Biocompatibility and antimicrobial activity of zinc(II)-doped hydroxyapatite, synthesized by a hydrothermal method

Abstract

In order to obtain multifunctional materials with good biocompatibility and antimicrobial effect, hydroxyapatite (HAp) doped with Zn2+ was synthesized by a hydrothermal method. Powders with different content of zinc ions were synthesized and compared with undoped HAp to investigate the influence of Zn2+ on the antimicrobial activity of HAp. Analyses of undoped and Zn2+-doped powders before and after thermal treatment at 1200°C were performed by SEM and XRD. The antimicrobial effects of the powders were examined in relation to Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans in liquid medium. The results showed that the obtained powders had good antimicrobial activity, but higher antimicrobial activities of the powders doped with Zn2+ were observed after annealing at 1200°C. For powders annealed at 1200°C, in vitro biocompatibility tests: reduction of the tetrazolium salt 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT test) and Trypan Blue dye exclusion test (DET test) with MRC-5 fibroblast cells in liquid medium were performed. Based on the MTT and DET tests, it was shown that the powders do not have a significant cytotoxic effect, which was confirmed by SEM analysis of MRC-5 fibroblast cells after their in vitro contact with the powders.

U cilju dobijanja multifunkcionalnih materijala sa dobrom biokompatibilnošću i dobrim antimikrobnim dejstvom, hidroksiapatit (HAp) sa ugrađenim Zn2+ sintetisan je hidrotermalnom metodom. Za potrebe istraživanja uticaja Zn2+ na anti-mikrobnu aktivnost, sintetisani su HAp prahovi sa različitim sadržajem Zn2+ i upoređeni sa čistim HAp. Čisti prahovi i oni sa ugrađenim cinkom, pre i posle termičkog tretmana na 1200°C, analizirani su skenirajućom elektronskom mikroskopijom (SEM) i metodom rendgenske difrakcije. Antimikrobni efekat prahova ispitivan je prema sojevima Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa i Candida albicans u tečnom medijumu. Antimikrobni test je pokazao da dobijeni prahovi imaju dobru antimikrobnu aktivnost. Poboljšana antimikrobna aktivnost prahova u koje je ugrađen Zn2+ postignuta je žarenjem na 1200°C. In vitro testovi biokompatibilnosti, MTT i DET, sa MRC-5 fibroblastnim ćelijama u tečnom medijumu urađeni su za prahove žarene na 1200°C. Na osnovu MTT i DET testova zaključeno je da prahovi nemaju značajan citotoksični uticaj što je potvrđeno SEM analizom MRC-5 fibroblastnih ćelija nakon njihovog in vitro kontakta sa prahovima.