Energy Transfer between Semiconducting Polymer Dots and Gold Nanoparticles in a Photoelectrochemical System: A Case Application for Cathodic Bioanalysis

We report herein the energy transfer (ET) between semiconducting polymer dots (Pdots) and gold nanoparticles (Au NPs) in a photoelectrochemical (PEC) system and its feasibility for cathodic bioanalysis application. Specifically, COOH-capped Pdots were first fabricated and then assembled onto the indium tin oxide (ITO) surface, followed by the modification of single-strand (ss) DNA probe (pDNA). After the DNA hybridization with the Au NP tethered complementary ssDNA (Au NPADNA), the Au NPs were brought into the close proximity of Pdots. Upon light stimulation, photoluminescence (PL) was annihilated, fluorescence was attenuated, and the photocurrent intensity was evidently decreased. This ET-based PEC DNA sensor exhibited a linear range from 1 fM to 10 pM with a detection limit of 0.97 fM at a signal-to-noise ratio of 3. The present work first exploited the ET between Pdots and Au NPs, and we believe this phenomenon will spark new interest in the study of various Pdots-based ET-influenced PEC systems and thus catalyze increasing studies for specific bioanalytical purposes.