Surface Functionalization of Bioactive Glasses with Polyphenols from Padina pavonica Algae and In Situ Reduction of Silver Ions: Physico-Chemical Characterization and Biological Response

Abstract

Bioactive glasses (BGs) are attractive materials for bone replacement due to their tailorable chemical composition that is able to promote bone healing and repair. Accordingly, many attempts have been introduced to further improve BGs’ biological behavior and to protect them from bacterial infection, which is nowadays the primary reason for implant failure. Polyphenols from natural products have been proposed as a novel source of antibacterial agents, whereas silver is a well-known antibacterial agent largely employed due to its broad-ranged activity. Based on these premises, the surface of a bioactive glass (CEL2) was functionalized with polyphenols extracted from the Egyptian algae Padina pavonica and enriched with silver nanoparticles (AgNPs) using an in situ reduction technique only using algae extract. We analyzed the composite’s morphological and physical-chemical characteristics using FE-SEM, EDS, XPS and Folin–Ciocalteau; all analyses confirmed that both algae polyphenols and AgNPs were successfully loaded together onto the CEL2 surface. Antibacterial analysis revealed that the presence of polyphenols and AgNPs significantly reduced the metabolic activity (>50%) of Staphylococcus aureus biofilm in comparison with bare CEL2 controls. Finally, we verified the composite’s cytocompatibility with human osteoblasts progenitors that were selected as representative cells for bone healing advancement.

Characterization and Antimicrobial Activity of Silver Nanoparticles Synthesized with the Peel Extract of Mango

“…Although the synthesized AgNP solution displayed prominent antibacterial activity against E. coli and S. aureus , their effects differed because S. aureus was probably more sensitive to AgNPs than E. coli [ 60 ]. Furthermore, using MIC tests and standard growth curves, we have shown that increasing concentrations of nano-silver colloid can reduce the growth of bacteria.…”

“…The synthesized AgNPs were all smaller than 150 nm, allowing easy absorption on the surface of the bacterial cell wall to react with the -NH-, and -COOH functional groups of the peptidoglycan, corroding the cell wall. However, the cell membranes were destroyed due to the antioxidant activity of the polyphenols in the mango peel extract, resulting in biomolecule leakage into the bacterial cells [ 60 ]. In addition, cellular respiration may be inhibited by AgNPs.…”

Special Issue on Surfaces Modification and Analysis for Innovative Biomaterials

“…Abdelgeliel and coworkers described antibacterial bioactive glasses through a particular surface functionalization [2]. Indeed, an antibacterial polyphenolic extract of the Egyptian algae Padina Pavonica was exploited both to coat the bioactive glasses and to reduce silver ions in situ, leading to silver nanoparticles.…”

Polymer-Based Honeycomb Films on Bioactive Glass: Toward a Biphasic Material for Bone Tissue Engineering Applications

“… 28 , 29 Due to their high interest in bone regeneration, the surface chemistry of BaGs, as well as their ability to be functionalized in view of increasing the adsorption rate of biomolecules or to increase the connectivity between the glass and the polymeric phase, have been widely studied. 30 − 33 …”