Colorimetric nanozyme sensor array for the pattern recognition of monoamine neurotransmitters using dendritic mesoporous silica embedded with metal nanoparticles

There is a pressing demand for developing effective methods for the detection of monoamine neurotransmitters because of their similar structures, low concentrations, and easy oxidation properties. Herein, a colorimetric nanozyme sensor array was developed and fabricated for the pattern recognition of six monoamine neurotransmitters in biological samples. To this aim, three metal nanoparticles were grown in situ within dendritic mesoporous silica spheres, and they acted as nanozymes to catalyze the reaction of 3, 3′,5,5′-tetramethylbenzidine dihydrochloride (TMB) and H2O2. The catalytic efficiencies of the nanozymes were inhibited to varying degrees in the presence of different monoamine neurotransmitters, which resulted in various color change patterns of the catalytic reaction. These color change patterns provided a fingerprint response for the monoamine neurotransmitters, which could be accurately discriminated using linear discriminant analysis. Also, the proposed sensor array could successfully discriminate between monoamine neurotransmitters as low as 800 nM, and quantification of the monoamine neurotransmitters at different concentration ratios was realized. Moreover, the detection limits of the sensor array for the monoamine neurotransmitters were calculated by the total Euclidean distances, and they ranged from 0.03 to 0.38 μM. Overall, the proposed colorimetric nanozyme sensor array showed great potential in practical application by discriminating between different concentrations of monoamine neurotransmitters in human serum.