We herein report a self-powered and renewable cytosensing device based on ZnO nanodisks(NDs)@g-C3N4 quantum dots. The device features enhanced photoelectrochemical (PEC) activity compared to ZnO NDs or g-C3N4 QDs alone. The enhanced PEC ability is attributed to the synergistic effect of the high visible light sensitivity of g-C3N4 QDs and the staggered band alignment heterojunction structure with suitable band offset, which affords higher photoelectron transfer and separation efficiency. In addition, the hybridization of g-C3N4 QDs further accelerates interfacial electron transfer and blocks recombination between electron donors and photo-generated holes. The device was applied to the detection of CCRF-CEM cells. By conjugation to Sgc8c aptamer, which preferentially interacts with membrane-bound PTK7 on CCRF-CEM membranes, capture of target CCRF-CEM cells resulted in a decrease in apparent power output, which was then exploited for the ultrasensitive detection of the target cells. This decrease in power output can be recovered by simply increasing the temperature to release the cells, thus recycling the cytosensing performance. The device displayed a linear relationship between the change of power output and the logarithm of the cell concentration from 20 to 20,000 cell/mL (R2 = 0.9837) and a detection limit down to 20 cell/mL, as well as excellent selectivity and reproducibility. Thus, this ZnO NDs@g-C3N4 QDs-based device exhibits high potential for the detection of CCRF-CEM cells.
Keywords: Cytosensing; Heterojuncture; Photoelectrochemistry; Regeneration; Self-powered.