Versatile Photochemical Surface Modification of Biopolyester Microfibrous Scaffolds with Photogenerated Silver Nanoparticles for Antibacterial Activity

Abstract

A straightforward and versatile method for immobilizing macromolecules and silver nanoparticles on the surface of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) electrospun fibers is developed with the objective of designing a new functional material having significant antibacterial activity. The approach relies on a two-step procedure: UV photografting of poly(methacrylic acid) (PMAA) on the surface of PHBHV fibers according to a "grafting from" method, and complexation of in situ photogenerated silver nanoparticles (Ag NPs) by carboxyl groups from tethered PMAA chains. The photografting process is conducted through a photoinduced free-radical process employing a ketone-based photoinitiator in aqueous medium. Under appropriate conditions, the photogenerated radicals abstract hydrogen atoms from the PHBHV backbone, thus initiating the UV-mediated photopolymerization of MAA from the PHBHV microfibrous surface. The photochemical mechanism of the ketone photolysis is entirely described by the electron spin resonance/spin-trapping technique, and the modified PHBHV microfibrous scaffold is extensively characterized by ATR-FTIR spectroscopy, water contact-angle measurements, and mercury intrusion porosimetry. In a second step, the in situ synthesis of Ag NPs within the microfibrous scaffold is implemented by photoreduction reaction in the presence of both a silver precursor and a photosensitizer. The photoinduced formation of Ag NPs is confirmed by UV spectrophotometry and XPS analysis. SEM and TEM experiments confirm the formation and dispersion of Ag NPs on the surface of the modified fibers. Finally, a primary investigation is conducted to support the antibacterial activity of the new functionalized biomaterial against Staphylococcus aureus and Escherichia coli.

Hierarchical Self‐Assembly of Poly(Urethane)/Poly(Vinylidene Fluoride‐co‐Hexafluoropropylene) Blends into Highly Hydrophobic Electrospun Fibers with Reduced Protein Adsorption Profiles

“…When used as implants for medical purposes, cell material interactions are governed by chemical and physical surface properties that trigger initial protein adsorption, and regulate further downstream signals for cell adhesion, cell proliferation, and/or differentiation . Typically, improved biointerfaces and surface functionalization are addressed by post‐treatment such as plasma coating processes, layer by layer assembly, photochemical surface modifications, wet chemical treatment, or gas phase induced coating processes . Recently, fluorine‐functionalized surfaces have gained increasing interest in the field of biomedical applications due to their outstanding properties of hydrophobicity and oleophilicity, chemical resistance, low friction coefficient, and mechanical stability.…”

A (Triphenylphosphine)Silver (I) Complex as a New Performance Additive in Free‐Radical Photopolymerization under Air

“…The XPS spectrum exhibits an Ag 3d doublet at a binding energy of 374 eV for Ag 3d 3/2 with a doublet splitting of 6 eV. The second peak at 367.9 eV is attributed to the Ag 3d 5/2 signal which clearly indicates the presence of metal Ag 0 . Accordingly, these results evidence that the in situ photoinduced reduction of [Ag](PPh 3 ) is a powerful way to generate nanometer‐size silver NPs.…”

Biomedical Processing of Polyhydroxyalkanoates

“…Different chemical modification strategies have been also adopted to improve cell adhesion onto electrospun PHA meshes, e.g., epoxy functionalization [65] and polysaccharide-grafting [66,67]. Other PHA fibers functionalization approaches include combination with antibacterial particles (e.g., silver [68] and zinc oxide [69] nanoparticles) or electrosprayed osteoconductive ceramics (e.g., HA nanoparticles [70]), as well as grafting with carbon nanotubes mechanical-reinforcing fillers [71].…”