Application progress in synthetic and natural polymer materials for dural membrane repair / 国际生物医学工程杂志

The dura mater is a double-layer tough membrane tissue located between the surface of the brain and the inner surface of the skull that supports and protects the brain tissue. The phenomenon of dural defects caused by tumor resection, inflammation destruction, and craniotomies is becoming more common clinically. Therefore, the development of effective dural repair materials can not only reduce the leakage of cerebrospinal fluid and the occurrence of epilepsy complications but also promote the recovery of the dural defect to its normal physiological structure. With the continuous development of modern medicine, many biomaterials have been developed for dural defect repair. At present, the most promising and most researched biomaterials are synthetic polymer materials and natural polymer materials. Synthetic polymer materials have been extensively studied by domestic and foreign scholars due to their stable performance, low foreign body infection, and easy mass production advantages. Natural polymer materials are the most promising biomaterials because of their extensive sources, excellent biocompatibility, and biodegradability advantages. This article summarizes the research progress based on synthetic polymer materials and natural polymer materials in dural repair materials. In this review paper, the application progress of synthetic polymer materials and natural polymer materials in dural membrane repair was reviewed.

Biocompatibility evaluation of collagen suture and collagen biofilm / 国际生物医学工程杂志

Objective:To evaluate the biocompatibility of collagen suture (CS) and collagen biofilm (CB) preliminarily.Methods:The pyrogenic contaminants test was used to analyze the pyrogen in CS and CB. The skin stimulation and intradermal stimulation tests were used to evaluate the stimulation effects of CS and CB to the skin. The hemolytic test was used to evaluate the hemolytic effect of CS and CB. The muscle implantation experiment was used to evaluate the stimulation and toxicity of CS and CB.Results:The results of pyrogenic contaminants test show that the temperature increment of rabbits in each group is lower than 0.6 ℃, and the total temperature increment is lower than 1.4 ℃ indicating that the two materials meet the requirements of pyrogenic examination and the pyrogenic contaminants test is qualified. The results of skin stimulation test and intradermal stimulation test of collagen suture and collagen biofilms were negative indicating that the two materials have no skin irritation. The hemolysis rates of collagen suture and collagen biofilm were 2.943% and 4.127% respectively (all P<0.05) indicating that the two materials will not cause hemolysis. The muscle was tolerated well and the tissue response was not serious after two biomaterials were embedded, which was reduced over time gradually. Conclusions:Both the collagen suture and collagen biofilm have good biocompatibility.

Preparation technology of oyster hydroxyapatite porous material for bone repair / 国际生物医学工程杂志

Objective To verify the feasibility of applying hydrothermal synthesis for preparing oyster hydroxyapatite(HA) and to develop a preparation method of oyster HA porous material for bone repair.Methods Hydrothermal synthesis was applied for preparing oyster HA,and the reaction condition was 220 ℃ for 6 h.Then,the prepared oyster HA was used as the raw material for porous scaffold preparation by sponge-soaking and sintering,successively.The porosity and compressive strength of the scaffold were adjusted by controlling the soaking time and absorbed HA slurry of the sponges.Results Hydrothermal synthesis was an effective method for preparing oyster HA.When the volume of the sponge cube was 1 cm3,the material absorbed by one to three times sponge-soaking were 0.184 8 g,0.318 1 g and 0.426 1 g,respectively,the corresponding porosity were 91.5％,82.9％ and 78.5％,and the compressive strength were 1.06 MPa,3.99 MPa and 8.49 MPa.Conclusion The oyster shell powder can be effectively converted into HA under the hydrothermal reaction condition of 220 ℃ for 6 h.The preparation of HA porous bone repair material by sponge-soaking method can obtain ideal porosity and mechanical strength.However,in this preparation process,the number of sponge-soaking and the weight of the absorbed HA slurry should be exactly controlled in order to obtain desired properties.

Effects of FGF2 administration for different time periods on chondrocytes / 国际生物医学工程杂志

Objective To study the effects of fibroblast growth factor 2 (FGF2) on the proliferation and gene expression profiles of rabbit articular chondrocytes in vitro after different time periods of stimulation.Methods The chondrocytes were isolated and cultured in vitro,and the 3rd generation cells were harvested.Cells were divided into three groups.In the group 1 (FGF2 short-time action group),chondrocytes were cultured in medium with FGF2 for one day,and then transferred to fresh culture medium without FGF2 and cultured for another 6 days.In the group 2 (FGF2 long-time action group),chondrocytes were cultured in medium with FGF2 for 7 days.In the Group 3 (control group),chondrocytes were cultured in culture medium without FGF2 for 7 days.After culture for 1,3,and 7 days,the proliferation of chondrocytes in the all groups was detected respectively.Following extraction of mRNA,the gene expressions of BMP2,BMP4,SOX9 and COL2A1 of the chondrocytes in the all groups were determined by quantitative real-time polymerase chain reaction (qRT-PCR).The content of type Ⅱ collagen was measured via immunofluorescence staining.Results Compared with the control group,FGF2 promoted the proliferation of chondrocytes in the short-and long-time action groups and there was no significant difference between the two FGF2-treated groups.The results of qRT-PCR indicated that different treatment induced different gene expression profile.Particularly,compared with the control group and the FGF2 long-time action group,the expression of BMP2,BMP4,SOX9 and COL2A1 in the short-time action group were significantly upregulated at the 7th day.Immunofluorescence intensity of type Ⅱ collagen in the group 1 was stronger than that in the control group and group 2.Conclusions Different administration of FGF2 for different time periods induced different responses of chondrocytes.Short-term FGF2 stimulation was more beneficial to maintain the phenotype of chondrocytes and the synthesis of extracellular matrix.

Application of growth factor in repair of articular cartilage injury / 国际生物医学工程杂志

The joint is an important athletic organ,and has special structure,i.e.no blood supply in the mature articular cartilage.Hence,once articular cartilage is damaged and is difficult to self-repair.Nowadays,there are several clinical methods for articular cartilage injury,such as micro-fracture,transplant of articular cartilage,replacement of articular cartilage and cartilage tissue engineering.But the repairing effects of these methods are unsatisfactory.Growth factors are biologically active substances that are synthesized by cells in vivo and can accelerate cell growth,promote cell proliferation and induce cell migration etc.There are many growth factors participate in the development of cartilage,such as fibroblast growth factor (FGF),bone morphogenetic protein(BMP),insulin-like growth factor (IGF) and so on.Some research showed that the addition of exogenous growth factor in articular cartilage repair can effectively promote the repair of articular cartilage injury.In this paper,the main growth factors used for articular cartilage injury repair were reviewed,and the functions of these factors in the development and the repair of articular cartilage were discussed.The problems of growth factors in the application of articular cartilage repair were analyzed.

Application of growth factor in repair of articular cartilage injury / 国际生物医学工程杂志

The joint is an important athletic organ,and has special structure,i.e.no blood supply in the mature articular cartilage.Hence,once articular cartilage is damaged and is difficult to self-repair.Nowadays,there are several clinical methods for articular cartilage injury,such as micro-fracture,transplant of articular cartilage,replacement of articular cartilage and cartilage tissue engineering.But the repairing effects of these methods are unsatisfactory.Growth factors are biologically active substances that are synthesized by cells in vivo and can accelerate cell growth,promote cell proliferation and induce cell migration etc.There are many growth factors participate in the development of cartilage,such as fibroblast growth factor (FGF),bone morphogenetic protein(BMP),insulin-like growth factor (IGF) and so on.Some research showed that the addition of exogenous growth factor in articular cartilage repair can effectively promote the repair of articular cartilage injury.In this paper,the main growth factors used for articular cartilage injury repair were reviewed,and the functions of these factors in the development and the repair of articular cartilage were discussed.The problems of growth factors in the application of articular cartilage repair were analyzed.

Long-circulating methotrexate-loaded liposomes exhibit an antitumor effect on human osteosarcoma in vitro / 中国组织工程研究

BACKGROUND:Liposomes as a new drug delivery system are characterized by few adverse reactions, no immunogenicity and biodegradation. Furthermore, methotrexate-loaded liposomes can significantly reduce drug toxicity and improve anti-tumor effect. OBJECTIVE:To prepare long-circulating methotrexate-loaded liposomes and to evaluate its antitumor activity in MG-63 in vitro. METHODS:The methotrexate-loaded liposomes were prepared using the film dispersion method, and the long-circulating ones were prepared using the post-insertion method. The initial concentrations of methotrexate were 9.1, 1.82, 0.364 g/L. The ultracentrifugation method and spin column method with Sephadex G-10 or G-50 as packing were employed to separate free drugs from the methotrexate-loaded liposomes. Their recovery, size, morphology, encapsulation efficiency and drug-to-lipid ratio were evaluated. The cytotoxity of the long-circulating methotrexate-loaded liposomes purified with ultracentrifugation method and spin column G-50 method under three dose levels (0, 1, 5, 25 mg/L) were determined by MTS method. RESULTS AND CONCLUSION:According to the recovery rates of three methods, the spin column G-50 method was considered as optimal for the long-circulating methotrexate-loaded liposomes. The long-circulating liposomes were spherical or el ipsoidal under transmission electron microscope, about 200 nm in size. At the certain initial concentration of methotrexate, the encapsulation efficiency and drug-to-lipid ratio of the liposomes purified using the spin column G-50 method were remarkably higher than those purified using the other two methods. At the same mass concentration, the cytotoxity of the liposomes purified with ultracentrifugation or spin column G-50 was significantly higher than that of free methotrexate, and furthermore, the cytotoxity of the liposomes purified with spin column G-50 was higher than that of the liposomes purified with ultracentrifugation method. To conclude, the long-circulating methotrexate-loaded liposomes show a higher antitumor activity than free methotrexate in MG-63 cel s in vitro, providing the basis for further investigation of its antitumor effect on human osteosarcoma in vivo.

The experimental study on osteogenic potential of goat adipose derived stromal cells induced by PRP with rhBMP-2 / 中华显微外科杂志

Objective To evaluate the feasibilty of modified osteogenic culturing of goat adipose derived stromal cells(ADSCs).Methods From March,2013 to September,2014,platelet-rich plasma(PRP) was made from goat autogenous vein blood,and abodimoneal fat was aspirated,following aspetic procedure,primary and series passage of ADSCs was established.Osteoinduced ADSCs was carried out according to following group:combinative osteoinduction group(PRP+rhBMP-2 +ADSCs),growth factor group(rhBMP-2+ADSCs),conventional inductive group(dexamathasone+ascorbic acid + ADSCs) and noninductive group(blank group).Converted microscope was used to observe cellular pattern,cell activity,osteocalcin and collagen type Ⅰ level were detected at 1,3,5,7,9,13,17,21 days.Red Alazarin and Von Kossa staining were also assayed at different interval.Results Under observation of converted microscopy,remarkable cell proliferation with abundant ECM was noticed in combinative osteoinduction group,compared with other groups,level of cell activity,osteocalcin,collagen type Ⅰ [(0.82 ± 2.19)AU,(79.82 ± 1.36)U/L at,(78.51 ± 4.32)μ g/ml at]were significantly higher than other groups (P ＜0.05),and remarkable ALP expression and calcifed nodules were also seen.Conclusion PRP can enhance the inductive effect of rhBMP-2,and combinative osteoinduction procedure acts as a satisfactory culturing method.

Interaction between bovine serum albumin and pullulan acetate nanoparticles / 国际生物医学工程杂志

Objective To investigate the interaction of pullulan acetate nanoparticles (PANs) and bovine serum albumin (BSA),and to provide the basis for in vivo pharmacokinetic study of PANs.Methods Mixed solutions of different concentration of PANs and BSA solution was prepared,the interaction was studied by fluorescence quenching method and circular dichroism (CD) measurement.Apparent quenching constant (Kq) between the PANs and BSA was calculated,and the anti-stress effect induced by urea and heating of PANs-BSA solution was observed.Results The fluorescence spectrum of BSA was affected by PANs on density-related manner,and Kq calculated by the modified Stern-Volmer plot increased from 2.64×104 to 3.55 ×l05 with the concentration of PANs increased from 0.015 mg/ml to 0.25 mg/ml.With the denaturation of urea or heating,the CD spectrum of PANs-BSA and free BSA had the similar variation tendency.Conclusions The fluorescence spectrum display results show that interaction between PANs and BSA exists,but the interaction does not protect the BSA from degeneration by urea and heating.

Research Progress in Polyethylene Glycol Modified Chitosan Applied in Biomedical Field / 中国药师

Objective:To provide reference for the intensive study on polyethylene glycol modified chitosan. Methods:The relat-ed literatures at home and abroad were looked up and retrieved from 2004 to 2014, and the related contents were summarized. Results:The methods for the preparation of polyethylene glycol modified chitosan were various. Polyethylene glycol modified chitosan could be used as the carrier for nano-drug and gene therapy, the base of temperature-sensitive hydrogel, polymeric prodrug and the repair mate-rial of tissue engineering. Conclusion:Polyethylene glycol modified chitosan can be wildely used in biomedical field. However, the re-lated research is only in vitro. The in vivo studies should be further systematic and intensive.

Influence of molecular weight and spacer length on the properties of modified pullulan carriers / 国际生物医学工程杂志

Objective To investigate the influence of pullulan molecular weight and spacer length on the properties of modified pullulan carriers including morphologies,sizes and in vitro release behaviours of drug-loading carriers.Methods Using cholesterol as hydrophobic ligand,succinic anhydride and 1,6-hexyldiisocyanate as spacers,hydrophobic modified pullulans with different molecular weights were prepared.Self-assembled nanoparticles were then formed in the aqueous solution,and drug-loaded nanoparticles were prepared by dialysis method.The influence of pullulan molecular weight and spacer length on the loading-content,morphologies and in vitro release behaviours of drug-loading nanoparticles were then investigated in detail.Results Self-assembled nanoparticles could be formed by the cholesterol-modified pullulan,and doxorubicin and mitoxantrone could be loaded into cholesterol-modified pullulan to form nanoparticles.Pullulan molecular weight and spacer length show influences on sizes,morphologies and stabilities of pullulan nanoparticles and drug-loaded nanocarriers.Conclusions Before drug loading,nanoparticles with larger moleculare weight and shorter spacer length are more stable in solution,while after drug loading,the influences of these two factors on the nanoparticles are drug-type depended.

Preparation and characterization of self-assembled thiolated chitosan derivatives and gold nanoparticles / 国际生物医学工程杂志

Objective To prepare self-assembled thiolated chitosan derivatives gold nanoparticles (CS-GNRs) and carry out the feature tests.Methods CS-GNRs was prepared by chitosan derivatives and GNRs through strong metal sulfur chemical bond between thiols and gold on GNRs surface.Morphology features was tested by transmission electron microscope,dynamic light scattering was adopted to observe the size of nanoparticles.Ultraviolet-visible spectrophotometer was used to detect the optical properties and the property change.Meanwhile,the surface-enhanced Raman scattering (SERS) activity of CS-GNRs was investigated by using crystal violet (CV) as a probe molecular.Results CS-GNRs were in good shape,uniform particle size and good dispersion.The SERS of CV was enhanced,and the enhancement factor of CV adsorbed on CS-GNRs was up to 2×103.Conclusions The nanoparticles have potential application in molecular detection and Raman spectra detection.

Preparation of hydroxyapatite in the presence of amino acids by hydrothermal method / 国际生物医学工程杂志

Objective To investigate the preparation method of hydroxyapatite by amino acids induced hydrothermal technique.Methods The hydroxyapatite nanorods were obtained using alanine and glycine as templates by hydrothermal method.The samples were characterized by X-ray diffraction (XRD),Fourier infrared spectroscopy (FTIR),transmission electron microscopy (TEM).Results The results showed that amino acids induced the formation of hydroxyapatite.Amino acids could affect crystallinity and dispersion of the formed hydroxyapatite.In addition,the substituent content of carbonate ions in hydroxyapatite was reduced by changing the ratio of amino acids.Conclusion Hydroxyapatite with high crystallinity and low carbonate ions can be prepared by hydrothermal method in the presence of amino acids.

Expression and purification of GPS2 and its antibody preparation / 国际生物医学工程杂志

ObjectiveThe aim was to construct the recombinant plasmid of pET-28a-G-protein pathway suppressor 2 (GPS2) GPS2,express GPS2 protein in E.coli,and obtain specific polyclonal antiserum of GPS2.MethodsGPS2 gene was obtained and the amplified fragment was then cloned into E.coli expression vector pET-28a to construct recombinant plasmid.The recombinant plasmid was transformed into E.coli expression strain BL21(DE3).IPTG induces the expression protein GPS2 protein,and the induction conditions were optimized.The induced product was purified by Ni2+ affinity chromatography,and the purified product was dialyzed with buffer for refolding.The purified protein can be used as antigen,injected to immunize male New Zealand white rabbit to get polyclonal antiserum.The titer and specificity of the rabbit antiserum were detected by ELISA and Western Blotting.ResultsThe E.coli expression vector pET-28a-GPS2 was constructed successfully and the recombinant protein was efficiently expressed and purified.The purified protein was used to immunize male New Zealand white rabbit to get polyclonal antiserum and the ELISA and Western Blot results showed that the high titer of specific polyclonal antiserum.ConclusionGSP2 could be highly expressed in E.coli.Antiserum of GPS2 protein can be obtained by the purified recombinant to analyze its function.

Research progress of additives for improving therapeutic peptides and proteins stability in PLGA microspheres / 国际生物医学工程杂志

Microspheres made of poly-lactic-co-glycolic acid (PLGA) have been frequently proposed as drug delivery systems.A very significant challenge in the development of controlled PLGA releasing systems is the instability of drugs especially therapeutic peptides and proteins.Additional approaches,particularly the use of additives,are needed to optimize PLGA delivery of drugs.This article reviews the effects of additives,especially the effects of stabilizing protein during the preparation of PLGA microsphere and the sustained drug releasing processes.

Experimental study on the potential role of BME-10X collagen/hydroxyapatite bone graft in periodontal tissue regeneration of beagle / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the potential role of BME-10X collagen/hydroxyapatite (HA) bone graft in periodontal tissue regeneration.</p><p><b>METHODS</b>Four 18 months old male beagles in the experiment were treated with non-surgical periodontal therapy. At the sites of mandibular 3rd and 4th premolars at the time of dogs were treated with non-surgical periodontal therapy one week later, the teeth with the same name in the same jaw were selected to the experimental group (T group) or the control group (C group) at random. The defects in T group were filled with BME-10X collagen/HA bone graft while the defects in C group were filled with nothing. The dogs were sacrificed in twelve weeks and analyzed by histopathology.</p><p><b>RESULTS</b>The defects in T group got more tissue regeneration compared with the defects in C group. The height of new bone (NB) was (3.01 +/- 0.14) mm in T group versus (1.32 +/- 0.11) mm in C group (P < 0.05). The height of new periodontal ligament (NP) was (3.12 +/- 0.19) mm in T group versus (1.35 +/- 0.12) mm in C group (P < 0.05). The height of new cementum (NC) was (3.30 +/- 0.15) mm in T group versus (2.70 +/- 0.12) mm in C group (P > 0.05). The new tissue guided by the bone graft was the same as the normal tissue in histopathology analysis.</p><p><b>CONCLUSION</b>The results of the study suggest that BME-10X collagen/HA bone graft is a good bone graft for periodontal tissue regeneration.</p>

Extraction and application of Perna viridis foot protein as bioadhesive / 生物医学工程学杂志

Mussel adhesive proteins have attracted increasing interests for their potential use as environmentally friendly bioadhesives in medicine and aqueous conditions. In this study, surface coating analysis, quartz crystal microbalance (QCM), cell and bone tissue adhesion and cytotoxicity assay were used to study the properties of the Perna viridis foot proteins (Pvfp) extract as bioadhesive. The results of coating ability on various materials and QCM analysis revealed that Pvfp extract has comparable or superior adsorbtion ability to that of Cell-Tak (the naturally extracted MAP mixture from Mytilus edulis, and has been commercialized), and also, the cell adhesion ability of Pvfp extract was stronger than that of Cell-Tak and poly-L-lysine. No cytotoxicity was detected using human HeLa and 293T cells. Furthermore, broken bones of mouse could be stuck together by use of Pvfp extract. In bulk-scale adhesion tests, Pvfp extract showed much greater tensile strength than did fibrin glue for conglutinating poly (vinl chloride) sticks and for binding together pig's femur segments. These results suggested that Pvfp extract be an efficient cell and tissue adhesive in biotechnological application and it might be a potential bioadhesive in medical practice.

Effect of curcumin on the induction of glutathione S-transferases and NADP(H):quinone oxidoreductase and its possible mechanism of action / 药学学报

This study is to investigate the effect of curcumin on the induction of glutathione Stransferases (GST) and NADP(H):quinone oxidoreductase (NQO) and explore their possible molecular mechanism. The activity of GST, NQO and cellular reduced glutathione (GSH) content were measured by spectrophotometrical methods. Cellular changes in the distribution of NF-E2 related factor 2 (Nrf2) were detected by Western blotting analysis. Nrf2-AREs (antioxidant-responsive elements) binding activity was examined by electrophoretic mobility shift assay (EMSA). Treatment of HT-29 human colon adenocarcinoma cells with curcumin dramatically induced the activity of GST and NQO at the range of 10-30 μmol·L-1. Curcumin exposure caused a significant increase in cellular GSH content rapidly as early as 3 h. Moreover, curcumin triggered the accumulation of Nrf2 in nucleus, and increased Nrf2 content in ARE complexes. These results demonstrated that induction of GST and NQO activity by curcumin may be mediated by translocation of transcription factor Nrf2 from cytoplasm to nuclear and increased binding activity of Nrf2-ARE complexes.

Effects of preparation technique on the structure and properties of collagen scaffold / 国际生物医学工程杂志

Objective To investigate the effects of collagen concentration and pre-freezing temperature on structure and properties of the scaffold. Method A series of porous collagen scaffolds were fabricated with different collagen concentration and pre-freezing temperature by freezing-drying. The effective pore sizes and other properties of the porous scaffolds were evaluated and compared with each other. Chondrocytes of rabbit were separated and cultured on these scaffolds to evaluate their biocompatibility. Result The collagen scaffolds had interconnected pore ranging from 50 to 200 ?m in pore size. With increasing the collagen concentration density and tensile strength of the scaffolds increased, while pore size and degradation rate of the scaffolds decreased, as well as become less homogeneous. Reducing pre-freezing temperature resulted in smaller poresize and slower degradation rate of scaffolds. MTT analyses demonstrated that all the scaffolds availed to cell attachment and proliferation, while increasing collagen concentration and decreasing pre-freezing temperature evidently restrained chondrocytes attachment and proliferation. Conclusion The collagen concentration and pre-freezing temperature have crucial influence on the structure and properties of collagen scaffolds. The suitable collagen scaffolds were obtained by adjusting the collagen concentration and pre-freezing temperature. The bigger of the pore size was. The faster cell proliferation was achieved.

A simple way to improve fibroblast seeding efficiency and uniformity in constructing 3-D dermal equivalent / 第二军医大学学报

Objective:To explore a simple way to improve seeding efficiency and uniformity in constructing 3-D dermal equivalent,in order to effectively construct tissue engineered skin.Methods: Human dermal fibroblasts were added onto collagen sponge scaffolds and cultured in the following 3 ways:(1)oscillating seeding and oscillating culture(OO),(2)oscillating seeding and static culture(OS),and(3)static seeding and static culture (SS).Samples were obtained and subjected to light microscopy,scanning electron microscopy(SEM) and quantitative cell number assay at planed times.Results: Oscillating seeding achieved more uniform spatial cell distribution within scaffolds as compared to static seeding.Moreover,fibroblast seeding efficiency was significantly higher in oscillating conditions(\%) than in static conditions(\%,P