Structure Regulation Of The Paper-based Au Nanomaterials And Its Application In Biosensing

With the development of science and technology,the electrochemical biosensors based on multidisciplinary cross-fusion have become a hot research topic due to their merits of high sensitivity,good selectivity,and simple operation.In order to develop miniaturized and integrated electrochemical biosensors,paper with good flexibility and designability has attracted widespread attention.Although paper is inherently insulating,the introduction of nanomaterials will greatly improve the performance of paper and make it an excellent electrochemical substrate,which opens a new way for the construction of portable electrochemical biosensors.In this paper,paper modified by gold nanomaterials with different structures was prepared by regulating the in-situ growth method to improve the performance of paper chips.Using paper chip modified by gold nanomaterials as the sensing substrate and combining different signal amplification strategies,two different paper-based electrochemical biosensors were constructed to achieve simple,fast,and highly sensitive detection of multiple targets.The main research work was carried out as follows:(1)By changing the types of reducing agents and other experimental conditions,the structures of gold nanomaterials were effectively regulated.Porous gold nanoparticles(AuNPs)and triangular gold nanosheets were successfully grown in-situ on the paper fibers,realizing all-around conductivity of paper chips.What's more,the large specific surface area of nanomaterials also enlarged the real electro-active surface area of the paper chips,which could provide more active sites for the fixation of biomolecules.(2)Using the paper chip modified with porous AuNPs as the sensing substrate to immobilize biomolecules.Cyclodextrin functionalized AuNPs,which exhibited mimicking properties of both glucose oxidase and horseradish peroxidase simultaneously,were prepared to replace the traditional natural enzymes in the construction of electrochemical biosensors.The introduction of nanoenzyme greatly improved the stability of the sensors.And the highly sensitive detection of two antigens was achieved by designing the carcinoembryonic antigen induced sandwich immune reaction and the prostate specific antigen induced peptide cleavage reaction.(3)The triangular gold nanosheets modified paper chip was used as the sensing platform.And by means of exonuclease ???-assisted analytes cyclic amplification,the sensitive electrochemical detection of manganese super oxide dismutase gene could be achieved.Paper has very good designability and foldability,so knife engraving technology and wax printing technology were used to design different fluid channels on paper to achieve multiple self-cleaning of the working zone,constructing an electrochemical biosensor integrated the processes of cleaning and testing simultaneously.