EIS-based biosensor for ultra-sensitive detection of TNF-α from non-diluted human serum.

Serum background is a critical issue for biosensor development as it interferes with the detection of target molecules and may give rise to false positive signal. We present here highly sensitive and selective TNF-α biosensor which is able to detect TNF-α from non-diluted human serum using magnetic bead coupled antibody and electrochemical impedance spectroscopy (EIS) techniques. The process is designed to detect TNF-α from human serum in three stages; (1) abundant protein backgrounds are depleted from the serum using magnetic bead coupled albumin and IgG antibodies, (2) after background depletion TNF-α is captured using magnetic bead coupled TNF-α antibody, and (3) the captured TNF-α is eluted from the magnetic beads and measured using EIS technique in which comb structured gold microelectrodes array (CSGM) is utilized to enhance the detection sensitivity.