Coordination-Assisted Self-Assembled Polypeptide Nanogels to Selectively Combat Bacterial Infection

In the present scenario, the invention of bacteria-selective antimicrobial agent comprising negligible toxicity and hemolytic effect is a great challenge. To surmount this challenge, here, a series of polypeptide nanogels (PNGs) have been fabricated by a coordination-assisted self-assembly of a mannose-conjugated antimicrobial polypeptide, poly(arginine-r-valine)-mannose (poly(Arg-r-Val)-M2), with Zn2+ ions. The fabricated PNGs are spherical in shape with a unique structural appearance similar to that of Taxus baccata fruits. PNGs, with a unique structural arrangement and threshold surface charge density, selectively interact with the bacterial membrane and exhibit potent antimicrobial activity, as reflected in their lower minimum inhibitory concentration values (varies from 2 to 16 μg/mL). PNGs show a remarkably high binding constant, 6.02 × 105 M–1 (from isothermal titration calorimetry, ITC), with the bacterial membrane which manifests its potent bactericidal effect. PNGs are nontoxic against mammalian...