Self-Assembly Method of Glucose Oxidase in a Fully Packaged Microfluidic Glucose Biosensor

Abstract

Abstract In this work, a self-assembly approach is proposed to bio-functionalize the fully microfluidic biosensors for catalyzing glucose based on the designed and fabricated microfluidic chip with suspending structure by micro-electro-mechanical system technology. Glucose oxidase is successfully immobilized on the surface of microelectrodes to build composite layers by the proposed self-assembly approach, with cysteamine applied as a functional linker. The biological activity and stability of glucose oxidase is optimized by the electrodeposition of chitosan membrane. Experiments results suggest that the fully packaged microfluidic biosensor integrated with self-assembled glucose oxidase can effectively detect the existence of glucose in sample solution. The detection range of glucose concentration is 0 ~ 10 mM. With SNR of 3, the detection limit is 51.2 µM and sensitivity is 23.47 ± 1.36 µA·cm− 2·mM− 1 within low concentration range of 0 ~ 0.1 mM, while the detection limit is 497 µM and the sensitivity is 10.63 ± 1.28 µA·cm− 2·mM− 1 among high concentration range of 0.1 ~ 10 mM. The proposed study provides a straightforward method to construct a microfluidic biosensor, which is promising in miniaturized clinical medical device.