Detection of C-reactive protein using BioFET and extended gate

A novel immunoassay based on a potentiometric measurement for C-reactive protein (CRP) has been developed using a BioFET and an extended gate. Both the BioFET and the extended gate were fabricated using CMOS process techniques. I-d-V-d (drain voltage versus drain current) characteristics of the BioFET only and the BioFET with the extended gate were measured in PBS (phosphate buffered saline), after SAM (self-assembled monolayer) formation, after anti-CRP immobilization and after CRP antigen-antibody interaction. The relation between a current variation ratio and CRP concentration (3-10 mu g/ml) was studied. Also, we observed the potential variation with increasing the area of the extended gate. The results show the feasibility of the BioFET and its integration with the extended gate for the detection of CRR In addition, it is expected that this sensing configuration could be used as a part of lab-on-a-chip for the detection of various other biomarkers.