenal rate, and this necessitates the requirement for significant improvement in the storage capacity of current storage devices. Compared with other conventional storage devices, electrical probe memory exhibits several storage superiorities and is considered as the candidate for the next-generation mainstreaming storage device. In this case, to further mitigate the performances of the electrical probe memory, its architecture was previously optimized by simulation while lacking adequate experimental support. Therefore, we measured the electrical resistivities of the diamond-like carbon (DLC) capping and bottom layers by varying the film thickness, sputter power, and sputter pressure to thus establish the physically realistic property values of the DLC film. According to experiments, a 10 nm DLC capping layer with a resistivity of 0.1 Ω·m, and a 30 nm DLC bottom layer with a resistivity of 0.01 Ω·m, which most closely matches the theoretical prediction, are introduced into the originally designed electrical probe memory, and the subsequent recording experiment demonstrated the ability to achieve ultra-high density, large data rate, and ultra-low energy consumption using the redesigned architecture.

Despite the recent synthesis and identification of a diverse set of new nanophotocatalysts that has exploded recently, titanium dioxide (TiO 2 ) remains among the most promising photocatalysts because it is inexpensive, non-corrosive, environmentally friendly, and stable under a wide range of conditions. TiO 2 has shown excellent promise for solar cell applications and for remediation of chemical pollutants and toxins. Over the past few decades, there has been a tremendous development of nanophotocatalysts for a variety of industrial applications (i.e. for water purification and reuse, disinfection of water matrices, air purification, deodorization, sterilization of soils). This paper details traditional and new industrial routes for the preparation of nanophotocatalysts and the characterization techniques used to understand the physical chemical properties of them, like surface area, ζ potential, crystal size, and phase crystallographic, morphology, and optical transparency. Finally we present some applications of the industrial nanophotocatalysts.

Magnetic nanoparticles are renowned for their anticancer activity. Recent studies have elucidated that magnetic nanoparticles induce cytotoxicity by induction of apoptosis in cancer cells. The magnetic nanoparticles can also be biosynthesized, and this presents an added advantage along with the concept of limited toxicity to normal cells. This review focuses on the mechanistic studies performed on the anticancer activity of different types of magnetic nanoparticles. Apoptosis was shown to be the most plausible reason behind the cell death mediated by various types of magnetic nanoparticles.

Multi-drug resistance (MDR) poses a large obstacle to various human malignancies. For a long period, combination of multiple therapeutic agents has been the conventional method used to reverse MDR in cancer. However, it is still not an effective method as rather than cancer its serious side effects causes patient’s death. Nanoparticles (NPs) are emerging as a class of therapeutics for cancer, including overcoming MDR. In the present review, we focus on the application of NPs to reverse MDR in cancer. Several kinds of NPs developed for the reversal of MDR are summarized. In addition, investigations in vitro and in vivo are also shown to highlight the advancement in the application of NPs to reverse MDR.