C-reactive protein detection based on ISFET structure with gate dielectric SiO2-CeO2

Abstract

This paper considers a new biosensor based on p-channel ion sensitive field effect transistors (ISFET) as a sensitive platform for low concentration detection of C-reactive protein (CRP). The ISFET structure is fabricated by a standard CMOS technology on a phosphorus-doped Si (111) wafer with ρ = 4.5 Ω.cm. A complex layer of gate dielectric SiO2-CeO2 (dSiO2 = 50 nm, dCeO2 = 10 nm) is chosen since such layers have previously proven their suitability and are technologically simple to manufacture. To improve the antigen binding to the sensitive surface, streptavidin and biotin with and without melanin agents are immobilized on the gate dielectric. Optical microscopy, SEM and AFM results showed that the immobilized streptavidin and biotin agents form porous dendrite structure. The limit of CRP detection is 0.1 mg/L, the range of measuring CRP concentrations is 0.1–2.5 mg/L, the measurement time is about 1 min, and the required amount of solution for analysis - 20 μL. The application of the sensor was evaluated using real samples of human blood serum.