ObjectiveTo evaluate the effect of a novel micro-arc oxidation (MAO) coated magnesium-zinc-calcium (Mg-Zn-Ca) alloy scaffold/autologous bone particles to repair critical size bone defect (CSD) in rabbit and explore the novel scaffold in vivo corrosion resistance and biocompatibility.MethodsSeventy-two New Zealand white rabbits were randomly divided into 3 groups (n=24), group A was uncoated Mg-Zn-Ca alloy scaffold group, group B was 10 μm MAO coated Mg-Zn-Ca alloy scaffold group, and group C was control group with only autologous bone graft. The animals were operated to obtain bilateral ulnar CSD (15 mm in length) models. The bone fragment was removed and minced into small particles and were filled into the scaffolds of groups A and B. Then, the scaffolds or autologous bone particles were replanted into the defects. The animals were sacrificed at 2, 4, 8, and 12 weeks after surgery (6 rabbits each group). The local subcutaneous pneumatosis was observed and recorded. The ulna defect healing was evaluated by X-ray image and Van Gieson staining. The X-ray images were assessed and scored by Lane-Sandhu criteria. The percentage of the lost volume of the scaffold (ΔV) and corrosion rate (CR) were calculated by the Micro-CT. The Mg2+ and Ca2+ concentrations were monitored during experiment and the rabbit liver, brain, kidney, and spleen were obtained to process HE staining at 12 weeks after surgery.ResultsThe local subcutaneous pneumatosis in group B was less than that in group A at 2, 4, and 8 weeks after surgery, showing significant differences between 2 groups at 2 and 4 weeks after surgery (P<0.05); and the local subcutaneous pneumatosis was significantly higher in group B than that in group A at 12 weeks after surgery (P<0.05). The X-ray result showed that the score of group C was significantly higher than those of groups A and B at 4 and 8 weeks after surgery (P<0.05), and the score of group B was significantly higher than that of group A at 8 weeks (P<0.05). At 12 weeks after surgery, the scores of groups B and C were significantly higher than that of group A (P<0.05). Meanwhile, the renew bone moulding of group B was better than that in group A at 12 weeks after surgery. Micro-CT showed that ΔV and CR in group B were significantly lower than those in group A (P<0.05). Van Gieson staining showed that group B had better biocompatibility and osteanagenesis than group A. The Mg2+ and Ca2+ concentrations in serum showed no significant difference between groups during experiments (P>0.05). And there was no obvious pathological changes in the liver, brain, kidney, and spleen of the 3 groups with HE staining at 12 weeks.ConclusionThe MAO coated Mg-Zn-Ca alloy scaffold/autologous bone particles could be used to repair CSD effectively. At the same time, 10 μm MAO coating can effectively improve the osteanagenesis, corrosion resistance, and biocompatibility of Mg-Zn-Ca alloy scaffold.
ObjectiveTo investigate the biocompatibility and immunogenicity of the tracheal matrix decellularized by sodium perchlorate (NaClO4).MethodsBone marrow mesenchymal stem cells (BMSCs) were divided from 2-month-old New Zealand white rabbits. The trachea of 6-month-old New Zealand white rabbits were trimmed to a length of 1.5 cm and randomly divided into control group (group A1, n=5, just stripped the loose connective tissue outside the trachea) and experimental group (group B1, n=5, decellularized by improved NaClO4 immersion method). The cytotoxicity of the scaffold leaching solution was detected by MTT assay, and the major histocompatibility complex (MHC) expression was detected by immunohistochemical method. The 4th generation of BMSCs were seeded onto the scaffold of 2 groups, and the cell activity around the material was observed by inverted microscope after Giemsa staining at 48 hours, while the cells states on the scaffold were observed at 7 and 14 days after culturing by scanning electron microscope. Another 10 6-month-old New Zealand white rabbits were randomly divided into control group (group A2, n=5) and experimental group (group B2, n=5), which implanted the native trachea and decellularized tracheal matrix into the subcutaneous sac of the back neck, respectively. The serum immunoglobulin IgM and IgG contents were analysed at 5, 10, 15, 20, 25, and 30 days after operation, and HE staining observation was performed at 30 days after operation.ResultsMTT assay showed that the proliferation activity of BMSCs cultured in the leach liquor of group B1 was well, showing no significant difference when compared with group A1 and negative control group with pure culture medium (P>0.05). The immunohistochemical staining showed that the decellularized process could significantly reducing the antigenicity of matrix materials. Giemsa staining showed that BMSCs grew well around the two tracheal matrixs (groups A1 and B1) in vitro. Scanning electron microscope observation showed that the cells were attached to the outer wall of the tracheal material in group A1, which present a flat, round, oval shaped, tightly arranged cells and cluster distribution; and in group B1, the cells formed a single lamellar sheet cover the outer wall of the tracheal material, whose morphology was similar to that in group A1, and the growth trend was better. In vivo experimental results showed that the rejection of group B2 was lower than that of group A2. The contens of IgM and IgG in group A2 were significantly higher than those in group B2 at each time point after operation (P<0.05). HE staining showed no signs of rejection, macrophagocyte, or lymphocyte infiltration occurred, and the collagen fibers maintained their integrity in group B2.ConclusionThe decellularized matrix treated by NaClO4 has a fine biocompatibility, while its immunogenicity decreased, and it is suitable for the scaffold material for constructing of tissue engineered trachea.
Biomedical metal materials have always been a major biomedical material with a large and wide range of clinical use due to their excellent properties such as high strength and toughness, fatigue resistance, easy forming, and corrosion resistance. They are also the preferred implant material for hard tissues (bones and teeth that need to withstand higher loads) and interventional stents. And nano-medical metal materials have better corrosion resistance and biocompatibility. This article focuses on the changes and improvements in the properties of several typical medical metal materials surfaces after nanocrystallization, and discusses the current problems and development prospects of nano-medical metal materials.
Objective To explore the clinical application value of mineralized collagen (MC) bone scaffolds in repairing various types of skull defects, and to assess the suitability and repair effectiveness of porous MC (pMC) scaffolds, compact MC (cMC) scaffolds, and biphasic MC composite (bMC) scaffolds. Methods A retrospective analysis was conducted on the clinical data of 105 patients who underwent skull defect repair with pMC, cMC, or bMC between October 2014 and April 2022. The cohort included 63 males and 42 females, ranging in age from 3 months to 55 years, with a median age of 22.7 years. Causes of defects included craniectomy after traumatic surgery in 37 cases, craniotomy in 58 cases, tumor recurrence or intracranial hemorrhage surgery in 10 cases. Appropriate MC scaffolds were selected based on the patient’s skull defect size and age: 58 patients with defects <3 cm² underwent skull repair with pMC (pMC group), 45 patients with defects ≥3 cm² and aged ≥5 years underwent skull repair with cMC (cMC group), and 2 patients with defects ≥3 cm² and aged <5 years underwent skull repair with bMC (bMC group). Postoperative clinical follow-up and imaging examinations were conducted to evaluate bone regeneration, the biocompatibility of the repair materials, and the occurrence of complications. Results All 105 patients were followed up 3-24 months, with an average of 13 months. No material-related complication occurred in any patient, including skin and subcutaneous tissue infection, excessive ossification, and rejection. CT scans at 6 months postoperatively showed bone growth in all patients, and CT scans at 12 months postoperatively showed complete or near-complete resolution of bone defects in all patients, with 58 cases repaired in the pMC group. The CT values of the defect site and the contralateral normal skull bone in the pMC group at 12 months postoperatively were (1 123.74±93.64) HU and (1 128.14±92.57) HU, respectively, with no significant difference (t=0.261, P=0.795). Conclusion MC exhibits good biocompatibility and osteogenic induction ability in skull defect repair. pMC is suitable for repairing small defects, cMC is suitable for repairing large defects, and bMC is suitable for repairing pediatric skull defects.
Silicon carbide (SiC) film and silicon dioxide (SiO2) film were deposited on the surface of carbon/carbon composite (C/C) by low pressure chemical vapor deposition (LPCVD). The biocompatibility of the three carbon-based composites, e. g. C/C, C/C-SiC, C/C-SiO2 were investigated by cytotoxicity test, cell direct contact and cell adhesion experiments. Cytotoxicity, cell direct contact and cell adhesion showed that the three materials had no toxic effect on mouse fibroblasts (L929 cells). However, the particles dropped off from the three materials had a great impact on evaluation accuracy of the thiazolyl blue (MTT) test. More the particles were lost, more growth inhibition to L929 cells. The evaluation accuracy of MTT method can be kept with the filtered extract of materials. Furthermore, the results of surface particles shedding experiment showed that the amount of surface particles shed from C/C-SiO2 was the most, followed by C/C and C/C-SiC in 72 hours. Particles shedding curves showed there was a peak reached at eighth hour and then declined to the thirty-sixth hour. The filtrate analysis showed that there was no ion exchange between the three materials and simulated body fluid (SBF) solution. The results of this study on biocompatibility of carbon-based composites have certain guiding significance for their future application in clinical filed.
Objective To investigate the biocompatibility of type I collagen scaffold with rat bone marrow mesenchymal stem cell (BMSCs) and its role on proliferation and differentiation of BMSCs so as to explore the feasibility of collagen scaffold as neural tissue engineering scaffold. Methods Type I collagen was used fabricate collagen scaffold. BMSCs were isolated by density gradient centrifugation. The 5th passage cells were used to prepare the collagen scaffold-BMSCs complex. The morphology of collagen scaffold and BMSCs was observed by scanning electron microscope (SEM) and HE staining. The cell proliferation was measured by MTT assay at 1, 3, 5, and 7 days after culturein vitro. After cultured on collagen scaffold for 24 hours, the growth and adhesion of green fluorescent protein positive (GFP+) BMSCs were observed by confocal microscopy and live cell imaging. Results The confocal microscopy and live cell imaging results showed that GFP+ BMSCs uniformly distributed in the collagen scaffold; cells were fusiform shaped, and cell process or junctions between the cells formed in some cells, indicating good cell growth in the collagen scaffold. Collagen scoffold had porous fiber structure under SEM; BMSCs could adhered to the scaffold, with good cell morphology. The absorbance (A) value of BMSCs on collagen scaffold at 5 and 7 days after culture was significantly higher than that of purely-cultured BMSCs (t=4.472,P=0.011;t=4.819,P=0.009). HE staining showed that collagen scaffold presented a homogeneous, light-pink filament like structure under light microscope. BMSCs on the collagen scaffold distributed uniformly at 24 hours; cell displayed various forms, and some cells extended multiple processes at 7 days, showing neuron-like cell morphology. Conclusion Gelatinous collagen scaffold is easy to prepare and has superior biocompatibility. It is a promising scaffold for neural tissue engineering.
ObjectiveTo observe the long-term outcome and biocompatibility of the porcine collagen membrane (DermalGen) after xenotransplantation in vivo.MethodsTwenty Sprague Dawley rats were randomly divided into 2 groups (n=10). DermalGen were implanted subcutaneously into the dorsum of rats in experimental group, and the rats in control group were treated with sham-operation. At 3, 7, and 15 days and 1, 3, 6, and 12 months after operation, the samples of experimental group were harvested and gross observation, histological observation, CD31 immunohistochemical staining, and transmission electron microscope observation were taken to observe the inflammatory reaction, angiogenesis, and collagen arrangement. The skin tissues of the control group at 12 months were observed and compared.ResultsAll incisions healed in experimental group, without obvious swelling and inflammatory reaction. The DermalGen was closely contact with the surrounding tissue without obvious rejection, and it was still legible at 12 months. Histological observation of experimental group showed that the infiltration of fibroblasts and inflammatory cells were seen at 7 days. More capillaries and fibroblast cells were seen and the inflammatory response gradually faded at 15 days and 1 month. There were abundant vessels and cells in the DermalGen at 3 months. The angiogenesis and fibroblasts decreased gradually, and the collagen started to format and margin blended simultaneously at 6 and 12 months. The inflammatory cells in experimental group at 15 days and 1 month were significantly more than that in control group (P<0.05), and no significant difference was found at 12 months between experimental group and control group (P>0.05). Immunohistochemical staining of experimental group showed that the angiogenesis changed obviously with the time, and the density of vessels decreased significantly at 12 months. Compared with control group, the possitive expressions of CD31 in experimental group at 15 days and 12 months after operation were significantly decreased (P<0.05), and were significantly increased at 1 month (P<0.05). Transmision electron microscope observation showed that the arrangement of collagen in grafted DermalGen had no obvious changed when compared with the DermalGen, and vascular endothelial cell, capillarypericytes and fibroblast cells could be seen inside.ConclusionThe DermalGen structure is stable after long-term xenotransplantation and with good tolerogenic property in vivo.
Objective To investigate the biocompatibility of true bone ceramic (TBC) and provide experimental basis for clinic application. Methods TBC was prepared from healthy adult bovine cancellous bone by deproteinization and high temperature calcinations. Mouse fibroblast cell line (L929 cells) were cultured with the leaching liquor of TBC in vitro, and the cytotoxicity was evaluated at 2nd, 4th, and 7th days. L929 cells were inoculated into the TBC and cultured for 4 days. The cell adhesion and proliferation on the surface of the TBC were observed by scanning electron microscopy, and evaluated the cell compatibility of TBC. Ten New Zealand white rabbits were divided into 2 groups, and drilled holes at the tibia of both hind limbs. TBC and hydroxyapatite (HA) were implanted into the left side (experimental group) and the right side (control group), respectively. And the biocompatibility of TBC was evaluated by general observation and histological observation at 4 and 26 weeks after implantation. Results Cytotoxicity test showed that the cytotoxicity level of leaching liquor of TBC was grade 0-1. Cell compatibility experiments showed that the L929 cells adhered well on the surface of TBC and migrated into the pores. The implantation test in vivo showed that experimental group and control group both had mild or moderate inflammatory response at 4 weeks, and new bone formation occurred. At 26 weeks, there was no inflammatory reaction observed in both groups, and new bone formation was observed in varying degrees. Conclusion TBC have good biocompatibility and can be used to repair bone defect in clinic.
Polydimethylsiloxane (PDMS) and hydroxyapatite (HA) were combined in our laboratory to fabricate an elastic porous cell scaffold with pore-forming agent, and then the scaffold was used as culture media for rat bone marrow derived mesenchymal stem cells (rBMSCs). Different porous materials (square and circular in shape) were prepared by different pore-forming agents (NaCl or paraffin spheres) with adjustable porosity (62%-76%). The HA crystals grew on the wall of hole when the material was exposed to SBF solutions, showing its biocompatibility and ability to support the cells to attach on the materials.
ObjectiveThe application progress of medical absorbable haemostatic material (MAHM) in hemostasis during orthoapedic surgery was reviewed, in order to provide reference for clinical hemostasis program. Methods The domestic and foreign literature on the application of MAHM for hemostasis in orthopedic surgery was extensively reviewed and summarized. ResultsAccording to biocompatibility, MAHM can be divided into oxidized cellulose/oxidized regenerated cellulose materials, chitosan and its derivatives materials, starch materials, collagen and gelatin materials, and fibrin glue materials, etc., which can effectively reduce blood loss when used in orthopedic surgery for hemostasis. Each hemostatic material has different coagulation mechanism and suitable population. Oxidized cellulose/oxidized regenerated cellulose, chitosan and its derivatives, starch hemostatic material mainly stops bleeding by stimulating blood vessel contraction and gathering blood cells, which is suitable for people with abnormal coagulation function. Collagen, gelatin and fibrin glue hemostatic materials mainly affect the physiological coagulation mechanism of the human body to stop bleeding, suitable for people with normal coagulation function. ConclusionReasonable selection of MAHM can effectively reduce perioperative blood loss and reduce the risk of postoperative complications, but at present, single hemostatic material can not meet clinical needs, and a new composite hemostatic material with higher hemostatic efficiency needs to be developed.