Biocompatibility of nanostructured carbonated calcium hydroxyapatite obtained by hydrothermal method

Evaluation of biomaterials as safe and effective therapies needs preclinical models to estimate their biologic potential. This paper investigates biocompatibility by the in vivo assessment of the muscle tissue reaction after implantation of the hidrothermally produced calciumhydroxyapatite. Specific attention has to be given to the synthesis technique which influences the stereology of the material and the behavior of the material in living tissues. The synthesized powders of hydroxyapatite are preferentially carbonated hydroxyapatite of the B type in the form of agglomerates that accommodate two-modal size pores of 1.5-10 nm and 50-200 nm. The particles are built from crystallites of 8-22 nm in size, bind inside of the prime particles sized is between 10 and 63 nm. They form agglomerates of 200 nm in size and these were further clustered building up the biggest agglomerates of 5- 20 _m. Biocompatibility assessment revealed that only mild to moderate inflammatory reaction was seen around the calciumhydroxyapatite implants. Calciumhydroxyapatite failed to show any substantional toxicity.
Evaluacija biomaterijala kao bezbednog i efikasnog materijala u terapiji zahteva prekliničke modele da bi se ocenio njihov biološki potencijal. U ovom radu je in vivo ocenjivana biokompatibilnost hidrotermalno sintetizovanog kalcijumhidroksiapatita metodom implantacije u mišićno tkivo životinja. Posebnu pažnju treba obratiti na tehniku sinteze jer ona utiče na stereologiju materijala i ima uticaj na ponašanje materijala u živom organizmu. Sintetizovani prah hidroksiapatita je uglavnom ugljenični B tip hidroksiapatita u formi aglomerata koji stvaraju dva modela veličine pora od 1,5-10 nm i 50-200 nm. Čestice su izgrađene od kristalita veličine od 8-22 nm, povezani unutar primarne čestice čija je veličina između 10 i 63 nm. Oni formiraju aglomerate od 200 nm veličine a oni dalje grade veće aglomerate od 5-20 µm. Ocenjivanjem biokompatibilnosti uočena je blaga do umerena inflamatorna reakcija u mišićnom tkivu oko implantiranih uzoraka. Kalcijum hidroksiapatit nije ispoljio značajniju toksičnost.