Composite Coating Enhance Porous Ha Ceramic Scaffolds And Properties Representation

Because of remarkable biological compatibility、excellent osteoconduction, HA is widely used in bone tissue engineering. However, its application is limited by high brittness and low compressive strength of HA. In addition, HA is highly crystalized during the sintering process, so, HA is low biological active and it is adverse to the new bone formation. Polymer coating is one of the major approaches to modify HA scaffolds. Bone tissue engineering scaffolds should satisfied following requires:(1) Remarkable biocompatibility;(2) Favorable connectivity and high porosity;(3) Excellent mechanical properties;(4) Well cell/material interface;(5) Nontoxic or low toxicty.Porous hydroxyapatite(HA)scaffolds were prepared by porogen leaching method in this research.Then the as-prepared HA scaffolds were lined with PCL containing nHA or micronano-bioglass(nBG)composite layer and the content of the single component of nano-hydroxyapatite powder or micronano-bioglass powder(nBG)was arranged from10wt%to40wt%microcosmic structure、porosity and mechanical of composite were represented. We choosed the mechanical properties of optimal stent for biomimetic mineralization、cell experiment and ectopic bone formation experiment and we gained satisfactory outcome.The main conclusions were summarized as follow:(1) Porous HA ceramic scaffold with remarkable connectivity、uniform pore size distribution high porosity were prepared by particle leaching method and mechanical properties almost meet the requirements of bone tissue engineering.(2) Mechanical properties were largely enhanced after porous HA were coated by composite layer and kept the original porosity.Optimal mechanical properties were both obtained when the content of the powder was30wt%the scaffolds were signed as nHA-PCL/HA、 nBG-PCL/HA composite scaffolds,the optimal compressive strength were1.98MPa and1.78MPa,respectively.(3) After mineralization of four types of scaffolds(HA、PCL/HA、nHA-PCL/HA and nBG-PCL/HA)for21days in SBF,the microstructure showed that no bone-like apatite layer was found on the surface of HA and PCL/HA scaffolds,a little apatite layer was found on the surface of nHA-PCL/HA scaffold,large amount of bone-like apatite was found on the surface of nBG-PCL/HA scaffold, which confirmed the nBG-PCL/HA composite scaffold were optimal bioactivity.(4) Cell experiment result showed that osteoblast growed well on all scaffolds which revealed the scaffolds were remarkable biological compatibility.(5) Histological section evaluation showed that there was a large amount of new bone forming in nHA-PCL/HA and nBG-PCL/HA scaffolds comparing to other two scaffolds after implanted for2months in the back muscle tissue of dogs,which exhibited that the two biological particles in composite coatings played a positive role in the induction of new bone formation at non-osseous sites...