Study On Chiral Sensors Based On Carbon Nanomaterials And Bimetallic Nanomaterials

Chiral structures influence chemical and biological processes,and biochemical systems contain numerous stereoisomeric interactions,resulting from the stereochemistry of biomolecules such as proteins,DNA,sugars and amino acid.Chiral molecules with various spatial structures could show the same chemical properties but obvious different pharmaceutical and biomedical activities.Hence,distinction of stereoisomeric molecules is a significant analytical target.With the aim of developing sensitive and rapid methods for recognition and detection of chiral molecules,numerous technologies including high performance liquid chromatography,capillary zone electrophoresis,quartz crystal microbalance and electrochemical methods have been reported.Among these,the integration of electrochemical sensor with stereoisomeric analysis exhibits the merits of convenience,easy operation,low cost and high sensitivity and gradually grows into a significant research technique for stereoselectivity recognition.In this paper,carbon nanomaterials?such as graphene,fullerenes,and carbon nanotubes?,bimetallic nanomaterials?such as gold-platinum,gold-palladium and platinum-palladium?and chiral selector?such as cyclodextrins and dipeptides?have been used for interacting with chiral electroactive molecules.The main research content is divided into the following three parts:1.A simple stereoselective sensing platform for recognition of ascorbic acid?AA?and isoascorbic acid?IAA?had been fabricated via immobilizing HS-?-cyclodextrin?HS-?-CD?on the nanocomposites modified glassy carbon electrodes?GCEs?surface,which prepared by Pt and Pd biometal nanowires?Pt-PdNWs?and reduced graphene oxide?rGO?.And the nanocomposites were characterized by scanning electron microscopy?SEM?,energy-dispersive X-ray spectroscopy?EDX?,cyclic voltammetry?CV?and differential pulse voltammetry?DPV?.After the interacting between the modified electrodes and analytes,the obvious differences of peak currents of AA and IAA were obtained,hinting the proposed sensor held the ability for identifying AA and IAA.2.A simple and convenient chiral sensor for tyrosine?Tyr?enantiomers recognition was developed based on simply synthesized nanomatrixs which coupling of L-cysteine decorated fullerene(C₆₀-L-Cys),porous Au@Pd bimetallic nanoparticles?Au@Pd NPs?and thiol-?-cyclodextrin?HS-?-CD?.The proposed nanomatrixs were characterized by scanning electron microscopy?SEM?,energydispersive X-ray spectroscopy?EDX?,transmission electron microscope?TEM?and Fourier transform infrared spectroscopy?FTIR?.Electrochemical interaction between Tyr enantiomers and the nanocomposites modified glassy carbon electrodes?GCEs?were investigated via square wave voltammetry?SWV?.The results showed obvious differences in the peak currents between Tyr enantiomers,hinting that Tyr enantiomers could be effectively recognized by the sensor.3.A simple dipeptides-based nanohybrid material was fabricated via immobilizing L-alanyl-L-glutamine?Ala-Glu?on the surface of reduced graphene oxide-multiwalled carbon nanotube?rGO-MWCNTs?and gold-platinum bimetallic nanomaterials?AuPt NCs?modified glassy carbon electrodes?GCEs?.The composite material was used for chiral interaction with tryptophan enantiomers.Herein,Ala-Glu was applied as a chiral selector,the rGO-MWCNTs and AuPt NCs not only acted as a supporter for high loading of Ala-Glu,but also served as the nanomaterial for signal amplification.The results showed obvious peak current differences between Trp enantiomers,indicating that this strategy could be employed to recognize Trp enantiomers.Under the optimum conditions,the sensor exhibited a good linear response to Trp enantiomers in a linear range of 1.0×10^-55.0×10^-3 M.