Development of a microcantilever-based immunosensing method for mycotoxin detection

Mycotoxins, such as aflatoxins and ochratoxin A, are presently considered as the most important chronic dietary risk factor, higher than food additives or pesticide residues. Therefore, the serious health and economic consequences of mycotoxin contamination have created the need for rapid, sensitive, and reliable techniques to detect such dangerous molecules within foodstuffs. We here report on the development of an innovative immunosensing method for mycotoxin detection, based on antibody-immobilized microcantilever resonators, a promising label free biosensing technique. A considerable part of the work is devoted to show the effect on microcantilever resonance frequency of the composition of the incubation buffer, as well as of the washing and drying procedure. We show the feasibility of using microcantilever resonator arrays to effectively identify total aflatoxins and ochratoxin A, at low concentrations (3 ng/mL and less than 6 ng/mL, respectively), with relatively low uncertainty (about 10%) and good reproducibility for the same target concentration. Furthermore, the developed immunosensing method shows limited cross-reactivity to different mycotoxins, paving the way to a highly specific technique, able to identify different mycotoxins in the same complex matrix. To our knowledge, this work represents the first example in literature of successfully immunodetection of low concentrations of multiple mycotoxins by microcantilever resonator arrays.