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.