TiO2 Nanolayer-Enhanced Fluorescence for Simultaneous Multiplex Mycotoxin Detection by Aptamer Microarrays on a Porous Silicon Surface

A new aptamer microarray method on the TiO2-porous silicon (PSi) surface was developed to simultaneously screen multiplex mycotoxins. The TiO2 nanolayer on the surface of PSi can enhance the fluorescence intensity 14 times than that of the thermally oxidized PSi. The aptamer fluorescence signal recovery principle was performed on the TiO2-PSi surface by hybridization duplex strand DNA from the mycotoxin aptamer and antiaptamer, respectively, labeled with fluorescence dye and quencher. The aptamer microarray can simultaneously screen for multiplex mycotoxins with a dynamic linear detection range of 0.1-10 ng/mL for ochratoxin A (OTA), 0.01-10 ng/mL for aflatoxins B-1 (AFB(1)), and 0.001-10 ng/mL for fumonisin B-1 (FB1) and limits of detection of 15.4, 1.48, and 0.21 pg/mL for OTA, AFB(1), and FB1, respectively. The newly developed method shows good specificity and recovery rates. This method can provide a simple, sensitive, and cost-efficient platform for simultaneous screening of multiplex mycotoxins and can be easily expanded to the other aptamer-based protocol.