Self-Powered PEC/EC Dual-Mode Sensing for Sensitive TNF-α Detection Based on Multifunctional Mesoporous Silica Nanospheres

Abstract

As a multifunctional cytokine, tumor necrosis factor-alpha (TNF-α) participates in the development of inflammationassociated carcinogenesis. Since TNF-α is overexpressed in patients with early-stage tumors, sensitive detection method is essential for disease diagnosis. In this wok, a self-powered platform for the photoelectrochemical-electrochemical (PEC-EC) detection of TNF-α has been constructed. This platform was comprised of a MgIn₂S₄@In₂O₃ photoanode and Cl/PPECu photocathode. MnO2-coated mesoporous silica@ferrocene (MFMSN) was used as the bifunctional material for PEC-EC dualmode detection. In the presence of TNF-α, MFMSN served as the photocathode quenching source to change the photocurrent through steric hindrance and consumption of ascorbic acid (AA). In the meantime, the ferrocene (Fc) was released from MFMSN during the dissociation of MnO2 and catalyzed with oxidation of AA for current response amplification. This principle enabled the achievement of high-sensitivity dual-mode determination for TNF-α. As a result, the self-powered platform achieved detection limits of 0.140 fg/mL and 2.65 fg/mL in PEC and EC modes respectively, with a detection range of 5.00 fg/mL-5.00 ng/mL (PEC) and 10.0 fg/mL-10.0 ng/mL (EC). In addition, this biosensors was also applied to quantify TNF-α in human serum with acceptable results. This dual-mode analysis strategy provided a highly reliable and accurate detection of TNF-α.