Microfluidic amperometric immunosensor based on porous nanomaterial towards claudin7 determination for colorectal cancer diagnosis

In this work, we present a microfluidic amperometric immunosensor for cancer biomarker claudin7 (CLD7) determination in circulating extracellular vesicles (EVs) as well as its validation in colorectal cancer (CC) paotients. The device is based on synthetized nanosized MIL-125-NH2 particles, covalently anchored to the central channel of the microfluidic immunosensor. This nanomaterial was employed as efficient platform for anti-CLD7 monoclonal antibodies immobilization for specifically recognize and capture CLD7 in EVs samples. Afterwards, the amount of this trapped CLD7 was quantified by HRP-conjugated anti-CLD7-antibody. HRP reacted with its enzymatic substrate in a redox process which resulted in the appearance of a current whose magnitude was directly proportional to the level of CLD7 in the sample. This immunosensor, under optimum conditions, gave the limit of detection for CLD7 of 0.1 pg mL(-1), with a wide linear range from 2 to 1000 pg mL(-1). The results reported herein open up the use of porous open framework platforms for sensing applications for biomedicine and diagnosis.