Silver-doped hydroxyapatite thin layers obtained by sol-gel spin coating procedure

Abstract

The main objective of this paper is to develop silver-doped hydroxyapatite suspensions (HApAg) with different concentrations of silver (xAg = 0.05 and xAg = 0.2) in order to obtain uniform and homogenous layers by spin-coating procedure. The colloidal properties of HApAg suspensions are evaluated by dynamic light scattering (DLS) analysis, ζ-potential (ZP), and ultrasound measurements. The ultrasound studies show that the HApAg20 sample revealed better stability than the HApAg5 sample. The structural and morphological analysis on suspensions and thin layers is also conducted. It is observed that the particles of the two samples have a similar shape and are uniform. The layers obtained present a homogeneous appearance of the surface without evidence of cracks or interruption of the coatings. The in vitro antifungal studies conducted on the two thin layers at two different time intervals (24 and 48 h) show that both HApAg5 (xAg = 0.05) and HApAg20 (xAg = 0.05) nanoparticles suspensions and composite layers inhibit the development of colony forming units (CFU) even after 24 h of incubation comparative to the control, represented by the Candida albicans (C. albicans) culture in a proper medium. The fungicidal effect was evident after 48 h of incubation in the case of both HApAg20 nanoparticles suspensions and composite layers.