Research On SPR Sensor For Detection Of Low-Molecular-Weight Analytes

Surface Plasmon Resonance（SPR） technology has been widely used in many ifeldssuch as environmental monitoirng, drug screeningjife sciences, food safety andoptical passive devices. Sensors based on SPR technology have the advantages oflabel-free, real-time detection, high sensitivity, without purification of samples andstrong anti-interference ability. But it is dififcult that direct detection with highsensitivity for low-molecular-weight analytes for the traditional SPR sensor. But atpresent on food safety, water quality analysis and many other ifelds，fast and effectivedetection for low-molecular-weight analytes is a problem to be solved. In order toimprove the detection sensitivity of SPR sensor for low-molecular-weight analytes，poly（sodium4.styrenesulfonate）（PSS） and poly allylaminehydrochloride（PAH）polyelectrolyte multilayer thin-films and （DNA/TiO]） n nanoporous thin-films weredeposited on the surface of gold layer covered glass substrate using layer-by-layerself-assembly technique.In addition.to construct TiO₂nanowire arrays of opticalsensor, the preparation of the sensor is very simple and the sensitivity of detection forlow-molecular-weight analytes is high.The innovation of this paper is summarized as follows:1. Polyelectrolyte multilayer thin-films were deposited on the gold surface by usingPSS and PAH self-assembly, the effect of multilayer polyelectrolyte thin-film on SPRsensor was researched with controllable thickness and morphology of thepolyelectrolyte thin-films. The detection sensitivity of SPR for low-molecular-weightanalytes is higher than before assembly in the best assembly layer. At the same timethe sensing layer produced in the optimum thickness of specific adsorption detection.2‘Fabricating （DNA/TiO₂） n nanoporous thin-iflm leaky-mode waveguide resonancesensor by self-assembling （DNA/TiO₂） n on the gold surface. By using self-assemblytechnique on the metal surface self-assemble （DNA/TiO₂） n nanoporous thin-film,morphology and thickness of the thin-iflm is adjustable.This high sensitivity resultsfrom absorption of a large amount of low-molecular-weight analytes molecules in the nanoporous waveguiding layer by using large surface area of （DNA/TiO₂） nnanoporous thin-iflm.3. Constructing optical sensor using TiO： nanowire arrays. TiO： nanowire arrays wereprepared using the heat flux synthesis method in fluorine doped tin oxide （FTO）surface, nanowire array shape is adjustable. TiO： nanowires array sensor canresponse to TM and TE polarized incident light. The sensitivity of sensor higher onTE polarized incident light. Presents two optimal schemes, in order to improve thesensitivity of the sensor:1.Change the morphology of TiO： nanowires array：2.Fabricate the sensing layer on surface of TiO₂nanowire arrays to specific adsorption.DNA sensing layer was prepared through the system, to detect the AcridineOrange（AO） solution, the sensitivity of the sensor is greatly improved. TiOananowires array optical sensor for low-molecular-weight Analytes detection withhigh sensitivity, simple preparation, chemical tailoirng is good and has a goodapplication prospect.