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Magnetic nanoparticles (MNP) have been widely used as biomaterials due to their unique magnetic responsiveness and biocompatibility, which also can promote osteogenic differentiation through their inherent micro-magnetic field. The MNP composite scaffold retains its superparamagnetism, which has good physical, mechanical and biological properties with significant osteogenic effects and . Magnetic field has been proved to promote bone tissue repair by affecting cell metabolic behavior. MNP composite scaffolds under magnetic field can synergically promote bone tissue repair and regeneration, which has great application potential in the field of bone tissue engineering. This article summarizes the performance of magnetic composite scaffold, the research progress on the effect of MNP composite scaffold with magnetic fields on osteogenesis, to provide reference for further research and clinical application.
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Diferenciación Celular , Nanopartículas de Magnetita , Osteogénesis , Ingeniería de Tejidos , Andamios del TejidoRESUMEN
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.
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BACKGROUND: Repair materials for bone tissue engineering should hold good biocompatibility and degradability. There are various related studies, but the Chinese medicine composite cellular bioscaffolds are little reported. OBJECTIVE: To detect the in vitro cytotoxicity of rabbit bone marrow mesenchymal stem cells-cuttlebone bioscaffold based on the Biological Evaluation of Medical Device, and assess its cytotoxicity level in order to provide the theoretical support for its clinical application. METHODS: Bone marrow mesenchymal stem cells-cuttlebone bioscaffold extract was prepared according to an ISO standard — material area: extraction medium volume = 3-6 cm2:1 mL. L-929 cell suspension was prepared, and the cells were then cultured with a density of 1×107/L. There were three groups: positive group (DMEM medium containing phenol), experimental group (material extract), and negative group (DMEM culture medium). The absorbance value of L-929 cells was detected by MTT assay after 24, 48 and 72 hours of culture. The relative proliferation rate of cells was then calculated and the toxicity level was valued in each group. RESULTS AND CONCLUSION: The absorbance values in the experimental, negative and positive groups were not exactly same at different time points (P=0.000 < 0.01). The absorbance values in the experimental and negative groups were significantly higher than those in the positive group (P < 0.01).The cytotoxicity of bone marrow mesenchymal stem cells-cuttlebone bioscaffold was grade 1. To conclude, the bone marrow mesenchymal stem cells-cuttlebone bioscaffold has no obvious toxic effects, and meets the requirements of biomaterial application.
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Results: The scaffolds in 3 groups were all showed a cross-linked and pore interconnected with pore size of 400-500 μm, porosity of 56%, and fiber orientation of 0°/90°. For dopamine modification, the scaffolds in groups B and C were dark brown while in group A was white. Similarly, water static contact angle was from 76° of group A to 0° of groups B and C. After cultured for 24 hours, the cell adhesion rate of groups A, B, and C was 34.3%±3.5%, 48.3%±1.5%, and 57.4%±2.5% respectively, showing significant differences between groups ( P<0.05). Live/Dead staining showed good cell activity of cells in 3 groups. MTT test showed that hBMSCs proliferated well in 3 groups and the absorbance ( A) value was increased with time. The A value in group C was significantly higher than that in groups B and A, and in group B than in group A after cultured for 4, 7, 14, and 21 days, all showing significant differences ( P<0.05). The mRNA relative expression of collagen type Ⅱ and Aggrecan increased gradually with time in 3 groups. The mRNA relative expression of collagen type Ⅱafter cultured for 7, 14, and 21 days, and the mRNA relative expression of Aggrecan after cultured for 14 and 21 days in group C were significantly higher than those in groups A and B, and in group B than in group A, all showing significant differences ( P<0.05).
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OBJECTIVE: To investigate the effect of repairing radial bone defect with scaffold material of attapulgite/collagen type I/poly (caprolactone) (ATP/Col I/PCL) in rabbits and the possibility as bone graft substitutes. METHODS: ATP/Col I/PCL materials were prepared via adding ATP to hexafluoroisopropanol after dissolved Col I/PCL (3:2), and Col I/PCL materials via dissolving Col I/PCL (3:2) in hexafluoroisopropanol served as control. The structure of scaffolds was observed under scanning electron microscope (SEM). Twenty-four Japanese white rabbits (male, 2 months old) were used to establish the bilateral radius defect model of 15 mm in length, and randomly divided into group A (6 rabbits, 12 defects), group B (9 rabbits, 18 defects), and group C (9 rabbits, 18 defects); then the Col I/PCL scaffold was implanted in the bone defect area in group B, the ATP/Col I/PCL scaffold in group C, no treatment was done in group A as control. The general condition of rabbits was observed after operation, and bone defect repair was evaluated by X-ray at 4, 8, and 12 weeks. At 12 weeks, the tissue of defect area was harvested for the general, SEM, Micro-CT, histological, and immunohistochemical staining to observe defect repair and material degradation. RESULTS: SEM observation showed that two kinds of materials were porous structure, ATP/Col I/PCL structure was more dense than Col I/PCL. All animals survived to the end of experiment, and no incision infection occurred during repair process.X-ray films showed that the bone marrow cavity was re-opened in defect area of group C with time, the repair effect was superior to that of groups A and B. At 12 weeks after operation, general observation showed that scaffold material had good fusion with the surrounding tissue in groups B and C, defect was filled with connective tissue in group A. SEM indicated that the surface and pore of the scaffold were covered with a large number of cells and tissues in groups B and C. Micro-CT demonstrated that the new bone volume, bone mineral content, tissue mineral content, and connectivity density of group C were significantly higher than those of groups A and B (P<0.05). The observation of histology and immunohistochemical staining indicated that there were lots of connective tissues in defect area of group A, and ALP, Col I, and OPN were weakly expressed; there were many collagen fibers in scaffold degradation area in group B, and the expression levels of ALP, Col I, and OPN were higher than those of group A; there was few new bone in group C, the degradation rate of the scaffold was slower than that of group B, and the expression of Col I and OPN were enhanced, while ALP was weakened when compared with groups A and B. CONCLUSIONS: ATP/Col I/PCL composite scaffold material can degrade in vivo, and has dense three-dimensional porous structure, good biocompatibility, and high potentiality of bone repair, so it can be used as bone substitute material.
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Objective To fabricate nano-hydroxyapatite (Nano-HA)/poly-ε-colactone (PCL) scaffolds with the selective laser sintering (SLS) technique and to study the mechanical strength, biocompatibility and bioactivity of the prepared scaffolds. Methods Nano-HA and PCL powders with Nano-HA weight ratio accounting for 0%, 5%, 10%, and 15% were mixed, and PCL and Nano-HA/PCL scaffolds (5%, 10% and 15%) were fabricated using SLS technique. The porosity and mechanical strength of scaffolds were determined. Isolated rabbit bone marrow stromal cells were seeded onto the Nano-HA/ PCL or PCL scaffolds and cultured in vitro. Cell adhesion and proliferation were observed. The osteogenesis for pure PCL and nano-HA/PCL scaffolds were compared by detecting alkaline phosphatase (ALP) expression and Alizarin Red S staining. Results Both the pure PCL and Nano-HA/PCL composite scaffolds showed good mechanical strength and cell adhesion without obvious cell toxicity. The expression of ALP in all groups showed no significant difference on the first day of seeding, but with the extension of culture time, ALP expression in Nano-HA/PCL group was significantly increased compared with PCL group and blank group(P<0. 05). The expression of ALP increased with the increase of Nano-HA ratio(P<0. 05). The positive intensity of Alizarin Red S staining in Nano-HA/PCL group was higher than those in PCL group and blank group; moreover, the number of calcium nodules and positive intensity of staining were inceased with the increase of nano-HA the ratio. Conclusion The nano-HA/PCL composite scaffold fabricated with SLS technique in the present study has good mechanical strength, biocompatibility and osteoinduction, and t may serve as an alternative material for bone repair.
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BACKGROUND:Preparation of titanium/hydroxyapatite composite by conventional methods has the deficiency of simple structure, low degree of automation and difficulty in porosity and pore size control, which limits the diverse process and manufacture. OBJECTIVE:To evaluate the feasibility of three-dimensional printing technology for the preparation of titanium/hydroxyapatite composite and titanium/hydroxyapatite functional y graded material molding. METHODS:A CAD model of titanium/hydroxyapatite composite was designed to be the cylinder (diameter 25 mm, height 20 mm), while the titanium/hydroxyapatite functional y graded implant designed as a CAD model of the cylinder with 25 mm in diameter asnd 10 mm in height with two layers, the upper layer with titanium powder and the lower layer with titanium/hydroxyapatite powder. The composite and functional y graded implant were processed by the three-dimensional printing and sintered. The sintered titanium/hydroxyapatite composite and titanium/hydroxyapatite functional y graded implant were observed for their microstructures, and the X-ray diffraction analysis and compressive strength testing were performed. RESULTS AND CONCLUSION:The sintered titanium/hydroxyapatite composite and titanium/hydroxyapatite functional y graded implant had uniform contraction and no obvious distortion. The sintered titanium/hydroxyapatite composite had the aperture size from 50 to 150μm. There occurred a chemical reaction between titanium and hydroxyapatite during the sintering process, obtaining the new creations of Ca3(PO4)2, CaTiO3, TiO2 and CaO. Its compressive strength was (184.3±27.1) MPa. The microstructure of titanium/hydroxyapatite functional y graded implant had graded structures with a visible line between the two layers. The results of the microstructure and mechanical properties of titanium/hydroxyapatite composite and titanium/hydroxyapatite functional y graded implant can meet the requirements of medical biological implant materials.
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BACKGROUND:Through a ful investigation of biodegradable scaffolds, we propose a new self-expanding degradable poly-L-lactide coated endotracheal stent based on the design, production, experimental and clinical applications of nickel titanium memory alloy stent. OBJECTIVE:To design a kind of biodegradable endotracheal stent with poly-L-lactide and hydroxyapatite, and to test its mechanical properties, biocompatibility and biodegradation capacity. METHODS:With the technology of computer aided design, the stents were prepared with poly-L-lactide (Mr RESULTS AND CONCLUSION:The average radial supporting force of the tracheal stent was 7.8 kPa, the percentage of stent surface coverage was less than 20%, the stent expansion rate was≥4%, and the stent longitudinal shortening rate was≤9%, which reached the mechanical requirements for degradable endotracheal stents. After 4-16 weeks, there was no significant inflammatory response. The decline in molecular weight changes and weight loss ratio was higher for in vivo degradation than in vitro degradation at different time (P<0.05). These findings indicate that poly-L-lactide/hydroxyapatite composite stents have good mechanical properties, biocompatibility and biodegradability. 150 000) and hydroxyapatite materials, 20 mm to 26 mm in diameter. The mechanical properties were tested using a universal testing machine. These poly-L-lactide/hydroxyapatite stents were implanted into dog models of tracheal stenosis at an appropriate size. The histopathological changes of the tracheas were observed, and biodegradation property was studied via molecular weight changes and weight loss ratio after 4, 8, 12, 16 weeks.
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10.3969/j.issn.2095-4344.2013.25.013
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10.3969/j.issn.2095-4344.2013.25.014
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10.3969/j.issn.2095-4344.2013.25.010
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0.05).CONCLUSION: The rabbit calvarial defect was not successfully repaired by silk fibroin/nano-hydroxyapatite/corn starch composite scaffold and may have been due to an inflammatory reaction caused by silk powder. In the future, the development of composite bone graft material based on various components should be performed with caution.
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Animales , Conejos , Regeneración Ósea , Fibroínas , Osteogénesis , Hueso Parietal , Seda , Almidón , Trasplantes , Microtomografía por Rayos X , Zea maysRESUMEN
Objective To determine whether the small intestinal submucosa(SIS)/nano meter crystal ?-tricalcium phosphate(nm ?-TCP) composite can enhance the regeneration of rabbit mandibular defects. Methods Twenty-six mandibular defects were made on thirteen New Zealand rabbits,and were ramdonly divided into four groups: groupⅠ,single SIS was applied to each defects;group Ⅱ,nm ?-TCP;groupⅢ,the composite scaffold materials of SIS and nm ?-TCP;groupⅣ,control.Twelve weeks after the operation,the samples were extracted for gross observation,histological analysis,X-ray examination,and relative bone density(RBD) recording.Results Twenty weeks after the operation,the newborn bone trabecula took up most of the area with defects.The restorative materials in the SIS group and composite scaffold materials group had almost degraded,and little remained in the ?-TCP group.The composite scaffold materials group was found more newborn bone trabecula with mature formation,and the average RBD was relatively higer,while less newborn bone trabecula with irregular formation and more collagen were observed in the control group. Conclusion The composite materials of SIS and nm ?-TCP,which enjoy favourable bone formation characteristics and histocompatibility, can enhance bone regeneration in rabbit mandibular defects.
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Various kinds of scaffold materials are studied and used in cartilage tissue engineering, but none are ideal for the needs of tissue engineering. Mixing different materials together to form a better composite scaffold may brighten the prospect. The present review summarizes the studies of composite materials in cartilage tissue engineering.