Sensitive photoelectrochemical biosensors based on AuNPs/MXenes electrode coupled with light-harvesting UiO-66-NH2 probes for protein kinase detection

Abstract

Sensitive detection of protein kinase activity is critical for the relevant disease diagnosis and drug discovery. Here, a label-free photoelectrochemical (PEC) biosensor was developed for protein kinase activity detection and its inhibitor screening. Kemptide was immobilized on gold nanoparticles (Au NPs)-decorated Ti3C2 MXenes (Au NPs/MXenes). After catalyzed by protein kinase A (PKA), the UiO-66-NH2 probes were modified on the phosphorylated kemptide due to the interaction between the phosphate groups and Zr4+ in UiO-66-NH2. Following irradiation by visible light, photogenerated electrons from the UiO-66-NH2 framework structure were promptly transferred to the Au NPs/MXenes, ultimately generating photocurrent for detection of PKA. The photocurrent signal was amplified for three reasons. Firstly, Au NPs/MXenes acted as a highly efficient biocompatible immobilization matrix for kemptide. Secondly, large photocurrent was produced by the light-harvesting UiO-66-NH2 probes. Thirdly, Au NPs/MXenes served as electron transfer bridges, accelerating the transfer of electrons from the UiO-66-NH2 structure to the electrode surface and preventing the electron-hole recombination. Therefore, the PEC biosensor exhibited high sensitivity toward the PKA with a low detection limit of 0.0026 U/mL. Furthermore, the assay was utilized to screen inhibitors successfully, indicating its promising potential in other protein kinase detection and clinical diagnosis.

Keywords

• UiO-66-NH2
• Au NPs/MXenes
• Protein kinase
• Photoelectrochemical biosensor
• Label free