DNAzyme-based and smartphone-assisted colorimetric biosensor for ultrasensitive and highly selective detection of histamine in meats

Herein, a colorimetric biosensor for histamine detection in meat is first established based on the enhancement of DNAzyme with peroxidase-mimic activity. Histamine can boost the generation of G-quadruplex sequences, and make them more easily bond with hemin to produce many DNAzyme molecules. In addition, histamine increases the affinity of DNAzyme to the substrate 3,3′,5,5′-tetramethylbenzidine (TMB). Therefore, the obtained DNAzyme can catalyze H2O2 and dissolved oxygen to produce many reactive oxygen species (ROS), which cause the TMB molecule to lose two electrons and generate yellow products, exhibiting a clear absorption peak at 450 nm. The colorimetric biosensor has excellent sensitivity, and the detection limit is as low as 38 μg·L−1 for histamine. Moreover, the biosensor has high selectivity and anti-interference ability, and exhibits a good recovery rate in actual meats. The above results show that the strategy has potential for application in the detection of trace histamine in meats.