PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 15020158

Bioresorbable composite bone paste using polysaccharide based nano hydroxyapatite.

R Murugan·S Ramakrishna
View original source ↗Export metadata ↓

Abstract

Aim of this study concerns to the development of bioresorbable composite materials for bone repair and regeneration. Despite nano hydroxyapatite (HA) has wide range of medical applications, particles mobilization and slow resorbable nature limits its use in certain applications particularly, periodontal and alveolar ridge augmentation. To enhance its usage, we have prepared HA composite bone paste with a natural polysaccharide, chitosan, using wet chemical method at low temperature. The prepared composites were analyzed by various physicochemical methods and suggesting that the nano HA crystallites are well intact with the chitosan macromolecules. FT-IR results are indicating the existence of hydroxyl and amide groups in addition to the characteristic peaks of nano HA in the composite paste. The physical nature of paste form implies that it would be highly beneficial for the particle immobilization upon implantation. In vitro physiological stability and solubility of the composite was performed in phosphate buffered saline under physiological condition and found that the rate of resorbability of composite was quite higher than nano HA. These findings suggest that the HA/chitosan composites may have a great impact on human health care systems as bioresorbable bone substitute.

Explore related subjects

Absorbable ImplantsBiocompatible MaterialsBody FluidsBone CementsChitinChitosanCrystallizationDurapatiteFeasibility StudiesHydrogen-Ion ConcentrationManufactured MaterialsMaterials TestingMolecular ConformationNanotubesPolysaccharidesSurface PropertiesTemperatureComparative StudyEvaluation StudyJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

R Murugan, S Ramakrishna. 2004. Bioresorbable composite bone paste using polysaccharide based nano hydroxyapatite.. https://doi.org/10.1016/j.biomaterials.2003.10.016

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2006

Effects of Runx2 genetic engineering and in vitro maturation of tissue-engineered constructs on the repair of critical size bone defects.

Genetic and tissue engineering strategies are being pursued to address the clinical limitations of current bone grafting materials. Based on our previous work demonstrating that overexpression of the Runx2 osteoblastic transcription factor and in vitro construct maturation synergistically enhanced in vivo mineralization in an ectopic site (Byers et al., Tissue Eng 2004;10:1757-1766), we examined the effects of these two parameters on the repair of critical size bone defects. Primary rat bone marrow stromal cells transduced with Runx2 or control (no Runx2 insert) retroviral vector were seeded onto 3D fused deposition-modeled polycaprolactone scaffolds. Runx2-modified cells produced biologically-equivalent mineralized matrices at nearly 2-fold higher rates than control cells. Constructs cultured in vitro for 1 day (immature) or 21 days (mineralized) were subsequently implanted into critical size calvaria defects in syngeneic rats, and bone healing was analyzed by micro-CT and histomorphometry at 28 days. Runx2-modified and control constructs precultured for 1 day healed to a greater extent than defects receiving no implant. Cell-free scaffolds yielded equivalent levels of bone formation as constructs precultured for 1 day. Interestingly, defects treated with control cell-seeded constructs precultured for 21 days exhibited low bone formation compared to other construct treatments, and repair was comparable to empty defects. In contrast, Runx2-modified constructs precultured for 21 days contained twice as much bone as control constructs precultured for 21 days and equivalent levels of new bone as cell-free and 1 day precultured constructs. These results demonstrate interplay between Runx2 genetically-modified cells and in vitro construct maturation in bone healing responses.

Absorbable Implants↗
PubMed2006

Physical and biological performance of a novel block copolymer nerve guide.

Although the ability to regenerate is evident in the nervous system, lesioned neurites are unable to cross gaps in neuronal pathways. In order to bridge gaps, guiding cues are essential to direct neurite regrowth. To overcome many of the shortcomings of polymer-based nerve guides, we developed a bioresorbable nerve guide composed of a novel trimethylene carbonate-caprolacton block copolymer (TMC-CL). Pore formation was controlled by using special solvent/precipitation media compositions in combination with the pore forming agent poly ethylene glycol (PEG). NMR spectroscopy, shear force-, compression-, and permeation assays were used for conduit characterization. The polymer conduit has a semipermeable wall with submicron pores to allow free metabolite/drug exchange. In order to investigate the principle of temporally controlled expression of therapeutic proteins in nerve guides, Neuro-2a cells were genetically engineered to express the reporter gene product green fluorescent protein (GFP) under the control of the Tet-On system. When these transduced cells were encapsulated in nerve guides, GFP expression could be induced for days by adding the antibiotic tetracycline derivative doxycycline to the nerve guide environment. Furthermore, encapsulated dorsal root ganglia (DRG) produced long neurites in vitro. In subsequent in vivo experiments, nerve guides filled with Schwann cells (SC) were implanted into lesioned spinal cords of adult rats. Regeneration of spinal cord axons into nerve guides was promoted by co-implanted Schwann cells. The data suggest that the novel TMC-CL nerve guides provide a promising tool for neuroregeneration.

Absorbable Implants↗
PubMed2006

Triclosan release from coated polyglycolide threads.

Copolymerization of lactide, epsilon-caprolactone, and trimethylene carbonate is performed. The synthesis is focused on obtaining materials with adequate properties for application as a suture coating that could contain an antimicrobial agent like triclosan. An amorphous character, a low glass transition temperature, a moderate susceptibility to degradation, and a hydrophobic nature are the conditions required for the optimal behavior of this coating. These properties can be attained with a copolymer of composition 10:60:30. Triclosan is added to the surface of polyglycolide threads and its release is studied in different media with high-performance liquid chromatography. The influence of the temperature, the diameter of the thread, the initial concentration of the antibacterial agent, and the applied procedure on the incorporation of triclosan is also evaluated. A total release of triclosan is attained after a few days of exposure to a Dulbecco's based medium, whereas equilibrium concentrations are reached when a Sörensen hydrophilic medium is used. Partition and diffusion coefficients are also estimated.

Absorbable Implants↗