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At least 91 records · Page 5Linked to original sources
PubMed1993

Prostacyclin secretion by human endothelial cells grown on carbodiimide cross-linked proteins: an assessment of the cytocompatibility of a substratum.

Prostacyclin production by human umbilical vein endothelial cells cultured on carbodiimide cross-linked albumin and/or gelatin was quantified during the exponential growth phase and in confluent cultures as a response to arachidonic acid stimulus. In confluent cultures, basal production of prostacyclin measured by radioimmunoassay of the stable metabolite 6-keto-PGF1 alpha was comparable for both substrates to a control culture. Maximal release of prostacyclin occurred during the first 24 h following cell seeding and these values were significantly higher in media from cultures performed on membranes. In both cases, PGI2 production decreased as cell density increased. After stimulation with 20 microM arachidonic acid for 20 min, media from confluent cells grown on membranes contained slightly greater amounts of PGI2 than control culture medium. These results indicate involvement of substratum in PGI2 Release. Early enhancement of PGI2 secretion could improve biocompatibility of membranes by preventing platelet aggregation.

Albumins↗
PubMed1993

In-vitro evaluation of the cytocompatibility of wear particles generated by UHMWPE/zirconia friction.

Cytotoxicity of wear products generated by UHMWPE/yttria partially stabilized zirconia (YPSZ) friction and UHMWPE/surface-nitrided Ti-6Al-4V friction in pseudo-extracellular fluid (PECF) at 37 degrees C was evaluated. Though the amount of abraded UHMWPE against YPSZ was almost the same as that against nitrided Ti-6Al-4V, the wear products generated by UHMWPE/YPZ friction significantly inhibited cell growth while those by UHMWPE/nitrided Ti-6Al-4V friction showed no growth inhibition. Dissolved Zr and Y ions were at least 70 times less than the amount causing growth inhibition. The cytotoxicity was caused mainly by the particles less than 0.22 mum in size. Amorphous zirconium-containing particles (5-20 nm) found in the PECF, formed presumably by stress corrosion, would be a responsible factor for the cytotoxicity.

Biocompatible Materials↗
PubMed2005

Variable cytocompatibility of six cell lines with photoinitiators used for polymerizing hydrogels and cell encapsulation.

The development of biocompatible photopolymerizing polymers for biomedical and tissue engineering applications has the potential to reduce the invasiveness and cost of biomaterial implants designed to repair or augment tissues. However, more information is needed about the cellular toxicity of the compounds and initiators used in these systems. The current study evaluates the cellular toxicity of three ultraviolet sensitive photoinitiators on six different cell populations that are used for engineering numerous tissues. The photoinitiator 2-hydroxy-1-[4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone (Irgacure 2959) caused minimal toxicity (cell death) over a broad range of mammalian cell types and species. It was also demonstrated that different cell types have variable responses to identical concentrations of the same photoinitiator. While inherent differences in the cell lines may contribute to the variable cytotoxicity, a correlation between cellular proliferation rate (population doubling time) and increased cytotoxicity of the photoinitiator was observed. Cell lines that divided more quickly were more sensitive to photoinitiator-induced cell death. In summary, the photoinitiator Irgacure 2959 is well tolerated by many cell types over a range of mammalian species. Cell photoencapsulation strategies may be optimized to improve cell survival by manipulating proliferation rate.

Biocompatible Materials↗
PubMed2005

Surface modification of poly(ethylene terephthalate) via hydrolysis and layer-by-layer assembly of chitosan and chondroitin sulfate to construct cytocompatible layer for human endothelial cells.

Surface modification of poly(ethylene terephthalate) (PET) film was performed by surface hydrolysis and layer-by-layer (LBL) assembly followed a mechanism of electrostatic adsorption of oppositely charged polymers, exemplified with chitosan and chondroitin sulfate (CS). Hydrolysis of PET in concentrated alkaline solution produced a carboxyl-enriched surface. The changes of weight loss and surface chemistry, morphology and wettability were monitored and verified by UV-vis spectroscopy, atomic force microscopy (AFM) and water contact angle. Assembly of positively charged chitosan and negatively charged CS was then conducted in a LBL manner to create multilayers on the hydrolyzed PET film. The process of layer growth and oscillation of surface wettability were monitored by UV-vis spectroscopy and water contact angle measurement, respectively. In vitro cell culture revealed that the adherence of endothelial cells was significantly enhanced on the biomacromolecules-modified PET film with preserved endothelial cell function, in particular on those assembled with larger number of chitosan/CS layers. However, with regard to cell proliferation and viability properties after cultured for 4 days, minor difference was determined between the modified and the unmodified PET films.

Adsorption↗
PubMed2006

Structure and in vitro cytocompatibility of the gastropod shell of Helix pomatia.

Distinguishing features of biological constructions are high stability and adaptation to their environment. Beside biocompatibility, nontoxicity and degradability these characteristics are demanded for new biomaterials in the field of tissue engineering. This study investigated the chemical composition, the organization and the in vitro osteoconductive potential of the terrestrial gastropod shell (Helix pomatia) on CAL72 and human osteoblast-like cells. Chemical composition of the biomaterial was examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) was performed to analyze the architecture of the snail shell and the morphology of the seeded cells. A double staining procedure (FDA/PI) and a proliferation test (EZ4U) assessed the viability of the cells. Microscopical images showed the multilayered architecture of the aragonite shell with hexagonal crystals on the inner side. The cells spread well on the biomaterial and the highest proliferation rate could be measured with CAL72 cells on the inner shell surface. The osteoconductive effects of this natural biomaterial could encourage further experiments in the field of tissue engineering.

Animals↗
PubMed2001

Cytocompatibility and response of osteoblastic-like cells to starch-based polymers: effect of several additives and processing conditions.

This work reports on the biocompatibility evaluation of new biodegradable starch-based polymers that are under consideration for use in orthopaedic temporary applications and as tissue engineering scaffolds. It has been shown in previous works that by using these polymers it is both possible to produce polymer/hydroxyapatite (HA) composites (with or without the use of coupling agents) with mechanical properties matching those of the human bone, and to obtain 3D structures generated by solid blowing agents, that are suitable for tissue engineering applications. This study was focused on establishing the influence of several additives (ceramic fillers, blowing agents and coupling agents) and processing methods/conditions on the biocompatibility of the materials described above. The cytotoxicity of the materials was evaluated using cell culture methods, according to ISO/EN 109935 guidelines. A cell suspension of human osteosarcoma cells (HOS) was also seeded on a blend of corn starch with ethylene vinyl alcohol (SEVA-C) and on SEVA-C/HA composites, in order to have a preliminary indication on cell adhesion and proliferation on the materials surface. In general, the obtained results show that all the different materials based on SEVA-C, (which are being investigated for use in several biomedical applications), as well as all the additives (including the novel coupling agents) and different processing methods required to obtain the different properties/products, can be used without inducing a cytotoxic behaviour to the developed biomaterials.

Animals↗
PubMed2001

Study of a (trimethylenecarbonate-co-epsilon-caprolactone) polymer--part 2: in vitro cytocompatibility analysis and in vivo ED1 cell response of a new nerve guide.

Future surgical strategies to restore neurological function in peripheral nerve loss may involve replacement of nerve tissue with cultured Schwann cells using biodegradable guiding implants. Random copolymers of trimethylene carbonate and epsilon caprolactone (P(epsilonCL-TMC), 50: 50) have been synthesized by ring opening polymerization using rare earth alkoxides as initiator. Their potential use as nerve guide repairs has been assessed through indirect and direct in vitro biocompatibility tests and in vivo soft tissue response to EDI subclass macrophages. In vitro, we exposed monolayers of human skin fibroblasts and an established continuous cell line (Hela) to liquid extracts (either pure or diluted in the culture medium) of epsilonCL-TMC copolymer including positive (phenol) and negative controls. Then, colorimetric assays (Neutral red and MTT) were performed. The extracts of epsilonCL-TMC induced no significant cytotoxic effect. We also exposed in vitro Schwann cells to pieces of P(epsilonCL-TMC) and P(LA-GA) copolymers. We evaluated cell attachment at 1 and 3 h by measuring the activity of the lysosomal enzyme (N-acetyl-beta-hexosaminidase) and cell proliferation at 1, 3, 6 and 9 days by measuring the cell metabolic activity (MTT assay). Values for attachment slightly decreased between 1 and 3 h but were significantly higher than on agars (negative control). Cells plated on epsilonCL-TMC showed a rate of proliferation comparable with that of normalized controls and higher than on PGA-PLA at day 9. Finally, we evaluated in vivo the soft tissue response after implantation of cylindrical tubes of P(epsilonCL-TMC) and P(LA-GA) copolymers with an immunohistochemistry staining procedure for the newly recruited ED1 macrophages. An image analysis system automatically measured the optical density of labelled positive ED1 cells at 9, 21 and 60 days after implantation. epsilonCL-TMC copolymer showed a mild soft tissue reaction with no adverse chronic inflammatory reaction. These data allowed us to consider this conduit as a potential effective substitute in nerve repair. El sevier Science Ltd. All rights reserved.

Animals↗
PubMed2002

In vitro cytocompatibility of porcine type I atelocollagen crosslinked by oxidized glycogen.

Oxidized glycogen is used as collagen crosslinker to obtain materials with defined crosslinking degrees. These materials are characterized by their swelling ratio. calorimetric properties and the crosslinking level. Direct and indirect cytotoxicities of the materials obtained as sheets, are evaluated in vitro in cultures of human fibroblasts. The crosslinking degree depends on the ratio CHO glycogen/NH2 glycogen, but whatever this ratio (4.0, 2.0 or 0.4), an important percentage of the introduced CHO groups remains free and these groups are responsible for the cytotoxicity observed with the strongly crosslinked materials. This cytotoxicity appears in cell shape modification and in significant reduction of cell growth. Whatever the crosslinking degree, this toxicity can be suppressed by a single treatment with sodium borohydride, which reduced the remaining free CHO groups in OH functions and stabilizes the materials by a concomitant reduction of the crosslinking imine bonds. After reduction, all materials allow cellular adhesion and proliferation. This new crosslinking method of the collagen by the oxidized glycogen could be promising in the preparation of matrix for in vitro and in vivo tissue regeneration.

Animals↗
PubMed1998

Corrosion resistance, mechanical properties, corrosion fatigue strength and cytocompatibility of new Ti alloys without Al and V.

The effects of various metallic ions using various metallic powders on the relative growth ratio of fibroblasts L929 and osteoblasts MC3T3-E1 cells were carried out. Ti, Zr, Sn, Nb and Ta had evidently no effect on the relative growth ratios of cells. Otherwise, Al and V ions exhibit cytotoxicity from a concentration of > or = 0.2 ppm. This Al effect on cells tend to be stronger in medium containing small quantity of V ions (< or = 0.03 ppm). The new Ti-15%Zr-4%Nb-4%Ta-0.2%Pd alloy exhibited a higher corrosion resistance in physiological saline solution. The addition of 0.02%O and 0.05%N to Ti-Zr alloy improved the mechanical properties at room temperature and corrosion fatigue strength. The relative growth ratios for the new Ti alloy plate and the alloy block extraction were unity. Further, the relative growth ratios were almost unity for the new Ti alloy against apatite ceramic pins up to 10(5) wear cycles in Eagle's MEM solution. However, there was a sharp decrease for Ti-6%Al-4%V ELI alloy from 3 x 10(4) wear cycles as V ion was released during wear into the wear test solution since the pH of the Eagle's MEM increases with increasing wear cycles.

3T3 Cells↗
PubMed1999

In vitro cytocompatibility of radio-opacifiers used in ureteral endoprosthesis.

Ureteral endoprostheses are urinary catheters made of polymeric biomaterials made radio-opaque through the addition of X-ray absorbing additives such as barium, bismuth, tantale or tungsten. The aim of this work was to study the in vitro toxicity of solutions of these radio-opacifiers using two cell culture models. Primary-cultures of human urothelial cells (HUC) arising from normal adult urinary tract and permanent urothelial cell line were used. Solutions at different dilutions were placed into the wells containing monolayers of confluent cells. After 24 h incubation period, the solutions were removed and cell viability and cell metabolic activity tests were performed (Neutral Red assay and MTT assay). At a concentration lower than 1 mg l(-1) the different radio-opacifiers used showed no toxicity. From 1 to 3 mg l(-1) one can note a significant dose-dependent decrease of cell metabolic activity of solely HUC for barium chloride. At 3 mg l(-1) one can note a significant deleterious effect on HUC metabolic activity, with bismuth and tantale. For tungsten, there is no deleterious effect, but on the contrary a significant increase in HUC metabolic activity at a 0.5 mg l(-1) concentration. None of the solutions did provoke alterations in HUC viability for concentrations less than 3 mg l(-1). Interestingly, for permanent cell line one can note a solely significant decrease of cell viability at 3 mg l(-1) for tantale. All the other tested salts on permanent cell line were not significantly different from controls for cell viability as well as cell metabolic activity. HUC culture model may be of relevance for the screening of radio-opacifiers intended for ureteral endoprostheses.

Adult↗
PubMedDate not supplied

Synthesis, characterization and cytocompatibility of polyurethaneurea elastomers with designed elastase sensitivity.

In designing a synthetic scaffold for engineering soft, mechanically active tissues, desirable properties include elasticity, support of cell adhesion and growth, ease of processability, and responsiveness to in vivo remodeling. To achieve these properties, we have developed a family of thermoplastic elastomers, polyurethaneureas (PUs), that possess enzymatic remodeling capabilities in addition to simple hydrolytic lability. PUs were synthesized using either polycaprolactone or triblock copolymer polycaprolactone-b-poly(ethylene glycol)-b-polycaprolactone as the soft segment, 1,4-butanediisocyanate as the hard segment, and the peptide Ala-Ala-Lys as a chain extender. The synthesized PUs had high molecular weights, low glass transition temperatures (< -54 degrees C), and were flexible with breaking strains of 670-890% and tensile strengths of 15-28 MPa. Incubation in buffered saline without elastase for 8 weeks resulted in mass loss from 12% to 18% depending on soft segment composition. The degradation significantly increased (p < 0.05) in the presence of elastase, ranging from 19% to 34% with degradation products showing no cytotoxicity. To encourage cell adhesion, PUs were surface-modified with radio frequency glow discharge followed by coupling of Arg-Gly-Asp-Ser (RGDS). Endothelial cell adhesion was >140% of tissue culture polystyrene on PU surfaces and >200% on RGDS-modified surfaces. The synthesized PUs thus combine mechanical, chemical, and bioresponsive properties that might be employed in soft-tissue engineering applications.

Absorption↗
PubMed2001

Surface modification of polyurethane for promotion of cell adhesion and growth 1: surface photo-grafting with N,N-dimethylaminoethyl methacrylate and cytocompatibility of the modified surface.

Functional polyurethane (PU) surface was prepared by photo-grafting N,N-dimethylaminoethyl methacrylate (DMAEM) onto the membrane surface. Grafting copolymerization was conducted by the combined use of the photo-oxidation and irradiation grafting. PU membrane was photo-oxidized to introduce the hydroperoxide groups onto the surface, then the membrane previously immersed in monomer solution was irradiated by UV light. The X-ray photoelectron spectroscopy and water contact angle characterized the grafted copolymers and verified the occurrence of graft copolymerization. The results showed that UV irradiation could realize the graft copolymerization effectively. The grafted membrane showed minimal surface morphology. Human umbilical vein endothelium (HUVE) cells were seeded on the grafted surfaces. The performance of the surface in cell attachment correlated with the content of oxygen and nitrogen. Cells were spread more extensive and grown faster on the surface with lower degree of grafting.

Journal Article↗
PubMed2001

Human monocyte-derived macrophages and dendritic cells as targets for biomaterial cytocompatibility studies using an improved in vitro culture system.

Since macrophage plays a key role in the biocompatibility process, neoplastic macrophage cell lines and human blood monocytes are commonly used as target cells for in vitro biomaterial tolerance evaluation. However, tumor cells profoundly differ from normal tissue cells and monocytes are only precursors of macrophages. It has become possible to generate recently, under adherent-free conditions, fully mature macrophages and dendritic cells from human blood monocytes in the presence of GM-CSF and GM-CSF + IL4 respectively. In the present work, we examined the effects of titanium-alloy on morphology, adhesion, cell phenotype and TNF-alpha release activity of such differentiated cells grown in hydrophobic teflon bags. Scanning electron microscopy showed that macrophages substantially adhered and spread on titanium-alloy surface throughout the culture period, whereas only a few dendritic cells were adherent. The phenotype of both cell types remained unchanged in the presence of the tested material. However, titanium-alloy stimulated the secretion of TNF-alpha by the macrophages of some donors. This model of culture may offer new insights into the biomaterial evaluation and may be useful for studying individual responses induced by biomaterials.

Journal Article↗
PubMed1997

The use of rat, rabbit or human bone marrow derived cells for cytocompatibility evaluation of metallic elements.

Rat, rabbit and human bone marrow cells were cultured according to the method previously reported for cells of rat origin [1] and were exposed, or not (control), to corrosion products of a Co-Cr orthopaedic alloy as well as to metal salts containing Co2+, Cr3+ and Cr6+. Cells were cultured for 21 days and analysed for the following biochemical parameters: intracellular MTT reduction (i.e. cell viability/proliferation), alkaline phosphatase (ALP) activity and protein production. Morphological observations included both histochemistry (detection of ALP-positive cells, calcium and phosphate deposits) and scanning electron microscopy (SEM). Control cultures of rat and rabbit cells showed higher proliferation rates than human cells at the start of culture, but they all reached similar values on day 21. Protein production was parallel to cell proliferation. In contrast, ALP activity of rat cultures was much stronger than rabbit or human cultures. All cell types were able to develop the osteogenic phenotype in vitro.Co-Cr extract caused inhibitory effects on cell viability, on ALP activity and, to a lower extent, on protein production of all rat, rabbit and human cell cultures. Compared to rat and rabbit cultures, human cultures were the most sensitive to metal ions exposure.

Journal Article↗
PubMed2003

In vitro degradation and cytocompatibility evaluation of novel soy and sodium caseinate-based membrane biomaterials.

Soy- and casein-based membranes are newly proposed materials disclosing a combination of properties that might allow for their use in a range of biomedical applications. Two of the most promising applications are drug delivery carrier systems and wound dressing membranes. As for all newly proposed biomaterials, a cytotoxic scanning must be performed as a preliminary step in the process of the determination of the compatibility with biological systems (biocompatibility). In this study, the cytotoxicity of both soy- and casein-based protein biomaterials has been evaluated and correlated with the materials degradation behavior. It was possible to show, through morphological and biochemical tests that these natural origin materials do not exert any cytotoxic effect over cells, and in some cases can in fact enhance cell proliferation. The different treatments to which the membranes were subjected during their processing (that include crosslinking with glyoxal and tannic acid, and physical modification by thermal treatment) seemed to have a clear effect both on the materials mechanical properties and on their in vitro biological behavior.

Journal Article↗
PubMedDate not supplied

Injectable nanospheres from a novel multiblock copolymer: cytocompatibility, degradation and in vitro release studies.

The aim was to develop and characterize nanospheres made from a newly synthesized poly (D,L-lactide-co-ethyleneglycol) (-PLA-PEG-PLA-)n multiblock copolymer. Nanospheres were prepared under optimized conditions of modified emulsion-solvent evaporation technique in a continuous flow process using rhodamine B as a drug model. They were characterized for size distribution, zeta (zeta) potential, porosity and morphology. Drug loading and yield were also determined. In vitro degradation studies of the copolymer were conducted in phosphate buffer (pH 7.4) at 37 degrees C. The cytotoxic properties of the polymer and vector were analysed by dimethylthiazoldiphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays on the B16 mouse cell line. Release of rhodamine B from the nanospheres was assayed in vitro using a dialysis bag in isotonic phosphate buffer (pH 7.4) at 37 degrees C. Spherical and non-porous nanospheres with mean size less than 800 nm could be prepared. The (zeta) potential was neutral. The average yield was approximately 70% with 7% rhodamine loading. A total of 50% of the multiblock underwent initial degradation after 4 weeks, while degradation was complete after 16 weeks. Cellular proliferation was not inhibited as no cytotoxicity was observed with the copolymers and nanospheres. Rhodamine B was released in a stepwise pattern. The initial burst was 20%, and release was prolonged thereafter for 29 days. Thus, injectable nanospheres with prolonged rhodamine B release have been designed and characterized as a potential drug-delivery system.

Animals↗
PubMed2002

Long-term cytocompatibility of various endodontic sealers using a new root canal model.

It was the purpose of our study to determine the cytotoxicity of several types of root canal sealers in vitro over the period of 1 yr by using a new test model. Roots of extracted human teeth were filled with N2, Apexit, Roekoseal, AH Plus, Ketac Endo, Endomethasone, and one gutta-percha point. In addition, roots filled with laterally condensed gutta-percha/N2. Teeth filled with one gutta-percha point only were controls. All specimens were consecutively extracted with distilled water for a total period of 1 yr. Extracts were investigated for cytotoxicity by using immortalized 3T3 fibroblasts and primary human periodontal ligament fibroblasts. Results were statistically analyzed with Dunnett's t tests (p < 0.05). Pronounced cytotoxic effects were only caused by N2-extracts in both cell cultures (p < 0.05). Furthermore, statistically significant cytotoxic alterations were also induced by 10-week eluates of Endomethasone (p < 0.05). All other investigated materials did not significantly alter cell metabolism.

3T3 Cells↗
PubMed1997

The cytocompatibility of hydrocolloid dressings.

The purpose of this study was to evaluate the effect on fibroblast proliferation of hydrophilic particles isolated from six commercial hydrocolloid dressings. The hydrophobic adhesive matrix of six hydrocolloid dressings was removed using a reflux extraction method with an organic solvent (xylene). The remaining hydrophilic particles were dissolved in complete cell growth medium containing 10% (v/v) foetal calf serum and added to confluent human dermal fibroblasts grown in monolayer in final concentrations of 0.1 and 0.01% (w/v). Control cells received growth medium alone. The fibroblasts were incubated with the hydrophilic particles and the thymidine analogue 5-bromo-2'-deoxyuridine (BrdU) for 24 hours. The incorporation of BrdU into DNA was used as a measure of cell proliferation and determined using an ELISA kit. The results were expressed in percentage of control-treated wells and analysed using analysis of variance. Apart from Comfeel Plus, the hydrophilic particles of hydrocolloid dressings significantly inhibited fibroblast proliferation at 0.1% compared to control-treated fibroblasts (p < 0.05).

Analysis of Variance↗