Volume 31, Issue 1

The phase of the molecular response can be exploited to improve selectivity without sacrificing speed in both narrowband and broadband coherent anti-Stokes Raman scattering (CARS) microscopy, both of which will be considered in this review of the work that was performed in our group.

During the last two decades, redox cycling techniques have evolved as a promising technique for the electrochemical detection of molecules that can undergo subsequent redox reactions. In particular, chip-based techniques received growing attention due to the option of parallel fabrication and easy integration into lab-on-a-chip devices. In here, we provide a review on current implementations of on-chip redox cycling sensors. Advantages and limitations of various approaches are discussed with regard to their fabrication process and performance.

Surface plasmon resonance (SPR) sensors have matured over the last 2 decades into very powerful tools for the study of biomolecular interactions, chemical detection and immunoassays. The performance of the sensor depends on several parameters, such as the choice of the metal thin film where the plasmonic wave propagates, the excitation wavelength and the refractive index (RI) of the glass prism. Next to these physical parameters, the strategy selected to bind the desired receptors to the SPR chip, has a strong influence on the overall sensitivity and selectivity of the device. This review focuses on the advancement made using lamellar SPR structures, where a thin dielectric layer is deposited onto the surface plasmon active metal thin film. Silver-based SPR interfaces can be developed using this approach, as these overlayers allow an efficient protection of the underlying silver film. At the same time, these interfaces open the scope for new surface functionalization schemes, which can be employed for anchoring ligands to the SPR sensor chip. While self-assembled monolayers (SAMs) are widely used, due to the possibility of easily incorporating carboxylate, amine or hydroxyl groups, the drawbacks of such films include limited chemical and electrochemical stability. Moreover, a poor orientation and potential problems of protein adsorption and fouling, is often encountered if no synthetic effort in the synthesis of more sophisticated thiols is made. In addition, while the surface chemistry developed on gold has been of great value, the limitations of working on gold are becoming more noticeable, with increasingly complex fabrication requirements for biometric systems and arrays. Lamellar SPR interfaces represent an alternative route. Finally, the contribution of the thin dielectric top layer to the sensitivity of SPR sensors will be discussed.

Protein phosphorylation is a key regulator in many biological processes, such as homeostasis, cellular signaling and communication, transcriptional and translational regulation, and apoptosis. The defects in this tightly controlled reversible post-translational modification have been described to contribute to genesis and progression of various diseases, emphasizing the importance of a systematic research of this phenomenon. Although considerable effort has been devoted to improving the analysis of phosphorylation by mass spectrometry, which is currently the method of choice to study protein phosphorylation, the detection and identification of phosphorylation sites remains challenging because of the low abundance and low ionization efficacy of phosphoproteins in comparison with nonphosphorylated proteins. To overcome this obstacle, different enrichment strategies for phosphorylated peptides/proteins have been established and optimized for subsequent mass spectrometry analysis. In this review, we will give an overview of the methods currently available for the enrichment of phosphorylated proteins and peptides including immunoprecipitation, chemical derivatization and affinity enrichment techniques.

Phospholipids (PLs) are a class of compounds essential for living organisms, including human beings. This paper presents a brief review concerning the extraction as well as thin-layer chromatographic separation and determination of phospholipids. After a short introduction regarding phospholipids and their specific characteristics, the extraction techniques will be discussed. Then, phospholipid separation and system detection for thin-layer chromatography (TLC) will be presented. The focus will be on phospholipids that are most abundant in biological systems; that is why chosen examples of PLs determination in biological samples will be revealed as well as general PL determination schemes. In the Summary section, there will also be a short discussion about advantages and disadvantages of PL determination with the use of TLC.

The emergence of graphene (GR) has recently opened up an exciting new field in the science and technology of two-dimensional (2D) nanomaterials with continuously growing academic and technological impetus. GR exhibits unique electronic, optical, magnetic, thermal, and mechanical properties arising from its strictly 2D structure and, thus, has many important technical applications. In the last 2 years, GR, as novel sensing material has attracted tremendous attention and research interest. To further improve electrochemical property, large numbers of GR-based hybride materials have been well designed, synthesized, and investigated for sensing application. The hybridization can be an effective strategy to enhance functionality of the materials, and the integration of nanomaterials on GR potentially paves a new way to enhance their electronic, chemical, and electrochemical properties. As a result, the GR composites often offer better analytical characteristics than GR materials alone. However, the immobilizations of GR-based material and enzyme are important to enhance electrochemical properties and use of the biosensor. Classical coating method results in poor stability due to loss of the enzyme/antibody. To resolve the problem, we developed a green and controllable strategy to fabricate well-dispersed GR-metal nanocomposite modified functional conducting polymer film containing carbonyl groups with electrochemical deposition. Horseradish peroxidase was finally connected covalently to the film with 1-ethyl-3-(3-dimethylaminepropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS) as activator. The as-prepared GR/gold nanocomposite offers remarkable catalysis performance to the redox of hydrogen peroxide on the electrode surface. In this review, from the viewpoint of chemistry and materials, we will cover recent significant advances in hybrids, design, and synthesis of GR-based film, as well as immobilization of enzyme/antibody on the electrode, and analytical application together with discussion on the major challenges and opportunities for future GR research.

No abstract available