A disposable MEMS biosensor for aflatoxin M1 molecule detection

Abstract

In this work, a paper-based perforated disposable biosensing device is proposed as an alternative method for aflatoxin M1 molecule detection. The demonstrated system is designed to achieve a quick and novel biosensing operation with low-cost materials using competitive assay method. For that purpose, the main fabrication material has opted as a 190 μm thick filter paper. 50 μm thick piezoresistive graphite paste is coated onto both sides of the paper-based cantilever beam with the aim of acquiring more sensitive magnetic nanoparticle weight sensing capability. Additionally, the structure has arrays of closely spaced perforations to augmented effective Young’s modulus of the cantilever beam and further increase the system’s sensitivity. An electrocoil positioned 1 mm below the sensor tip to apply an Hext and magnetically increase weight of the aflatoxin M1 with bovine serum albumin compound. An electronic read-out circuitry is implemented and integrated into the system. Average values of sensitivity and limit of detection (LoD) for each detection approach were calculated without blank subtraction and are shown with the standard error of the mean (SEM). LoD is calculated as 4.63 μg AFM1 which corresponds to 0.20127 V/V after subtracting standard deviation from the average value. It is experimentally demonstrated that the proposed system can detect a minimum of 14 μg of AFM1 molecules (0.14155 V/V). We magnetically amplified this tiny fragment of targeted molecules approximately 2731 times to 38.237 mg and made it detectable even with a disposable system. The sensitivity of the proposed system is 45.953 μV/mg. Finally, the maximum detectable AFM1 weight is reported as 71 μg.