Microfluidic based electrochemical detection of Fumonisin-B1 using silver-ceria nanocomposite

Abstract

Contamination of food by toxins and biological organisms like bacteria or virus is a major issue in food industry.[1] Food may be contaminated due to different reasons. It may be due to using chemicals like preservatives and pesticides or due to mycotoxins which are secreted by various fungal species. From these, the mycotoxins which are produced naturally are more dangers as we cannot restrict their secretion. The presence of any mycotoxin during production of food, packaging and shipment can readily contaminate the food.[2] This is a serious matter which should be taken care due to presence of very less amount of device for their detection. From different types of mycotoxins fumonisin, aflatoxin, and ochratoxin are considerable causes for food contamination globally.[3] Fumonisin is a secondary metabolite which is secreted by Fusarium proliferatum and Fusarium moniliform. Fumonisin is usually found mycotoxin in food products like rice, maize, corn, cowpeas, wheat, and bear. This induces contagious diseases, like immunosuppression, hydrothorax, pulmonary edema, and leukoencephalomalacia.[4] Mycotoxin contamination can induce serious infection to lungs, kidney, brain, and liver in humans and also in other animals.[5] Many international agencies have announced them as possible carcinogen. Primarily fumonisin have three subtypes fumonisin B1 (FU-B1), FU-B2, and FU-B3. From all subtypes, HU-B1 have 15 sub-structures and also found more abundantly (>70%). The current techniques for detection of FU-B1 are gas chromatography, high-performance liquid chromatography, etc. These techniques possess a limitation of incapability of point of care (POC) detection.[6] Also these techniques depend upon costly equipment, machines, trained manpower, and are non-portable with long processing time. So, for rapid, reliable, and cost-friendly mycotoxins detection, there is a requirement of a machine which can be operated immediately.[7] Microfluidics is a device which can be used for same purpose which fabricate a device and have more advantages beyond conventional methods. It contributes to quick response time, feasibility, less amount of antibiotics and antigen requirement, easy setup, less burden, and less knowledge for operation.[8]

From different nanomaterials, cerium oxide (CeO₂) is well known for its electrochemical properties.[9] In the current work, a novel electrochemical biosensor was developed which was fabricated by using maskless lithography by using Ag-CeO₂nc for FU-B1 detection. The response study was done by using DPV technique contrary to rising FU-B1 concentration.[10] the current value increases with increasing concentration of FU-B1 shown in Figure(a). Enlarged view of peak current is shown in Figure(b). Plot of FU-B1 concentration vs. peak current is shown in Figure1(c). Linear response of 10 pg ml^-1 to 100 ng ml^-1 was achieved. The sensitivity was calculated using the slope which is obtained from linear response and the electrochemical microfluidic nanobiochip show great sensitivity at 7.33 µA [log (ng mL^-1)]^-1cm^-2. Figure 2(a) shows interference studies which show specificity of electrochemical microfluidic biosensing platform for the detection of FU-B1. Spiked corn samples were used for checking real food samples which shows a recovery rate of 85% with magnificent linear response, which confirm its of detection in real samples.