Magnetic photoactive Fe3O4@Sb2S3 nanospheres assisted homogeneous photoelectrochemical–electrochemical biosensing platform integrating with MOFs-derived bifunctional NPC@Thi nanopolyhedra-mediated dual “signal-on” strategy for protein tyrosine kinase activity

Abnormal protein tyrosine kinase (PTK) expression is associated with various diseases and thus it is of great significance in analysis of PTK activity via a reliable method. Herein, magnetic photoactive Fe3O4@Sb2S3 nanospheres and bifunctional thionine-embedded metal organic frameworks (MOFs)-derived nitrogen-doped porous carbon (NPC@Thi) nanopolyhedra were successfully synthesized for constructing a highly sensitive magnetic-assisted homogeneous photoelectrochemical (PEC)–electrochemical (EC) dual-mode biosensing platform for the detection of PTK (c-Src) activity. The Fe3O4@Sb2S3 nanospheres with good magnetic and photoactive properties assisted adequate biological recognition in a homogeneous system, simplified sample separation and facilitated sensor construction. After c-Src-mediated specific recognition, bifunctional NPC@Thi nanopolyhedra were connected to Fe3O4@Sb2S3 nanospheres. NPC@Thi not only enhanced the photocurrent of Fe3O4@Sb2S3 but also acted as the electrochemical probe. Thus, highly sensitive and reliable dual “signal-on” assay of c-Src activity with wide linear response ranges and low detection limits was achieved by the successful cooperation of PEC (10 fM to 10 nM, 7.2 fM) and EC (5 fM to 10 nM, 3.8 fM) biosensing strategies. The proposed homogeneous PEC–EC dual-mode biosensing platform is prospective to be extended to the analysis of other PTK activity and the discovery of PTK-targeted drug.