Research On The Sensor Application Of Cyclodextrin-three-dimensional-graphene-based Nanocomposites

Chapter 1: The structure,properties,preparation methods,functionalization,research progress and applications of three-dimensional-graphene based nanomaterials have been emphatically reviewed in this chapter.Chapter 2: A facile chiral sensing platform has been proposed focused on electrochemical recognition of the enantiomers based on the combining three-dimensional-graphene with hydroxypropyl-?-cyclodextrin?3D-G/HP-?-CD?.The chiral platform not only inherts the peculiarity of HP-?-CD as a supramolecular chiral recognizer but the assets of 3D-G as an electrochemical indicator,to distinguish tryptophan isomers?L-/D-Trp?by differential pulse voltammetry?DPV?approach with significantly discoverable electrochemical responses.It's due to different host–guest interactions between D-/L-Trp and HP-?-CD that lead to higher binding affinity to L-tryptophan than D-enantiomer in terms of sensing tryptophan enantiomers.Meanwhile,it can be observed that the peak currents of the two isomers exhibited a linear curve in the concentration range of 0.5-175 m M and low detection limits of 9.6 n M and 38 n M for L-and D-Trp?S/N = 3?,respectively,revealing excellent sensitivity,good reproducibility together with great stability.Considering the initial construction of ?-cyclodextrin functionalized 3D-G for chiral recognition application,this proces would potentially provides a new idea for enantiosensing.Chapter 3: A facile and novel hydroxypropyl-?-cyclodextrin?HP-?-CD?functionalized three-dimensional reduced graphene oxide magnetic nanocomposite?3D-r GO/Fe₃O₄/HP-?-CD?was successfully prepared and coated on a glassy carbon electrode?GCE?to develop an electrochemical sensing platform for the simultaneous determination of serotonin?5-HT?,dopamine?DA?,and ascorbic acid?AA?.The 3D interconnected porous graphene framework tightly anchored with Fe₃O₄ nanoparticles ensure excellent electrical conductivity and efficient catalytic activity,meanwhile,the HP-?-CD as a supramolecular host molecule has a high recognition ability for small biomolecules.Benefiting from the above charming peculiarity,the well-separated oxidation peaks and enhanced peak currents of 5-HT,DA,and AA were observed separately and simultaneously by differential pulse voltammetry?DPV?approach under the optimized conditions.For the simultaneous electrochemical determination of three coexisting species,the linear concentration ranges are 0.01-25 ?M,0.05-25?M and 10-350 ?M for 5-HT,DA and AA with detection limits of 3.3 n M,6.7 n M and 3.3 ?M?S/N = 3?,respectively.Additionally,the developed sensor was also successfully applied to the measurement of these three biomolecules in human serum samples with good accuracy,providing a promising view of electrochemical biosensing for simultaneous detection in practical application.Chapter 4: An electrochemical biosensor,based on hydroxypropyl-?-cyclodextrin?HP-?-CD?modified Fe₃O₄-Au NPs nanoparticles conjugated three-dimensional reduced graphene oxide nanocomposite?3D-r GO/Fe₃O₄-Au NPs/HP-?-CD?coated glassy carbon electrode?GCE?,has been designed to be utilized to simultaneous determinate guanine?G?and adenine?A?.The constructed sensor synergistically exploits the charming electrical conductivity of 3D-r GO,efficient catalytic activity of Fe₃O₄-Au NPs as well as host-guest recognition ability of HP-?-CD,providing the highly sensitive electrochemical signals for simultaneous recognition of guanine?G?and adenine?A?.It turned out that the wide linear ranges of 1-150 ?M and 1-190?M for G and A with detection limits of 0.026 and 0.031 ?M have been obtained by differential pulse voltammetry?DPV?under the optimized conditions,which illustrates a great improvement in sensitivity for modified electrode to the detection of G and A.Additionally,this sensor was also successfully used to detect the content of G and A in denatured fish sperm DNA with satisfactory accuracy,which indicates that this proposed method is expected to pave the way to the development of the analysis and application of electrochemical biosensors.Chapter 5: The electrochemical sensor application based on cyclodextrinthree-dimensional-graphene nanocomposites have been briefly summarized and the potential research on the other applications of these nanomaterials have also been prospected.