Microheterogeneous Electrocatalytic Chiral Recognition at Monoclinic Vanadium-Doped Zirconias: Enantioselective Detection of Glucose

Time-Resolved Visual Chiral Discrimination of Cysteine Using Unmodified CdTe Quantum Dots

Herein, we demonstrate a simple yet novel luminescence assay for visual chiral discrimination of cysteine. Thioglycolic acid (TGA)-capped cadmium-telluride (CdTe) quantum dots (QDs) exposing green emission were directly synthesized in aqueous solution. The interaction between cysteine molecules and CdTe QDs induced the aggregation of QDs via hydrogen bonding. As a result of electronic coupling within these aggregates, a redshift both in the absorption and emission spectra of QDs occured. The difference in the kinetics of the interactions between L- and D-cysteine with CdTe QDs led to chiral recognition of these enantiomers. Addition of D-cysteine to CdTe QDs in a basic media caused a green-to-yellow color change, while no color alteration in QDs emission was observed in the presence of L-cysteine after 2 hours. Notably, the QDs used in the proposed assay are free from any labling/modification, which makes the present strategy highly attractive for sensing applications. Furthermore, the presented chiral assay is able to determine the enantiomeric excess (ee) of D-cysteine in the whole range of ee values (from -100% to 100%).

Recent advances in non-enzymatic electrochemical glucose sensors based on non-precious transition metal materials: opportunities and challenges

We summarize the latest advances of non-enzymatic glucose detection using non-noble transition metal materials, highlighting their opportunities and challenges.

Hyper-Branched Cu@Cu2O Coaxial Nanowires Mesh Electrode for Ultra-Sensitive Glucose Detection

Electrode design in nanoscale is expected to contribute significantly in constructing an enhanced electrochemical platform for a superb sensor. In this work, we present a facile synthesis of new fashioned heteronanostructure that is composed of one-dimensional Cu nanowires (NWs) and epitaxially grown two-dimensional Cu2O nanosheets (NSs). This hierarchical architecture is quite attractive in molecules detection for three unique characteristics: (1) the three-dimensional hierarchical architecture provides large specific surface areas for more active catalytic sites and easy accessibility for the target molecules; (2) the high-quality heterojunction with minimal lattice mismatch between the built-in current collector (Cu core) and active medium (Cu2O shell) considerably promotes the electron transport; (3) the adequate free space between branches and anisotropic NWs can accommodate a large volume change to avoid collapse or distortion during the reduplicative operation processes under applied potentials. The above three proposed advantages have been addressed in the fabricated Cu@Cu2O NS-NW-based superb glucose sensors, where a successful integration of ultrahigh sensitivity (1420 μA mM(-1) cm(-2)), low limit of detection (40 nM), and fast response (within 0.1 s) has been realized. Furthermore, the durability and reproducibility of such devices made by branched core-shell nanowires were investigated to prove viability of the proposed structures. This achievement in current work demonstrates an innovative strategy for nanoscale electrode design and application in molecular detection.

V-containing ZrO2 inorganic yellow nano-pigments

Inorganic yellow nano-pigments based on monoclinic vanadium–zirconia solid solutions for digital decoration prepared by a polyol approach.

Calixarene-based chemosensors by means of click chemistry

Click chemistry, a new strategy for organic chemistry, has been widely used in the chemical modification of calixarenes because of its reliability, specificity, biocompatibility, and efficiency. Click-derived triazoles also play a critical role in sensing ions and molecules. This in-depth review provides an overview of calixarene-based chemosensors that incorporate click-derived triazoles, and their three characteristics (chromogenic, fluorescence, and wettability) are reviewed.

Synthesis, characterization and electrochemical properties of iron-zirconia solid solution nanoparticles prepared using a sol-gel technique

The range of compositions and temperatures at which single-phase tetragonal and monoclinic Fe-containing zirconia nanoparticles are stable is reported. Both types of iron-doped zirconia particles were synthesized by annealing dried gels FexZr1-xO2, with nominal compositions in the range 0 ≤ x ≤ 0.15, over the range of temperatures between 400 °C and 1300 °C. Monophasic crystalline specimens of Fe-ZrO2 solid solutions were characterized by different techniques including X-ray powder diffraction (XRD), infrared and Raman spectroscopies (IR and Raman), and transmission electron microscopy (TEM). Energy gaps were estimated from diffuse reflectance ultraviolet-visible spectra (DRUV-Vis) and compared with those obtained from electrochemical data. Upon increasing the amount of iron in both types of iron-containing zirconia-based structures the energy gaps slightly lowered. The electrochemical properties of those solid solutions obtained using the voltammetry of microparticles (VPM) technique indicated the presence of a small portion of iron as Fe(2+) in both types of crystalline Fe-doped ZrO2. Electrochemical data suggest that the monoclinic solid solutions provide a particularly high accessibility for promoting catalytic processes such as electrochemical oxygen reduction.

Bipyrene-functionalized graphene as a "turn-on" fluorescence sensor for manganese(II) ions in living cells

1,2-bis-(2-pyren-1-ylmethylamino-ethoxy) ethane (NPEY) was synthesized and brought to the surface of graphene nanosheets (GNs) via π-π stacking, which provided a simple and convenient route for processing "turn-on" fluorescent sensor by simply mixing the diluted aqueous solutions of both components. The synthesized NPEY modified graphene nanosheets (NPEY-GNs) not only allows good selectivity toward Mn(2+) with the detection limit of 4.6 × 10(-5) M, but also shows "turn-on" response for Mn(2+) both in vitro and in living cells. These sensing capabilities of NPEY-GNs in living cells make it a robust candidate for many biological fields, such as intracellular tracking, intracellular imaging, etc.

Fabrication of boron-doped diamond nanorod forest electrodes and their application in nonenzymatic amperometric glucose biosensing

A boron-doped diamond nanorod forest (BDDNF) electrode has been fabricated by hot filament chemical vapor deposition (HFCVD) method. This BDDNF electrode exhibits very attractive electrochemical performance compared to conventional planar boron-doped diamond (BDD) electrodes, notably improved sensitivity and selectivity for biomolecule detection. The BDDNF electrode, with the possibility of fabricating a sensitive biosensor for glucose without any catalyst or mediators, shows good activity toward direct detection of glucose by simply putting the bare BDDNF electrode into the glucose solution. Furthermore, the marked selectivity of the BDDNF electrode is very favorable for the determination of glucose in the presence of ascorbic acid (AA) and uric acid (UA). The robust sensitive and selective responses of this nanostructure indicate the promise of this kind of diamond electrode for real applications.