Pullulan (Pull) decorated with monodisperse Ag and Au nanoparticles (NPs) was synthesized by a simple and green method. Samples were characterized by FTIR, UV–vis, NMR, XRD, TGA, SEM, XPS, DLS, and TEM. SEM images showed highly oriented microforms reported for the first time for Pull, because of the supramolecular self-assembling behavior of Pull chains. Antimicrobial and quorum sensing (QS) inhibition activities were tested against six pathogen bacteria and reporter and biomonitor strain. Pull decorated with NPs, in particular, Ag-modified ones, outperformed pristine Pull. The cell proliferation was tested with an MTT assay. NPs-decorated Pull was studied for the first time as an inhibitory agent against bacterial signal molecules and found to be a good candidate. The promising performance of AgNPs@Pull compared to the commercial antibiotic gentamicin showed that it has great potential as a therapeutic approach to overcome the bacterial resistance that has developed against conventional antibiotics.

Paenibacillus polymyxa is a microorganism used for the production of carbohydrate biopolymer levan in this work. Film samples were prepared with different contents of levan/bentonite. Film samples were evaluated for thickness, water vapor permeability, tensile strength and elongation properties. The most suitable film composite was chosen to evaluate antimicrobial activity. Antimicrobial properties were determined on different microorganisms by adding calendula oil, citronella oil, lemon oil, tamanu oil, peppermint (medical peppermint) oil in varying amounts to the film samples. The highest activity of levan/ bentonite/oil composite film on microorganisms was measured with a diameter of 40 mm on Candida albicans in the composition of 0.5 mL of film content ?1.5 mL of peppermint (medical peppermint) oil. This high antimicrobial activity film composite was characterized by TGA and SEM. It was made with levan/bentonite and peppermint oil, and the determination of antimicrobial effects of this film composite was reported for the first time. The biodegradable film obtained has a high potential for use in different areas, especially in food packaging.

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.