A High-Sensitivity CMOS-Compatible Biosensing System Based on Absorption Photometry

An optical biosensing system based on a standard CMOS technology and absorption photometry is proposed. Within the compact prototype, a CMOS sensor consisting a P⁺/N_well finger photodiode and a transimpedance amplifier was implemented in a standard 0.35-mu m CMOS technology. The ABTS/H₂O₂/HRP method was adopted to be coupled with various analytes of interest, such as glucose and histamine, which can serve as the basis for medical diagnosis. The experimental results demonstrate that the minimum concentrations successfully detected for H₂O₂ , glucose, and histamine are 1 muM, 1 muM, and 10 muM, respectively. The detection limits are at least one order of magnitude better than those of reported CMOS biosensors, and are even comparable to those of a commercial spectrophotometer.