Phosphoprotein Detection in Sweat Realized by Intercalation Structure 2D@3D g-C3N4@Fe3O4 Wearable Sensitive Motif

Abnormal protein phosphorylation in sweat metabolites is closely related to cancer, cardiovascular disease, and other diseases. The real-time monitoring of phosphoproteins in sweat is significant for early monitoring of disease biomarkers. Here, a high-efficiency electrochemical sensor for phosphoprotein in sweat was realized by 2D@3D g-C3N4@Fe3O4 with intercalation structure. Common phosphoprotein beta-Casein was selected to demonstrate the platform's functionalities. The detection limit of beta-C3N4@Fe3O4 could be as low as 9.7 mu M, and the detection range was from 0.01 mg/mL to 1 mg/mL. In addition, the sensing platform showed good selectivity, reproducibility, and stability. We also investigated the effects of interface structure on adsorption properties and electronic properties of the g-C3N4 and Fe3O4 heterostructure using DFT. More electrons from Fe3O4 were transferred to g-C3N4, which increased the electrons in the energy band of N atoms and promoted the formation of stable N-H bonds with H atoms in phosphoproteins. We demonstrated phosphoprotein sensor functionality by measuring the phosphoprotein in human sweat during exercising. This work realizes a sensing platform for noninvasive and continuous detection of sweat phosphoproteins in wearable devices.

Automated summary

This paper presents a highly efficient electrochemical sensor for detecting phosphoproteins in sweat using a 2D@3D g-C3N4@Fe3O4 intercalation structure. The sensor shows low detection limit, good selectivity, reproducibility, and stability. The effects of the interface structure on the sensor performance were also investigated using density functional theory. The sensor functionality was demonstrated by measuring phosphoproteins in human sweat during exercise.