| Chirality is one of the fundamental properties of nature, and reasearches about it have important application value in the fields of life science, food science, medical science and materials science. Therefore, it is of great significance to develop analytical methods for chiral recognition which are responsive, simple, low cost, fast.Electrochemiluminescence technique is a new and powerful tool, which can act as effectively analytical approach for chiral recognition. Metallic nanomaterials and functional carbon nanomaterials possess a multitude of advantanges, which can be widely applied in chiral recogniton via electrochemiluminescence. The combination of the nanomaterials with biomolecules and other chiral selectors can be well achieved by using excellent electrochemical performance, large specific surface area and good biocompatibility, which is the key step for constructing the chiral sensing platforms to enantioselectively distinguish amino acid enantiomers. The main resrearch of the work includes three fractions as follows:1. A sensitive, stable and stereoselective electrochemiluminescence(ECL)sensor has been designed to enantioselectively discriminate proline enantiomers by immobilizing Ru(bpy)32+-gold nanoparticles(Ru-Au NPs) andβ-cyclodextrin-reduced graphene oxide(β-CD-r GO) on glassy carbon electrode.More Ru(bpy)32+ could be immobilized on the surface of electrode stably via preparing Ru-Au NPs and better stereoselectivity could be introduced to the sensor via the synthesis of β-CD-r GO. When the developed sensor interactedwith proline enantiomers, obvious difference of ECL intensities towards L- and D-proline was observed, and a larger intensity was obtained from D-proline. As a result, ECL technique might act as a promising method to chiral recognize of amino acids enantiomers or chiral drugs.2. A new biosensor specified for D-amino acids(DAAs) based on the electrochemiluminescence(ECL) of luminol was proposed by coupling D-amino acid oxidase(DAAO) to in situ generate coreactant with functionalized Multi-walled carbon nanotubes(F-MWCNTs) and Au-Pt alloy nanoparticles as catalysts for the ECL reaction.The stepwise fabrication process of the biosensor was characterized via cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS) and scanning electron microscopy(SEM). Furthermore, the Au–Pt nanostructures with different molar ratios between Au and Pt precursors were investigated by scanning electron microscopy(SEM), energy-dispersive spectroscopy(EDS) and ECL technique, and the optimum Au/Pt ratio for ECL measurements was 1:1 with an optimized electrodeposition time at 400 s. The proposed biosensor showed excellent performance in the stereoselective recognition of D-alanine with a low detection limit of 1.67×10-9M. Hence, this paper would provide a new platform on the specific detection of D-alanine with high sensitivity, good selectivity and acceptable stability.3. A novel electrochemiluminescence biosensor based on hemin-reduced graphene oxide(H-RGO) and Au-Pd alloy nanoparticles, and L-glutamate oxidase(L-Glu Ox) for the specific sensing of L-glutamate(L-Glu) has been developed. The Au-Pd alloy nanoparticles were coated on the H-RGO modified glass carbon electrodes by electrodeposition. The stepwise fabrication of nanomaterials was characterised by using scanning electron microscopy(SEM), UV-Vis spectra and electrochemical methods. In addition, energy-dispersive spectroscopy(EDS) was applicated to invstigate the chemical compositions of the Au-Pd alloy nanoparticles. The proposed biosensor showed good analytical performance in detection of L-Glu with a wide liear range, low detection limit, good stability and excellent selectivity. |
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