Selective Ag⁺ Sensing and Cellular Imaging Based on Hydrophilic Modulated Peptide Probe

Silver is a highly toxic heavy metal pollutant. Its excessive release into the environment and long-term accumulation in living organisms can have serious impacts on ecosystems and human health. Therefore, developing precise detection methods for Ag⁺ is crucial for environmental monitoring and biomedical applications. Currently, common peptide fluorescent probes neglect the effects of self-assembly of probe molecules to form nanoparticles. In this study, we focused on this factor and systematically adjusted the hydrophilicity of peptides to design and synthesize three Ag⁺ responsive fluorescent probes: DNSCI-SPPW, DNSCI-APGYHA, and DNSCI-GPTHC. Among them, DNSCI-APGYHA exhibits stable morphological characteristics in solution and better selectivity for Ag⁺. Additionally, this probe shows a lower detection limit (19 nM) and stronger resistance to interference. Notably, DNSCI-APGYHA demonstrates good cell permeability and low cytotoxicity, and has been successfully applied for fluorescent imaging detection of Ag⁺ in CT26 cells.