Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing comp...Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing composite coatings are usually complicated and time-consuming.Herein,a novel composite coating,composed of bioactive magnesium thioctic acid(MTA)layer formed by deposition and corrosion-resistant magnesium hydroxide(Mg(OH)_(2))layer grown in situ,is simply fabricated on ZE21B alloys via one-step electrodeposition.Scanning electron microscopy(SEM)shows that the electrodeposited coating has a compact and uniform structure.And the high adhesion of the MTA/Mg(OH)_(2)hybrid coating is also confirmed by the micro-scratch test.Electrochemical test,scanning kelvin probe(SKP),and hydrogen evolution measurement indicate that the hybrid coating effectively reduces the degradation rate of Mg substrates.Haemocompatibility experiment and cell culture trial detect that the composite coating is of fine biocompatibility.Finally,the preparation mechanism of MTA/Mg(OH)_(2)hybrid coatings is discussed and proposed.This coating shows a great potential application for cardiovascular stents.展开更多
The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human ...The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human bone.The aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion concentration.In this study,we prepared and modified Mg-3Zn,Mg-3Zn-1Y,and Mg-2Zn-1Mn by hot extrusion,and used Mg-2.5Y-2.5Nd was as a control.We then investigated the effect of additions of Y and Mn on alloys'properties.Our results show that Mn and Y can improve not only compression strength but also corrosion resistance.The alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro,and for this reason we selected it for implantation in vivo.The degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction,and the degradation products left no signs of damage to the heart,liver,kidney,or brain.Furthermore,we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.展开更多
Developing high-performance aqueous Zn-ion batteries from sustainable biomass becomes increasingly vital for large-scale energy storage in the foreseeable future.Therefore,γ-MnO_(2) uniformly loaded on N-doped carbon...Developing high-performance aqueous Zn-ion batteries from sustainable biomass becomes increasingly vital for large-scale energy storage in the foreseeable future.Therefore,γ-MnO_(2) uniformly loaded on N-doped carbon derived from grapefruit peel is successfully fabricated in this work,and particularly the composite cathode with carbon carrier quality percentage of 20 wt%delivers the specific capacity of 391.2 mAh g^(−1)at 0.1 A g^(−1),outstanding cyclic stability of 92.17%after 3000 cycles at 5 A g^(−1),and remarkable energy density of 553.12 Wh kg^(−1) together with superior coulombic efficiency of~100%.Additionally,the cathodic biosafety is further explored specifically through in vitro cell toxicity experiments,which verifies its tremendous potential in the application of clinical medicine.Besides,Zinc ion energy storage mechanism of the cathode is mainly discussed from the aspects of Jahn–Teller effect and Mn domains distribution combined with theoretical analysis and experimental data.Thus,a novel perspective of the conversion from biomass waste to biocompatible Mn-based cathode is successfully developed.展开更多
AIM: To establish an untransfected human corneal epithelial (HCEP) cell line and characterize its biocompatibility with denuded amniotic membrane (dAM). METHODS: The torn HCEP pieces were primarily cultured in DMEM/F1...AIM: To establish an untransfected human corneal epithelial (HCEP) cell line and characterize its biocompatibility with denuded amniotic membrane (dAM). METHODS: The torn HCEP pieces were primarily cultured in DMEM/F12 media (pH 7.2) supplemented with 20% fetal bovine serum and other necessary factors, yielding an HCEP cell line which was its growth performance, chromosome morphology, tumorigenicity and expression of marker proteins analyzed. In addition, the biocompatibility of HCEP cells with dAM was evaluated through histological and immunocytochemistry analyses and with light, electron and slit-lamp microscopies. RESULTS: HCEP cells proliferated to confluence in 3 weeks, which have been subcultured to passage 160. A continuous untransfected HCEP cell line, designated as utHCEPC01, was established with a population doubling time of 45.42 hours as was determined at passage 100. The cells retained HCEP cell properties as were approved by chromosomal morphology and the expression of keratin 3. They, with no tumorigenicity, formed a multilayer epithelium-like structure on dAMs through proliferation and differentiation during air-liquid interface culture, maintained expression of marker proteins including keratin 3 and integrin p 1 and attached tightly to dAMs. The reconstructed HCEP was highly transparent and morphologically and structurally similar to the original. CONCLUSION: An untransfected and non-tumorigenic HCEP cell line was established in this study. The cells maintained expression of marker proteins. The cell line was biocompatible with dAM. It holds the potential of being used for in vitro reconstruction of tissue-engineered HCEP, promising for the treatment of diseases caused by corneal epithelial disorders.展开更多
Mg-Ca alloys have recently attracted great attention towards the research in the field of orthopedic biodegradable implants.This study presents an in vitro degradation assessment of Mg-0.8Ca(0.8 wt.%of Ca)alloy in Han...Mg-Ca alloys have recently attracted great attention towards the research in the field of orthopedic biodegradable implants.This study presents an in vitro degradation assessment of Mg-0.8Ca(0.8 wt.%of Ca)alloy in Hank’s balanced salt solution(HBSS).Immersion,hydrogen evolution and electrochemical behavior was studied as well as the cytotoxicity of the degradation products.Morphology and phase composition of the corrosion products were studied using SEM,EDX and XRD techniques.Degradation in HBSS resulted in the formation of the needle-shaped carbonated hydroxyapatite which was similar to the biological apatite in the human bone.Degradation kinetics showed that Mg-0.8Ca alloy had approximately 3-fold faster degradation rate than the pure Mg(1.08±0.38 mm/year for Mg-0.8Ca and 0.35±0.17 mm/year for pure Mg),as observed in two independent experiments.Both,pure Mg and Mg-0.8Ca alloy were biocompatible,generating no cytotoxic degradation products against human-derived HEK 293 cells.Thus,the Mg-0.8Ca alloy was found to be a promising biodegradable implant in terms of bioactivity and compatibility with human cell lines.Depending on the application of the implant and the estimated healing time of the bone,the desired degradation rate of an implant can be controlled by the Mg-Ca composition of such alloys.展开更多
A modified electrolyte (CH3COOH-HClO4-A-B) for electropolishing (EP) of NiTi was presented for improving the corrosion resistance and biocompatibility of the alloy. Using the proposed parameters, a homogeneous and...A modified electrolyte (CH3COOH-HClO4-A-B) for electropolishing (EP) of NiTi was presented for improving the corrosion resistance and biocompatibility of the alloy. Using the proposed parameters, a homogeneous and uniform surface was obtained. Atomic force microscopy (AFM) revealed that the surface roughness (Ra) for EP sample (23.21 nm) was close to mechanical polishing (MP) sample (19.36 nm). Analysis by X-ray photoelectron spectroscopy (XPS) showed that Ti/Ni ratio increased from 3.1 for MP sample to 27.6 for EP sample. Measurements using potentiodynamic polarization in Hanks' solution showed that no pitting occurred for EP sample even though the applied potential increased up to 1500 mV (vs SCE), while the MP sample was broken down at 650 mV. The present study indicates that electropolishing NiTi with this modified electrolyte contributes to the improved biocompatibility of NiTi.展开更多
AIM: To establish an untransfected human corneal stromal (HCS) cell line and characterize its biocompatibility to acellular porcine corneal stoma (aPCS). METHODS: Primary culture was initiated with a pure population o...AIM: To establish an untransfected human corneal stromal (HCS) cell line and characterize its biocompatibility to acellular porcine corneal stoma (aPCS). METHODS: Primary culture was initiated with a pure population of HCS cells in DMEM/F12 media (pH 7.2) containing 20% fetal bovine serum and various necessary growth factors. The established cell line was characterized by growth property, chromosome analysis, tumorigenicity assay, expression of marker proteins and functional proteins. Furthermore, the biocompatibility of HCS cells with aPCS was examined through histological and immunocytochemistry analyses and with light, electron microscopies. RESULTS: HCS cells proliferated to confluence 2 weeks later in primary culture and have been subcultured to passage 140 so far. A continuous untransfected HCS cell line with a population doubling time of 41.44 hours at passage 80 has been determined. Results of chromosome analysis, morphology, combined with the results of expression of marker protein and functional proteins suggested that the cells retained HCS cell properties. Furthermore, HCS cells have no tumorigenicity, and with excellent biocompatibility to aPCS. CONCLUSION: An untransfected and non-tumorigenic HCS cell line has been established, and the cells maintained positive expression of marker proteins and functional proteins. The cell line, with excellent biocompatibility to aPCS, might be used for in vitroreconstruction of tissue-engineered HCS.展开更多
AIM: To study the optical property and biocompatibility of a tissue engineering cornea. METHODS: The cross-linker of N- (3-Dimethylaminoropyl)-N'ethylcarbodiimide hydrochloride (EDC)/ N-Hydroxysuccinimide (NHS) wa...AIM: To study the optical property and biocompatibility of a tissue engineering cornea. METHODS: The cross-linker of N- (3-Dimethylaminoropyl)-N'ethylcarbodiimide hydrochloride (EDC)/ N-Hydroxysuccinimide (NHS) was mixed with Type I collagen at 10% (weight/volume). The final solution was molded to the shape of a corneal contact lens. The collagen concentrations of 10%, 12.5%, 15%, 17.5% and 20% artificial corneas were tested by UV/vis-spectroscopy for their transparency compared with normal rat cornea. 10-0 sutures were knotted on the edges of substitute to measure the corneal buttons's mechanical properties. Normal rat corneal tissue primary culture on the collagen scaffold was observed in 4 weeks. Histopathologic examinations were performed after 4 weeks of in vitro culturing. RESULTS: The collagen scaffold appearance was similar to that of soft contact lens. With the increase of collagen concentration, the transparency of artificial corneal buttons was diminished, but the toughness of the scaffold was enhanced. The scaffold transparency in the 10% concentration collagen group resembled normal rat cornea. To knot and embed the scaffold under the microscope, 20% concentration collagen group was more effective during implantation than lower concentrations of collagen group. In the first 3 weeks, corneal cell proliferation was highly active. The shapes of cells that grew on the substitute had no significant difference when compared with the cells before they were moved to the scaffold. However, on the fortieth day, most cells detached from the scaffold and died. Histopathologic examination of the primary culture scaffold revealed well grown corneal cells tightly attached to the scaffold in the former culturing. CONCLUSION: Collagen scaffold can be molded to the shape of soft contact corneal lens with NHS/EDC. The biological stability and biocompatibility of collagen from animal species may be used as material in preparing to engineer artificial corneal scaffold.展开更多
BACKGROUND:It has been reported that chitosan nerve conduits could support axon elongation and improve relevant function during in vivo nerve regeneration. OBJECTIVE: To investigate in vitro biocompatibility of thre...BACKGROUND:It has been reported that chitosan nerve conduits could support axon elongation and improve relevant function during in vivo nerve regeneration. OBJECTIVE: To investigate in vitro biocompatibility of three novel, chitosan/polycation composite materials for nerve regeneration in cultured mouse Schwann cells and PC12 cells. DESIGN, TIME AND SETTING: The observational, control experiments for nerve tissue engineering were performed at the Department of Biological Sciences and Biotechnology of Tsinghua University from August 2007 to January 2008. MATERIALS: Mouse Schwann cells were isolated from the sciatic nerve of 5–7-day-old BALB/C mice. PC12 cells were purchased from the American Type Culture Collection (ATCC, USA). Chitosan was purchased from Tsingdao Haisheng Co., China. Poly-L-lysine hydrochloride (PLL), polyethyleneimine (PEI) poly-L-ornithine hydrobromide (POR), and S-100 antibody was purchased from Sigma Chemical Co., USA. Cell Counting Kit-8 (CCK-8) was purchased from Dojindo Chemical Co., Japan. METHODS: Three chitosan/polycation composite materials for nerve regeneration (PLL-0.25, PEI-0.25, and POR-0.25) were produced by blending chitosan with 0.25% (w/w) poly-L-lysine, polyethyleneimine, and poly-L-ornithine. Pure chitosan was utilized as the control. After 3 days of culture, the morphology of mouse Schwann and PC12 cells cultured on all substrates was observed with an inverted phase contrast microscope. Mouse Schwann cells were stained by immunofluorescence labeling S-100 protein and nuclei, followed by identification with a confocal laser-scanning microscope. The amount of proliferating mouse Schwann and PC12 cells was determined by CCK-8 after 1, 3, and 5 days in culture. The level of PC12 cell differentiation on all substrates was assessed by measuring neurite length at 1, 3, and 5 days after seeding. MAIN OUTCOME MEASURES: Morphology and amount of proliferation of mouse Schwann cells and PC12 cells cultured on chitosan and three polycation-modified materials, as well as amount of differentiation in PC12 cells on these substrates. RESULTS: (1) Morphology of mouse Schwann cells and PC12 cells on all substrates: after 3 days in culture on three different chitosan/polycation composite substrates, Schwann cells were connected to each other and exhibited greater proliferation, compared to the chitosan control. In particular, on PLL-0.25 and POR-0.25 substrates, some cells congregated and nearly reached confluence. The PC12 cells on chitosan substrate, after 3 days in culture, maintained a round shape; few exhibited a bipolar shape and began to form neurite extensions. However, on PLL-0.25 and POR-0.25 substrates, most PC12 cells displayed a bipolar shape with obvious neurite outgrowth, and almost grew as an adherent, spreading monolayer. (2) Proliferation of mouse Schwann cells and PC12 cells on all substrates: on the first day, Schwann cell proliferation on the three composite substrates was significantly greater than the cells on chitosan control (P 〈 0.01). After 3 and 5 days in culture, PLL-0.25 and POR-0.25 substrates resulted in greater cell proliferation when compared to pure chitosan (P 〈 0.01). On the third and fifth day in culture PC12 cell proliferation on PLL-0.25 and POR-0.25 was significantly greater than on chitosan substrate (P 〈 0.01). (3) Differentiation of PC12 cells on all substrates: at all time points, the average neurite length of cells cultured on composite materials was significantly longer than on chitosan control (P 〈 0.05-0.01). Cells on PLL-0.25 exhibited the longest average neurite length at days 3 and 5. CONCLUSION: Mouse Schwann cells and PC12 cells exhibit in vitro biocompatibility with poly-L-lysine-and poly-L-ornithine-modified substrates, which indicates that these substrates could serve as suitable substrates for peripheral nerve regeneration.展开更多
Recently,tissue engineering (TE)is one of the fast growing research fields due the accessibility of extra-molecular matrix (ECM)at cellular and molecular level with valuable potential prospective of hydrogels.The enha...Recently,tissue engineering (TE)is one of the fast growing research fields due the accessibility of extra-molecular matrix (ECM)at cellular and molecular level with valuable potential prospective of hydrogels.The enhancement in the production of hydrogel-based cellular scaffolds with the structural composition of ECM has been accelerated with involvement of rapid prototyping techniques.Basically,the recreation of ECM has been derived from naturally existed or synthetic hydrogelbased polymers.The rapid utilization of hydrogels in TE puts forward the scope of bioprinfing for the fabrication of the functional biological tissues,cartilage,skin and artificial organs.The main focus of the researchers is on biofabrication of the biomaterials with maintaining the biocompatibility,biodegradability and increasing growth efficiency.In this review, biological development in the structure and cross-linking connections of natural or synthetic hydrogels are discussed.The methods and design criteria that influence the chemical and mechanical properties and interaction of seeding cells before and after the implantations are also demonstrated.The methodology of bioprinting techniques along with recent development has also been reviewed.In the end,some capabilities and shortcomings are pointed out for further development of hydrogels-based scaffolds and selection of bioprinting technology depending on their application.展开更多
The objective of this study was to evaluate the biocompatibility of vessel extracellular matrix (VECM) from rabbit and to discuss the feasibility of vessel extracellular matrix as a matrix for urethral reconstructio...The objective of this study was to evaluate the biocompatibility of vessel extracellular matrix (VECM) from rabbit and to discuss the feasibility of vessel extracellular matrix as a matrix for urethral reconstruction. Primary cultured bladder smooth muscle cells isolated from New Zealand rabbits were implanted on VECM .The effects of VECM on rabbit bladder smooth muscle cells (RBSMCs) metabolic activity, attachment, proliferation were monitored in vitro with the aid of an inverted light microscope and a scanning electron microscope. The cell viability was monitored by MTT(methythiazolye tetrazolium bromide) after 1, 3, 5 days seeding. The in vivo tissue response to VECM was investigated by implanting them into the subcutaneous of rabbits. VECM exhibited a nontoxic and bioactive effect on RBSMCs. RBSMCs could be attached to and proliferated on VECM and maintained their morphologies. MTT assay showed RBSMCs cultured with the extracts of VECM were not significantly different from those of negative controls. In vivo, VECM demonstrated a favorable tissue compatibility without tissue necrosis, fibrosis and other abnormal response. VECM exhibited nontoxic and bioactive effects on RBSMC. It is a suitable material for urethral reconstruction.展开更多
This study aimed to examine the biocompatibility of calcium titanate(CaTiO3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO3coating as an alternative to current implant coati...This study aimed to examine the biocompatibility of calcium titanate(CaTiO3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO3coating as an alternative to current implant coating materials. CaTiO3-coated titanium screws were implanted with hydroxyapatite(HA)-coated or uncoated titanium screws into medial and lateral femoral condyles of 48 New Zealand white rabbits. Imaging, histomorphometric and biomechanical analyses were employed to evaluate the osseointegration and biocompatibility 12 weeks after the implantation. Histology and scanning electron microscopy revealed that bone tissues surrounding the screws coated with CaTiO3were fully regenerated and they were also well integrated with the screws. An interfacial fibrous membrane layer, which was found in the HA coating group, was not noticeable between the bone tissues and CaTiO3-coated screws. X-ray imaging analysis showed in the CaTiO3coating group, there was a dense and tight binding between implants and the bone tissues; no radiation translucent zone was found surrounding the implants as well as no detachment of the coating and femoral condyle fracture. In contrast, uncoated screws exhibited a fibrous membrane layer, as evidenced by the detection of a radiation translucent zone between the implants and the bone tissues. Additionally, biomechanical testing revealed that the binding strength of CaTiO3coating with bone tissues was significantly higher than that of uncoated titanium screws, and was comparable to that of HA coating. The study demonstrated that CaTiO3coating in situ to titanium screws possesses great biocompatibility and osseointegration comparable to HA coating.展开更多
Chitosan, collagen I and gelatin were mixed in appropriate quantities to develop a new nerve repair material, with good arrangement and structure, as well as even aperture size. The composite material was sterilized b...Chitosan, collagen I and gelatin were mixed in appropriate quantities to develop a new nerve repair material, with good arrangement and structure, as well as even aperture size. The composite material was sterilized by 60Co irradiation for 24 hours prior to implantation in the right thigh of rats following sciatic nerve damage. Results showed that the material was nontoxic to the kidneys and the liver, and did not induce an inflammatory response in the muscles. The composite material enhanced the recovery of sciatic nerve damage in rats. These experimental findings indicate that the composite material offers good biocompatibility and has a positive effect on injured nerve rehabilitation.展开更多
Biodegradable magnesium alloy stents(MAS)have great potential in the treatment of cardiovascular diseases.However,too fast degradation and the poor biocompatibility are still two key problems for the clinical utility ...Biodegradable magnesium alloy stents(MAS)have great potential in the treatment of cardiovascular diseases.However,too fast degradation and the poor biocompatibility are still two key problems for the clinical utility of MAS.In the present work,a functional coating composed of hydrophilic polymers and bioactive peptides was constructed on magnesium alloy to improve its corrosion resistance and biocompatibility in vitro and in vivo.Mg-Zn-Y-Nd(ZE21B)alloy modified with the functional coating exhibited moderate surface hydrophilicity and enhanced corrosion resistance.The favourable hemocompatibility of ZE21B alloy with the functional coating was confirmed by the in vitro blood experiments.Moreover,the modified ZE21B alloy could selectively promote the adhesion,proliferation,and migration of endothelial cells(ECs),but suppress these behaviors of smooth muscle cells(SMCs).Furthermore,the modified ZE21B alloy wires could alleviate intimal hyperplasia,enhance corrosion resistance and re-endothelialization in vivo transplantation experiment.These results collectively demonstrated that the functional coating improved the corrosion resistance and biocompatibility of ZE21B alloy.This functional coating provides new insight into the design and development of novel biodegradable stents for biomedical engineering.展开更多
A new scaffold material composed of extracellular matrix (ECM) and thermal sensitive hydrogel (HG), and evaluated its biocompatibility were investigated. We cultured bladder smooth muscle cells with this compound ...A new scaffold material composed of extracellular matrix (ECM) and thermal sensitive hydrogel (HG), and evaluated its biocompatibility were investigated. We cultured bladder smooth muscle cells with this compound material, and then observed with phase contrast microscopy and scanning electron microscope (SEM) to assess the cell growth and morphology. The cell adhesion and proliferation were detected with MTT assay and cell count. Results show the ECM/HG compounds appeared as a net-like and red-stained construction with enough meshes and without any cellular fragments. 6 h after implantation, cells were observed adhere on the compounds and extend spurious along the fibers 12 h later. Under SEM even some ECM was observed to be secreted. MTT assay shows there was obvious statistic difference among 3 groups (P〈0.05). ECM/HG compound materials show a good biocompatibility, which confirms that it would be an ideal tissue engineering scaffolds.展开更多
The biocompatibility of silicone rubber (SR) based electrodes coating with poly (vinyl alcohol) (PVA) films after implanted in the brain of rats was investigated. Twenty-two Wistar rats were used and implanted w...The biocompatibility of silicone rubber (SR) based electrodes coating with poly (vinyl alcohol) (PVA) films after implanted in the brain of rats was investigated. Twenty-two Wistar rats were used and implanted with SR electrodes and PVA/PAA films coated electrodes in left and right cerebral cortex respectively. After 4 and 8 weeks, the expression of glial fibrillary acidic protein (GFAP, a specific marker of astrocytes) and cluster of differentiation 68 (CD68, a specific marker of macrophages) were evaluated by immunohistochemistry. After 8 weeks, GFAP and CD68 expressions around PVA electrodes were significantly lower than those around SR electrodes in every stratified area (0-50 μm, 50-100 μm, 100 μm from further up to the electrode-tissue interface). The resuits show that PVA coating can reduce the expressions of GFAP and CD68, suggesting the PVA coating can improve the biocompatibility of the SR while it is implanted in brain.展开更多
Summary: By culturing bone marrow mesenchymal stem cells of rabbits with fibrin glue in vitro, the biocompatibility of fibrin glue was investigated to study whether this material can be used as scaffolds in bone tissu...Summary: By culturing bone marrow mesenchymal stem cells of rabbits with fibrin glue in vitro, the biocompatibility of fibrin glue was investigated to study whether this material can be used as scaffolds in bone tissue engineering. After 2-months old New Zealand rabbits had been anesthetized, about 4-6 ml of bone marrow were aspirated from rabbit femoral trochanter. The monocytes suspension was aspirated after bone marrow was centrifuged with lymphocyte separating medium and cultured primarily. Then the cells were divided into two groups: one was cultured with complete medium and the other with induced medium. The cells of the two groups were collected and inoculated to the culture plate containing fibrin glue. In the control group, cells were inoculated without fibrin glue. The implanted cells and materials were observed at different stages under a phase-contrast microscope and scanning electron microscope. MTT and alkaline phosphatase (ALP) were measured. Bone marrow mesenchymal stem cells grew on the surface of fibrin glue and adhered to it gradually. Cells light absorption value (A value) and the ALP content showed no significant difference. Fibrin glue had no inhibitory effect on cell morphology, growth, proliferation and differentiation. It has good biocompatibility and can be used as scaffold materials for bone marrow mesenchymal stem cells in bone tissue engineering.展开更多
Biodegradable polymers have been widely used in the field of tissue engineering.The adhesive characteristic of polymer surfaces must be modified for cell seeding and growth before being used.The modified method poly-...Biodegradable polymers have been widely used in the field of tissue engineering.The adhesive characteristic of polymer surfaces must be modified for cell seeding and growth before being used.The modified method poly-β-hybroxybutyric acid (PHB) was introduced and the biocompatibility of modified PHB to adrenocortical cells was studied here,Gelatin was used as a modifier to retrofit PHB and adrenocortical cells were seeded in the modified PHB.The effects of PHB on the proliferation and secreting function of adrenocortical cells were evaluated by MTT and RIA methods.It shows that adrenocortical cells were able to grow and survived in PHB and no influence on the proliferation and secreting function of the cells was observed.The morphology study shows that the modified PHB was easy for cells seeding and growing.The modified PHB is a good biodegradable material as cell carrier for transplantation of adrenocortical cells.展开更多
Silicon nitride (Si3N4) ceramic is an attractive material for dental applications, especially used as a dental core material, due to its unique properties including high fracture toughness, high strength, high wear re...Silicon nitride (Si3N4) ceramic is an attractive material for dental applications, especially used as a dental core material, due to its unique properties including high fracture toughness, high strength, high wear resistance and non-cytotoxicity. In this study, the Si3N4 ceramic was fabricated by a non-pressure sintering technique at a relatively low sintering temperature of 1650℃ in nitrogen atmosphere. Borosilicate glass and 5 wt% ZrO2-added borosilicate glass were used for coating on the Si3N4 core surface because of their compatibility in thermal expansion, high chemical resistance and bio-inert. The specimens were then fired in electric tube furnace at 1100℃. The Vickers microhardness of borosilicate glass and 5 wt% ZrO2-added borosilicate glass veneering materials were measured and compared with the commercial dental veneer porcelain as a control (VITA VMK 95). The cytotoxicity of the Si3N4 ceramic and the veneering materials were tested by MTT assay, using human gingival fibroblasts (HGF) and periodontal ligament fibroblasts (HPDLF). The results indicate that the Si3N4 ceramic and Si3N4 ceramic veneered with borosilicate glass or 5 wt% ZrO2-added borosilicate glass veneering materials tested in this study are not toxic to oral tissue and can be used to produce dental prostheses.展开更多
DNA synthesis and collagen formations on the implant material by cell culture in vitro are the most important phenotypical expression to estimate the biocompatibility. In this part, DNA synthesis and collagen formatio...DNA synthesis and collagen formations on the implant material by cell culture in vitro are the most important phenotypical expression to estimate the biocompatibility. In this part, DNA synthesis and collagen formation on implant materials were quantitatively and qualitatively estimated by radioactive isotope H + thymidine to incorporate into DNA chains, H + proline to incorporate into type I collagen proteins followed by scin tillation counting and antibody antigen immunocytochemistry staining, respectively. Research results demonstrate that hydroxyapatite (HA) stimulates DNA synthesis and collagen formation on the material whereas this stimulation is restricted by adding spinel to the materials. There are statistical differences between the influences of material components on both DNA synthesis and collagen formation. It is supposed that porous materials can supply more platforms for cell anchoring, and more DNA and collagen are synthesised on the porous materials. Immersion in culture medium results in new HA crystal formation on the porous HA materials.展开更多
基金the National Key Research and Development Program of China(2018YFC1106703)the National Natural Science Foundation of China(No.U1804251)。
文摘Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based stents.Nevertheless,the steps for preparing composite coatings are usually complicated and time-consuming.Herein,a novel composite coating,composed of bioactive magnesium thioctic acid(MTA)layer formed by deposition and corrosion-resistant magnesium hydroxide(Mg(OH)_(2))layer grown in situ,is simply fabricated on ZE21B alloys via one-step electrodeposition.Scanning electron microscopy(SEM)shows that the electrodeposited coating has a compact and uniform structure.And the high adhesion of the MTA/Mg(OH)_(2)hybrid coating is also confirmed by the micro-scratch test.Electrochemical test,scanning kelvin probe(SKP),and hydrogen evolution measurement indicate that the hybrid coating effectively reduces the degradation rate of Mg substrates.Haemocompatibility experiment and cell culture trial detect that the composite coating is of fine biocompatibility.Finally,the preparation mechanism of MTA/Mg(OH)_(2)hybrid coatings is discussed and proposed.This coating shows a great potential application for cardiovascular stents.
基金supported by the Hunan Provincial Science and Technology Department Project(2015WK3012)the National Natural Science Foundation of China(No.81571021)+3 种基金R&D of Key Project of Hunan Provincial Science and Technology Department(2022SK2010)R&D of Key Technology of Light Metal Air Battery,Transformation and Industrialization of Scientific and Technological Achievements of Hunan Province(2020GK2071)R&D of Key Technology and Materials of Magnesium Air Battery,Transformation of Scientific and Technological Achievements of Changsha City(Kh2005186)Technology Fundation(2021JCJQ-JJ-0432)。
文摘The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human bone.The aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion concentration.In this study,we prepared and modified Mg-3Zn,Mg-3Zn-1Y,and Mg-2Zn-1Mn by hot extrusion,and used Mg-2.5Y-2.5Nd was as a control.We then investigated the effect of additions of Y and Mn on alloys'properties.Our results show that Mn and Y can improve not only compression strength but also corrosion resistance.The alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro,and for this reason we selected it for implantation in vivo.The degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction,and the degradation products left no signs of damage to the heart,liver,kidney,or brain.Furthermore,we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.
基金supported by the National Natural Science Foundation of China[Grant no.51821004].
文摘Developing high-performance aqueous Zn-ion batteries from sustainable biomass becomes increasingly vital for large-scale energy storage in the foreseeable future.Therefore,γ-MnO_(2) uniformly loaded on N-doped carbon derived from grapefruit peel is successfully fabricated in this work,and particularly the composite cathode with carbon carrier quality percentage of 20 wt%delivers the specific capacity of 391.2 mAh g^(−1)at 0.1 A g^(−1),outstanding cyclic stability of 92.17%after 3000 cycles at 5 A g^(−1),and remarkable energy density of 553.12 Wh kg^(−1) together with superior coulombic efficiency of~100%.Additionally,the cathodic biosafety is further explored specifically through in vitro cell toxicity experiments,which verifies its tremendous potential in the application of clinical medicine.Besides,Zinc ion energy storage mechanism of the cathode is mainly discussed from the aspects of Jahn–Teller effect and Mn domains distribution combined with theoretical analysis and experimental data.Thus,a novel perspective of the conversion from biomass waste to biocompatible Mn-based cathode is successfully developed.
基金Supported by National High Technology Research and Development Program ("863" Program) of China(No. 2006AA02A132)
文摘AIM: To establish an untransfected human corneal epithelial (HCEP) cell line and characterize its biocompatibility with denuded amniotic membrane (dAM). METHODS: The torn HCEP pieces were primarily cultured in DMEM/F12 media (pH 7.2) supplemented with 20% fetal bovine serum and other necessary factors, yielding an HCEP cell line which was its growth performance, chromosome morphology, tumorigenicity and expression of marker proteins analyzed. In addition, the biocompatibility of HCEP cells with dAM was evaluated through histological and immunocytochemistry analyses and with light, electron and slit-lamp microscopies. RESULTS: HCEP cells proliferated to confluence in 3 weeks, which have been subcultured to passage 160. A continuous untransfected HCEP cell line, designated as utHCEPC01, was established with a population doubling time of 45.42 hours as was determined at passage 100. The cells retained HCEP cell properties as were approved by chromosomal morphology and the expression of keratin 3. They, with no tumorigenicity, formed a multilayer epithelium-like structure on dAMs through proliferation and differentiation during air-liquid interface culture, maintained expression of marker proteins including keratin 3 and integrin p 1 and attached tightly to dAMs. The reconstructed HCEP was highly transparent and morphologically and structurally similar to the original. CONCLUSION: An untransfected and non-tumorigenic HCEP cell line was established in this study. The cells maintained expression of marker proteins. The cell line was biocompatible with dAM. It holds the potential of being used for in vitro reconstruction of tissue-engineered HCEP, promising for the treatment of diseases caused by corneal epithelial disorders.
基金The authors would like to thank the Helmholtz-Zentrum Geesthacht and Fesil Company(Germany)for the alloys syn-thesis and casting.
文摘Mg-Ca alloys have recently attracted great attention towards the research in the field of orthopedic biodegradable implants.This study presents an in vitro degradation assessment of Mg-0.8Ca(0.8 wt.%of Ca)alloy in Hank’s balanced salt solution(HBSS).Immersion,hydrogen evolution and electrochemical behavior was studied as well as the cytotoxicity of the degradation products.Morphology and phase composition of the corrosion products were studied using SEM,EDX and XRD techniques.Degradation in HBSS resulted in the formation of the needle-shaped carbonated hydroxyapatite which was similar to the biological apatite in the human bone.Degradation kinetics showed that Mg-0.8Ca alloy had approximately 3-fold faster degradation rate than the pure Mg(1.08±0.38 mm/year for Mg-0.8Ca and 0.35±0.17 mm/year for pure Mg),as observed in two independent experiments.Both,pure Mg and Mg-0.8Ca alloy were biocompatible,generating no cytotoxic degradation products against human-derived HEK 293 cells.Thus,the Mg-0.8Ca alloy was found to be a promising biodegradable implant in terms of bioactivity and compatibility with human cell lines.Depending on the application of the implant and the estimated healing time of the bone,the desired degradation rate of an implant can be controlled by the Mg-Ca composition of such alloys.
文摘A modified electrolyte (CH3COOH-HClO4-A-B) for electropolishing (EP) of NiTi was presented for improving the corrosion resistance and biocompatibility of the alloy. Using the proposed parameters, a homogeneous and uniform surface was obtained. Atomic force microscopy (AFM) revealed that the surface roughness (Ra) for EP sample (23.21 nm) was close to mechanical polishing (MP) sample (19.36 nm). Analysis by X-ray photoelectron spectroscopy (XPS) showed that Ti/Ni ratio increased from 3.1 for MP sample to 27.6 for EP sample. Measurements using potentiodynamic polarization in Hanks' solution showed that no pitting occurred for EP sample even though the applied potential increased up to 1500 mV (vs SCE), while the MP sample was broken down at 650 mV. The present study indicates that electropolishing NiTi with this modified electrolyte contributes to the improved biocompatibility of NiTi.
基金National High Technology Research and Development Program("863" Program) of China(No.2006AA02A132)
文摘AIM: To establish an untransfected human corneal stromal (HCS) cell line and characterize its biocompatibility to acellular porcine corneal stoma (aPCS). METHODS: Primary culture was initiated with a pure population of HCS cells in DMEM/F12 media (pH 7.2) containing 20% fetal bovine serum and various necessary growth factors. The established cell line was characterized by growth property, chromosome analysis, tumorigenicity assay, expression of marker proteins and functional proteins. Furthermore, the biocompatibility of HCS cells with aPCS was examined through histological and immunocytochemistry analyses and with light, electron microscopies. RESULTS: HCS cells proliferated to confluence 2 weeks later in primary culture and have been subcultured to passage 140 so far. A continuous untransfected HCS cell line with a population doubling time of 41.44 hours at passage 80 has been determined. Results of chromosome analysis, morphology, combined with the results of expression of marker protein and functional proteins suggested that the cells retained HCS cell properties. Furthermore, HCS cells have no tumorigenicity, and with excellent biocompatibility to aPCS. CONCLUSION: An untransfected and non-tumorigenic HCS cell line has been established, and the cells maintained positive expression of marker proteins and functional proteins. The cell line, with excellent biocompatibility to aPCS, might be used for in vitroreconstruction of tissue-engineered HCS.
基金Scientific and Technological Research Projects of Educational Committee of Liaoning Province of China(No.2008S243)
文摘AIM: To study the optical property and biocompatibility of a tissue engineering cornea. METHODS: The cross-linker of N- (3-Dimethylaminoropyl)-N'ethylcarbodiimide hydrochloride (EDC)/ N-Hydroxysuccinimide (NHS) was mixed with Type I collagen at 10% (weight/volume). The final solution was molded to the shape of a corneal contact lens. The collagen concentrations of 10%, 12.5%, 15%, 17.5% and 20% artificial corneas were tested by UV/vis-spectroscopy for their transparency compared with normal rat cornea. 10-0 sutures were knotted on the edges of substitute to measure the corneal buttons's mechanical properties. Normal rat corneal tissue primary culture on the collagen scaffold was observed in 4 weeks. Histopathologic examinations were performed after 4 weeks of in vitro culturing. RESULTS: The collagen scaffold appearance was similar to that of soft contact lens. With the increase of collagen concentration, the transparency of artificial corneal buttons was diminished, but the toughness of the scaffold was enhanced. The scaffold transparency in the 10% concentration collagen group resembled normal rat cornea. To knot and embed the scaffold under the microscope, 20% concentration collagen group was more effective during implantation than lower concentrations of collagen group. In the first 3 weeks, corneal cell proliferation was highly active. The shapes of cells that grew on the substitute had no significant difference when compared with the cells before they were moved to the scaffold. However, on the fortieth day, most cells detached from the scaffold and died. Histopathologic examination of the primary culture scaffold revealed well grown corneal cells tightly attached to the scaffold in the former culturing. CONCLUSION: Collagen scaffold can be molded to the shape of soft contact corneal lens with NHS/EDC. The biological stability and biocompatibility of collagen from animal species may be used as material in preparing to engineer artificial corneal scaffold.
基金National Basic Research Program of China, ("973" Program), No. 2005CB623905Tsinghua-Yue-Yuen Medical Science Fund, Beijing Municipal Science & Technology Commission, No. H060920050430the National Natural Science Foundation of China, No. 30670528, 30700848, 30772443
文摘BACKGROUND:It has been reported that chitosan nerve conduits could support axon elongation and improve relevant function during in vivo nerve regeneration. OBJECTIVE: To investigate in vitro biocompatibility of three novel, chitosan/polycation composite materials for nerve regeneration in cultured mouse Schwann cells and PC12 cells. DESIGN, TIME AND SETTING: The observational, control experiments for nerve tissue engineering were performed at the Department of Biological Sciences and Biotechnology of Tsinghua University from August 2007 to January 2008. MATERIALS: Mouse Schwann cells were isolated from the sciatic nerve of 5–7-day-old BALB/C mice. PC12 cells were purchased from the American Type Culture Collection (ATCC, USA). Chitosan was purchased from Tsingdao Haisheng Co., China. Poly-L-lysine hydrochloride (PLL), polyethyleneimine (PEI) poly-L-ornithine hydrobromide (POR), and S-100 antibody was purchased from Sigma Chemical Co., USA. Cell Counting Kit-8 (CCK-8) was purchased from Dojindo Chemical Co., Japan. METHODS: Three chitosan/polycation composite materials for nerve regeneration (PLL-0.25, PEI-0.25, and POR-0.25) were produced by blending chitosan with 0.25% (w/w) poly-L-lysine, polyethyleneimine, and poly-L-ornithine. Pure chitosan was utilized as the control. After 3 days of culture, the morphology of mouse Schwann and PC12 cells cultured on all substrates was observed with an inverted phase contrast microscope. Mouse Schwann cells were stained by immunofluorescence labeling S-100 protein and nuclei, followed by identification with a confocal laser-scanning microscope. The amount of proliferating mouse Schwann and PC12 cells was determined by CCK-8 after 1, 3, and 5 days in culture. The level of PC12 cell differentiation on all substrates was assessed by measuring neurite length at 1, 3, and 5 days after seeding. MAIN OUTCOME MEASURES: Morphology and amount of proliferation of mouse Schwann cells and PC12 cells cultured on chitosan and three polycation-modified materials, as well as amount of differentiation in PC12 cells on these substrates. RESULTS: (1) Morphology of mouse Schwann cells and PC12 cells on all substrates: after 3 days in culture on three different chitosan/polycation composite substrates, Schwann cells were connected to each other and exhibited greater proliferation, compared to the chitosan control. In particular, on PLL-0.25 and POR-0.25 substrates, some cells congregated and nearly reached confluence. The PC12 cells on chitosan substrate, after 3 days in culture, maintained a round shape; few exhibited a bipolar shape and began to form neurite extensions. However, on PLL-0.25 and POR-0.25 substrates, most PC12 cells displayed a bipolar shape with obvious neurite outgrowth, and almost grew as an adherent, spreading monolayer. (2) Proliferation of mouse Schwann cells and PC12 cells on all substrates: on the first day, Schwann cell proliferation on the three composite substrates was significantly greater than the cells on chitosan control (P 〈 0.01). After 3 and 5 days in culture, PLL-0.25 and POR-0.25 substrates resulted in greater cell proliferation when compared to pure chitosan (P 〈 0.01). On the third and fifth day in culture PC12 cell proliferation on PLL-0.25 and POR-0.25 was significantly greater than on chitosan substrate (P 〈 0.01). (3) Differentiation of PC12 cells on all substrates: at all time points, the average neurite length of cells cultured on composite materials was significantly longer than on chitosan control (P 〈 0.05-0.01). Cells on PLL-0.25 exhibited the longest average neurite length at days 3 and 5. CONCLUSION: Mouse Schwann cells and PC12 cells exhibit in vitro biocompatibility with poly-L-lysine-and poly-L-ornithine-modified substrates, which indicates that these substrates could serve as suitable substrates for peripheral nerve regeneration.
文摘Recently,tissue engineering (TE)is one of the fast growing research fields due the accessibility of extra-molecular matrix (ECM)at cellular and molecular level with valuable potential prospective of hydrogels.The enhancement in the production of hydrogel-based cellular scaffolds with the structural composition of ECM has been accelerated with involvement of rapid prototyping techniques.Basically,the recreation of ECM has been derived from naturally existed or synthetic hydrogelbased polymers.The rapid utilization of hydrogels in TE puts forward the scope of bioprinfing for the fabrication of the functional biological tissues,cartilage,skin and artificial organs.The main focus of the researchers is on biofabrication of the biomaterials with maintaining the biocompatibility,biodegradability and increasing growth efficiency.In this review, biological development in the structure and cross-linking connections of natural or synthetic hydrogels are discussed.The methods and design criteria that influence the chemical and mechanical properties and interaction of seeding cells before and after the implantations are also demonstrated.The methodology of bioprinting techniques along with recent development has also been reviewed.In the end,some capabilities and shortcomings are pointed out for further development of hydrogels-based scaffolds and selection of bioprinting technology depending on their application.
基金the Key Program of Education Department of Hubei Province(No.301130697)
文摘The objective of this study was to evaluate the biocompatibility of vessel extracellular matrix (VECM) from rabbit and to discuss the feasibility of vessel extracellular matrix as a matrix for urethral reconstruction. Primary cultured bladder smooth muscle cells isolated from New Zealand rabbits were implanted on VECM .The effects of VECM on rabbit bladder smooth muscle cells (RBSMCs) metabolic activity, attachment, proliferation were monitored in vitro with the aid of an inverted light microscope and a scanning electron microscope. The cell viability was monitored by MTT(methythiazolye tetrazolium bromide) after 1, 3, 5 days seeding. The in vivo tissue response to VECM was investigated by implanting them into the subcutaneous of rabbits. VECM exhibited a nontoxic and bioactive effect on RBSMCs. RBSMCs could be attached to and proliferated on VECM and maintained their morphologies. MTT assay showed RBSMCs cultured with the extracts of VECM were not significantly different from those of negative controls. In vivo, VECM demonstrated a favorable tissue compatibility without tissue necrosis, fibrosis and other abnormal response. VECM exhibited nontoxic and bioactive effects on RBSMC. It is a suitable material for urethral reconstruction.
基金supported by the National Natural Science Foundation of China(Nos.81572150,81571939)the Natural Science Foundation of Hunan Province(No.2015JJ2187)the Wu Jie-Ping Medical Foundation of the Minister of Health of China(No.320675014118)
文摘This study aimed to examine the biocompatibility of calcium titanate(CaTiO3) coating prepared by a simplified technique in an attempt to assess the potential of CaTiO3coating as an alternative to current implant coating materials. CaTiO3-coated titanium screws were implanted with hydroxyapatite(HA)-coated or uncoated titanium screws into medial and lateral femoral condyles of 48 New Zealand white rabbits. Imaging, histomorphometric and biomechanical analyses were employed to evaluate the osseointegration and biocompatibility 12 weeks after the implantation. Histology and scanning electron microscopy revealed that bone tissues surrounding the screws coated with CaTiO3were fully regenerated and they were also well integrated with the screws. An interfacial fibrous membrane layer, which was found in the HA coating group, was not noticeable between the bone tissues and CaTiO3-coated screws. X-ray imaging analysis showed in the CaTiO3coating group, there was a dense and tight binding between implants and the bone tissues; no radiation translucent zone was found surrounding the implants as well as no detachment of the coating and femoral condyle fracture. In contrast, uncoated screws exhibited a fibrous membrane layer, as evidenced by the detection of a radiation translucent zone between the implants and the bone tissues. Additionally, biomechanical testing revealed that the binding strength of CaTiO3coating with bone tissues was significantly higher than that of uncoated titanium screws, and was comparable to that of HA coating. The study demonstrated that CaTiO3coating in situ to titanium screws possesses great biocompatibility and osseointegration comparable to HA coating.
基金supported by the Department of Science and Technology of Jilin Province, China, No. 20070417
文摘Chitosan, collagen I and gelatin were mixed in appropriate quantities to develop a new nerve repair material, with good arrangement and structure, as well as even aperture size. The composite material was sterilized by 60Co irradiation for 24 hours prior to implantation in the right thigh of rats following sciatic nerve damage. Results showed that the material was nontoxic to the kidneys and the liver, and did not induce an inflammatory response in the muscles. The composite material enhanced the recovery of sciatic nerve damage in rats. These experimental findings indicate that the composite material offers good biocompatibility and has a positive effect on injured nerve rehabilitation.
基金project was the National Natural Science Foundation of China(Grant No.52101291)China Postdoctoral Science Foundation(Grant No.2020TQ0273)+1 种基金the National Key Research and Development Program of China(Grant No.2018YFC1106703)the Key Projects of the Joint Fund of the National Natural Science Foundation of China(Grant No.U1804251)。
文摘Biodegradable magnesium alloy stents(MAS)have great potential in the treatment of cardiovascular diseases.However,too fast degradation and the poor biocompatibility are still two key problems for the clinical utility of MAS.In the present work,a functional coating composed of hydrophilic polymers and bioactive peptides was constructed on magnesium alloy to improve its corrosion resistance and biocompatibility in vitro and in vivo.Mg-Zn-Y-Nd(ZE21B)alloy modified with the functional coating exhibited moderate surface hydrophilicity and enhanced corrosion resistance.The favourable hemocompatibility of ZE21B alloy with the functional coating was confirmed by the in vitro blood experiments.Moreover,the modified ZE21B alloy could selectively promote the adhesion,proliferation,and migration of endothelial cells(ECs),but suppress these behaviors of smooth muscle cells(SMCs).Furthermore,the modified ZE21B alloy wires could alleviate intimal hyperplasia,enhance corrosion resistance and re-endothelialization in vivo transplantation experiment.These results collectively demonstrated that the functional coating improved the corrosion resistance and biocompatibility of ZE21B alloy.This functional coating provides new insight into the design and development of novel biodegradable stents for biomedical engineering.
基金the Natural Science Foundation of Hubei Province (No.2003ABA187)Hubei Education Bureau (No.2003X123)
文摘A new scaffold material composed of extracellular matrix (ECM) and thermal sensitive hydrogel (HG), and evaluated its biocompatibility were investigated. We cultured bladder smooth muscle cells with this compound material, and then observed with phase contrast microscopy and scanning electron microscope (SEM) to assess the cell growth and morphology. The cell adhesion and proliferation were detected with MTT assay and cell count. Results show the ECM/HG compounds appeared as a net-like and red-stained construction with enough meshes and without any cellular fragments. 6 h after implantation, cells were observed adhere on the compounds and extend spurious along the fibers 12 h later. Under SEM even some ECM was observed to be secreted. MTT assay shows there was obvious statistic difference among 3 groups (P〈0.05). ECM/HG compound materials show a good biocompatibility, which confirms that it would be an ideal tissue engineering scaffolds.
基金Funded by the "863" Program of China (No.2006AA02Z4E6)the National Nature Science Foundation of China (No.30570516)
文摘The biocompatibility of silicone rubber (SR) based electrodes coating with poly (vinyl alcohol) (PVA) films after implanted in the brain of rats was investigated. Twenty-two Wistar rats were used and implanted with SR electrodes and PVA/PAA films coated electrodes in left and right cerebral cortex respectively. After 4 and 8 weeks, the expression of glial fibrillary acidic protein (GFAP, a specific marker of astrocytes) and cluster of differentiation 68 (CD68, a specific marker of macrophages) were evaluated by immunohistochemistry. After 8 weeks, GFAP and CD68 expressions around PVA electrodes were significantly lower than those around SR electrodes in every stratified area (0-50 μm, 50-100 μm, 100 μm from further up to the electrode-tissue interface). The resuits show that PVA coating can reduce the expressions of GFAP and CD68, suggesting the PVA coating can improve the biocompatibility of the SR while it is implanted in brain.
文摘Summary: By culturing bone marrow mesenchymal stem cells of rabbits with fibrin glue in vitro, the biocompatibility of fibrin glue was investigated to study whether this material can be used as scaffolds in bone tissue engineering. After 2-months old New Zealand rabbits had been anesthetized, about 4-6 ml of bone marrow were aspirated from rabbit femoral trochanter. The monocytes suspension was aspirated after bone marrow was centrifuged with lymphocyte separating medium and cultured primarily. Then the cells were divided into two groups: one was cultured with complete medium and the other with induced medium. The cells of the two groups were collected and inoculated to the culture plate containing fibrin glue. In the control group, cells were inoculated without fibrin glue. The implanted cells and materials were observed at different stages under a phase-contrast microscope and scanning electron microscope. MTT and alkaline phosphatase (ALP) were measured. Bone marrow mesenchymal stem cells grew on the surface of fibrin glue and adhered to it gradually. Cells light absorption value (A value) and the ALP content showed no significant difference. Fibrin glue had no inhibitory effect on cell morphology, growth, proliferation and differentiation. It has good biocompatibility and can be used as scaffold materials for bone marrow mesenchymal stem cells in bone tissue engineering.
文摘Biodegradable polymers have been widely used in the field of tissue engineering.The adhesive characteristic of polymer surfaces must be modified for cell seeding and growth before being used.The modified method poly-β-hybroxybutyric acid (PHB) was introduced and the biocompatibility of modified PHB to adrenocortical cells was studied here,Gelatin was used as a modifier to retrofit PHB and adrenocortical cells were seeded in the modified PHB.The effects of PHB on the proliferation and secreting function of adrenocortical cells were evaluated by MTT and RIA methods.It shows that adrenocortical cells were able to grow and survived in PHB and no influence on the proliferation and secreting function of the cells was observed.The morphology study shows that the modified PHB was easy for cells seeding and growing.The modified PHB is a good biodegradable material as cell carrier for transplantation of adrenocortical cells.
文摘Silicon nitride (Si3N4) ceramic is an attractive material for dental applications, especially used as a dental core material, due to its unique properties including high fracture toughness, high strength, high wear resistance and non-cytotoxicity. In this study, the Si3N4 ceramic was fabricated by a non-pressure sintering technique at a relatively low sintering temperature of 1650℃ in nitrogen atmosphere. Borosilicate glass and 5 wt% ZrO2-added borosilicate glass were used for coating on the Si3N4 core surface because of their compatibility in thermal expansion, high chemical resistance and bio-inert. The specimens were then fired in electric tube furnace at 1100℃. The Vickers microhardness of borosilicate glass and 5 wt% ZrO2-added borosilicate glass veneering materials were measured and compared with the commercial dental veneer porcelain as a control (VITA VMK 95). The cytotoxicity of the Si3N4 ceramic and the veneering materials were tested by MTT assay, using human gingival fibroblasts (HGF) and periodontal ligament fibroblasts (HPDLF). The results indicate that the Si3N4 ceramic and Si3N4 ceramic veneered with borosilicate glass or 5 wt% ZrO2-added borosilicate glass veneering materials tested in this study are not toxic to oral tissue and can be used to produce dental prostheses.
文摘DNA synthesis and collagen formations on the implant material by cell culture in vitro are the most important phenotypical expression to estimate the biocompatibility. In this part, DNA synthesis and collagen formation on implant materials were quantitatively and qualitatively estimated by radioactive isotope H + thymidine to incorporate into DNA chains, H + proline to incorporate into type I collagen proteins followed by scin tillation counting and antibody antigen immunocytochemistry staining, respectively. Research results demonstrate that hydroxyapatite (HA) stimulates DNA synthesis and collagen formation on the material whereas this stimulation is restricted by adding spinel to the materials. There are statistical differences between the influences of material components on both DNA synthesis and collagen formation. It is supposed that porous materials can supply more platforms for cell anchoring, and more DNA and collagen are synthesised on the porous materials. Immersion in culture medium results in new HA crystal formation on the porous HA materials.