Papers by Keyword: Beta-Tricalcium Phosphate

Abstract: Porous beta-tricalcium phosphate (β-TCP) bioceramic has been reported as synthetic graft for cancellous bone substitute due to its biocompatibility and biodegradability properties. A highly porous and interconnected porosity architecture of bone scaffold facilitates attachment and in-growth of new bone tissue. β-TCP foam, a porous 3-dimensional scaffold was fabricated by employing polymeric foam replica method in this study. Polyurethane (PU) foam was used as the sacrificial template, in which β-TCP slurry with powder to water ratio of 10g:10ml was coated on PU template and sintered to 1100, 1200, 1250 and 1300°C. Observation on architecture of the foam, macrostructure and microstructure of pores and surface topography of porous strut showed that sintering at 1250°C produced sufficient densification of grains and micropores on the β-TCP strut. The β-TCP foams exhibited high porosity (92 – 97%) and large pore size (200 - 750um) that resemble cancellous bone structure.

Abstract: Many techniques are used to assess biomaterials implants, always intending to measure osseointegration success and tissue response facing the implanted material. Calcium phosphates are widely used as biomaterial and a major component of bone. Many processing methods have been used to achieve porous materials to allow bone ingrowth with an osteoconductive scaffold for bone. To obtain the macroporous BCP implant it was processed by direct consolidation using the protein-action technique, a globular protein based consolidation with ovalbumin. The samples were sintered at 1250°C for 30 minutes, after sintering samples were cut in 4mm diameter cylinders, with 73% volume of porosity and mean pore size ranging about 100 µm. In the present work the macroporous BCP of HAp:β-TCP is assessed after bone implantation in rabbits tibia by lectinhistochemistry (LHC) technique. Lectins are proteins from non-imune origin which binds with strong specificity carbohydrates, LHC is a technique which mark histologically carbohydrates present in glycoproteins of cells. The macroporous BCP cylindrical samples were implanted in male rabbits tibia to the evaluation of biocompatibility and osseointegration in a period of 2 weeks to 4 weeks. After euthanasia of rabbits, tibia samples from the surgery site were taken and fixed with formalin, decalcified, dehydrated and embedded with paraffin to perform histological slides for both morphological and molecular evaluation. The morphological evaluation were performed on histological slides stained with Haematoxilin and Eosin (HE), while for molecular evaluation LHC was performed on histological slides using the lectins PNA, UEA-1, WGA, sWGA and RCA-1 (Vector Labs). All samples osseointegrated well with the bone and the neoformed bone surrounding the implant took the shape of its surface. The implants also allowed bone ingrowth inside the pores towards the center of implant, characterized by islets of round bone present in the HE stained slides.

Abstract: Magnesium and strontium both play important roles in the growth of bone and so are desirable ions for substitution into hydroxyapatite (HA) intended for use as bioinstructive bone substitutes. A range of compositions were prepared by a solid state method based on the nominal composition of HA (Ca₁₀(PO₄)₆(OH)₂), with various levels of strontium and/or magnesium substitution: strontium-substituted HA (Ca₈Sr₂(PO₄)₆(OH)₂), magnesium-substituted HA (Ca_9.8Mg_0.2(PO₄)₆(OH)₂ and Ca₉Mg (PO₄)₆(OH)₂), and strontium and magnesium co-substituted HA (Ca_7.8Sr₂Mg_0.2(PO₄)₆(OH)₂ and Ca₇Sr₂Mg (PO₄)₆(OH)₂). Materials were characterised by powder X-ray diffraction, Fourier-transform infrared spectroscopy and Raman spectroscopy. These analyses indicated that the co-substituted materials were composed of mixtures of strontium-substituted hydroxyapatite and magnesium and strontium co-substituted β-tricalcium phosphate. In the magnesium-substituted materials, increased magnesium content was related to increased proportion of β-tricalcium phosphate phase, both with and without strontium co-substitution. The unsubstituted and strontium mono-substituted materials, however, were pure apatite phase, suggesting that magnesium was the destabilising factor in the phase compositions of the magnesium mono-substituted and magnesium and strontium co-substituted materials.

Abstract: In this work, thepreparation and morphology of biphasic calcium phosphate (BCP) have been studied. The biphasic calcium phosphate (BCP) ceramics were prepared by mixing between hydroxyapatite (HA) and Beta-tricalcium phosphate (β-TCP) powderby ball milling technique with different ratios (100:0,80:20,60:40,50:50,40:60, 20:80 and 0:100). After that the mixtures were forming by Gel casting method and then sintered at 1200°C, respectively. The phase formation of the biphasic calcium phosphateceramics were studied by X-ray diffraction (XRD) and their ceramic microstructure,shrinkage and density were investigated.

Abstract: A kind of drug release bionic scaffold with gradient structure was designed to release drugs. The scaffold mould had been designed with CAD software and fabricated with rapid prototype. The bionic beta-tricalcium phosphate (β-TCP) scaffold was fabricated with freeze drying. It was composed of two coaxial cylindrical porous scaffolds. The internal loose scaffold was embedded in the outer dense layer. The two different density layers of the scaffold could be used to adjust the drug releasing rate through regulating the slurry concentration. The scaffold was distributed with pores ranged from 30μm to 100μm. The research indicated that the scaffold with gradient structure could be loaded with two kinds of drugs which were released at different rate. The scaffolds were fit as the substitute materials for bone repairing.