Ag@polyDOPA-b-polysarcosine hybrid nanoparticles with antimicrobial properties from in-situ reduction and NTA polymerization

Abstract Poly(α-amino acid)s are promising materials due to their excellent biocompatibility and biodegradability. α-Amino acid N-thiocarboxyanhydrides (NTAs), the thio-analogues of the corresponding N-carboxyanhydrides (NCAs), are able to synthesize polypept(o)ides by ring-opening polymerization with the tolerance of hydroxyl’s nucleophilic attack. In this work, polyDOPA-b-polysarcosine (PDOPA-b-PSar, named as DoS) copolymers are synthesized by sequential polymerizations of 3,4-dihydroxy-L-phenylalanine N-thiocarboxyanhydride (DOPA-NTA) and sarcosine N-thiocarboxyanhydride (Sar-NTA) initiated by benzylamine in tetramethylene sulfone. With the reduction of catechol ligand, PDOPA-b-PSar act as the reducing and stabilizing agents for silver nanoparticles. The obtained Ag@PDOPA-b-PSar (Ag@DoS) nanoparticles have the average diameters of 81 nm with 10 nm core and narrow distributions. More than 95% bacterial killing efficiency to E.coil and S.aureus by Ag@DoS nanoparticles shows the potential for biomedical applications.