Simultaneous Grafting Polymerization of Acrylic Acid and Silver Aggregates Formation by Direct Reduction Using γ Radiation onto Silicone Surface and Their Antimicrobial Activity and Biocompatibility

Abstract

The modification of medical devices is an area that has attracted a lot of attention in recent years; particularly, those developments which search to modify existing devices to render them antimicrobial. Most of these modifications involve at least two stages (modification of the base material with a polymer graft and immobilization of an antimicrobial agent) which are both time-consuming and complicate synthetic procedures; therefore, as an improvement, this project sought to produce antimicrobial silicone (PDMS) in a single step. Using gamma radiation as both an energy source for polymerization initiation and as a source of reducing agents in solution, PDMS was simultaneously grafted with acrylic acid and ethylene glycol dimethacrylate (AAc:EGDMA) while producing antimicrobial silver nanoparticles (AgNPs) onto the surface of the material. To obtain reproducible materials, experimental variables such as the effect of the dose, the intensity of radiation, and the concentration of the silver salt were evaluated, finding the optimal reaction conditions to obtain materials with valuable properties. The characterization of the material was performed using electronic microscopy and spectroscopic techniques such as 13C-CPMAS-SS-NMR and FTIR. Finally, these materials demonstrated good antimicrobial activity against S. aureus while retaining good cell viabilities (above 90%) for fibroblasts BALB/3T3.

Fouling Prevention in Polymeric Membranes by Radiation Induced Graft Copolymerization

“…The subsequent reduction in the complexed metal ions leads to the formation of metal nanoparticles covalently bounded to the membrane, adding another significant step towards the development of reactive membranes with biofouling resistance [ 230 ]. The reduction reaction of the metal ions in the salt form or metal precursors was carried out either by direct reduction through H radicals that were formed during irradiation [ 237 ] or by chemical reduction using a reducing agent [ 238 ]. The in situ synthesis of nanoparticles can be performed during or after RIGC.…”

“…In a study by Sawada et al [ 238 ], a PES hollow fiber membrane containing Ag nanoparticles was prepared by RIGC of AAm with UV irradiation in the presence of BP, followed by complexation with AgNO 3 and subsequent reduction by NABH 4 [ 238 ]. The obtained composite membrane containing Ag nanoparticles in a poly(AAm) gel layer exhibited high potential for applications requiring both organic antifouling and antibacterial properties [ 238 ].…”

“…In a study by Sawada et al [ 238 ], a PES hollow fiber membrane containing Ag nanoparticles was prepared by RIGC of AAm with UV irradiation in the presence of BP, followed by complexation with AgNO 3 and subsequent reduction by NABH 4 [ 238 ]. The obtained composite membrane containing Ag nanoparticles in a poly(AAm) gel layer exhibited high potential for applications requiring both organic antifouling and antibacterial properties [ 238 ]. Further work by He et al [ 240 ] also reported the loading of Ag nanoparticles on a PES membrane in the same manner, following the UV induced graft copolymerization of the hydrophilic PSBMA, and the membrane showed improved antibacterial properties and biocompatibility.…”

Water-Soluble Starch-Based Copolymers Synthesized by Electron Beam Irradiation: Physicochemical and Functional Characterization

“…The presence of silver in a metallic form does not have the ability to interfere in the initiation and termination steps of free-radical polymerization and thus it cannot affect the unreacted monomer amount. Recently, Velazco-Medel et al [ 60 ] showed also that the presence of silver in the form of silver nitrate did not change the grafting yields for in the case of production of an antimicrobial silicone simultaneously grafted with acrylic acid and ethylene glycol dimethacrylate by using gamma radiation. However, it is possible that metallic silver rather participates in the design of the copolymer shape, which is not discernible by assessing the level of grafting.…”

Binary Graft of Poly(acrylic acid) and Poly(vinyl pyrrolidone) onto PDMS Films for Load and Release of Ciprofloxacin

“…The graft procedure was taken from work carried out by Velazco-Medel, et.al., changing the parameters of monomer concentration and the applied dose [ 23 ].…”