Development And Application Of Gold Nanoparticles Based Novel POCT Sensors

Objective: To prepare a new type of low cost POCT（testing point-of-care） biosensor, and applying the technology to detect a variety of targets.Method:We applied the fluorescence quenching techniques and the characteristics of Hg²⁺ can selectively bind between two DNA thymine（T） bases and form stable T-Hg²⁺-T base pairs to lateral flow strip, to prepare an aptamer-based fluorescence-quenching lateral flow strip（AFQ-LFS） for Hg²⁺ detection, and the producing and testing process conditions were optimized; Pt@Au NPs are able to efficiently catalyze the reaction of H2O2 to generate oxygen gas, thus pushing liquid droplets in the capillary forward, based on this feature, a Pt@Au NPs Integrated Visually Quantitative Capillary-Based Biosensor（PI-VQCB） device is designed and fabricated, then, the fabrication methods of the sensor are optimized, and the feasibility and stability of the sensor are demonstrated, with the corresponding antigen-antibody or aptamer, PSA and CEA were detected combined with double-antibody sandwich assay method, Ractopamine（Rac） was detected using competition law, Thrombin was detected using double-aptamer sandwich assay, and the testing processes were optimized, respectively.Results: An AFQ-LFS for Hg²⁺ detection in water was established, the fluorescence signal intensity of this AFQ-LFS was positively related to the concentration of Hg²⁺, and its sensitivity was about 20 times as much as that of the traditional colloidal gold test strip, and it can be applied to the detection of the river water; A PI-VQCB device was successfully accomplished, and the detection for PSA, CEA, Rac and Thrombin is realized, the lowest detection limit（LOD） were 0.014 ng/m L, 0.44 ng/m L, 0.0556 ng/m L and 0.0247 ng/m L, respectively. With a variety of targets detection, they demonstrated the novel PI-VQCB has good applicability. It has great significant application in the field of clinical diagnosis and screening, personalized medicine, environmental monitoring, food safety inspection, and so.