A rapid and specific immunosensor for the detection of aflatoxigenic Aspergilli

Abstract

In this research, a rapid immunosensor targeting aflatoxigenic Aspergilli was developed based on impedimetric electrochemical technology, involving the use of polyclonal antibody specific to extracellular antigen produced by Aspergillus parasiticus GIM 3.395. This sensor was fabricated by immobilization of antibody on gold nanoparticle/l-cysteine-coated electrode. All results showed that the immunosensor exhibited high sensitivity with a detection limit of 18 colony-forming unit (cfu/mL) (S/N = 3) and required simple sample treatment free of the pre-enrichment step. Moreover, the whole detection time was only 30 min and more rapid as compared to conventional culture-based techniques or PCR methods. Other 16 strains of Aspergilli were also used to determine the immunosensor specificity, and the results showed that the immunosensor had high specificity. The immunosensor exhibited a long-term stability, and high reproducibility of the signal could be obtained up to 100 times with an R.S.D. of 2.5 %. To assess the applicability of the immunosensor for pathogen detection in food process, soybean paste of naturally fermentation with koji-making process was analyzed. The average recovery rate was ranged from 81.5 to 113.5 %. It was shown that the immunosensor provided a fast, sensitive and specific detection of aflatoxigenic Aspergilli and could potentially be used as a real-time and early diagnosis tool for aflatoxin B1 in foods.