Differential Multiplexed Signalling Strategy Enables Ultrasensitive Photoelectrochemical DNA Detection Via Direct Electron Transfer between Plasmonic and Semiconductive Nanoparticles

摘要

Introduction: Biosensors are devices that are capable of capturing biologically-relevant targets and transducing this detection event into a measurable signal. There is a growing need for the development of high-quality, efficient, ultrasensitive biosensors for disease diagnosis. The dawn of advancements in synthetic biology has given rise to the incorporation of dynamic biorecognition agents that are capable of reconfiguring their conformation in response to the presence of target analytes and their environments. These DNA constructs, such as switchable aptamers, DNA tile lattices and DNAzymes, are increasingly lucrative given their ability to target elusive small molecule analytes, compatibility with real-time monitoring and facile incorporation at local reporter sites on the biosensor. There is a growing interest in using electrochemical readout for enabling multiplexed analysis at the point-of-care (POC) due to the ease of multiplexing, capability of real-time in-situ monitoring and the potential for enhanced signal-to-noise ratio offered by this particular transduction method. To this end, redox species are often integrated into dynamic biorecognition systems as reporters signalling the capture of the desired biomolecular target. However, the instability of these redox labels in complex biological or environmental conditions - due to varying oxygen levels, temperature, and pH - and the difficulty of their programmability (signal on and off modes) are often limiting. In order to overcome these limitations, a programmable signalling strategy using a single non-redox label system for electrochemical readout by harnessing the interaction between plasmonic metallic gold (Au) nanoparticles and semiconductor (TiO_2) nanoparticle was developed.