The aim of this research was to estimate the bioactivity of nano-hydroxyapatite/poly (L-lactic acid) composites in simulated body fluid. In vitro test showed that the pH value of simulated body fluid (SBF) declined gradually and the existence of hydroxyapatite (HA) particles neutralized the acid degradation product of poly (L-lactic acid) (PLLA). Bone-like apatite deposited on the surface, and silkworm-like crystals and plate-like clusters appeared after soaking. At the same time, there were many honeycomb-like pores caused by nano-composite degraded. The results indicated that the hydroxyapatite/poly (L-lactic acid) nano-composites have good bioactivity and degradation characteristics.
Biocompatible Materials ; Bone Substitutes ; chemical synthesis ; chemistry ; Durapatite ; chemical synthesis ; chemistry ; Lactic Acid ; chemistry ; Microscopy, Electron, Scanning ; Nanoparticles ; Polyesters ; chemical synthesis ; chemistry ; Polymers ; chemistry ; Porosity ; X-Ray Diffraction

Strontium added into porous hydroxyaptite ceramics has the functions of improving its osseointegration, decreasing its dissolution rate and improving the bone density. Strontium-containing hydroxyaptite (Sr-HA) ceramics has been used as bone replacement and scaffold to treat the osteoporosis and bone default in clinic, but the mechanism of interfacial tissue response caused by the trace element Sr in Sr-HA ceramics still remains to be further studied. Four types of Sr-HA ceramic samples with different contents of Sr were prepared by microwave plasma sintering for testing the response of the soft tissue implanted in dog muscles in our laboratory. The contents of Sr element in the samples are 0 mol%, 1 mol%, 5 mol%, and 7 mol%, respectively. The samples were implanted in the muscle of the dogs for 4 weeks, 8 weeks and 12 weeks, respectively. The histological observations at the end of each period showed that the irritant ranking increased with the content of Sr in Sr-HA ceramics at the end of 12 weeks, and there were rich bone tissue in Sr-HA ceramic samples with 5 mol% Sr element. The overdose of element Sr is harmful to soft tissues. When the content of Sr in Sr-HA ceramic was below 5 mol%, the soft tissue response was very slight and the new bones were induced to grow well.
Animals ; Bone Substitutes ; chemical synthesis ; Ceramics ; chemical synthesis ; chemistry ; Dogs ; Durapatite ; chemical synthesis ; chemistry ; Female ; Male ; Muscle, Skeletal ; surgery ; Osseointegration ; physiology ; Porosity ; Prostheses and Implants ; Strontium ; chemistry ; Tissue Engineering

Porous HA ceramics were prepared by using NH4 HCO3/PVA as pore-formed material along with biological glass as intensifier, and these ceramics were immersed in Locke's Physiological Saline and Simulate Body Fluid (SBF). The changes of phase composition, grain size and crystallinity of porous HA ceramics before and after immersion were investigated by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The biological activity was evaluated. The porous HA ceramics showed various degrees of decomposition after immersion in the two solution systems, but there was no evident change in respect to crystallinity. Besides, the impact of different degrees of solution systems on the change of grain size and planar preferred orientation was observed. The TCP phase of the ceramics immersed in Locke's Physiological Saline decomposed and there was no crystal growth on the surface of ceramics; however, the grain size of ceramics immersed in SBF became refined in certain degree and the surface of ceramics took on the new crystal growth.
Bicarbonates ; chemistry ; Biomimetic Materials ; chemical synthesis ; chemistry ; Ceramics ; chemical synthesis ; chemistry ; Durapatite ; chemical synthesis ; chemistry ; Polyvinyl Alcohol ; chemistry ; Porosity

Compound membranes of chitosan/hydroxyapatite were prepared by blending. The physical performance showed that the air-water contact angles decreased from chitosan's 103 degrees to chitosan/hydroxyapatite's 57 and the water adsorption rate increased slightly. When immersed into culture medium, the materials adsorbed Ca2+, and low crystalline hydroxyapatite deposited on the surface of the membranes. Chitosan/hydroxyapatite compound membranes could enhance the attachment and proliferation of mescenchymal stem cells (MSCs). After 12 days' induction on the materials, the alkaline phosphatase (ALP) activity value of MSCs on the compound membrane was 10.1, being much higher than 1.6 on chitosan membrane (P<0.01). All these results indicate that chitosan does not have very good affinity for MSCs, but the biocompatibility of chitosan can be apparently enhanced after mixing with hydroxyapatite. The compound membrane stimulates MSCs to differentiate into osteoblasts and it may be a good potential material for bone substitution.
Alkaline Phosphatase ; metabolism ; Animals ; Bone Substitutes ; pharmacology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Chitosan ; chemical synthesis ; pharmacology ; Durapatite ; chemical synthesis ; pharmacology ; Membranes, Artificial ; Mesenchymal Stromal Cells ; cytology ; Rats

Hydroxyapatite (HA) is one of ideal materials for bone substitutions due to its intrinsic biocompatibility. However, its relatively poor mechanical properties such as brittleness and low strength have hindered its use in high-load applications. Biotic bones themselves are nanocomposites mainly composed of nanohydroxyapatite (n-HA) and collagen. From biomimetic point of view, nanocomposites of HA could potentially improve both biocompatibility and mechanical properties of bone grafting materials. Recent progress in this field branched into nanocomposites of HA with nonbiodegradable and biodegradable polymers, the latter including collagen, gelatin, chitosan, polylactides as well as polyanhydrides. In this paper, the preparation, biological reactions and mechanical properties of different nanocomposites are reviewed in detail.
Biocompatible Materials ; chemistry ; Bone Substitutes ; chemical synthesis ; chemistry ; Durapatite ; chemistry ; Humans ; Nanocomposites ; chemistry ; Nanoparticles ; chemistry ; Particle Size

Porous nano-hydroxyapatite/polyamide 66 (n-HA/PA66) composite was developed by injection molding method. Uniformly distributed and interconnected pores with an average size of about 500 microm in matrix were obtained. The evaluation of biological safety of the porous composite including cell cytoxicity test, sensitivity test, pyrogen test, haemolysis test was carried out according to GB/T16886 and GB/T16175. The results showed that the porous n-HA/PA66 composite was of no cytotoxicity, no allergen and pyrogen reactions as well as no hemolytic effect.
Animals ; Bone Substitutes ; chemical synthesis ; toxicity ; Durapatite ; chemistry ; Guinea Pigs ; Implants, Experimental ; Materials Testing ; Mice ; Nanocomposites ; chemistry ; Nanoparticles ; chemistry ; Nylons ; chemistry ; Porosity ; Rabbits ; Tissue Engineering

OBJECTIVEFabricate series of the controllable degradation coral-hydroxyapatite.

METHODSThe natural coral undergo a chemical reaction with (NH4)2 HPO4 at high temperature and pressure for different time-lengths. After getting the products, the components and the special structures were analyzed. Observe the biologic degradation of the reaction products and analyze the metal elements and their contents. Haemolysis tests, cytotoxity tests and bone compatibility tests were performed to assess the biocompatibility of the products.

RESULTSWhen hydrothermal reactions happened under different conditions, the different gradients of CaCO3/hydroxyapatite materials were produced. These types of materials kept the characteristic of interconnected micro-porous network structures. A thin layer of compact material can be seen on the surface of its trabecula ultra-micro structure. The SCHA-200R has a good biocompatibility.

CONCLUSIONSGradient HA (SCHA-200R) materials can be formed by adjusting the same temperature, same pressure and different time-length of the reaction. This kind of gradient material keeps the quality of micro-porous network structures. The SCHA-200R is a potential candidate scaffold for bone tissue engineering.

Absorbable Implants ; Animals ; Anthozoa ; chemistry ; Bone Substitutes ; Durapatite ; chemical synthesis ; Male ; Materials Testing ; Rabbits ; Tissue Engineering ; methods

This is a report on the research of HA/Ti6Al4V composite implants that were successfully fabricated by radio frequency magnetron sputtering (RF-MS) technique. The mechanism and bioactivity of these implants immersed in simulated body fluid (SBF) were investigated. Changes in surface morphology, interfacial bond state, crystal structure and phase composition of HA coating before and after immersing in SBF were characterized by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Results indicate that a new substance on the surface of HA implant coatings produces accompanying with the dissolution of coatings. The substance is bone-like apatite containing CO3(2-) and lacking of Ca2+. Its ratio of n(Ca)/n(P) is about 1.56. This substance has very small grain size and similarly amorphous structure. Its structure and composition are similar to those of natural bone. Thus, it has good biocompatibility and bioactivity.
Biocompatible Materials ; Coated Materials, Biocompatible ; chemical synthesis ; Durapatite ; chemical synthesis ; Magnetics ; Materials Testing ; Prosthesis Implantation ; Radio Waves ; Titanium ; chemistry

In the present work, NiTi alloy substrates were activated by three different pretreatment processes. 5 X SBF1 and 5 X SBF2 concentrated simulated body fluids were prepared with citric acid buffer reagent, and then calcium phosphate coatings were formed quickly on NiTi alloy surface by accelerated biomimetic synthesis after pretreatment. The microstructure, composition and surface morphology of calcium phosphate coatings were studied. The results indicate that calcium phosphate coatings possess porous and net structure, which are composed of precipitated spherical particles with diameter less than 3 microm. The analysis of XRD shows that the main component of calcium phosphate coatings is hydroxyapatite, whereas the concentrated 5 x SBF simulated body fluid, which is in the absence of Mg2+ and HCO3- crystal growth inhibitors, apparently accelerates the growth rate of hydroxyapatite coatings.
Biomimetic Materials ; Body Fluids ; Calcium Phosphates ; chemistry ; Coated Materials, Biocompatible ; chemical synthesis ; Computer Simulation ; Durapatite ; chemical synthesis ; Humans ; Nickel ; Titanium

Oligopeptide T2, a kind of PA (Peptide Amphiphile) molecule, which could build up nano-fiber by self-assembly was designed and synthesized in this study. And the double-diffusion gel system was applied on this molecule to investigate its biomineralization features in vitro. The results showed that T2 could obviously reduce the hydroxyapatite (HA) formation period. And HA was found to possess the characteristics of non-crystalline by analysis of X-ray diffraction (XRD) and scanning electronic microscopy (SEM). These findings point to the conclusion that the negatively charged zone in T2 might make this molecule have the function of promoting HA biomineralization in vitro. And the mechanism responsible for the procession of HA biomineralization needs further research.
Biocompatible Materials ; chemical synthesis ; chemistry ; Bone Substitutes ; chemistry ; Calcification, Physiologic ; Durapatite ; chemistry ; Oligopeptides ; chemical synthesis ; chemistry