Study On Novel Optical Biosensing Technology Based On Nanomaterials

Recently, a type of newly emerged functional fluorescent probe, DNA-templated metal nanomaterials, has been widely used for label-free detection of biomarkers due to their outstanding optical properties, low toxicity, facile surface modification and good biocompatibility. In order to solve some prombles existed in the assay of biological enzyme and toxins in food, such as high cost, low sensitivity, and complex operation, three optical detection methods have been developed for selective and sensitive detection of biological enzyme and toxins in food based on the advantages of the DNA-templated nanomaterials and optical biosensor. The main contents are as follows:(1) In chapter 2, a novel label-free fluorescent method for MTase activity assay by coupling double-stranded DNA(dsDNA)-templated copper nanoparticles(CuNPs) with endonuclease-assisted signal transduction system has been developed. This strategy was demonstrated to provide excellent platform to screen the inhibitors for Dam MTase.(2)In chapter 3, based on the inhibition of the synthesis of Poly(thymine)-Templated fluorescent copper nanoparticles(CuNPs) by pyrophosphate(PPi), a novel label free fluorescent strategy for detecting ALP has been developed. This strategy has been demonstrated to exhibit high sensitivity and high selectivity in homogeneous solution with a detection limit of 0.25U/L.( 3) In chapter 4, based on hybrid systems consisting of nucleic-acid-functionalized silver nanoclusters(Ag NCs) and Tungsten disulfide(WS2), another novel fluorescent biosensor for multiplexed toxins analysis has been created. This strategy has been demonstrated to exhibit good selectivity, high sensitive, low cost with a detection limit of 0.5ng/mL and 0.5ng/mL to OTA and AFB1 respectively.