Negatively Charged Peptide-Assistant Gold Nanoparticles for Mitochondria Targeting and High-Fidelity Intracellular Bioimaging Enterokinase Levels

Mitochondria are key organelles in mammalian cells whose dysfunctions are linked to various diseases. The current moieties for mitochondria targeting are mostly lipophilic cation categories, which show the potential toxicity resulting from their accumulation in the mitochondrial matrix. Herein, we report the first example of a mitochondria-targeting AuNP-based nanosensor with negatively charged peptide modification. Furthermore, we directly introduce the peptide motif via diselenide-modified AuNPs instead of traditional Au-S/Se bonds. In vitro and living cell-based assays show that our designed strategy is low cost, easy to operate, simple to prepare and highly feasible. Furthermore, we have demonstrated that the nanosensor AuNP@DSe-P linker TMR can monitor enterokinase (ENTK) levels in the mitochondria of HeLa cells with a high-fidelity fluorescent signal under physiological conditions, thus providing a new idea for the design and preparation of ultrastable AuNP-based nanosystem.