Nanozyme-based dual-signal sensing system for colorimetric and photothermal detection of AChE activity in the blood of liver-injured mice.

Acetylcholinesterase (AChE), a crucial enzyme related to liver function, is involved in numerous physiological processes such as neurotransmission and muscular contraction. The currently reported techniques for detecting AChE mainly rely on a single signal output, limiting their high-accuracy quantification. The few reported dual-signal assays are challenging to implement in dual-signal point-of-care testing (POCT) because of the need for large instruments, costly modifications, and trained operators. Herein, we report a colorimetric and photothermal dual-signal POCT sensing platform based on CeO2-TMB (3,3',5,5'-tetramethylbenzidine) for the visualization of AChE activity in liver-injured mice. The method compensates for the false positives of a single signal and realizes the rapid, low-cost portable detection of AChE. More importantly, the CeO2-TMB sensing platform enables the diagnosis of liver injury and provides an effective tool for studying liver disease in basic medicine and clinical applications. Rapid colorimetric and photothermal biosensor for sensitive detection of acetylcholinesterase (I) and acetylcholinesterase levels in mouse serum (II).

Dual-signal output paper sensor based on coordinative self-assembly biomimetic nanozyme for point-of-care detection of biomarker.

Paper-based point-of-care (POC) devices exhibit the advantages of simplicity, rapidity, trim sizes, and low cost, which are of particular importance for food safety, biological analysis, and medical diagnosis. However, the materials utilized to make paper-based POC rarely produce multiple signals, hampering further applications in diverse situations. Herein, we present an appealing approach, namely Colorimetric-Temperature Dual-Signal Output Sensor (CTDSS), and construct a CTDSS based on coordinative self-assembly biomimetic nanozymes Fe-GMP-L-His CPNs as a proof of concept. These CPNs mimic the structure of horseradish peroxidase (HRP), in which Fe (II) is the center, nucleotide GMP and histidine are chosen as ligands to simulate metal coordination of the pyrrole ring and protein function in HRP, respectively. This strategy allows CPNs to show an excellent peroxidase-like activity, efficiently converting H2O2 into •OH and oxidizing TMB to generate colorimetric-temperature dual-signal. As a proof-of-concept application, we exploited cholesterol as the target and successfully applied this CTDSS to detect cholesterol, displaying extraordinary features of rapidity, dramatic specificity, and high sensitivity. By utilizing the colorimetric test strip and temperature discoloration sticker, the paper-based POC tools were constructed to visualize the target. Meanwhile, two proposed test strip POC devices generating different signal outputs exhibited remarkable feasibility and were further employed to detect cholesterol in human serum. We anticipate that this CTDSS platform will inspire innovative concepts for future portable detection tools.