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At least 73 records · Page 4Linked to original sources

Collagen/poloxamine hydrogels: cytocompatibility of embedded HepG2 cells and surface-attached endothelial cells.

The effects of cross-linked poloxamine hydrogels on the cellular function of embedded HepG2 cells and surface-attached endothelial cells were assessed. HepG2 cells embedded within collagen/poloxamine-methacrylate gel survived photo-cross-linking (MTT viability, 78%). There was a gradual increase in cell number during the first week. The cumulative secretion of alpha1-antitrypsin by HepG2 cells showed an almost linear profile. However, lower levels for the collagen/poloxamine-methacrylate matrix were observed when compared with collagen. Endothelial cells attached poorly to poloxamine gels without collagen (alamarBlue reduction ranged from 36 to 63%) and did not spread well. The addition of collagen led to spread cells and alamarBlue reduction levels of 75-93% (24 h after seeding). On day 5, some detachment was noted through analysis of vascular endothelial cadherin staining. Finally, the collagen-containing matrix was used to prepare cylindrical modules containing HepG2 cells to show the utility of this material in modular tissue constructs. A fluorescent cytoplasmic tracer, Vybrant CFDA SE, showed that embedded cells remained viable for more than 2 months, confirming the good cytocompatibility of collagen/poloxamine-methacrylate in the form of modules. The suitability of these modules for preparing uniform, scaleable, and vascularized constructs remains to be demonstrated.

Animals↗

Surface modification of poly-L-lactic acid (PLLA) membrane by grafting acrylamide: an effective way to improve cytocompatibility for chondrocytes.

Poly-L-lactic acid (PLLA) membranes were photo-oxidized in hydrogen peroxide solution under ultraviolet light (UV) to introduce hydroperoxide groups onto the PLLA membrane surfaces. The photo-oxidized membranes were then immersed in acrylamide (AAm) solution containing Fe2+ to graft polyacrylamide (PAAm) onto the PLLA membrane surfaces. The density of the hydroperoxide groups introduced on the PLLA membrane surfaces varied with the temperature and the photo-oxidization time. The occurrence of grafting was verified by X-ray photoelectron spectroscopy (XPS). The degree of grafting increased with the monomer concentration and the polymerization time. Water contact angle measurements showed that the wettability of the modified PLLA membranes had improved. Chondrocytes proliferated more rapidly and were more spread out on the modified membrane than on the control PLLA membrane, indicating that the PAAm-grafted PLLA membrane has better cytocompatibility for chondrocytes.

Acrylamide↗

Cytocompatibility study of NHLBI primary reference materials using human endothelial cells.

Four different materials, low density polyethylene (LDPE), polydimethylsiloxane (PDMS), polyvinylcholoride (PVC) and cellulose, were selected by the Devices and Technology Branch of the National Heart Lung and Blood Institute (NHLBI) as primary reference materials for blood contacting. Among the wide variety of tests proposed to assess hemocompatibility of short-term blood contacting catheters, it was desirable to rule out whether these materials could release toxics for vascular cells of the physiological environment. Thus, the cytocompatibility of these materials have been checked towards human umbilical vein endothelial cells: the method used avoids direct contact between cells and materials but evaluates the effect of possible toxic substances leached from materials. These substances were obtained under defined conditions according to a standard. The results show that the extracts of cellulose and LDPE provoke an important cytotoxic effect on the endothelial cell cultures, while the extracts of PDMS and PVC allow the obtention of endothelial cell lining of the reference surface, with a correct global metabolic activity and the intracellular presence of von Willebrand factor.

Biocompatible Materials↗

The release of zinc ions from and cytocompatibility of two zinc oxide dressings.

OBJECTIVE: These in vitro studies examined the release of zinc ions from and the response of human dermal fibroblasts to two zinc oxide-medicated dressings: one with zinc oxide in an ointment base and one using polyvinylpyrrolidone (PVP), a hydrophilic polymer for the binding of zinc oxide particles. METHOD: Zinc release from the dressings in buffered-saline (pH 7.4) was studied through a high-pore-density membrane (pore size, 0.40 microm) in a two-compartment model at 37 degrees C for three hours. Cytocompatibility of the dressings and 500 micromol/l of zinc ions was assessed using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay after exposure to monolayers of confluent normal human dermal fibroblasts to the dressing extracts for four hours. RESULTS: The zinc release rate from PVP-bound zinc oxide was more than two-fold higher than from zinc oxide in the ointment. Extract of the zinc oxide ointment, containing 150 micromol/l solubilised zinc, elicited a cytotoxic reaction, while the zinc oxide-PVP extract, containing 410 micromol/l solubilised zinc, and 500 micromol/l zinc chloride were non-cytotoxic to the fibroblasts. CONCLUSION: Zinc release in a simulated wound milieu appears to be inhibited when zinc oxide is incorporated in a lipophilic vehicle. It is hypothesised that the ointment vehicle induced cytotoxicity rather then the solubilised zinc oxide. DECLARATION OF INTEREST: None.

Administration, Cutaneous↗

[A comparative study on cytocompatibility of medical PVA and intelligent PVA-g-NIPAAm hydrogels].

"Intelligent" Polymers which resonse with large property changes to small physical or chemical stimuli are attracting more and more attention in the field of medical science. One trend in the area is to modify some conventional medical polymers to form intelligent biomaterials. This investigation was designed to evaluate and compare in vitro cytocompatibility of PVA hydrogel, which could be used as a kind of solid support with good biomcompatibility, and PVA-g-NIPAAm, which was produced by irradiation grafting of NIPAAm onto the said PVA hydrogel support. Cytotoxicity test was carried out with a modified Cell Relative Growth Rate test (RGR test). On the day 2, day 4 and day 7, the RGRs of the PVA hydrogel were 82%, 90% and 102% respectively while the RGRs of the PVA-g-NIPAAm were 77%, 86% and 100%. The grades of the cytotoxicity of the PVA and PVA-g-NIPAAm hydrogels were 0, so they had no cytotoxicity as judged by our tests. After 24 hours, cells in direct contact with the two kinds of samples were observed morphologically through the Olympus inverted microscope and had a normal development. The conclusion suggests that irradiation grafting is a good way to modify conventional medical polymers to produce intelligent biomaterials.

Acrylamides↗

[Preparation of human acellular amniotic membrane and its cytocompatibility and biocompatibility].

OBJECTIVE: To prepare human acellular amniotic membrane (HAAM) and to measure its cytocompatibility and biocompatibility. METHODS: HAAM were prepared by chemical detergent-enzymatic extraction. Fresh human amnion was crosslinked with glutaradehyde, shaken in 0.5% SDS for 24 hours, and then treated with 0.25% trypsin for 4 hours. The production were freeze-drying and sterilized using ethylene oxide. Human fibroblasts were isolated from embryo and expanded in vitro. The fibroblasts were seeded in HAAM. HAAM and specimen were stained with HE and Mallory, and observed grossly, under light microscopy and scanning electron microscopy. The HAAM were implanted in the back of SD rats. RESULTS: There were no residues of cells in the HAAM (HE, Mallory staining). One side of HAAM had reticular and porous structure, the other side had compact fibrous structure. Pore size was from 10 to 80 nm. The HAAM could be seeded with expanded fibroblasts in vitro, and fibroblasts had the potential of spread and proliferation. The SD rat in the implant test had no death, convulsions and other abnormal response. CONCLUSION: The detergent-enzymatic extraction process can remove cells and solvable components effectively and preserve the tissue matrix well and keep the reticular structure. The HAAM can be used as an ideal scaffold of biological membrane for tissue engineering.

Amnion↗

[The preparation of a new hydroxyapatite and the study on its cytocompatibility].

The cuttlebones, harvested from cuttles, undergo the chemical reaction in high temperature and high pressure for a certain time. The products are qualitatively analysed, and spacial structure observation and cytocompatibility are tested. The results show that the chemical component of the cuttlebone is CaCO3 and the crystal type is aragonite. Cuttlebones undergo a hydro-thermal reaction, and thus transform into hydroxyapatite-that is, the cuttlebone-transformed hydroxyapatite(CBHA). The CBHA materials have the interconnected microporous network structures. Under the high magnification, CBHAs appear to have many micro-spheres, thus construct a new self-assembled nano-material system. The marrow stromal osteoblasts can adhere to and proliferate well on the surface of the CBHAs. These results show that CBHAs have good biocompatibility. Therefore, it can be a potential candidate scaffold for bone tissue engineering.

Animals↗

[Cytocompatibility of dense polycrystalline hydroxyapatite particles as bone substitute].

The vitro cell culture was used to study cytocompatibility of dense polycrystalline hydroxylapatite. Histologic examination and scanning electron microscopy were used to study qualitatively the growth and adhesion of fibroblasts when they came into contact with hydroxylapatite in culture. The proliferation of fibroblasts in vitro, using the tritiated thymidine uptake method, allows a quantitative analysis of cell activation in response to the extracted solution of the materials. The results of experiment indicated that there were no adverse effects on the growth, adhesion and proliferation rate of human gingiva fibroblasts when they came into contact with hydroxylapatite.

Animals↗

[In vitro study of the cytocompatibility of 3 biological glues].

Human derived fibrin glues are being used with increasing frequency in periodontal surgery. Three different fibrin glues were tested in an in vitro system for gingival fibroblast proliferation. The results show a cytocompatibility of these products which justifies their employment in periodontal therapy.

Biocompatible Materials↗

Preparation, solubility, and cytocompatibility of zinc-releasing calcium phosphate ceramics.

Zinc is an essential trace element with stimulatory effects on bone formation. Therefore, zinc was doped into beta-tricalcium phosphate to develop zinc-releasing biomaterials to promote bone formation. The zinc-doped beta-tricalcium phosphate, beta-tricalcium phosphate, and hydroxyapatite powders were mixed at a (Ca+Zn)/P molar ratio of 1.60, followed by sintering into a dense body at 1100 degrees C for 1 h. The sintered body was a composite ceramic consisting of zinc-doped beta-tricalcium phosphate and hydroxyapatite phases. The composite ceramic contained zinc oxide when the zinc content was higher than 1.20 wt %. The composite ceramic released zinc under pseudophysiological conditions. However, the release of calcium and phosphate decreased with an increase in zinc content in a range higher than 0.12 wt % owing to a decrease in solubility of the zinc-doped beta-tricalcium phosphate phase. Proliferation of osteoblastic MC3T3-E1 cells was significantly increased on the composite ceramic with a zinc content from 0.6 to 1.20 wt %, compared with those without zinc. When the zinc content was higher than 1.20 wt %, release of zinc from the zinc oxide caused cytotoxicity. Therefore, the zinc content of the composite ceramic must be <1.20 wt %.

Animals↗

Synthesis, characterization, and cytocompatibility of elastomeric, biodegradable poly(ester-urethane)ureas based on poly(caprolactone) and putrescine.

The engineering of tissue for mechanically demanding applications in the cardiovascular system is likely to require mechanical conditioning of cell-scaffold constructs prior to their implantation. Scaffold properties amenable to such an application include high elasticity and strength coupled with controllable biodegradative and cell-adhesive properties. To fulfill such design criteria, we have synthesized a family of poly(ester-urethane)ureas (PEUUs) from polycaprolactone and 1,4-diisocyanatobutane. Lysine ethyl ester (Lys) or putrescine was used as chain extenders. To encourage cell adhesion, PEUUs were surface modified with radio-frequency glow discharge followed by coupling of Arg-Gly-Asp-Ser (RGDS). The synthesized PEUUs were highly flexible, with breaking strains of 660-895% and tensile strengths from 9.2-29 MPa. Incubation in aqueous buffer for 8 weeks resulted in mass loss, from >50% (Lys chain extender) to 10% (putrescine chain extender). Human endothelial cells cultured for 4 days with medium containing the degradation products from PEUUs with either the Lys or putrescine chain extender showed no toxic effects. Cell adhesion was 85% of that measured on tissue-culture polystyrene for unmodified PEUU surfaces (p < 0.01) and >160% (p < 0.001) of polystyrene on RGDS-modified PEUUs. These biodegradable PEUUs demonstrate potential for future application as cell scaffolds in cardiovascular tissue-engineering or other soft-tissue applications.

Absorbable Implants↗

Immobilization of natural macromolecules on poly-L-lactic acid membrane surface in order to improve its cytocompatibility.

With the use of a grafting-coating method, three kinds of natural macromolecules, that is, gelatin, collagen, or chitosan, were immobilized on poly-L-lactic acid (PLLA) membrane surfaces with the goal of improving of cellular interactions. Attenuated total reflectance infrared spectroscopy (ATR-IR), x-ray photoelectron spectroscopy (XPS) and surface morphology analysis using scanning electronic microscopy (SEM) confirmed that the natural macromolecule layers adhered tightly to the hydrophobic PLLA membrane surfaces. Chondrocyte culture showed that the modified PLLA membranes had higher cell attachment, higher cell proliferation rate, and higher cell activity than the control PLLA membrane. Moreover, the chondrocytes were more spread out on the modified PLLA membranes than on the control PLLA membranes.

Animals↗

Cytocompatibility of albuminated polyester fabrics.

An alternative to the usual technique of preclotting porous textile vascular prostheses prior to surgical implantation is to render them impermeable to blood by impregnation with a cross-linked albumin filler matrix. This material subsequently becomes the foundation for cellular development. The compatibility of such impregnated fabrics with newly formed endothelial cells has been evaluated by an in vitro organotypic culture method. This technique enables the characterization and numeration of cells that develop on blood contact surfaces and enables determination of their rate of development. Woven, knitted, and velour fabrics were evaluated following coating with albumin and either storage in Tyrode solution or 40% ethanol or desiccation by critical point drying. Preclotted cardiovascular repair fabrics prepared according to conventional surgical protocol served as controls. The identification of the newly formed cells was confirmed histologically. The most extensive and rapid cellular development was observed on the woven fabric and is believed may have resulted from the smoother surface topography of this substrate. Good cellular development was noted particularly on fabrics which had been stored in Tyrode solution. Ethanol had a deleterious effect on the apparent compatibility.

Albumins↗

In vitro cytocompatibility assessment of beta-tricalcium phosphate/carboxymethyl-chitin composite.

A novel bioabsorbable bone substitute composed of a beta-tricalcium phosphate (beta-TCP) and a carboxymethyl-chitin (CM-chitin) sodium has been developed. Rabbit tibia defects (4 mm in diameter) were repaired after 4 weeks more effectively by the composite compared with a sham-operation group. To further investigate the biological safety of the components, genotoxicity and carcinogenicity of an extract prepared from the composite were determined using four different in vitro assays. The main extract component was identified as CM-chitin sodium [average molecular weight (Mw) approximately 230 kDa] as determined by Fourier transform infrared spectroscopy and gel permeation chromatography analysis. The concentrations of P and Ca possibly derived from beta-TCP were 17.7 and 37.1 microg/g, respectively, as determined by inductively coupled plasma mass spectroscopy. Both the metabolic activation and nonactivation (-S9) systems of the rat microsome S9 fraction were used to perform a genotoxicity evaluation using the Ames test and chromosome aberration assay on Chinese hamster lung fibroblast cells treated with the extract. In these assays, no genotoxicity was detected with doses < or =5 mg/mL (maximum concentration). The cell transformation assay using BALB/c 3T3 cells and the metabolic cooperation assay with V79 cells both showed negative results for any tumor-promoting activity caused by the extract (approximately 5 mg/mL). These results indicate that the bioabsorbable beta-TCP/CM-chitin composite is a highly biocompatible bone substitute.

3T3 Cells↗

Investigation of nickel suppression and cytocompatibility of surface-treated nickel-titanium shape memory alloys by using plasma immersion ion implantation.

Nickel-titanium (NiTi) shape memory alloys are increasingly being used in orthopedic applications. However, there is a concern that Ni is harmful to the human body. We have recently investigated the use of nitrogen, or oxygen plasma immersion ion implantation to mitigate this deleterious effect. Our results reveal that the near-surface Ni concentration in all the treated samples is significantly suppressed. In addition, our in vitro tests show that the plasma-treated surfaces are cytologically compatible allowing the attachment and proliferation of osteoblasts. Among the two types of samples, the best biological effects are found on the samples with nitrogen implantation.

Animals↗

Corrosion resistance, surface mechanical properties, and cytocompatibility of plasma immersion ion implantation-treated nickel-titanium shape memory alloys.

Nickel-titanium shape memory alloys are promising materials in orthopedic applications because of their unique properties. However, for prolonged use in a human body, deterioration of the corrosion resistance of the materials becomes a critical issue because of the increasing possibility of deleterious ions released from the substrate to living tissues. We have investigated the use of nitrogen, acetylene, and oxygen plasma immersion ion implantation (PIII) to improve the corrosion resistance and mechanical properties of the materials. Our results reveal that the corrosion resistance and mechanical properties such as hardness and elastic modulus are significantly enhanced after surface treatment. The release of nickel is drastically reduced as compared with the untreated control. In addition, our in vitro tests show that the plasma-treated surfaces are well tolerated by osteoblasts. Among the three types of samples, the best biological effects are observed on the nitrogen PIII samples.

Alloys↗

Surface characteristics, mechanical properties, and cytocompatibility of oxygen plasma-implanted porous nickel titanium shape memory alloy.

Good surface properties and biocompatibility are crucial to porous NiTi shape memory alloys (SMA) used in medical implants, as possible nickel release from porous NiTi may cause deleterious effects in the human body. In this work, oxygen plasma immersion ion implantation (O-PIII) was used to reduce the amount of nickel leached from porous NiTi alloys with a porosity of 42% prepared by capsule-free hot isostatic pressing. The mechanical properties, surface properties, and biocompatibility were studied by compression tests, X-ray photoelectron spectroscopy (XPS), and cell culturing. The O-PIII porous NiTi SMAs have good mechanical properties and excellent superelasticity, and the amount of nickel leached from the O-PIII porous NiTi is much less than that from the untreated samples. XPS results indicate that a nickel-depleted surface layer predominantly composed of TiO(2) is produced by O-PIII and acts as a barrier against out-diffusion of nickel. The cell culturing tests reveal that both the O-PIII and untreated porous NiTi alloys have good biocompatibility.

Alloys↗

Cytocompatibility of novel tin oxide thin films.

The capacity of tin oxide films to support cell growth was investigated. Three substrates were used for the test: glass coverslips, glass coverslips spin coated with tin oxide and commercially available 316 stainless steel. The wettabilities and surface roughness of the three surfaces were measured before seeding 3T3 fibroblasts onto the samples. The behaviour of the cells grown on the tin oxide was compared to the uncoated glass and the steel and results showed that the cell growth on tin oxide compared favourably with the other substrates. The surface wettability appeared to have the strongest effect on cell adhesion to tin oxide.

3T3 Cells↗