AgNP/Alginate Nanocomposite hydrogel for antimicrobial and antibiofilm applications. (1st January 2021)

• Record Type: Journal Article
• Authors: Porter, Gemma C.; Schwass, Donald R.; Tompkins, Geoffrey R.; Bobbala, Sharan K.R.; Medlicott, Natalie J.; Meledandri, Carla J.
• Is Part Of: Carbohydrate polymers. Volume 251(2021)
• Publication Date: 2021-01-01
• Subjects: Alginic acid sodium salt (PubChem CID: 2366571) -- Calcium chloride dehydrate (PubChem CID: 24844) -- silver nitrate (PubChem CID: 24470) -- sodium borohydride (PubChem CID: 4311764) -- Thioctic acid (PubChem CID: 864); AgNPs silver nanoparticles -- TEM transmission electron microscopy -- SEM scanning electron microscopy -- CLSM confocal laser scanning microscopy -- EPS extracellular polymeric substance; silver nanoparticles -- hydrogels -- antimicrobial -- nanocomposite; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2020.117017
• Languages: English
• ISSNs: 0144-8617

Abstract

Graphical abstract: Highlights: Prevention of AgNP aggregation, by surface functionalization, within alginate gel. Discrete 10 nm AgNPs in snowflake-like assemblies throughout hydrogel matrix. Three-hour bactericidal kill curves at [Ag]25 μg/mL. Significant antibiofilm activity and low silver ion release over time. Abstract: The synthesis and specific surface functionalization of antimicrobial silver nanoparticles (AgNPs) and their incorporation into an alginate hydrogel is described. Divalent cation-mediated ionic crosslinking was used to disperse the AgNPs throughout the gel, made possible by –COO - cross-linking sites provided by the surface-enhanced nanoparticles, inspired by the classic egg-box model crosslinking of calcium alginate. An AgNP concentration, 10-20 μg g -1 increased hygrogel elasticity, viscosity, and shear resistance by 45, 30, and 31% respectively. Cryo-TEM revealed evenly distributed AgNP assemblies of discrete AgNPs throughout the gel matrices. FTIR-ATR indicated AgNPs were involved in alginate carboxylate-Ca 2+ -COO - AgNP crossbridging, which was not achieved through mixing of AgNPs into preformed gels. Live/dead fluorometric assays determined a minimal bactericidal concentration of 25 μg g -1 Ag for 6 microorganisms. Anti-biofilm assays showed species-dependent cell death of 44 -61%, with limited silver ion release of 0.41% and 1.1% after 7 days for Gram positive and negative bacteria, respectively.