Novel colorimetric aptasensor based on unmodified gold nanoparticle and ssDNA for rapid and sensitive detection of T-2 toxin

A novel colorimetric aptasensor based on unmodified gold nanoparticle (AuNPs) and single-strand DNA (ssDNA) aptamer was developed for the rapid and sensitive detection of T-2 toxin. In the absence of T-2, the AuNPs were wrapped by the aptamer to avoid the salt-induced aggregation and the solution remains red. In the presence of T-2, the aptamer was bound with T-2 and released from the surface of AuNPs, resulting in the aggregation of AuNPs under proper salt solution and the color change from red to purple-blue. The aptasensor exhibited a high sensitivity and selectivity for the detection of T-2. The range of linearity and detection limit were 0.1 ng/mL-5000 ng/mL (0.21435 nM-10717.5 nM) and 57.8 pg/mL (0.124 nM), respectively. The aptasensor developed here was applicable to assay T-2 in wheat and corn samples. These results implied that the colorimetric aptasensor was potentially useful in food detection.