An analytical and experimental biosensor for human MIG using AlGaN/GaN based HEMT devices.

摘要

An amperometric biosensor using AlGaN/GaN based HEMT devices is constructed experimentally and validated through analytical and numerical techniques for detection of a key protein in allograft rejection (Human MIG/CXCL9). The prototype developed provides a reliable sensing platform that will allow label-free and marker-free detection. By exploiting characteristics unique to AlGaN/GaN based HEMT devices, a floating gate configuration is employed to allow reliable sensing without the need for any reference electrode. This ensures that any response in drain current will be attributed to the bio-conugation of the target antibody with its appropriate analyte. Self-assembled monolayers (SAM) are formed at the gate surface by using a crosslinker (DSP) to allow for appropriate immobilization of target antibodies. A theoretical analytical and numerical model is developed using the Charge-control and net neutrality equations to explain the mechanism of action of the proposed biosensor. Furthermore, other issues such as repeatability, influence of the substrate, threshold shifting, and device packaging are addressed. Finally, an experimental circuit is constructed with the previously prepared biosensor to validate the claims made in this thesis.