Fabrication and nano-engineering of non-/noble metal-coupled plasmonic heterostructures for ultrasensitive photoelectrochemical immunoassays

To achieve reliable and ultrasensitive detection for disease markers in PEC bioanalysis, constructing and nanoengineering of ideal photoelectrodes and signal transduction strategies are of vital importance. Herein, a non-/ noble metal coupled plasmonic nanostructure (TiO2/r-STO/Au) was tactically designed with high-efficient PEC performance. Evidenced by the DFT and FDTD calculations, the reduced SrTiO3 (r-STO) was found to support the localized surface plasmon resonance due to the sufficiently increased and delocalized local charge in r-STO. Under the synergistic coupling of plasmonic r-STO and AuNPs, the PEC performance of TiO2/r-STO/Au was found remarkably promoted with reduced onset potential. This merit supported TiO2/r-STO/Au as a selfpowered immunoassay via a proposed oxygen-evolution-reaction mediated signal transduction strategy. With the increase of the target biomolecules (PSA), the catalytic active sites of TiO2/r-STO/Au would be blocked and result in the decrease of the oxygen evaluation reaction. Under optimal conditions, the immunoassays exhibited an excellent detection performance with a LOD as low as 1.1 fg/mL. This work proposed a new type of plasmonic nanomaterial for ultrasensitive PEC bioanalysis.

Automated summary

In order to achieve reliable and ultrasensitive detection for disease markers in PEC bioanalysis, constructing and nanoengineering of ideal photoelectrodes and signal transduction strategies are of vital importance. This study tactically designed a non-/ noble metal coupled plasmonic nanostructure (TiO2/r-STO/Au) with high-efficient PEC performance. The research proposed a new type of plasmonic nanomaterial for ultrasensitive PEC bioanalysis, showing excellent detection performance with a LOD as low as 1.1 fg/mL.