BIOLOGICAL AND MECHANICS CHARACTERIZATION OF MICROMETRIC AND NANOMETRIC α-ALUMINA LIKE POTENTIAL MATERIAL FOR BONE TISSUE RECONSTRUCTION

Abstract

Thick and micrometric aluminum oxide has been used for several years in orthopedic surgery because of its good mechanical properties, low friction and wear coefficients, and inert nature, which makes it chemically stable in physiological environments guaranteeing high biocompatibility.  Regarding  its  use  as  a  component  of  microporous  matrixes  for  bone  tissue  regeneration,  it  has  been  tasted  its cytotoxicity in vivo and in vitro, confirming that porous shape has no cytotoxic effects, while the enhancing in mechanical strength of porous pieces is still being investigated. This research compared the biological viability  in vitro and the flexural strength of matrixes formed  with  aluminum  oxide  of  micro  and  nanometric  order,  in  order  to  study  the  possibility  of  employing  nanometric  alumina  in fabrication of matrixes for bone regeneration with higher mechanical strength than bioceramics, which are currently offered. Cytotoxic and genotoxic in vitro studies were tasted using MTT test, cometa test and micronucleus test; which suggest that conditioned media with α-Al2O3 nanometric powder are biocompatible bearing no negative effects or alterations in mononuclear cells DNA of peripheral human blood.  Nanometric  alumina  provided  matrixes  with  higher  equibiaxial  flexural  strength  (11,40±1,72MPa)  than  micrometric  material specimens  (5,27±0,82  MPa),  evaluated  according  to  ASTM  C1499  –  09,  which  evidence  the  effect  of  size  particle  in  mechanical strength,  likely  due  to  differences  in  pre-sintering  process  and  densification  of  each  material.  Aluminum  oxide  nanometric  sized provided  biocompatible  matrixes  with  better  flexural  strength  than  samples  made  with  micrometric  particles;  therefore  it  becomes  a promising material for using in bone regeneration.