Preparation Of Motor-Based Microsensor And Its Application For Biomarker Detection

Immunosensors are miniaturized analytical devices that combine high selective bio-recognition reactions with sensitive and convenient transducers. Compared with other immunoassay techniques, biosensor is cheaper, simpler and more convenient. Immunosensors have been widely used in diagnostics, environmental and food safety monitoring, however, their applications are facing great challenges because most of them require long assay time, multiple washing and separation steps, and diverse signaling reagents. Micro/nanomotors have been gradually applied in many fields such as bioanalysis and drug delivery owing to the advantages of simple preparation, mass production and easy bio-functionalization. This thesis proposes a motor-based autonomous microsensor for in situ visualization immunoassay of cancer biomarker. The research of this work is as following:1. Motor-based Autonomous Microsensor for Motion and Counting Immunoassay of Cancer BiomarkerA motor-based autonomous microsensor is proposed for in situ visualization immunoassay of cancer biomarker through motion readout or tag counting. The microsensor is prepared by functionalizing a newly designed gold nanoparticle-modified self-propelled polyaniline/Pt (AuNP/PANI/Pt) micromotor with capture antibody. The autonomous movement of microsensor in the fuel-enhanced sample mixture results in fast and selective recognition of protein target and subsequently loading of the secondary antibody-modified glycidyl methacrylate microspheres (GMA), which slows down the movement of the sensing microengine. The velocity of microsensor and the number of GMA conjugated on microsensor can be conveniently visualized using optical microscopy. They are negatively and positively correlated with the target concentration, respectively. Therefore, the microsensor can conveniently distinguish the concentration of carcinoembryonic antigen in a range of 1-1000 ng/mL. The motor-based microsensor can easily be prepared in batch using AuNP/PANI/Pt. The whole detection procedure for protein target can be completed in 5 min without any washing and separation step. This method shows considerable promise for diverse clinical and diagnostic applications.