Poly(acrylic acid)-b-Poly(vinylamine) Copolymer: Decoration with Silver Nanoparticles, Antibacterial Properties, Quorum Sensing Activity, and Cytotoxicity on Breast Cancer and Fibroblast Cell Lines

An elegant integration of primary amine-bearing segments into the acrylic acid-containing blocks and the subsequent addition of silver nanoparticles (Ag NPs) to this double hydrophilic block copolymer endowed the resulting well-defined self-assembled construct with promising antimicrobial and anti-quorum-sensing activity and high cytotoxicity against breast cancer cells. Poly(N-vinylformamide) (PNVF), precursor of amphoteric poly(vinyl amine) (PVAm), was chain-extended from pH-responsive poly(acrylic acid) (PAA) macro-chain-transfer agent synthesized via reversible addition–fragmentation chain transfer polymerization by the interchange of xanthates (RAFT/MADIX). PAA-b-PNVF block copolymers with molecular weights in the range of 12500–21800 Da and dispersities between 1.29 and 1.44 were characterized by FTIR, elemental analysis, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, and size exclusion chromatography (SEC). PAA-b-PVAm copolymer was obtained by hydrolysis of the PNVF block. The decoration of PAA-b-PVAm with monodisperse Ag NPs to yield AgNPs@PAA-b-PVAm proceeded through a simple and green approach by amine-induced reduction of Ag ions in aqueous media. The formation of AgNPs@PAA-b-PVAm was characterized by UV/vis spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). AgNPs@PAA-b-PVAm displayed superior antimicrobial and anti-QS activity. The cell proliferation was tested with an MTT assay on L929 and MCF-7 cell lines. Both the AgNP-decorated and the bare copolymer showed significantly higher cytotoxicity on cancer cells compared to healthy ones.