A Novel Guided Bone Regeneration Membrane Composed of Nano-hydroxyapatite and Aliphatic Polyester-amide

Hydrothermally synthesized nano-hydroxyapatite（n-HA ） varmg m wetght Jrom 10% to 30% was used us filler to make guided bone regeneration （ GBR ） composite membranes with navel aliphatic polyesteramide （ PEA ）. The structare and properties of PEA and its n- HA composites were investigated through TEM, IR, XRD, SEM and EDX. The shape and size of the n- HA crystals are similar to the apatite crystals in nataral bone. Molecule interactions are present between the n- HA and PEA in the compasite, which allows the uniform dispersion of n- HA in PEA matrix. This contributes enhanced mechanical property and bioactivhy to the compasite. The cytacompatibilhy of the composites has been investigated by culturing osteoblasts on the membranes. Good cell attachment and proliferation manner were observed on the membranes after 1 week. These results suggest that the PEA/ n-HA compasite membrane prepared in this study may serve us barrier membranes for guided bone regeneration and potential candidate scaffold for tissue engineering.

Appropriately adapted properties of hot-extruded Zn-0.5Cu-xFe alloys aimed for biodegradable guided bone regeneration membrane application

Appropriately adapted comprehensive mechanical properties,degradation behavior and biocompatibility are prerequisites for the application of Zn-based biodegradable implants.In this study,hot-extruded Zn-0.5Cu-xFe(x=0.1,0.2 and 0.4 wt%)alloys were fabricated as candidates for biodegradable materials for guided bone regeneration(GBR)membranes.The hot-extrusion process and Cu alloying were expected mostly to enhance the mechanical properties,and the Fe alloying was added mainly for regulating the degradation.The microstructure,mechanical properties and in vitro degradation behavior were systematically investigated.The ZnCuFe alloys were composed of a Zn matrix and FeZn13 phase.With increasing Fe content,a higher FeZn13 phase precipitation with larger particles was observed.Since elongation declined significantly until fracture with increasing Fe content up to 0.4 wt%,the ZnCuFe(0.2 wt%)alloy achieved a good balance between mechanical strength and ductility,with an ultimate tensile strength of 202.3 MPa and elongation at fracture of 41.2%.Moreover,the addition of Fe successfully accelerated the degradation of ZnCuFe alloys.The ZnCuFe(0.2 wt%)alloy showed relatively uniform corrosion in the long-term degradation test.Furthermore,extracts of the ZnCuFe(0.2 wt%)alloy showed no apparent cytotoxic effects against L929 fibroblasts,Saos-2 osteoblasts or TAg periosteal cells.The ZnCuFe(0.2 wt%)alloy exhibited the potential to inhibit bacterial adhesion of Streptococcus gordonii and mixed oral bacteria.Our study provides evidence that the ZnCuFe(0.2 wt%)alloy can represent a promising material for the application as a suitable GBR membrane.

Improving chitosan-based composite membrane by introducing a novel hybrid functional nano-hydroxyapatite with carboxymethyl cellulose and phytic acid

A functional hybrid nano-hydroxyapatite(carboxymethyl cellulose-phytic acid-n-HA,CMC-PA-n-HA)was prepared by adding CMC and PA.The results of Fourier transformation infrared spectra,X-ray diffraction,thermal gravimetric analysis and dispersion experiments indicated that the addition of CMC and PA affected the morphology,crystallinity and crystal size of hybrid n-HA,and CMC endowed hybrid n-HA with excellent dispersion.Scanning electron microscope results showed that CMC-PA-n-HA nanoparticle could be uniformly dispersed in chitosan(CS)matrix to obtain composite membrane by casting technology,so that the highest tensile strength of CMC-PA-n-HA/CS composite membrane was 69.64%and 144.45%higher than that of CS membrane and n-HA/CS composite membrane,respectively.Contact angle test showed that CMC-PA-n-HA effectively improved hydrophilicity of the CS membrane.The simulated body fluid immersion results indicated that the CMC-PA-n-HA/CS composite membrane not only exhibited good degradability but also promoted bone-like apatite deposition.The cell proliferation experiments proved that the introduction of PA made the composite membrane have better cell adhesion and proliferation ability.Antibacterial tests demonstrated that PA could effectively improve the antibacterial properties of the composite membrane,which is expected to be applied as guide bone tissue regeneration membrane.