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.
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.
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.
ObjectiveTo study the biocompatibility of bioprosthetic heart valve material with a non-glutaraldehyde-based treatment, and to provide the safety data for the clinical application. MethodsAll the tests were conducted according to GB/T16886 standards. The in vitro cytotoxicity was determined by methyl thiazolyl tetrazolium assay. Fifteen guinea pigs were divided into a test group (n=10) and a control group (n=5) in the skin sensitization test. Three New Zealand white rabbits were used in the intradermal reactivity test. Five sites on both sides of the rabbit back were set as test sites and control sites, respectively. In the acute systemic toxicity test, a total of 20 ICR mice were randomly assigned to 4 groups: a test group (polar medium), a control group (polar medium), a test group (non-polar medium) and a control group (non-polar medium), 5 in each group. Forty SD rats were divided into a test group (n=20) and a control group (n=20) in the subchronic systemic toxicity test. ResultsThe viability of the 100% extracts of the bioprosthetic heart valve material with a non-glutaraldehyde-based treatment was 75.2%. The rate of positive reaction was 0.0%. The total intradermal reactivity test score was 0. There was no statistical difference in the body weight between the test group and control group in the acute systemic toxicity test. There was no statistical difference in the body weight, organ weight, organ weight/body weight ratio, blood routine test or blood biochemistry between the test group and control group in the subchronic systemic toxicity test. ConclusionThe bioprosthetic heart valve material with a non-glutaraldehyde-based treatment has satisfying biocompatibility, which conforms to relevant national standards. The material might be a promising material for application in valve replacement.
Objective
To prepare nano polypyrrole (PPy)/chitin composite membrane and observe their biocompatibility.
Methods
The nano PPy was synthesized by microemulsion polymerization, blended with chitosan and then formed membranes. The membranes were then modified by acetylation to get the experimental membranes (nano PPy/chitin composite membranes, group A). The chitosan membranes (group B) and chitin ones (group C) modified by acetylation acted as control. Scanning electron microscopy and FT-IR spectra were used to identify the nano PPy and the membranes of each group. And the conductivity of membranes of each group was measured. Schwann cells were co-cultured in vitro with each group membranes to observe the biocompatibility by inverted microscope observing, living cell staining, cell counting, and immunofluorescence staining. The lysozyme solution was used to evaluate the degradation of the membranes in vitro.
Results
The FT-IR spectra showed that the characteristic vibrational absorption peaks of C=C from nano PPy appeared at 1 543.4 cm–1 and 1 458.4 cm–1. Scanning electron microscopy observation revealed that the size of nano PPy particles was about 100-200 nm. The nano PPy particles were synthesized. It was successful to turn chitosan to chitin by the acetylation, which was investigated by FT-IR analysis of membranes in groups A and C. The characteristic peaks of the amide Ⅱ band around 1 562 cm–1 appeared after acetylated modification. Conductivity test showed that the conductivity of membranes in group A was about (1.259 2±0.005 7)×10–3 S/cm, while the conductivity of the membranes in groups B and C was not detected. The nano PPy particles uniformly distributed on the surface of membranes in group A were observed by scanning electron microscope; the membranes in control groups were smooth. As a result, the nano PPy/chitin composite membranes with electrical conductivity were obtained. The cultured Schwann cells were found to survive with good function by fluorescein diacetate live cell staining, soluble protein-100 immunofluorescence staining, and inverted microscope observing. The cell counting showed that the proliferation of Schwann cells after 2 days and 4 days of group A was more than that of the two control groups, and the differences were significant (P<0.05). It indicated that the nano PPy/chitin composite membranes had better ability of adhesion and proliferation than those of chitosan and chitin membranes. The degradation of membranesin vitro showed that the degradation rates of membranes in groups A and C were significantly higher than those in group B at all time points (P<0.05). In a word, the degradation performance of the membranes modified by acetylation was better than that of chitosan membranes under the same condition.
Conclusion
The nano PPy and chitosan can be blended and modified by acetylation successfully. Nano PPy/chitin composite membranes had electrical conductivity, degradability, and good biocompatibility in vitro.
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.
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.
As one of the stimulus-response polymeric intelligent materials, shape memory polymers have been widely applied in biomedicine due to their better biocompatibility, higher controllability, stronger deformation restorability and biodegradability compared with shape memory alloys and shape memory ceramics. This review will introduce the structural principles of shape memory polymers and summarize their applications in the treatment of vascular diseases, especially in endovascular therapy. At the same time, the related technical problems and the future of shape memory polymers are prospected. With the continuous development of processing technology and materials, it can be predicted that shape memory polymers will be more widely used in the medical field.
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.
This article aims to interpret the consensus report of the 30th Acute Disease Quality Initiative (ADQI) workgroup on hemoadsorption (HA) technology, providing reference for clinical practice and research. HA has shown therapeutic advantages in various diseases. The ADQI workgroup assessed the research progress of HA technology, confirming its clinically acceptable short-term biocompatibility, safety, and technical feasibility, as well as experimental demonstration of specified target molecule removal. Preliminary studies have shown a potential benefit of endotoxin-based HA in sepsis. However, due to insufficient clinical evidence, HA is still considered an experimental intervention. The ADQI consensus report focuses on filling existing knowledge gaps, pointing out future research directions, and providing important guidance for the clinical application and further research of HA technology.
