Antifungal properties and biocompatibility of silver nanoparticle coatings on silicone maxillofacial prostheses in vitro.

Patients with facial prostheses suffer from yeast, Candida albicans, infections. This study aimed to determine the biocompatibility and antifungal properties of silicone facial prostheses coated with silver nanoparticles (Ag NPs) in vitro. Medical grade silicone discs were coated with 5 and 50 mg L-1 dispersions of either Ag NPs or AgNO3 . Coatings were fully characterized using scanning electron microscopy and energy dispersive X-ray spectroscopy. The biocompatibility was examined using human dermal fibroblasts (Hs68), whereas antifungal efficacy was tested against C. albicans (NCPF-3179). The fibroblast viability was assessed by measuring lactate dehydrogenase (LDH) activity, protein content and tissue electrolytes. There were no effects on the LDH activity of fibroblast cell homogenates, and leak of LDH activity into external media remained low (0.1-0.2 IU mL-1 ). Sublethal effects of Ag NP coatings on membrane permeability/ion balance was not observed, as measured by stable homogenate Na+ and K+ concentrations. Some Ag (13 mg L-1 ) was detected from the AgNO3 coatings in the media, but total Ag remained below detection limit (<1.2 µg L-1 ) for the Ag NP coatings; indicating the latter were stable. When fibroblasts grown on silver coatings were challenged with C. albicans, the Ag NP coating was effective at preventing fungal growth as measured by ethanol production by the yeast, and without damaging the fibroblasts. Ethanol production decreased from 43.2 ± 25.02 in controls to 3.6 µmol mL-1 in all the silver treatments. Data shows that silicone prosthetic materials coated with Ag NPs are biocompatible with fibroblast cells in vitro and show antifungal properties.