A portable thermal detection method based on the target responsive hydrogel mediated self-heating of a warming pad.

A simple thermal aptasensing platform was devised for the sensitive detection of organophosphate pesticides (using malathion as a model target) based on the efficient self-heating reaction of a warming pad with a switchable target responsive enzyme-encapsulated three-dimensional (3D) DNA hydrogel using a portable thermometer as a signal readout in this work. The existence of the target malathion would open the catalase-3D network and lots of catalase was released from the hydrogel, which could efficiently convert H2O2 to an O2 molecule. The product O2 is the critical condition for the self-heating of the warming pad. Thereafter, the temperature was enhanced with the increasing amount of O2. The strategy displays outstanding specificity, reproducibility and stability. Moreover, this method can be easily extended to monitor other molecules using different aptamer sequences in practical applications.