Biomimetic Mineralization Of Gold Nanoclusters As Multifunctional Thin Films For Glass Nanopore Modification,Characterization And Sensing

In contemporary society,nanopore has offered a practical platform for addressing a number of challenging questions in chemistry,biotechnology,and materials science.Due to its advantages of easily made,low cost,excellent mechanical and chemical stability,and adjustable orifice diameter,the glass nanopipette-based nanopore platform is attracting more and more attention.Different functionalization strategies have been developed to detect substances including nucleotides,proteins,and metal ions,etc.Although these approaches have their own advantages,they all face the challenges of the uncontrollability of surface property and the destructiveness of TEM characterization.This paper adopts a facial,green and controllable biomimetic mineralization method to decorate glass nanopore with structurally well-defined gold nanocluster films based on the capability of a common protein.The BSA-Au NC film with unique fluorescence properties allows fast and nondestructive characterization of the glass-based single nanopore through fluorescence imaging.The BSA-Au NC-decorated conical glass nanopore with significant analytical performance was successfully applied for enantioselective detection of arginine and selective detection of cysteine without addition modification which opened up new possibilities of glass nanopore in the field of biological sensing.The full text is divided into four parts,as follows:Charpter 1:OverviewIn this chapter,the preparation and functionalization of nanopores are firstly introduced.Secondly,the characterization method of nanopores is discussed emphatically.Then,two kinds of detection methods based on nanopores and their application in biosensor are summarized.Finally,the significance and content of this paper are expounded.Charpter 2:Biomimetic preparation and fluorescent characterization of BSA-Au film-modified glass conical nanoporesThrough layer-by-layer electrostatic deposition,structurally well-defined BSA-Au film-modified nanopore was successfully prepared based on the reduction of HAuCl4 by BSA.The characterization of gold modification to glass nanopore has been addressed by transmission electron microscope(TEM),energy-dispersive X-ray(EDX)spectrum and elemental mappings and ?-? curves.The versatile bovine serum albumin-protected Au nanocluster film allows facile and nondestructive characterization of the glass-based single nanopore through fluorescence imaging.Besides,the BSA-Au NC film was highly stable in solution with a high salt concentration and in solution of a broad pH range.Utilizing the potential of BSA-Au NCs in biosensing,the BSA-Au NC-decorated conical glass nanopore would have a boarder application space in biological research.Charpter 3:Chiral recognition of arginine by BSA-Au film-modified glass conical nanoporesUtilizing the ability of BSA in chiral separation,the BSA-Au NC-decorated conical glass nanopore was successfully applied for enantioselective detection of arginine(Arg)in this chapter.The ionized carboxyl groups(-COO-)of BSA coating layer on Au NCs can interact with Arg via guanidine groups,forming ion pairs through cooperative interactions.It was demonstrated by zeta potential and AFM that Arg enantiomers had different acting force with BSA-Au NCs.Then the glass nanopore decorated by BSA-Au NC film was directly used for selective recognition of Arg enantiomers through monitoring of ionic current.The current change ratios of L-Arg and D-Arg were respectively 25%and 6%.The result showed that this nanosensor based on glass nanopore could be used to distinguish Arg enantiomers.Charpter 4:Selective detection of cysteine by BSA-Au film-modified glass conical nanoporesBased on steric hindrance,the electrostatic repulsion and many other reasons,the BSA-Au film-decorated conical glass nanopore was successfully applied for the selective detection of cysteine(Cys)resulting from the adsoption of Cys to Au NCs by forming Au-S bond in this chapter.First,we investigated the feasibility of the scheme by Zeta potential and infrared spectroscopy.It was found that cysteine could be modified to the Au film by the formation of Au-S bond and compensated for the surface defects of bovine serum albumin-encapsulated Au clusters.Once Cys combinded with the BSA-Au film,the inner surface charge of nanopore changed and the corresponding ion current change ratio of-1 V reached 65%.BSA-Au film-decorated conical glass nanopore could not only be used to detect Cys,but also had an anti-interferece over other thiols with similar structure.