A polydopamine-polyethyleneimine/quantum dot sensor for instantaneous readout of cell surface charge to reflect cell states

Cell surface charge serves a significant role in maintaining cell membrane stability and integrity, affecting cell structure/functions and the expression of signaling molecules. With the aggravation of the cell injury, cell surface charge would have a difference, which could be treated as a vital indicator for the discernment of cell pathological states. Herein, we developed a novel and instantaneous response method for the determination of cell viability based on cell surface charge. This study introduced a fluorescence resonance energy transfer-based polydopamine-polyethyleneimine/quantum dot (PDA-PEI/QD) sensor constructed by PDA-PEI with positive charge and QD with negative charge via electrostatic interaction, which can be used to instantaneously read out the cell injured states through fluorescent signal change induced by the comprehensive charged materials on the cell surface. The resulting fluorescence signals induced by different hepatotoxic drugs showed the difference. Furthermore, it was worth noting that the fluorescence change induced by 12 hepatotoxic drugs had a close relationship with cellular states, presenting the consistent tendency with cell viability. Accordingly, this method may have applications in the fields of cell viability detection, drug toxicity evaluation, and even elucidating the mechanism of drug-induced liver injury in the future.