Integrated biosensors for portable on-site detection

Abstract

Over the past a few years, biosensors have been widely used in biomedical detection and environmental monitoring due to their advantages of high sensitivity and good selectivity. However, most biosensor works are still in the “proof-of-concept” phase. There are still great challenges moving from the lab to the field. This thesis work explores the feasibility of transferring the benchtop methods to the practical integrated biosensors for portable on-site detection. In the first work, a new integrated electrochemical magnetoimmunosensor (EC-MIS) based on graphene and gold nanoparticles for interleukin-6 (IL-6) detection is described. An gold nanoparticles/graphene-modified electrode is fabricated to increase the sensitivity. Second, we employ magnetic beads in immunoassay. Combining these two features on a microfluidic device enables a potential portable detection on IL-6. A linear range from 0.97 to 250 pg/mL and a limit of detection (LoD) of 0.412 pg/mL are obtained. The second work is the first integrated and fully portable microbial whole-cell biosensing platform for cadmium and lead detection. Escherichia coli (E. coli) cells are transformed. The optics of the platform are designed to minimize the aberration with good spectral resolution, while the electronics are designed to limit the noise. Experiments show the platform has limit of detection of 518 ppb for Pb²⁺ and 44.8 ppb for Cd²⁺.

Date of Award	2021
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	George Jie YUAN (Supervisor)