Anal Chem 2018 08 1;90(16):9708-9715. Epub 2018 Aug 1.
Beijing National Research Center for Molecular Sciences, CAS Key Laboratories of Analytical Chemistry for Living Biosystems and Organic Solids, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry , Chinese Academy of Sciences , Beijing , 100190 , China.
Peptides with modular structure provide a tailorable platform for constructing responsive supramolecular assemblies, which are attractive as functional biomaterials and smart sensors. In this work, the feasibility of regulating small peptides assembly with molecular design and metal ion recognition was demonstrated. Tripeptides were designed and found to have diverse response and self-assembly behavior to Hg. The incorporation of an aggregation-induced emission fluorophore TPE enabled the visualization of Hg recognition and the assembly phenomenon. A structural analogue (Pep2) to γ-glutathione was identified with high specificity and nanomolar response to Hg both in buffer solution and living cells. Driven by the coordination force and noncovalent intramolecular stacking, assembling of twisted nanofibers from Pep2-TPE and Hg were observed. Benefiting from its biocompatibility, fast and switchable fluorescence response, Pep2-TPE was applied for imaging and monitoring Hg distribution in living cells and zebrafish. With good permeability to plasma membrane and tissues, Pep2-TPE indicated the preferential distribution of Hg in cell nucleoli and brain of zebrafish, which is related with the deleterious effect of inorganic mercury in living biosystems.