Split-Type Electrochemical Immunoassay System Triggering Ascorbic Acid-Mediated Signal Magnification Based on a Controlled-Release Strategy

This research put forward a novel split-type electrochemical (EC) immunosensor which integrated the controlled-release strategy with EC detection for application in the field of biosensing. Concretely, ascorbic acid (AA) was packaged in a cadmium sulfide (CdS)-capped spherical mesoporous bioactive glass (SBG) nanocarrier (SBG(CdS)) on account of encapsulation technology. To reduce the complexity of the bioanalysis, the detection antibody-labeled SBG(CdS)-AA bioconjugate was applied in a 96-well microplate for the immunoreaction process, which is independent of the EC determination procedure. Thus, the immune interference and steric hindrance caused by the accumulation of nanomaterials on the electrode could be minimized. Subsequently, AA was released efficiently via the destruction effect of dithiothreitol on the disulfide bond. In addition, for the asprepared FcAI/L-Cys/gold nanoparticles (GNPs)/porous BiVO4 (pBVO)/ITO EC sensing platform in the detection solution, the synergetic catalysis of Fc and GNPs/p-BVO toward the oxidation of the released AA could be realized, which triggered AA-mediated significant signal magnification throughout this study. In particular, p-BVO with an ordered nanoarray structure could accelerate the electron transfer to assist in sensitivity improvement of this system. This novel biosensor was capable of assaying the neuron-specific enolase (NSE) biomarker sensitively, from which a linear range of 0.001-100 ng/mL was derived along with a low detection limit of 1.08 pg/mL. An innovative way could be paved in the bioanalysis of NSE and other biomarkers.

Automated summary

This study introduced a novel split-type EC immunosensor that integrates a controlled-release strategy with EC detection for sensitive detection of neuron-specific enolase (NSE) biomarker. The sensor utilizes encapsulation technology to package ascorbic acid (AA) in a cadmium sulfide (CdS)-capped spherical mesoporous bioactive glass (SBG) nanocarrier to reduce complexity and minimize immune interference on the electrode. Additionally, efficient release of AA is achieved with the destruction effect of dithiothreitol on the disulfide bond, enabling significant signal magnification for NSE detection.