Smartphone-Controlled Portable Photoelectrochemical Biosensor Exploiting Chirality-Resolved Ratiometric Sensing Strategy: A Proof of Concept

Integrating ratiometric photoelectrochemical (PEC) strategy with a smartphone-based portable biosensor to build a bioanalysis device is usually subject to large-volume space-resolved facilities and is picky about the polarity or excitation wavelength of the photoactive materials. Herein, a chirality-resolved ratiometric portable PEC biosensor on a platform rich in crystalline-amorphous interfaces addresses this issue. Concretely, the crystalline Bi₂WO₆ bulk phase/amorphous BiOBr surfaces with Bi₂S₃ nanoparticles attached (a-BWO-s) platform and the paired photoactive markers with specific chirality Fe₃O₄@Ag-l-(and d-)histidine are integrated on the portable biosensor. Since the crystalline-amorphous interfaces of a-BWO-s exhibit considerable photocurrent signals. In the meantime, with the increase of targeted analytes' NSE concentration, the PEC performance of the markers shows an opposite trend in different chiral electron donors. So that double photocurrent signals can be output to realize the ratiometric sensing strategy, which furnishes an innovative universal strategy for bioanalysis. Unlike the other typical ratiometric PEC sensing strategies, this research proposes the first ratiometric PEC biosensor based on diverse chiral chemical environments. Generally speaking, this paper provides direction for the design of a chirality-resolved ratiometric sensing strategy and brings a unique new perspective to explore in practical analysis.