Nano-gold mediated aptasensor for colorimetric monitoring of acrylamide: Smartphone readout strategy for on-site food control.

A simple aptasensor is embedded in the internal surface of a micropipette tip as the aptasensor substrate for the label-free monitoring of acrylamide. The aptasensor is based on the formation of the triple-helix molecular switch (THMS) structure of the DNA strands that induces the salt-enforced aggregation of gold nanoparticles (AuNPs). A smartphone imaging readout-based strategy is applied to quantify acrylamide. The developed aptasensor is novel for the naked-eye monitoring of the target through the color change of the solution inside the micropipette tip. The colorimetric aptasensor detects acrylamide in the concentration range of 0.05-200 nmol L and at the trace level of 0.038 nmol L with the comparable selectivity. The aptasensor can successfully quantify acrylamide in the chips, coffee, and bread samples with recoveries range from 92 to 102 %. The designed aptasensor paves an efficient device for the portable, on-site, facile, and real-time target sensing, superior for food safety control.