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.

Eco-friendly regeneration of end-of-life PVDF membrane with triethyl phosphate:Efficiency and mechanism

Membrane will inevitably reach the end of its lifespan due to the irrecoverable fouling accumulation in membrane bioreactors(MBRs)during long-term operation.Herein,we developed an eco-friendly membrane regeneration strategy with triethyl phosphate(TEP),which successfully prolonged the lifespan of end-of-life(EOL)polyvinylidene fluoride(PVDF)membranes in a large-scale MBR.The regenerated(Rg)membrane exhibited a water permeance of 534.8±45.7 L m^(-2)h^(-1)bar-1,along with stable rejection rate,which was comparable with that of the new membrane.Furthermore,compared to the membrane subjected solely to preliminary cleaning,the Rg membrane presented a more hydrophilic surface due to the combination of preliminary cleaning and solvent-based processing.Besides,the Rg membrane presented less fouling propensity with the critical flux of 15.2 L m^(-2)h^(-1),significantly higher than that of the EOL membrane(4.0 L m^(-2)h^(-1)).Importantly,the membrane regeneration strategy was capable of guaranteeing the effluent quality in MBR systems for treating real municipal wastewater.This study provides an eco-friendly membrane regeneration strategy for effectively removing the irrecoverable foulants,thereby promoting the advancement of sustainable membrane-based wastewater treatment technology.

CHARACTERIZATION OF REGENERATED CELLULOSE MEMBRANES HYDROLYZED FROM CELLULOSE ACETATE

A series of cellulose acetate membranes were prepared by using formamide as additive, and then were hydrolyzed in 4 wt% aqueous NaOH solution for 8 h to obtain regenerated cellulose membranes. The dependence of degree of substitution, structure, porous properties, solubility and thermal stability on hydrolysis time was studied by chemical titration, Fourier transform infrared spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, and differential scanning calorimetry, respectively. The results indicated that the pore size of the regenerated cellulose membranes was slightly smaller than that of cellulose acetate membrane, while solvent-resistance, crystallinity and thermostability were significantly improved. This work provides a simple way to prepare the porous cellulose membranes, which not only kept the good pore characteristics of cellulose acetate membranes, but also possessed solvent-resistance, high crystallinity and thermostability. Therefore, the application range of cellulose acetate membranes can be expanded.

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.

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.

Chinese herbal medicine Yougui Pill reduces exogenous glucocorticoid-induced apoptosis in anterior pituitary cells

Long-term glucocorticoid use may result in sustained suppression of one or more secreted components from the hypothalamo-pituitary-adrenal axis, and often results in apoptosis. Yougui Pill（YGP）, a 10-component traditional Chinese herbal medicine, has been shown to be clinically effective for glucocorticoid-induced suppression of the hypothalamo-pituitary-adrenal axis. However, the pharmacological and molecular mechanisms remain unclear. We hypothesized that YGP would exert an anti-apoptosis effect on dexamethasone-treated anterior pituitary cells. In vivo experiments showed that YGP significantly reduced the number of apoptotic cells, down-regulated m RNA expression of cytochrome c, caspase-3, and caspase-9, and up-regulated m RNA expression of Bcl-2. These findings suggest that YGP reduced glucocorticoid-induced apoptosis in rat anterior pituitary cells by regulating the mitochondria-mediated apoptosis pathway.

3′-Daidzein sulfonate sodium improves mitochondrial functions after cerebral ischemia/reperfusion injury

3′-Daidzein sulfonate sodium is a new synthetic water-soluble compound derived from daidzein（an active ingredient of the kudzu vine root）. It has been shown to have a protective effect on cerebral ischemia/reperfusion injury in rats. We plan to study the mechanism of its protective effect. 3′-Daidzein sulfonate sodium was injected in rats after cerebral ischemia/reperfusion injury. Results showed that 3′-daidzein sulfonate sodium significantly reduced mitochondrial swelling, significantly elevated the mitochondrial membrane potential, increased mitochondrial superoxide dismutase and glutathione peroxidase activities, and decreased mitochondrial malondialdehyde levels. 3′-Daidzein sulfonate sodium improved the structural integrity of the blood-brain barrier and reduced blood-brain barrier permeability. These findings confirmed that 3′-daidzein sulfonate sodium has a protective effect on mitochondrial functions after cerebral ischemia/reperfusion injury, improves brain energy metabolism, and provides protection against blood-brain barrier damage.

In vivo field recordings effectively monitor the mouse cortex and hippocampus under isoflurane anesthesia

Isoflurane is a widely used inhaled anesthetic in the clinical setting. However, the mechanism underlying its effect on consciousness is under discussion. Therefore, we investigated the effect of isoflurane on the hippocampus and cortex using an in vivo field recording approach. Our results showed that 1.3%, 0.8%, and 0.4% isoflurane exerted an inhibitory influence on the mouse hippocampus and cortex. Further, high frequency bands in the cortex and hippocampus showed greater suppression with increasing isoflurane concentration. Our findings suggest that in vivo field recordings can monitor the effect of isoflurane anesthesia on the mouse cortex and hippocampus.

Effects of Nano-patterning Modification on the Cell Proliferation and Adhesion in Burn Wound Healing of Regenerated Silk Fibroin Membrane

Objective:To investigate the effect of nano-patterning modification on the cell proliferation and adhesion in burn wound healing of regenerated silk fibroin membrane.Methods:A total of 60 healthy SD mice were randomly divided into three groups:group A received treatment involving nano-patterning on the surface of regenerated silk fibroin membrane,group B received treatment with recombinant human epidermal growth factor gel,and group C received the same treatment with recombinant human epidermal growth factor gel,with 20 cases in each group.Wound healing,surface structure,protein adsorption,cell proliferation and adhesion were assessed at intervals of 5th,15th and 25th d after treatment.Results:The findings indicated that:(1)The duration and pace of wound healing in groups A and B surpassed those of group C,with group A exhibiting superior results compared to group B(P<0.05);(2)Histopathological analysis revealed a progressive increase in neovascularization and fibroblast count in wound tissue across the 5th,15th,and 25th days for all three groups,with group C exhibiting a higher count of neovascularization and fibroblasts in unhealed tissue compared to groups A and B.(3)The levels of basic calponin expression in group A and group B showed an increase on the 5th and 15th day,followed by stabilization on the 25th day.In group C,the expression of basic calponin was initially high on the 5th day,and then stabilized on the 15th and 25th day(P<0.05);(4)The expression of fibroblast proliferating cell nuclear antigen in the wound tissue of mice in all three groups peaked on the 15th day and subsequently declined.The expression of PCNA in group A and group B was higher than that in group C at each time point,with group A exhibiting higher levels than group B(P<0.05);(5)As wounds healed,there was a reduction in apoptotic cells within the wound tissues of mice across three groups,with group a exhibiting a lower count compared to groups B and C(P<0.05).Conclusion:Nanopatterning on the surface of regenerated silk fibroin membrane can enhance the biocompatibility of burn wound treatment and promote the proliferation and adhesion of reparative cells.

Effect of Rolling Temperature on the Mechanical Properties and Corrosion Behavior of Mg-Zn-Y-Nd Alloy Thin Sheets

There is a growing demand for degradable membranes with sufficient mechanical properties to guide tissue regeneration in dental surgery.In the present work,a two-stage rolling process in which the first rolling stage(FRS)adopted a reduction rate of 30%for six passes at various temperatures,while the second rolling stage was rolling at 200℃for two passes,was employed to prepare a 150μm-grade Mg-2.0Zn-0.5Y-0.5Nd(ZE21B)Mg alloy sheets for guided tissue regeneration membrane.The microstructure of the thin sheets was gradually refined with increasing rolling passes,and the thin sheets that were rolled at different FRS temperatures exhibit an ellipse texture.The thin sheets rolled at 350℃for FRS show low elongation due to premature fracture caused by the coarse second phase particles.On account of uniform and fine grains,the thin sheets rolled at 400℃for the FRS have proper mechanical properties:yield strength of 214.6±8.5 MPa,ultimate tensile strength(UTS)of 246.8±10.3 MPa and elongation to failure of 28.3±1.2%.When rolling at 450℃for FRS,proper ductility of the thin sheets has been acquired,followed by a decline in UTS since a bimodal structure with fine and coarse grain was developed.Immersion tests demonstrated the FRS temperature had no significant effect on the corrosion behavior and corrosion rate of Mg alloy sheets after 7 days’immersion in artificial saliva solution.This research has great significance for the production of degradable Mg sheets for guided tissue regeneration membrane.