Microfluidic immunosensor based on mesoporous silica platform and CMK-3/poly-acrylamide-co-methacrylate of dihydrolipoic acid modified gold electrode for cancer biomarker detection

- A microfluidic immunosensor has been developed for epidermal growth factor receptor (EGFR) in human serum samples.
- In this immunoassay, the anti-EGFR antibodies are immobilized on a surface area amino mesoporous silica as platform.
- The gold electrodes are coated with CMK-3/poly-acrylamide-co-methacrylate of dihydrolipoic acid nanocomposite.
- The sensor's linear range is from 0.01 to 50 ng mL−1 with a single day RSD of 4.98%.

We report a hybrid glass-poly (dimethylsiloxane) microfluidic immunosensor for epidermal growth factor receptor (EGFR) determination, based on the covalent immobilization of anti-EGFR antibody (anti-EGFR) on amino-functionalized mesoporous silica (AMS) retained in the central channel of a microfluidic device. The synthetized AMS was characterized by N2 adsorption-desorption isotherm, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and infrared spectroscopy. The cancer biomarker was quantified in human serum samples by a direct sandwich immunoassay measuring through a horseradish peroxidase-conjugated anti-EGFR. The enzymatic product was detected at −100 mV by amperometry on a sputtering gold electrode, modified with an ordered mesoporous carbon (CMK-3) in a matrix of poly-acrylamide-co-methacrylate of dihydrolipoic acid (poly(AC-co-MDHLA)) through in situ copolymerization. CMK-3/poly(AC-co-MDHLA)/gold was characterized by cyclic voltammetry, EDS and SEM. The measured current was directly proportional to the level of EGFR in human serum samples. The linear range was from 0.01 ng mL−1 to 50 ng mL−1. The detection limit was 3.03 pg mL−1, and the within- and between-assay coefficients of variation were below 5.20%. The microfluidic immunosensor is a very promising device for the diagnosis of several kinds of epithelial origin carcinomas.

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