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Results for “Biocompatibility”

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At least 721 records · Page 40Linked to original sources

PubMed2005

[The study of cell biocompatibility of new pattern biphasic calcium phosphate nanocomposite in vitro].

OBJECTIVE: To study the cell biocompatibility of porous biphasic calcium phosphate nanocomposite in vitro. METHODS: Bone marrow mesenchymal cell (BMSCs) obtained from SD rat bone marrow were in vitro induced and proliferated. Afler their osteoblast phenotypes were verified, BMSCs were seeded onto prepared porous biphasic calcium phosphate nanocomposite (Experiment group) and common porous hydroxyapatite (Control group). The cell adhesion was evaluated by scanning electron microscope. Synthesis of alkaline phosphatase enzyme (ALP) and osteocalcin were detected and cell cycle was detected by flow cytometry. RESULTS: BMSCs could fully attach to and extend on the material in experiment and control group, Moreover, experiment group were superior to control group in adhesion, proliferative abilities and osteogenic activity. CONCLUSION: BMSCs can differentiate to osteoblast phenotype; the porous biphasic calcium phosphate nanocomposite as bone tissue engineering scaffold has good cell biocompatibility.

Alkaline Phosphatase↗

PubMed1992

Biocompatibility of ferric calcium phosphorous oxide ceramics.

The objective of this investigation was to ascertain the biocompatability of a ferric calcium phosphorous oxide ceramic (FECAP). The FECAP ceramic was fabricated from stock powders combined in a ratio of 46:40:14 by weight of Fe2O3:CaO:P2O5. The composite oxides were mixed for homogeneity, pressed into a 20g block, and calcined in a crucible at 1100 degrees C for 12 hours. The calcined ceramic was then ground in a ball mill before separation into particle sizes of 38-45 microns and 63-75 microns, by an automatic siever and shaker. Calcined powders of each particle size were mixed with polyvinyl alcohol binder (0.025g PVA/1.0g of FECAP), and pressed into 0.5g pellets in a 5/16" (internal diameter) die at a 1820 kilogram load using a Carver hydraulic press. FECAP pellets were then sintered at 1100 degrees C for 12 hours. For this investigation, sixty albino (Sprague-Dawley) rats weighing 125-425 g each, were distributed into four groups: non-operated controls, sham-operated controls, and two groups subcutaneously implanted with ceramics 38-45 microns and 63-75 microns FECAP ceramics, respectively. Three rats from each group were sacrificed at three, five, seven, and twenty-one days post-surgery. Morphologic examination of the implant and implant site as well as hematocrit data indicate that this ferric-calcium-phosphorous oxide ceramic is biocompatible. Data obtained todate suggest that sintered FECAP should have a wide variety of dental and medical applications, especially where iron deficiency is a concern.

Animals↗

PubMed2006

[Biocompatibility of graded zirconia-hydroxyapatite composite].

OBJECTIVE: To evaluate the biocompatibility and safety of a novel orthopedics materials-graded zirconia (ZrO2)-hydroxyapatite (HA) composite biomaterials. METHODS: First, ultrafine powers of ZrO2 and HA powder were prepared by chemical precipitation method, then graded ZrO2-HA composite was synthesized by dry-laying and sintering method. After the physiological saline and culture medium extracts of the composite were prepared, four experiments were conducted as follows: (1) The mouse acute toxic test consists of 2 groups (n=10). The extracts were intravenously injected to mice in the first group, and physiological saline to mice in the second group. The dose was 50 g/kg. Their toxicity manifestation, morality and the change of weight were recorded. (2) The standard curve of proliferation and metabolism of L929 cells was established. (3) The cytotoxic test consists of 3 groups: materials group (extracts of the materials), positive control group (culture fluid with 0. 64% phenol), and negative control group (RPMI-1640 culture fluid). Each of three was cultured with cell suspension, and then the morphology of the cells was observed, the relative proliferation rate (RGR) was calculated, and the toxicity was classified. (4) In vitro hemolytic test was divided into 3 groups: extracts, sterile distilled water (positive control) and 0.9% physiological saline. In each of three, 0.2 ml anticoagulant diluted fresh rabbit blood was added. The percentage of hemolysis was tested. (5) The muscle and implantation test were divided into 4 groups (n=3). The composite biomaterials were implanted into pygal muscles on either side and lateral condyles of femurs. After surgery, the rats of four groups were sacrificed at 3, 6, 12 and 24 weeks respectively. Tissue slice and scanning electronic microscopy were performed. RESULTS: (1) General acute toxic test: no mouse died within 3 weeks; no toxicity symptom or adverse effects were shown within 3 days. The weight of materials group increased by 3.57 +/- 0.49 g, and the control group by 3.62 +/- 0.61 g, showing no statistically significant difference (P>0.05). The standard curve of L929 cell proliferation and metabolism showed that their existed a positive correlation between the number of L929 cells and the proliferation. (3) Cytotoxic test: cytosomes in the positive control group diminished and appeared round, there were pyknotic nucleus, the attached cells agglomerated; the toxicity was level IV. The morphology of cells in materials group and negative control group was normal, and the number of them increased; the toxicity was level I and level 0, respectively. The MTT color experiments showed that positive control group was significantly lower than materials group and negative control group, showing statistically significant difference (P<0.01); there was no statistically significant difference between materials group and negative group. (4) Hemolytic test: in vitro hemolytic rate of negative control group was 0, of positive control group was 100%, and of materials group was 1.66%, which accords with the standard that hemolytic rate should be lower than 5% specified in ISO. (5) Implant test: No apparent rejection reaction took place after the composite was implanted; the composite bonded with the bones of the receptors firmly, which had good boned-induced effect. CONCLUSION: Graded ZrO2-HA composite bioceramic has good biocompatibility and is suitable for orthopedic biomaterials.

Animals↗

PubMed2006

[Biocompatibility test of polymethylmethacrylate denture base resin containing silver-supported antimicrobial agent STR-1 at nanometer level].

OBJECTIVE: To evaluate the biocompatibility of polymethylmethacrylate(PMMA) denture base resin containing silver-supported antimicrobial agent STR-1 of nanometer level in vitro. METHODS: According to the national standards for biological evaluation of dental materials, the cytotoxicity of denture base resin containing STR-1 at concentrations of 5 g/L and 10 g/L was examined by molecular filtrating method, and the hemolysis of STR-1, denture base resin containing STR-1 at concentrations of 5 g/L and 10 g/L was also surveyed. RESULTS: The control denture base resin without containing STR-1 and the denture base resins containing STR-1 at concentrations of 5 g/L and 10 g/L were not cytotoxic to L929 cells. Two hours and 24 hours after cell culturing, the filter membranes of the control and experimental groups were stained evenly with blue color. The staining intensity was not decreased and the fading areas were 0 mm2 during the culturing. The cytotoxicity grades were 0. The hemolysis rates of the antimicrobial agent STR-1 and the denture base resins containing STR-1 at concentrations of 5 g/L and 10 g/L were 1.7%, 3.5% and 3.7% respectively. They were less than the national guild standard 5% which represent no hemolysis. CONCLUSION: The PMMA denture base resins containing silver-supported antimicrobial agents STR-1 of nanometer level at concentrations of 5 g/L and 10 g/L exhibit good biocompatibility.

Animals↗

PubMed1991

Cellular immunology in regular dialysis: a biological model for biocompatibility evaluation.

Cellular immunity represents an interesting biological model for biocompatibility evaluation of artificial materials owing to its sensitivity to contact with the external environment and its capability of modulating response reactions to foreign agents. Advanced methodologies such as flow cytometry and the immunoenzyme techniques in particular have given new insights into lymphocyte structure and functions, enabling analysis of the in vivo modification of these cells. By means of these sophisticated techniques we investigated lymphocyte activation and proliferation during one single haemodialysis session. Findings clearly show that increases in HLA antigen density (class I and II), DNA synthesis, and interleukin-2 receptor serum concentration (Il-2R) take place during the dialysis procedure, and reach their maximum during the first hour of extracorporeal circulation. The relationship between dialysis procedure and cellular immunity appears noticeable and is of potential value in the evaluation and quantification of the biocompatibility of different dialysis membranes.

Adult↗

PubMed1990

[Animal experiment studies of the biocompatibility of colored and plain lens haptics of polymethylmethacrylate].

In spite of the great clinical success of cataract surgery and intraocular lens implantation, adverse reactions still occur. In 2-3% of all cases, there is acute or chronic inflammation. One reason might be that the biocompatibility of the lens material is insufficient. This study evaluates the biocompatibility of dyed and undyed transparent PMMA lens haptics. The haptics were implanted subcutaneously in mobile and immobile mice tissue. After different implantation periods varying from 1 week to 6 months, the haptics were removed and evaluated histologically. The undyed PMMA lens haptics showed no adverse reactions. The dyed PMMA lens haptics showed a strong inflammatory response caused by diffusion of the dye into the surrounding tissue.

Animals↗

PubMed1990

[Biocompatibility of dentinal adhesive systems in conservative dentistry].

Several studies have been published on "in vitro" and "in vivo" evaluations on pulpal and dentin effects of new dentinal bonding agents. The present study analyses the current status of biocompatibility of these materials. It has been suggested that a good biocompatibility it is only possible if no bacteria penetration and microleakage are present along dentinal walls and around restoration cavity. Finally it is not well defined the importance of smear layer removal from cut dentin surface.

Dental Cements↗

PubMedDate not supplied

[Biocompatibility of hydroxypropylmethylcellulose as a vitreous substitute in rabbits].

We have studied the biocompatibility of the hydroxypropylmethylcellulose in ten rabbits' eyes after lensectomy and posterior vitrectomy. In seven eyes the inflammatory reaction was severe. The reason why the hydroxypropylmethylcellulose is biocompatible in the anterior segment and not in the vitreous body seems to be explained by its quantity and its concentration in the eye at the end of the surgical procedure.

Animals↗

PubMed1989

Biocompatibility aspects of dialyzer reprocessing: a comparison of 3 re-use methods and 3 membranes.

While formalin reprocessing of cuprophan dialyzer membranes is known to improve their biocompatibility, the effects of different re-use methods have not been systematically investigated on different membranes. Therefore, the effects of reprocessing with formalin, hypochlorite-formalin and peracetic acid were successively investigated in 3 groups of 4 patients dialyzed on cuprophan (CU), cellulose acetate (CA) or polysulfone (PS). Leukocyte count, thrombocyte count and complement activation were studied during second and third use of the dialyzer. Formalin 3% storage was found to improve leukopenia, thrombocyte count and complement activation on CU but not on PS or CA where leukocyte and thrombocyte count worsened. Hypochlorite 1% rinsing prior to formalin 3% storage abolished the improvements observed on CU with formalin and induced on CA and PS the same leukopenia as formalin. In contrast, peracetic acid storage improved leukopenia, complement activation and thrombocyte count on the 3 membranes. In addition, it was found that storage of plasma-treated membrane fragments with peracetic acid abolished neutrophil oxygen radical production. Thus it appears that re-used membranes may not be systematically assumed to be more biocompatible, this property varying with both the type of membrane and the reprocessing technique.

Adult↗

PubMed1983

Haemodialyser reuse: impact on function and biocompatibility.

The functional performance (clearance of small molecules, ultrafiltration and blood loss) and biocompatibility (haemodialysis leucopenia) has been studied for disposable flat plate and hollow fibre haemodialysers utilizing Cuprophan membranes on their first use, and compared with that obtained when reusing by a manual and automated technique. The results obtained relating to functional performance remain unchanged with the exception of blood loss which shows an increase compared with first use. Biocompatibility is modified on reuse but only if the membrane has not been exposed to a rinsing process using sodium hypochlorite.

Humans↗

PubMed1994

[Use of biocompatible polymer implants in combination with extrafocal device fixation in the surgical treatment of spondylitis].

The author summarized the data on experimental application of biocompatible implants IIIIIM-1 covered with benemycin as a treatment modality in spondylitis. The polymer implanted into the disease focus is able to maintain high concentration of the drug for 60 days. The implants were inserted in 120 tuberculous and 27 nonspecific spondylitis patients. Surgical intervention performed in 147 patients comprising radical resection of the destruction focus and vertebral defect replacement with biocompatible implant in combination with extrafocal apparatus fixation decreased the operation trauma++, secured stability of the anterior and posterior parts of the operated spine and allowed early active rehabilitation of postoperative patients, 2-3 months after the surgery the author observed good spinal stabilization and definite signs of clavus formation in the resection zone.

Aged↗

PubMed1994

Phagocytic cell function as an index of biocompatibility.

This review describes the physiology and biochemistry of phagocytic cells and examines the rationale for using their function to assess biocompatibility. Haemodialysis modulates phagocyte adhesion receptors to a degree dependent on the level of complement activation by the membrane, and this modulation leads to a proportional change in the number of circulating phagocytes because of pulmonary sequestration of activated cells. However, it is not clear that other acute changes in phagocyte function are directly attributable to the nature of the membrane; they may merely reflect changes in the population of circulating cells resulting from pulmonary sequestration. While haemodialysis is associated with stimulation of monocyte cytokine production, the relative contributions to this phenomenon of the membrane material, its mass transfer properties, and the microbiological quality of the dialysate are incompletely understood. A lack of well-designed studies and difficulty in separating the effects of uraemia from those of dialysis make it impossible to know if chronic changes in phagocyte function are a consequence of the choice of dialysis membrane. Thus, while changes in the number of circulating phagocytes and their expression of adhesion receptors are useful indices of biocompatibility, a clear association has yet to be shown between membrane properties and changes in other measures of phagocytes function.

Cytokines↗

PubMed1996

Effect of different buffers on the biocompatibility of CAPD solutions.

Commercially available solutions for continuous ambulatory peritoneal dialysis (CAPD) affect the viability and function of the cells in the peritoneal cavity. The low biocompatibility of the solutions may be caused by a low pH, hyperosmolality, high glucose content, and lack of potassium, glutamine, and other components essential for normal cellular functions. The nature of the buffer employed is also important for the cytotoxicity of the solutions. Lactate, the most frequently used buffer, has been shown to inhibit cellular functions important for the peritoneal defense system including phagocytosis, bacterial killing, and secretion of cytokines. It is generally believed that the cytotoxicity of lactate is caused by lowering of intracellular pH and impairment of metabolism due to changed redox potentials. However, the cytotoxicity of lactate is highly dependent upon the pH of the solutions, indicating that passive or active diffusion across the cell membrane is determining the effects of lactate. Bicarbonate has been heavily advocated as an alternative buffer because it is the most important naturally occurring buffer in plasma and it enables a pH of approximately 7.4 in the solutions. However, due to sedimentation of calcium carbonate (CaCO3) and production of toxic glucose metabolites it is difficult to prepare and store bicarbonate-based solutions. Moreover, investigations have revealed that even bicarbonate-based solutions are not optimal regarding biocompatibility, presumably due to a paradoxical intracellular acidification caused by influx of carbon dioxide (CO2). More recently, the effect of other buffers such as pyruvate and histidine have been examined. Especially pyruvate is a promising new buffer candidate.

Acid-Base Equilibrium↗

PubMed2001

Biocompatibility of NDGA-polymerized collagen fibers. II. Attachment, proliferation, and migration of tendon fibroblasts in vitro.

The material properties of collagen fibers polymerized with nordihydroguaiaretic acid (NDGA) are equivalent to native tendon, suggesting that NDGA crosslinking may provide a viable approach to stabilizing collagenous materials for use in repairing ruptured, lacerated, or surgically transected fibrous tissues, such as tendons and ligaments (Koob & Hernandez, Biomaterials, in press). The present study evaluated the biocompatibility of these fibers with cultured bovine tendon fibroblasts. Fibroblast attachment, migration, and proliferation on NDGA-crosslinked materials were compared to those on prepolymerized type I tendon collagen constructs as well as on tissue-culture-treated plastic. Fibroblast attachment on NDGA-crosslinked collagen fibrils was equivalent to attachment on plates coated with collagen alone. Over a period of 8 days in culture, attached fibroblasts proliferated on NDGA-crosslinked collagen at a rate identical to that of fibroblasts attached to native collagen. In order for the biomaterial effectively to bridge gaps in fibrous tissues, fibroblasts must be able to migrate and replicate on the bridging fiber. Control and crosslinked fibers were inserted in calf tendon explants, with a portion of the fiber extending out of the sectioned end of the tendon. Explants were cultured for 9 weeks, and the number of cells was measured at weekly intervals. Cells appeared on the fibers after 1 week of culture. By 2 weeks, cells had colonized the entire fiber. The number of cells continued to increase throughout the 9 weeks in culture, forming a layer several cells thick. Histologic analysis indicated that the fibroblasts populating the fibers appeared to originate in the epitenon. There was no difference in the rate of fibroblast migration and replication, nor in the ultimate number of colonizing cells, between control collagen fibers and NDGA-crosslinked fibers. NDGA-crosslinked fibers may provide a means of bridging gaps in ruptured, lacerated, or surgically transected tendons by providing a mechanically competent scaffold on which tendon fibroblasts can migrate, attach, and proliferate.

Animals↗

PubMed2001

In vitro and in vivo biocompatibility testing of Ti-6Al-7Nb alloy with and without plasma-sprayed hydroxyapatite coating.

The Ti-6Al-7Nb alloy has been recently developed for biomedical use, particularly for orthopedics and dental applications. Osteosynthesis has been used to analyze biocompatibility and osseoconduction properties. The interaction of the implant with its biological environment, the formation of the implant material/tissue interface, and the long-term success or failure of integration in the human body is strongly connected with the surface properties of the implant device. This study was undertaken to evaluate the processes involved in biological responses of the Ti-6Al-7Nb alloy with and without hydroxyapatite coatings with both in vitro and in vivo tests. The results were analyzed by scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX) microanalysis. The morphology of the in vitro and in vivo testing results with hydroxyapatite coating was similar to those obtained on the uncoated samples. A mineralized extracellular matrix was formed on all materials. Observation of the interface between the cell layer and substrata showed the presence of calcium and phosphorous-rich globular deposits associated with collagen fibers on all materials in vitro and in vivo. A higher density of these globular deposits was observed in all samples.

Alloys↗

PubMed2003

Hydrophobic acrylic versus heparin surface-modified polymethylmethacrylate intraocular lens: a biocompatibility study.

BACKGROUND: The implant of intraocular lenses (IOLs) following cataract surgery induces a foreign-body reaction to the IOL and a response on the part of the lens epithelial cells (LECs). The purpose of this study was to compare these aspects after the implantation of two different IOL materials. METHODS: Thirty-six cataract patients were randomised to receive two different foldable lens: an acrylic hydrophobic IOL (Acrysof MA30BA) and a heparin surface-modified (HSM) polymethylmethacrylate IOL (Pharmacia & Upjohn 809C) after phacoemulsification. Slit-lamp biomicroscopy with specular technique was used to assess the inflammatory cell adhesion on the anterior IOL surface, anterior capsule opacification (ACO) and membrane growth from the rhexis edge at 7, 30, 90, 180 and 360 days after surgery. RESULTS: The 809C group showed a higher percentage of patients with slight inflammatory cell adhesion on the anterior cell surface and a higher small cellular density during the whole follow-up period. The epithelioid cell response was greater in the 809C group than the Acrysof group but the difference between the two groups was not statistically significant. The ACO increased during the follow-up in both groups but was significantly higher in the 809C group. CONCLUSION: Acrysof lenses are more biocompatible than HSM IOLs, showing a lower grade of inflammatory cell adhesion and ACO. The implantation of these lenses may be particularly indicated in patients with pathologies predisposing to blood-aqueous barrier damage.

Acrylates↗

PubMed2006

Hydroxyapatite/SiO(2)-CaO-P(2)O(5) glass materials: in vitro bioactivity and biocompatibility.

Materials obtained by the heat treatment of mixtures of hydroxyapatite (HA) and a silicate-based glass of the system SiO(2)-CaO-P(2)O(5) have been investigated. The influence of the glass content on the porosity, microstructure and on the constituent phases of the final materials was studied. The influence of these factors on the in vitro bioactive behaviour of the obtained materials was also investigated. In addition, an in vitro biocompatibility assay with osteoblastic-like cells was carried out. The addition of the glass to HA induced different solid-state reactions that yield the transformation of HA into alpha- and beta-tricalcium phosphate as well as the formation of silicon-containing phases (silicocarnotite or pseudowollastonite). In these mixtures an enhancement in the porosity, pore size and a heterogeneous microstructure was observed, compared with the precursors. As the sol gel glass content increased, the previous effects were higher. The materials showed the formation of an apatite-like layer on their surface when soaked in simulated body fluid, being faster in the sample with a higher content of glass. The formation of the new layer began in preferential zones in both samples, depending on the different reactivity of the crystalline phases formed. A synergistic effect between HA and glass was observed, showing in the mixtures a faster bioactive behaviour than in HA and glass themselves. The obtained materials allow a good attachment, spread and proliferation of the osteoblastic-like cells and no cytotoxic effect was observed.

Biocompatible Materials↗

PubMed1998

Complement and biocompatibility.

Blood contact with foreign surfaces induces a certain degree of activation of the defence systems including complement. Recent data using complement specific inhibitors have shown that complement is not only associated with, but in fact contributes to the whole body inflammatory reaction seen as a complication of cardiopulmonary bypass (artificial surfaces) and is responsible for the hyperacute rejection of xenografts (foreign endothelium). Complement activation products, particularly the terminal SC5b-9 complex (TCC), is a sensitive indicator of bioincompatibility. Modifications of the artificial surfaces by coating with heparin improves both coagulation and complement compatibility. The use of specific complement inhibitors in general improves biocompatibility both of artificial materials and foreign endothelium.

Animals↗