Using the newly microfluidic biosensor for carcinoembryonic antigen detection

A newly microfluidic biosensor was successfully utilized the microchannel, the sandwich immunoassay model, and a parallel electrode to detect the electrical signal of various carcinoembryonic antigen (CEA) concentrations. A microfluidic biosensor was based on AuNPs by using the specific binding of antibody to reduce the impedance measurement. The impedance variation can be easily detected with a LCR meter, and we observed an obvious and stable difference in impedance signals at 8 min. Moreover, a better linearity for impedance and CEA concentration in the frequency effect (100 to 1 MHz) was observed at 100 Hz. Finally, the detectable limit for CEA concentration was 0.1 ng/mL with 1 μg/mL of anti-CEA antibody and the 50X of the anti-CEA antibody-colloidal gold conjugates. Therefore, the developed microfluidic biosensor has advantages including smaller sample volume (10 μL, while the commercial product is 100 μL) and a rapidly quantitative measurement, and works with smaller detectable concentration (0.1 ng/mL) than other existing commercial products whose best limit of detection is 5 ng/mL.