Label-free electrochemical immunosensor for detection of oncomarker CA125 in serum

This paper reports the construction of a new electrochemical immunosensor for detection of oncomarker CA125 for diagnosis and monitoring of ovarian cancer. The platform was developed using screen-printed carbon electrodes modified with poly(3-hydroxyphenylacetic acid) and anti-CA125 as probe for evaluate the biomolecular interactions (anti-CA125:CA125) onto the solid surface. Current response of the system has a linear relationship of anti-CA125 concentration in the range of 5 to 80 U mL(-1) with a limit of detection of 1.45 U mL(-1), discriminating between negative and positive serum. The immunosensor was successfully applied to determination of CA-125 in real biological samples using differential pulse voltammetry (DPV), surface plasmon resonance (SPR) and atomic force microscopy (AFM). The results showed the developed immunosensor is versatile, easily integrated to the point of care applications, being an interesting platform to ovarian cancer diagnose in complex samples.