Production, characterization and testing of antibacterial PVA membranes loaded with HA-Ag3PO4 nanoparticles, produced by SC-CO2 phase inversion

BACKGROUND Silver‐loaded hydroxyapatite nanoparticles were incorporated into poly(vinyl alcohol) (PVA) membranes obtained by supercritical CO2 (SC‐CO2) assisted phase inversion. Ag3PO4 crystals of 2.2 ± 0.6 nm were dispersed in synthesized needle‐like hydroxyapatite nanoparticles (20 × 65 nm) and were uniformly deposited on the internal surfaces of the PVA membranes. Operative conditions to produce membranes by SC‐CO2, PVA concentration and the effect on membrane porosity and morphology were studied. RESULTS Solutions at 20% w/w PVA produced membranes with cellular morphology and nanoporous walls, whereas 30% and 50% w/w solutions produced nanostructured membranes. Silver ions were released from PVA membranes mainly by diffusion according to the Peppas–Sahlin model. Membranes obtained at 20% w/w PVA showed a significant E. coli inhibition at an Ag concentration of 9 ppm, reaching the minimal inhibitory concentration (MIC) and improving the bactericidal activity of the nanoparticles. CONCLUSION A concentration of Ag3PO4 crystals of about 22 ppm was calculated as being capable of completely destroying these bacteria, reaching the minimum bactericidal concentration.