Ultrasensitive Detection of Aflatoxin B1 Using a Polyimide-Based Piezoresistive Microcantilever Biosensor

In this work, we propose an ultrasensitive detection of aflatoxin B1 using a piezoresistive microcantilever biosensor, which is composed of doped piezoresistive layer, top polyimide (PI) passive layer and bottom silicon oxide (SiO
₂
) passive layer. Four microcantilevers with the same dimensions consist of a wheatstone bridge to achieve a higher sensitivity and better noise performance. The fabricated PI/Si/SiO
₂
microcantilever shows a steady output with less than 1 μV@3V fluctuation in PBS buffer, while the spring constant is 21.307 nN/μm and the deflection sensitivity is 3.54×10
^-7
nm
^-1
. Detections on aflatoxin B1 with a minimum concentration of 1 ng/mL were achieved.