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BACKGROUND:Cartilage defects are one of the major clinical challenges faced by orthopedic surgeons.Tissue engineering is an interdisciplinary approach that combines knowledge of engineering and cell biology to provide new ideas and approaches for the repair of cartilage defects. OBJECTIVE:To prepare a multi-component composite scaffold based on silk fibroin,gelatin,and chitosan to screen for a three-dimensional porous scaffold suitable for cartilage regeneration by evaluating its physicochemical properties and biological performance. METHODS:Four groups of porous scaffolds were prepared by vacuum freeze-drying method using silk fibroin,gelatin and chitosan as the base materials,namely chitosan/gelatin scaffold,silk fibroin/chitosan scaffold,silk fibroin/gelatin scaffold and silk fibroin/chitosan/gelatin scaffold.The suitable cartilage scaffolds were screened by scanning electron microscopy,X-ray diffractometer,porosity,water absorption and swelling rate,biodegradation rate and mechanical property detection.Then cartilage scaffolds were co-cultured with chondrocytes isolated and extracted from patients with osteoarthritis.The feasibility of porous scaffolds for cartilage injury repair was evaluated in vitro by cell adhesion rate assay,cell live-dead staining and cell activity proliferation assay. RESULTS AND CONCLUSION:(1)All four groups of scaffolds had porous structures.The comprehensive physical performance test results showed that the silk fibroin/gelatin/chitosan scaffold was more in line with the requirements of cartilage defect repair.This scaffold had a pore size of(176.00±53.68)μm,the porosity of(80.15±2.57)%,and water absorption and swelling rate of(3 712±358)%.After immersion in PBS containing lysozyme for 28 days in vitro,the biodegradation rate was(46.87±3.25)%,and it had good mechanical properties.(2)Chondrocytes could adhere well on the silk fibroin/gelatin/chitosan scaffold,and the cell adhesion rate increased with time.CCK8 and live/dead cell double staining results showed that silk fibroin/gelatin/chitosan scaffold had good biocompatibility and low cytotoxicity.(3)The results showed that silk fibroin/gelatin/chitosan scaffold had a highly hydrated 3D structure,suitable pore size and porosity,good biodegradability and superior mechanical properties,which can provide a good reticular skeleton and microenvironment for nutrient transport and chondrocyte attachment and proliferation.
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BACKGROUND:In the construction of guided bone regeneration membrane with biological function,a single material cannot meet the clinical needs due to its insufficient function,so the composite of multiple materials has become a trend of tissue repair engineering. OBJECTIVE:To prepare silk fibroin/bioactive glass composite fiber membranes by electrospinning technology,and to characterize the physicochemical properties and biocompatibility in vitro. METHODS:The solution of electrospinning was prepared by dissolving 0.8 g silk fibroin protein in 10 mL hexafluoro-isopropanol alcohol,and the nanofiber membrane of silk fibroin protein was prepared by electrospinning technology(denoted as SF fiber membrane).0.1,0.3,0.5,and 0.8 g of bioactive glass were added to the electrospinning solution,and the silk fibroin/bioactive glass composite fiber membrane was prepared by electrospinning technology(recorded as SF/1BG,SF/3BG,SF/5BG,and SF/8BG fiber membrane in turn).The physicochemical properties and biocompatibility of five groups of fiber membranes were characterized. RESULTS AND CONCLUSION:(1)The scanning electron microscopy results showed that nanofibers of the prepared composite membrane were smooth,continuous and uniform and had no beaded structure.There was no obvious adhesion between the silk fibers,and they all showed random arrangement of disordered porous structures.The fiber diameter of the fiber membrane decreased after the addition of bioactive glass.Fourier infrared spectroscopy and X-ray diffraction detection results showed that the chemical structure of silk fibroin protein and bioactive glass in fiber membrane was stable.The water contact angles of SF,SF/1BG,SF/3BG,SF/5BG,and SF/8BG were 105.02°,72.58°,78.13°,79.35°,and 72.50°,respectively.(2)Bone marrow mesenchymal stem cells were inoculated on five groups of fiber membranes.CCK-8 assay results showed that SF/1BG,SF/3BG,and SF/5BG fiber membranes could promote the proliferation of bone marrow mesenchymal stem cells compared with SF and SF/8BG.Live cell/dead cell staining showed that the cell vitality on the surface of the five groups of fiber membranes was better,and the number and distribution of cells on the surface of SF/5BG fiber membrane were more uniform.Rhodamine phalloidin staining and scanning electron microscopy exhibited that compared with SF fiber membrane,the SF/5BG fiber membrane was more favorable to the adhesion of bone marrow mesenchymal stem cells.Bone marrow mesenchymal stem cells were inoculated on the fiber membrane of the five groups for osteogenic induction differentiation,and the alkaline phosphatase activity of the SF/3BG and SF/5BG groups was higher than that of the other three groups(P＜0.05,P＜0.01,P＜0.001).Alizarin red staining showed that the formation of calcium nodules in fiber membrane increased after the addition of bioactive glass,and the formation of calcium nodules in the SF/5BG group was the most.(3)The results show that silk fibroin/bioactive glass composite fiber membrane has good biosafety and biocompatibility.
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BACKGROUND:Microglia cells play a major role in maintaining the balance as well as the development and function reconstruction of the central nervous system.As a histone deacetylase inhibitor,Scriptaid can inhibit neuroinflammation and enhance neuroprotection. OBJECTIVE:To investigate the effect of silk fibroin methacryloyl hydrogel loaded with Scriptaid on the behaviors of microglia cells. METHODS:Microglia(BV2 cells)were cultured in medium containing different concentrations of Scriptaid(0,0.1,0.5,1,2,5,10 μmol/L).The optimal concentration of Scriptaid was screened by the CCK-8 assay and live/dead cell staining.Silk fibroin methacryloyl hydrogels loaded with or without Scriptaid were prepared using photocuring.The micromorphology,swelling properties,mechanical properties,slow release properties,and hydrophilicity of the hydrogels were characterized.Microglia(BV2 cells)were inoculated in the subventricular region of 24-well Transwell and cultured in five groups.In the control group,the cell culture medium was added to the lower chamber.In the lipopolysaccharide group,Scriptaid group,hydrogel group,and drug-loaded hydrogel group,cell culture media containing lipopolysaccharide were added into the lower chamber.After 24 hours of lipopolysaccharide intervention,in the Scriptaid group,hydrogel group and drug-loaded hydrogel group,Scriptaid,silk fibroin methacryloyl hydrogel,and silk fibroin methacryloyl hydrogel loaded with Scriptaid were added to the upper chamber,respectively.The culture medium was replaced with ordinary culture medium and continued to culture for 24 hours.The cell viability was detected by CCK-8 assay,and the cell phenotype was detected by immunofluorescence staining of induced nitric oxide synthase and arginase 1. RESULTS AND CONCLUSION:(1)Compared with the group without Scriptaid,the viability and number of BV2 cells were decreased after Scriptaid added.When Scriptaid 2 μmol/L or above was added,the cell viability was lower than the standardized cell viability(70%),and the number of BV2 cells was significantly reduced.Therefore,1 μmol/L Scriptaid was selected to be loaded into the hydrogel.(2)Characterization experiments showed that the addition of Scriptaid did not affect the microscopic morphology,swelling rate of water absorption,compression modulus and hydrophilicity of silk fibroin methacryloyl hydrogel,and silk fibroin methacryloyl hydrogel had slow release performance.(3)The result of CCK-8 assay showed that compared with the control group,silk fibroin methacryloyl hydrogel significantly increased the viability of BV2 cells(P<0.001).(4)Immunofluorescence staining showed that compared with the control group,the expression of inducible nitric oxide synthase was increased in the lipopolysaccharide group(P<0.01);the expression of inducible nitric oxide synthase was decreased(P<0.01)and the expression of arginase 1 was increased(P<0.001)in the drug-loaded hydrogel group;the expression of arginase 1 was increased in the Scriptaid group(P<0.01).(5)The results indicate that Scriptaid-loaded silk fibroin methacryloyl hydrogel is able to promote polarization of microglia to the M2 type after lipopolysaccharide induction.
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Objective @#To develop a high modulus and high strength biodegradable silk fibroin GBR membrane to address the issue of maintaining the space for bone regeneration in the repair of osseous defects . @*Methods @#After purifying silk fibroin protein , membrane materials were prepared using evaporation-hot pressing method . The physi- cal and chemical properties and biological performance of the membranes were evaluated using stretching tests , in vitro simulations , and cell co-culturing methods . @*Results @#A silk fibroin GBR membrane was successfully fabrica- ted , resulting in a simulated degradation rate of 35 . 3% after 12 h in vitro . The wet-state elastic modulus reached 45 MPa , while the tensile strength reached 8. 39 MPa. Furthermore , the cell survival rate was nearly 100% after 7 days . @*Conclusion @#The biodegradable GBR membrane produced in this study possesses high modulus and strength , as well as excellent biocompatibility , offering a promise as a foundation for addressing the bone defect re- pair and bone space maintenance .
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Objective After hydrogen bonding between collagen ( COL) and silk fibroin ( SF ) at different concentrations, a composite scaffold with adjustable stiffness was prepared by combining with gel system, and its physical and chemical properties were characterized. Methods SF with different qualities was dissolved in sodium alginate (SA) solution, then COL solution at different concentration and calcium carbonate ( CaCO3 ) powder were added. The hydrogels of SC1, SC2, and SC3 groups were obtained by taking out the mixed solution and adding some gluconic acid lactone ( GDL) powder, and different SF scaffolds were obtained after freeze drying. Results The SF scaffolds with adjustable stiffness were successfully prepared. The compression moduli of SC1, SC2, and SC3 groups were (17. 31±2. 73), (24. 12±1. 81), (32. 54±1. 81) kPa, respectively. The innerstructure of the scaffolds was observed. From SC1 group to SC3 group, pores of the scaffolds were smaller and fewer, and hydrophilicity of the materials become better and better. Conclusions Three-dimensional ( 3D) porous scaffolds with different matrix stiffness can be prepared by changing the concentration of SF and COL solution. The concentration of SF and COL is proportional to the compression modulus, water absorption, water retention and swelling rate of SF scaffolds, while inversely proportional to porosity. The findings of this study are expected to provide theoretical guidance for construction of scaffolds with appropriate matrix stiffness for inducing osteogenic differentiation of mesenchymal stem cells
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This study aimed to prepare silk fibroin nanoparticles (SF-NPs) and assess the physicochemical properties and biocompatibility of the formulation. An optimized and simplified solvent displacement method was employed to obtain SF-NPs. Single-factor prescription screening, such as silk fibroin (SF) solution concentration, the ratio of SF solution to organic solvent, ultrasonication power and time, and different types of organic phases, was used to optimize the formulation. The characterization of the optimal formulation included particle size, polydispersity index (PDI), zeta potential, morphology, and stability. The in vitro cell compatibility of the nanoparticles was evaluated using CCK-8 and Calcein-AM/PI cell viability staining. The results showed that when SF concentration was 20 mg·mL-1, volume ratio of aqueous phase to acetone was 1∶6, ultrasonic power was 80 W and ultrasonic time was 3 min, the best SF-NPs was obtained. The nanoparticles prepared in this study exhibit a near-spherical shape, with a uniform size distribution, having an average size of 144.8 nm, a PDI of 0.174, and a zeta potential of -27.35 mV. Results from in vitro cell experiments demonstrate excellent cell compatibility of SF-NPs, showing the ability to promote cell proliferation. The SF-NPs which were successfully prepared in this study exhibit uniform particle size and excellent biocompatibility.
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Silk fibroin (SF) as a natural biopolymer has become a popular material for biomedical applications due to its minimal immunogenicity, tunable biodegradability, and high biocompatibility. Nowadays, various techniques have been developed for the applications of SF in bioengineering. Most of the literature reviews focus on the SF-based biomaterials and their different forms of applications such as films, hydrogels, and scaffolds. SF is also valuable as a coating on other substrate materials for biomedicine; however, there are few reviews related to SF-coated biomaterials. Thus, in this review, we focused on the surface modification of biomaterials using SF coatings, demonstrated their various preparation methods on substrate materials, and introduced the latest procedures. The diverse applications of SF coatings for biomedicine are discussed, including bone, ligament, skin, mucosa, and nerve regeneration, and dental implant surface modification. SF coating is conducive to inducing cell adhesion and migration, promoting hydroxyapatite (HA) deposition and matrix mineralization, and inhibiting the Notch signaling pathway, making it a promising strategy for bone regeneration. In addition, SF-coated composite scaffolds can be considered prospective candidates for ligament regeneration after injury. SF coating has been proven to enhance the mechanical properties of the substrate material, and render integral stability to the dressing material during the regeneration of skin and mucosa. Moreover, SF coating is a potential strategy to accelerate nerve regeneration due to its dielectric properties, mechanical flexibility, and angiogenesis promotion effect. In addition, SF coating is an effective and popular means for dental implant surface modification to promote osteogenesis around implants made of different materials. Thus, this review can be of great benefit for further improvements in SF-coated biomaterials, and will undoubtedly contribute to clinical transformation in the future.
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Materiales Biocompatibles/química , Seda/química , Fibroínas/farmacología , Implantes Dentales , Osteogénesis , Andamios del Tejido/química , Ingeniería de Tejidos/métodosRESUMEN
OBJECTIVES@#To design and prepare silk fibroin/hyaluronic acid composite hydrogel.@*METHODS@#The thiol modified silk fibroin and the double-bond modified hyaluronic acid were rapidly cured into gels through thiol-ene click polymerization under ultraviolet light condition. The grafting rate of modified silk fibroin and hyaluronic acid was characterized by 1H NMR spectroscopy; the gel point and the internal microstructure of hydrogels were characterized by rheological test and scanning electron microscopy; the mechanical properties were characterized by compression test; the swelling rate and degradation rate were determined by mass method. The hydrogel was co-cultured with the cells, the cytotoxicity was measured by the lactate dehydrogenase method, the cell adhesion was measured by the float count method, and the cell growth and differentiation on the surface of the gel were observed by scanning electron microscope and fluorescence microscope.@*RESULTS@#The functional group substitution degrees of modified silk fibroin and hyaluronic acid were 17.99% and 48.03%, respectively. The prepared silk fibroin/hyaluronic acid composite hydrogel had a gel point of 40-60 s and had a porous structure inside the gel. The compressive strength was as high as 450 kPa and it would not break after ten cycles. The water absorption capacity of the composite hydrogel was 4-10 times of its own weight. Degradation experiments showed that the hydrogel was biodegradable, and the degradation rate reached 28%-42% after 35 d. The cell biology experiments showed that the cytotoxicity of the composite gel was low, the cell adhesion was good, and the growth and differentiation of the cells on the surface of the gel were good.@*CONCLUSIONS@#The photocurable silk fibroin/hyaluronic acid composite hydrogel can form a gel quickly, and has excellent mechanical properties, adjustable swelling rate and degradation degree, good biocompatibility, so it has promising application prospects in biomedicine.
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Fibroínas/química , Hidrogeles/química , Ácido Hialurónico/química , Materiales Biocompatibles/química , Química Clic , Compuestos de Sulfhidrilo , Seda/químicaRESUMEN
Abstract Objective: This study aimed to develop a pro-angiogenic hydrogel with in situ gelation ability for alveolar bone defects repair. Methodology: Silk fibroin was chemically modified by Glycidyl Methacrylate (GMA), which was evaluated by proton nuclear magnetic resonance (1H-NMR). Then, the photo-crosslinking ability of the modified silk fibroin was assessed. Scratch and transwell-based migration assays were conducted to investigate the effect of the photo-crosslinked silk fibroin hydrogel on the migration of human umbilical vein endothelial cells (HUVECs). In vitro angiogenesis was conducted to examine whether the photo-crosslinked silk fibroin hydrogel would affect the tube formation ability of HUVECs. Finally, subcutaneous implantation experiments were conducted to further examine the pro-angiogenic ability of the photo-crosslinked silk fibroin hydrogel, in which the CD31 and α-smooth muscle actin (α-SMA) were stained to assess neovascularization. The tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were also stained to evaluate inflammatory responses after implantation. Results: GMA successfully modified the silk fibroin, which we verified by our 1H-NMR and in vitro photo-crosslinking experiment. Scratch and transwell-based migration assays proved that the photo-crosslinked silk fibroin hydrogel promoted HUVEC migration. The hydrogel also enhanced the tube formation of HUVECs in similar rates to Matrigel®. After subcutaneous implantation in rats for one week, the hydrogel enhanced neovascularization without triggering inflammatory responses. Conclusion: This study found that photo-crosslinked silk fibroin hydrogel showed pro-angiogenic and inflammation inhibitory abilities. Its photo-crosslinking ability makes it suitable for matching irregular alveolar bone defects. Thus, the photo-crosslinkable silk fibroin-derived hydrogel is a potential candidate for constructing scaffolds for alveolar bone regeneration.
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Silk fibroin is a natural polymer with certain water solubility, structural modification, good biocompatibility and biodegradability, which can be used as a drug delivery carrier material. As a promising drug delivery system, drug-loaded silk fibroin nanoparticles can control drug release, reduce toxicity and improve therapeutic effects. In this paper, the basic characteristics of silk fibroin, the preparation methods of drug-loaded silk fibroin nanoparticles and the application of silk fibroin in nanoparticulate drug delivery systems are reviewed, and on this basis, the further development of drug-loaded silk fibroin nanoparticles is prospected.
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Objective:To investigate the effect of tissue engineered bladder patch constructed by double-layer silk scaffold and adipose-derived stem cells (ADSCs) in the repair and reconstruction of bladder.Methods:This study was conducted from May 2020 to March 2021. The silk fibroin (SF) aqueous solution was obtained from silkworm cocoons, and a double-layer silk scaffold composed of silk fibroin film and silk fibroin sponge was further prepared. The rat ADSCs were isolated, cultured, and the ADSCs surface markers (CD29, CD90, CD45, CD106) were identified by flow cytometry. The ADSCs were planted on a double-layer silk scaffold to construct a tissue-engineered bladder patch. Thirty-six male SD rats were randomly divided into three groups: tissue engineered bladder patch group (SF-ADSCs group, n=15), double-layer silk scaffold group (SF group, n=15), control group ( n=6). The tissue engineered bladder patch (SF-ADSCs group) and double-layer silk scaffold (SF group) were wrapped on the omentum to promote vascularization. The vascularization was evaluated by HE and immunofluorescence staining. The wrapped tissue engineered bladder patch and double-layer silk scaffold were used to repair the defective bladder. In the control group (six rats), the incision was closed immediately after the bladder tissue fully exposed. At 4 weeks and 12 weeks after operation, the general morphology of bladder tissue and cystography were performed to evaluate the recovery of bladder morphology. After the graft was harvested, HE and Masson's trichrome staining and immunofluorescence staining were used to observe the regeneration of bladder wall tissue. Urodynamics was used to assess the recovery of bladder function at 12 weeks after operation. Results:The flow cytometry results confirmed that the isolated cells positively expressed CD29 and CD90, and there was no significant expression of CD45 and CD106. Gross observation and scanning electron microscope confirmed that the preparation of double-layer silk scaffold not only had a pore structure that was conducive to cell planting, but also had good toughness and was facilitated to surgical suture. The number (43.50±2.66) and area (0.73±0.03)% of vascular-like structures in the SF-ADSCs group after the omentum encapsulation was significantly higher than that in the SF group [(24.50±3.51), (0.55±0.05)%], and the difference was statistically significant ( P<0.05). At 4 weeks after bladder repair, the histological staining of the grafts in the SF-ADSCs and SF groups showed a large number of degraded fragments of double-layer silk scaffold. At 12 weeks, the morphology of the graft in the SF-ADSCs group showed uniform bladder morphology, which was similar to that of normal bladder tissue. Immunofluorescence staining showed that the continuous urothelial layer, abundant smooth muscle tissue, vascular structure and regenerated neurons could be observed in the SF-ADSCs group. Urodynamic test showed that the bladder maximum volume (0.74±0.03)ml and compliance (16.68±0.44)μl/cm H 2O in the SF-ADSCs group, which were better than that in the SF group [(0.47±0.05)ml, (14.89±0.37)μl/cm H 2O], but lower than that in the control group [(1.12±0.08)ml, (19.34±0.45)μl/cm H 2O], and the difference was statistically significant ( P<0.05). Conclusions:The tissue engineered bladder patch constructed with double-layer silk scaffolds and ADSCs could promote the morphological repair of bladder tissue, the regeneration of bladder wall structure and the recovery of bladder physiological function.
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OBJECTIVE To prepare apigenin silk fibroin（API@SF）nanoparticles and to evaluate their safety and anti-tumor activity. METHODS API@SF nanoparticles were prepared by nanoprecipitation method ，and their morphology ，particle size ，Zeta potential，drug loading amount and in vitro release were characterized. The safety of nanoparticles was evaluated by hemolysis test and HE staining. MTT assay was adopted to evaluate inhibitory effects of API@SF nanoparticles on breast cancer 4T1 cells in mice. RESULTS The prepared API@SF nanoparticles were spherical with uniform distribution. The average particle size was 406.61 nm， the polydispersity index was 0.154，the Zeta potential was －18.4 mV，and the average drug-loading amount was 5.20％. The in vitro release results showed that the release rate of the nanoparticles was relatively fast in the release medium of pH 5.0 and relatively slow in the release medium of pH 7.4. Results of hemolysis test and HE staining showed that the nanoparticles had good biocompatibility. Results of MTT assay showed that the inhibitory effect of API@SF nanoparticles on 4T1 cells was significantly higher than that of API raw materials （P＜0.05），and its mechanism may be related to increasing the level of reactive oxygen species in cells. CONCLUSIONS API@SF nanoparticles are prepared successfully ，which possess good safety and anti-tumor activity.
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SUMMARY OBJECTIVE: This study aimed to assess the effect of the collagen/silk fibroin scaffolds seeded with human umbilical cord-mesenchymal stem cells on functional recovery after acute complete spinal cord injury. METHODS: The fibroin and collagen were mixed (mass ratio, 3:7), and the composite scaffolds were produced. Forty rats were randomly divided into the Sham group (without spinal cord injury), spinal cord injury group (spinal cord transection without any implantation), collagen/silk fibroin scaffolds group (spinal cord transection with implantation of the collagen/silk fibroin scaffolds), and collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group (spinal cord transection with the implantation of the collagen/silk fibroin scaffolds co-cultured with human umbilical cord-mesenchymal stem cells). Motor evoked potential, Basso-Beattie-Bresnahan scale, modified Bielschowsky's silver staining, and immunofluorescence staining were performed. RESULTS: The BBB scores in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group were significantly higher than those in the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.05 or p<0.01). The amplitude and latency were markedly improved in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group compared with the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.05 or p<0.01). Meanwhile, compared to the spinal cord injury and collagen/silk fibroin scaffolds groups, more neurofilament positive nerve fiber ensheathed by myelin basic protein positive structure at the injury site were observed in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group (p<0.01, p<0.05). The results of Bielschowsky's silver staining indicated more nerve fibers was observed at the lesion site in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group compared with the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.01, p< 0.05). CONCLUSION: The results demonstrated that the transplantation of human umbilical cord-mesenchymal stem cells on a collagen/silk fibroin scaffolds could promote nerve regeneration, and recovery of neurological function after acute spinal cord injury.
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Humanos , Animales , Ratas , Traumatismos de la Médula Espinal , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas , Fibroínas , Médula Espinal , Cordón Umbilical , Colágeno , Recuperación de la Función , Andamios del TejidoRESUMEN
BACKGROUND: In the previous study, we have successfully prepared a silk fibroin/curcumin composite film, which possesses good physicochemical properties, sustained-release properties, antibacterial activity and biocompatibility. OBJECTIVE: To further observe the effect of the prepared silk fibroin/curcumin composite film, as the wound dressing, in the field of wound healing. METHODS: The silk fibroin/curcumin composite film was prepared by referring to the previously established methods. The mechanical properties and light transmittance of the prepared composite film were then investigated. Escherichia coli and Staphylococcus aureus were used as strains. The plate-counting technique was applied to evaluate the antibacterial activity of the light illuminated silk fibroin/curcumin composite film, silk fibroin/curcumin composite film without light exposure, and silk fibroin film without light exposure. The full-thickness excisional lesions were created on the dorsum of 20 Kunming mice. The wounds of 10 mice were covered with silk fibroin/curcumin composite film, and the wounds of other 10 mice were dressed with sterile gauze. The healing status and histological morphology of the wound sites were observed at 3, 7, and 14 days post operation. The animal experimental design and the protocols were approved by the Laboratory Animal Ethics Committee of Southwest University (approval number: IACUC-2019011). RESULTS AND CONCLUSION: (1) Compared to silk fibroin film, the fracture strength of silk fibroin/curcumin composite film increased significantly (P < 0.05), while the Young’s modulus of silk fibroin/curcumin composite film decreased significantly (P < 0.01). (2) Both silk fibroin film and the silk fibroin/curcumin composite film exhibited excellent transparency, but the silk fibroin/curcumin composite film showed a stronger absorption in visible light region at a wavelength of 400-450 nm. (3) Without light illumination, the silk fibroin/curcumin composite film exhibited stronger antibacterial activity than that of silk fibroin film. While, the silk fibroin/curcumin composite film with light illumination demonstrated stronger antibacterial activity than that of silk fibroin/curcumin composite film without light illumination. (4) The wound healing rate of the experimental group was higher than that of the control group at each time point (P <0.05). Analysis on histological morphology reveals that the length of regenerated epithelia of dermal tissue and the thickness of granulation tissue in the experimental group were greater than those in the control group at 3 and 7 days post operation (P < 0.01). While, the thickness of granulation tissue was smaller than that in the control group at 14 days post operation (P < 0.01). (5) The results indicated that the silk fibroin/curcumin composite film can facilitate skin wound healing.
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Silk fibroin has the characteristics of good biocompatibility, mechanical properties, degradation performance and easy shaping, which makes silk fibroin become the focus of biomedical material preparation and research, and has received extensive attention. This article reviews the prior art methods of silk fibroin degumming, dissolution and regeneration processing. The specific applications of silk fibroin materials in the field of biomedical materials are reviewed, and the application prospects of silk fibroin in the field of biomedical materials are prospected.
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Materiales Biocompatibles , FibroínasRESUMEN
Objective @#To explore the feasibility of antler powder/silk fibroin/polyvinyl alcohol scaffolds as tissue engineering bone scaffolds and the relationship between their degradation performance and the healing speed of bone defects.@*Methods @# Antler powder/silk fibroin/polyvinyl alcohol scaffolds and nano hydroxyapatite/silk fibroin/polyvinyl alcohol scaffolds were prepared by 3D printing. The whole bone marrow culture method was used to prepare blood cell sheets of Altay big tail sheep’s iliac bone marrow. With observation times of 1, 2 and 3 months, the mandibular defects of 4 sheep were established. The experimental group was coated with antler powder/silk fibroin/polyvinyl alcohol scaffolds. The control group was coated with nanohydroxyapatite/silk fibroin/polyvinyl alcohol scaffolds. The negative control group was coated with gel-free sponges. According to the self-control method of the bilateral mandible defect area, scaffolds wrapped with cell membranes or gel sponges wrapped with cell membranes were implanted. At the ends of the first, second and third months after implantation, the experimental animals were killed, cone beam CT was performed, and paraffin sections were taken for HE staining to evaluate the effect of different scaffold materials on bone regeneration and scaffold degradation.@* Results@# Scanning electron microscopy showed that both groups had regular pores and good continuity, and there was no difference in pore size and porosity between the two groups (P > 0.05). The results of CBCT imaging showed that in 3 months after operation, the experimental group had significantly better repair effects on bone defects than the control group, and the degradation rate matched the bone repair rate. The bone mineral density in the center of the defect was higher than that of the control group, which was close to that of normal bone tissue. The central bone mineral density of the experimental group at each time point was higher than those of the control group and the negative control group, and the difference was statistically significant (P < 0.05). HE staining results showed that the bone cells in the experimental group were more active, with more new capillaries and bone trabeculae formed, and the scaffold material absorbed more than the control group. @*Conclusion @#The antler powder/silk fibroin/polyvinyl alcohol scaffold can promote the repair of critical bone defects. Its degradability matches its bone tissue healing rate. It is expected to become a promising scaffold material for bone tissue engineering.
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Various animal models, especially rodents, are used to study pain, due to the difficulty of studying it inhumans. Many drugs that produce analgesia have been studied and there is evidence among whichNSAIDs deserve to be highlighted. Dexketoprofen (DEX) provides a broad antinociceptive profile indifferent types of pain; therefore, this study was designed to evaluate the profile of antinociceptivepotency in mice. Analgesic activity was evaluated using the acetic acid abdominal constriction test(writhing test), a chemical model of visceral pain. Dose-response curves for i.p. DEX administration (1,3, 10, 30 and 100 mg/kg), using at least six mice in each of at least five doses, was obtained before and30 min after pre-treatment with different pharmacological agents. Pretreatment of the mice with opioidreceptor antagonists was not effective; however, the serotonin receptor antagonist and nitric oxidesynthase inhibitor produce a significant increase in DEX-induced antinociception. The data from thepresent study shows that DEX produces antinociception in the chemical twisting test of mice, which isexplained with difficulty by the simple inhibition of COX. This effect appears to be mediated by othermechanisms in which the contribution of the NO and 5-HT pathways has an important effect on DEXinduced antinociception.
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BACKGROUND: Diffusion tensor imaging, as a relatively new method based on MRI, has become an important means of examination and diagnosis in the field of neuroimaging. OBJECTIVE: To investigate the role of using diffusion tensor tensor imaging data to predict 3D-bioprinted collagen/silk fibroin scaffolds in the locomotor function recovery after spinal cord injury. METHODS: Ordinary and 3D-bioprinted collagen/silk fibroin scaffold were prepared. Forty adult female SD rats provided by the Laboratory Animal Center of the Academy of Military Medical Sciences of the People’s Liberation Army were randomly divided into four groups with 10 rats in each group. In the sham operation group, only T10 vertebral plate was removed. In the model group, spinal cord injury was induced by total transection of spinal cord at T10 segment. In the ordinary collagen scaffold and 3D-printed scaffold groups, after induction of T10 spinal cord injury, ordinary collagen scaffold and 3D-printed scaffold were implanted, respectively. At 1, 2, 3, 4, 6 and 8 weeks after surgery, Basso, Beattie and Bresnahan (BBB) locomotor function scoring and oblique plate test of the hind limbs were carried out. At 8 weeks after surgery, electrophysiological test of the hind limbs was performed to evaluate locomotor function. At 8 weeks after surgery, diffusion tensor imaging of the lumbar spine was performed and the correlation between diffusion tensor imaging parameter and rat locomotor function was analyzed. Animal experiments were approved by the Animal Ethics Committee of Characteristic Medical Center of the Chinese people’s Armed Police Force (approval No. 27653/58). RESULTS AND CONCLUSION: (1) From 3 weeks after surgery, BBB score in the 3D-printed group was significantly higher than that in the model and ordinary collagen scaffold groups (P < 0.05 or P < 0.01). From 2 weeks after surgery, the slope angle in the 3D-printed scaffold group was significantly higher than that in the model and ordinary scaffold groups (P < 0.05 or P < 0.01). (2) The amplitude of motor evoked potential in the 3D-printed scaffold group was significantly greater than that in the model and ordinary collagen scaffold groups (P < 0.05 or P < 0.01). The latency of motor evoked potential in the 3D-printed scaffold group was significantly shorter than that in the model and ordinary collagen scaffold groups (P < 0.05 or P < 0.01). (3) Diffusion tensor imaging showed that the nerve fiber trajectories in the three groups were irregular and lacked the continuity of nerve fibers, but the number of regenerated nerve fiber bundles in the 3D-printed collagen scaffold group was greater than that in the model and ordinary collagen scaffold groups (P < 0.01). The fractional anisotropy at 9, 7.5, 4.5, -3, -6, -7.5, -9 mm from the center of spinal cord injury in 3D-printed collagen scaffold group was significantly higher than that in model and ordinary collagen scaffold groups (P < 0.05 or P < 0.01). (4) The BBB score, slope angle, amplitude of motor evoked potential, latency of motor evoked potential were positively correlated with the fractional anisotropy value of diffusion tensor imaging from head to tail of rats. (5) These results suggest that diffusion tensor imaging can be used as an effective predictor to evaluate the recovery of neurological function after spinal cord injury in experimental animals and clinical cases.
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BACKGROUND: Silk fibroin and chitosan are commonly used as scaffolds In tissue engineering, but there are some shortcomings In their separate application. When they are mixed, they can be modified each other. They give full play to each other’s advantages and become Ideal composite scaffolds. OBJECTIVE: To prepare Silk fibroin/chitosan composite scaffold and determineits properties. METHODS: The silk fibroin/chitosan composite scaffolds were prepared by freeze-drying method. The morphology and structure of the composite scaffolds were examined by scanning electron microscopy. The properties of the composite scaffolds were tested by thermogravlmetric analysis, mechanical properties test, and cytotoxicity test. The quaternion chitosan was prepared. The nuclear magnetic resonance spectrum was detected by nuclear magnetic resonance instrument. The potential and particle size distribution were detected by Zeta potentiometer. The protection of DNA was detected by gel electrophoresis. The binding with DNA was observed by transmission electron microscope. RESULTS AND CONCLUSION: (1 ) The results of scanning electron microscopy showed that the silk fibroin/chitosan composite scaffolds had a good three-dimensional pore structure, with a pore size of 50-100 urn. (2) The results of thermogravimetric analysis showed that when the temperature was less than 200 °C, the mass loss rate of silk fibroin/chitosan composite scaffold was lower. When the temperature Increased to 200-500 °C, the mass loss rate of the scaffold began to accelerate, and the loss amount increased. At 800 °C, the residual mass of the composite scaffold was 38%. (3) The maximum strain of silk fibroin/chitosan composite scaffold reached 94.94%, and the maximum stress was 7.01 MPa. (4) The results of CCK-8 experiment showed that silk fibroin/chitosan composite scaffolds had no cytotoxicity to rabbit bone marrow mesenchymal stem cells and had good cell compatibility. (5) The results of nuclear magnetic resonance spectra showed that the quaternion degree of quaternary ammonium chitosan was about 20%. (6) The particle size distribution of quaternized chitosan was (588.56±52.39) nm, and the surface of quaternized chitosan was positively charged with a potential of (16.3±3.92) mV, which was beneficial to the combination with DNA. (7) The results of gel electrophoresis experiments showed that the higher the proportion of quaternion chitosan, the better the encapsulation of DNA. When the ratio of chitosan/DNA was 1 : 3, the encapsulation effect was achieved. (8) The results of transmission electron microscopy showed that most of the particles of quaternized chitosan/DNA were solid and round; the particle size difference was small; and the average particle size was about 200 nm. (9) The results showed that silk fibroin/chitosan composite scaffolds had a good biocompatibility and cell permeability, which was conducive to the growth of cells between scaffolds.
RESUMEN
BACKGROUND: Silk fibroin material has good biocompatibility, excellent mechanical properties, biodegradation and other advantages. However, it has not been used as a kind of suture fixation material in the repair of meniscus tear. OBJECTIVE: To prepare gentamicin loaded silk fibroin material and analyze its biocompatibility and antibacterial properties. METHODS: After dissolving the degummed natural silkworm cocoon with ternary solution, the silk fibroin material was prepared by dialysis, freeze-drying, redissolution and molding, and gentamicin was dissolved in silk fibroin solution to prepare gentamicin loaded silk fibroin material. Silk fibroin material and gentamicin loaded silk fibroin material were co-cultured with mouse pre chondroblasts respectively. After 1, 3, and 5 days, cell proliferation was detected by MTT assay. After 24 hours of co-culture, the cytotoxic effect of the material was detected by calcein staining. The early apoptosis of cells was detected by flow cytometry. The adhesion of cells on the surface of the material was observed by scanning electron microscope. Silk fibroin material and gentamicin loaded silk fibroin material were mixed with anticoagulant separately. The hemolysis rate of the material was detected by hemolysis experiment. The silk fibroin material and gentamicin loaded silk fibroin material were co-cultured with S.aureus and E.coli respectively. The bacterial count, scanning electron microscope observation and bacteriostatic circle experiment were carried out. RESULTS AND CONCLUSION: (1) The two materials had no significant effect on cell proliferation and early apoptosis. (2) There was no obvious cytotoxicity between the two materials, and the cells adhered on the surfaces of the two materials grew well, arranged tightly, and the morphology of the cells expanded. (3) The two materials had good blood compatibility and did not cause hemolytic reaction. (4) Gentamicin loaded silk fibroin material had obvious inhibition on S.aureus and E.coli, and the inhibition on S.aureus was more obvious. (5) The results showed that the gentamicin loaded silk fibroin material has good biocompatibility and antibacterial property.