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PubMed1977

Biocompatibility and bioabsorption of microfibrillar collagen hemostat in experimental animals.

The effects of Microfibrillar Collagen Hemostat (MCH) and Gelfoam after surgical implantation into incision sites of the liver, kidney, and brain were studied in beagle dogs, rabbits, and beagle dogs, respectively. The results of these experimental animal studies suggest that MCH is comparable to Gelfoam with respect to biocompatibility, rate of bioassimilation, and a lack for adverse systemic effects. The brain, liver, and kidney tissues responded comparably to MCH and Gelfoam with a mild to moderate infiltration of macrophages and mononuclear cells. Most of the hemostatic compound had disappeared from the incision sites by Day 28 and completely disappeared by Day 84. The tissue degree response was interpreted as a factor in the process of bioassimilation of the two hemostatic materials. Both hemostatic compounds contributed to adhesion formation in the experimental models. The incidence of adhesions was somewhat lower for MCH than for Gelfoam, but both produced more adhesions than were found at the control sites. The adhesions were only to the adjacent structures and always localized to the surgical site. When MCH or Gelfoam is used under conditions similar to those in the present experimental study, where tissue approximation is impaired, and where growth of granulation tissue is stimulated by the physical presence of the hemostatic compound, there is the possibility for increased incidence of adhesion formation. However, when an intraperitoneal absorbable hemostatic compound is desired, the present studies in experimental animals suggest that MCH will be safe by exhibiting minimal tissue reaction.

Absorption↗

PubMed1989

Biocompatibility testing of a posterior composite and dental cements using a new organ culture model.

Mandibular first molars from day 14 and 17 mouse embryos were cultured in vitro for 7 days in chemically defined Pratt's medium in a submerged culture system. Ameloblast and odontoblast polarization and morphogenesis occurred in the control tooth germs. Discs of Occlusin, Silicate, ChemFil, IRM and Dycal were exposed to the culture system as either fresh material, leached discs (by pre-incubation in media) or the leachate from the incubated discs. Their effects on dental differentiation were assessed histologically. Day 17 tooth germs were slightly more sensitive to the effects of the exogenous agents than day 14 tooth germs. In general, silicate and ChemFil were toxic, IRM was slightly less toxic and the major effect was from the leachate. Dycal was toxic but most of this effect resulted from pH changes in the leachate. Occlusin was the most biocompatible material tested. Only a very mild adverse effect was detected, and this appeared to be caused by an agent (not a pH change) released into the leachate.

Aluminum Silicates↗

PubMed2006

Growth of hydroxyapatite in a biocompatible mesoporous ordered silica.

A novel biomaterial (HA-SBA-15) has been developed based on the growth of calcium phosphate hydroxyapatite (HA) nanoparticles within an organized silica structure (SBA-15). Characterization of the material was carried out using a combination of X-ray diffraction, X-ray fluorescence, transmission electron microscopy, N2 adsorption-desorption isotherms and nuclear magnetic resonance. Transmission electron microscopy observations and N2 porosimetry revealed the crystallization of hydroxyapatite nanoparticles inside the mesopore cavities of the silica structure. Specific surface areas of 760 m2 g(-1) and 260 m2 g(-1) were measured for the SBA-15 and the HA-SBA-15 material, respectively. The hydroxyl groups present in the silica nanostructure surface have brought about cationic defects in the silicium sites, mainly with those of tetrahedral symmetry, and promoted the formation of siloxanes. 29Si MAS-NMR analysis shows a significant reduction of the silanol groups concentration with HA growing within the base (SBA-15) material. Studies and brain tissue biocompatibility tests were carried out. Histopathological studies on the SBA-15 implant material showed no changes to the tissue nearby. The results confirmed the synthesis of a silica-based composite containing HA nanoparticles with the potential for biomedical applications.

Adsorption↗

PubMed2006

Microstructure and deformation behavior of biocompatible TiO2 nanotubes on titanium substrate.

Titanium oxide coatings have been shown to exhibit desirable properties as biocompatible coatings. We report on the quantitative microstructure characterization and deformation behavior of TiO(2) nanotubes on Ti substrate. Nanotubes were processed using anodic oxidation of Ti in a NaF electrolyte solution. Characterization of the as-processed coatings was conducted using scanning electron microscopy and focused ion beam milling. Increases in anodization time had no significant effect on tube diameter or tube wall thickness. Coating thickness, however, increased with time up to 2h of anodization, at which point an equilibrium thickness was established. Nanoindentation was used to probe the mechanical response in terms of Young's modulus and hardness. Progressively higher values of elastic modulus were obtained for thinner films consistent with increasing effects of the Ti substrate. A possible deformation mechanism of densification of the porous oxide and wear of the dense surface is suggested and discussed.

Biomechanical Phenomena↗

PubMed2005

Effects of methylprednisolone and a biocompatible copolymer circuit on blood activation during cardiopulmonary bypass.

BACKGROUND: Cardiopulmonary bypass (CPB) induces derangements in physiology characterized by activation of blood pathways that may contribute to multiorgan dysfunction. This trial addresses the efficacy of a biocompatible surface alone and in combination with steroids in inhibiting these changes. METHODS: In a factorial design, patients undergoing coronary artery bypass grafting were randomized (four groups; n = 17 per group) to CPB utilizing control circuits or a circuit prepared with a surface modifying active copolymer (SMA-CPB), with or without methylprednisolone (MPSS, 1 g intravenous). Leukocyte and complement activation, cytokine release, and bradykinin generation were measured. Clinical outcomes (blood loss, transfusion, arterial pressure response, and postoperative cardiac and pulmonary functions) were also examined. RESULTS: The SMA-CPB was associated with a significant inhibition of elastase release (p = 0.026) and bradykinin generation (p = 0.027) during CPB. Terminal complement complex (TCC) generation was inhibited as an effect of SMA-CPB (p = 0.047). There was an interaction of SMA-CPB and MPSS to decrease both TCC (p = 0.042) and bradykinin generation (p = 0.028). There were strong effects of MPSS in inhibiting release of interleukin 6 (IL-6) (p = 0.007) and IL-8 (p < 0.001) and tissue plasminogen activator over time (p = 0.009) as well as decreasing peak day 1 creatine kinase (CK, p = 0.015) levels. Clinical effects of MPSS included decreased atrial fibrillation (p = 0.02), improved cardiac index over time, increased pulmonary compliance, and increased insulin need. CONCLUSIONS: This trial suggests a potential beneficial effect for combined strategies to minimize inflammation after CPB. The specific effect of MPSS in decreasing postoperative atrial fibrillation and CK warrants further investigation of its role as a potential myocardial protective agent.

Biomarkers↗

PubMedDate not supplied

The biocompatibility of crosslinkable copolymer coatings containing sulfobetaines and phosphobetaines.

The comparison of copolymers containing sulfobetaine or phosphobetaine moieties for use as potential biocompatible coatings has been investigated. Two statistical copolymers were produced by a free radical polymerisation technique, one based on a sulfobetaine and the other on a phosphobetaine, both with a silyl group component to allow thermal crosslinking after coating. PMMA and glass discs were dip-coated with the polymers and their properties were compared to the uncoated controls. Bacterial adhesion to these coated materials was assessed using Staphylococcus epidermidis, Staphylococcus aureus and Pseudomonas aeruginosa. Human macrophages and granulocytes were used to assess the adhesion and activation of inflammatory cells whilst mouse 3T3 fibroblast cells were used to assess the propensity for the materials to support fibroblast cell adhesion. In all cases the polymer coatings reduced cell adhesion with respect to the base materials. The phosphobetaine-based copolymer coatings were shown to be markedly superior to the sulfobetaine-based copolymer coatings.

3T3 Cells↗

PubMed2004

Biocompatible nanocrystalline octacalcium phosphate thin films obtained by pulsed laser deposition.

We extended for the first time pulsed laser ablation to the deposition of octacalcium phosphate Ca8H2(PO4)6.5H2O (OCP) thin films. The depositions were performed with a pulsed UV laser source (lambda=248 nm, tau> or =20 ns) in a flux of hot water vapors. The targets were sintered from crystalline OCP powder and the laser ablation fluence was set at values of 1.5-2 J/cm2. During depositions the collectors, Si or Ti substrates, were maintained at a constant temperature within the range 20-200 degrees C. The resulting structures were submitted to heat treatment in hot water vapors for up to 6 h. The best results were obtained at a substrate temperature of 150 degrees C during both deposition and post-deposition treatment. High-resolution electron microscopy and XRD at grazing incidence indicated that the coatings obtained were made of nanocrystalline OCP. Cross-section TEM investigations showed that the coatings contained droplets stacked on Ti substrates as well as distributed across the entire thickness of the arborescence-like structure layers. The results of WST-1 assay, cell adherence, DNA replication, and caspase-1 activity confirmed the good biocompatibility of the coatings.

Animals↗

PubMed2004

Biocompatibility of sorbitol-containing polyesters. Part I: Synthesis, surface analysis and cell response in vitro.

A series of sorbitol-containing polyesters were synthesized via a one-pot lipase-catalyzed condensation polymerization. Thin films were prepared by spin coating on silicon wafers and surfaces were analyzed by tapping mode atomic force microscopy and contact angle measurements. Surface morphologies and surface energies across the series of polyester films, including a poly(epsilon-caprolactone) (PCL) control were nearly indistinguishable. Biocompatibility of the sorbitol-containing polyester series was evaluated against a PCL control by measuring cell spreading and proliferation of a mouse fibroblast 3T3 cell line in vitro. Results confirmed that the sorbitol-containing polyester surfaces elicited cell behavior similar to the PCL control. These results establish the sorbitol-containing polyester series as a promising material for tissue engineering research and development.

3T3 Cells↗

PubMed2004

Calcium phosphates and glass composite coatings on zirconia for enhanced biocompatibility.

Calcium phosphates (CaP) and phosphate-based glass (P-glass, xCaO-(0.55-x) Na(2)O-0.45P(2)O(5) composition) composite coatings were obtained on a strong ZrO(2) to improve biocompatibility, the mechanical strength and biological activity. Hydroxyapatite (HA) and P-glass mixed powder slurries were coated on the ZrO(2) substrate, and subsequently heat-treated to obtain CaP- and P-glass composite coatings. The effects of glass composition (x=0.3, 0.4, 0.5 mol), mixing ratio of glass to HA (30%, 40%, 50% wt/wt), and heat treatment temperature (800 degrees C, 900 degrees C, 1000 degrees C) on the coating properties were investigated. After heat treatment, additional calcium phosphates, i.e., dicalcium phosphate (DCP) and tricalcium phosphate (TCP), were crystallized, resulting in the formation of triphasic calcium phosphates (HA-TCP-DCP) surrounded by a glass phase. The relative amounts of the crystalline phases varied with coating variables. The higher heat treatment temperature and glass amount, and the lower CaO content in the glass composition rendered the composite coatings to retain the higher amounts of TCP and DCP while the initial HA decreased. These appearance of additional crystalline phases and reduction of HA amount were attributed to the combined effects, i.e., the melting-crystallization of P-glass and the reaction between glass liquid phase and HA powder during thermal treatment. As a result of the glass phase in the composite coatings, their microstructures became much denser when compared to the pure HA coating. In particular, a completely dense structure was obtained at coating conditions with large amount of glass addition (50 wt%) at the glass composition of lower CaO content (0.3 mol CaO), and the following heat treatment above 800 degrees C for 2h. As a result, the adhesion strengths of the composite coating layers were significantly improved when compared to the pure HA coating. The highest strength of the composite coating was approximately 40 MPa, an improvement of approximately 80% with respect to the pure HA coating. The composite coatings showed much higher dissolution rates than the pure HA coating due to the newly formed crystallines (TCP and DCP) and the remaining glass phase. The osteoblast-like cells grew and spread actively on the composite coating samples. The proliferation numbers and alkaline phosphate (ALP) activities of the cells on the composite coatings were improved by approximately 30-40% when compared to Thermanox control and ZrO(2) substrate, and were comparable to the pure HA coating. These findings suggested that the CaP and P-glass composites are potentially useful for hard tissue coating system, due to their morphological and mechanical integrity, enhanced bioactivity, and favorable responses to the osteoblast-like cells.

Adhesiveness↗

PubMed2005

Improvement in biocompatibility of ZrO2-Al2O3 nano-composite by addition of HA.

The biocompatibility of zirconia-alumina (ZA) nano-composites in load-bearing applications such as dental/orthopedic implants was significantly enhanced by the addition of bioactive HA. The ZA matrix was composed of nano-composite powder obtained from the Pechini process and had higher flexural strength than conventionally mixed zirconia-alumina composite. Because the ZA nano-composite powder effectively decreased the contact area between HA and zirconia for their reaction during the sintering process, the HA-added ZA nano-composites contained biphasic calcium phosphates (BCP) of HA/TCP and had higher flexural strength than conventionally mixed ZA-HA composite. From the in vitro test with osteoblastic cell-lines, the proliferation and the differentiation (as expressed by the alkaline phosphatase activity) of the cellular response on the HA-added ZA nano-composites gradually increased as the amount of HA added increased. From the mechanical and biological evaluations of the HA-added ZA nano-composites, 30HA (30 vol% HA + 70 vol% ZA) was found to be the optimal composition for load-bearing biological applications.

Alkaline Phosphatase↗

PubMed2005

Biocompatibility and stability of disulfide-crosslinked hyaluronan films.

Hyaluronan (HA) can be chemically modified to engineer robust materials with pre-selected mechanical properties and resorption rates that can be dictated by the intended clinical use. Disulfide-crosslinked HA films were prepared by air oxidation of thiol-modified HA, followed by treatment with 0.3% hydrogen peroxide. The degradation of the disulfide-crosslinked films in vitro was very slow (<10% in 7 days) in buffer alone and shorter (t1/2=3-5 days) in the presence of hyaluronidase (HAse). The cytocompatibility of the disulfide-crosslinked HA films was determined using two separate conditions: (i) in vitro culture of mouse fibroblasts in indirect contract with the films, and (ii) in vitro culture of fibroblasts directly on films coated with poly d-lysine. Excellent cytocompatibility was observed in murine fibroblasts that were cultured in indirect contact with thiolated HA films. Although cells were unable to attach and spread on thiolated HA films, pre-coating the thiolated HA films with poly D-lysine resulted in attachment and spreading equivalent to that observed on polystyrene. Rates of resorption in vivo were obtained by subcutaneous implantation of disulfide-crosslinked HA films into the backs of Wistar rats. Biocompatibility in vivo was determined in both subcutaneous flank and peritoneal cavity implantation of the films in Wistar rats. The disulfide-crosslinked HA films were less than 30% resorbed after 42 days in vivo, and histochemical and cytochemical analysis indicated that the films were well-tolerated with mild inflammatory response at both sites of implantation.

Absorbable Implants↗

PubMed2005

Molecularly engineered p(HEMA)-based hydrogels for implant biochip biocompatibility.

The strategy of phospholipid-based biomimicry has been used to molecularly engineer poly(2-hydroxyethyl methacrylate) [p(HEMA)]-based hydrogels for improved in vitro and potential in vivo biocompatibility. Two methacrylate-based monomers, poly(ethylene glycol) (200) monomethacrylate (PEGMA) and 2-methacryloyloxyethyl phosphorylcholine (MPC), were incorporated at varying mole fractions of 0.0-0.5 mol% PEGMA and 0-10 mol% MPC respectively, into 3 mol% tetraethyleneglycol diacrylate (TEGDA) cross-linked p(HEMA) networks. Upon hydration of these engineered hydrogels, a reduction in receding contact angle from 22+/-1.2 degrees for p(HEMA) to 8+/-2.7 degrees for p(HEMA) containing 0.5:10 mol% PEGMA:MPC was observed, reflecting the significant increase in surface hydrophilicity with increasing PEGMA and MPC content upon prolonged hydration. Hydrogels containing MPC showed a temporal increase in hydrophilicity following continuous immersion in DI water over 5 days. Hydrogels containing 0.5 mol% PEGMA and MPC in the range of 5-10 mol% displayed reduced protein adsorption when incubated with the common extracellular matrix proteins; fibronectin, collagen or laminin, producing up to 64% less protein adsorption compared to p(HEMA). Compositional optima for cell viability and proliferation established from two-factor Central Composite design analysis of human muscle fibroblasts cultured on these hydrogels suggest that those containing PEGMA between 0.3 and 0.5 mol% and MPC levels around 5-10 mol% exhibit desirable characteristics for implant material coatings-high viability (>80%) with low proliferation (<40%), confirming a lack of cytotoxicity.

Adsorption↗

PubMed2005

Biocompatibility analysis of poly(glycerol sebacate) as a nerve guide material.

No satisfactory method currently exists for bridging neural defects. Autografts lead to inadequate functional recovery, and most available artificial neural conduits possess unfavorable swelling and pro-inflammatory characteristics. This study examined the biocompatibility of a novel biodegradable elastomer, poly(glycerol sebacate) (PGS), for neural reconstruction applications, as the material possesses favorable mechanical property and degradation characteristics. The effect of PGS on Schwann cell metabolic activity, attachment, proliferation, and apoptosis were examined in vitro in comparison with poly(lactide-co-glycolide) (PLGA), a biomaterial widely utilized for tissue engineering applications. The in vivo tissue response to PGS was compared with PLGA implanted juxtaposed to the sciatic nerve; the physical changes in the implant material were measured during the degradation process. PGS had no deleterious effect on Schwann cell metabolic activity, attachment, or proliferation, and did not induce apoptosis; the in vitro effects of PGS were similar to or superior to that of PLGA. In vivo, PGS demonstrated a favorable tissue response profile compared with PLGA, with significantly less inflammation and fibrosis and without detectable swelling during degradation. PGS is an excellent candidate material for neural reconstruction applications given its lack of in vitro Schwann cell toxicity and minimal in vivo tissue response.

Animals↗

PubMed2005

The biocompatibility of dibutyryl chitin in the context of wound dressings.

Dibutyryl chitin (DBC) is a modified chitin carrying butyryl groups at 3 and 6 positions; its peculiarity is that it dissolves promptly in common solvents, while being insoluble in aqueous systems. The high biocompatibility of dibutyryl chitin in the form of films and non-wovens has been demonstrated for human, chick and mouse fibroblasts by the Viability/Cytotoxicity assay, In situ Cell Proliferation assay, Neutral Red Retention assay, Lactate Dehydrogenase Release assay, MTS cytotoxicity assay, and scanning electron microscopy. DBC was hardly degradable by lysozyme, amylase, collagenase, pectinase and cellulase over the observation period of 48 days at room temperature, during which no more than 1.33% by weight of the DBC filaments (0.3 mm diameter) was released to the aqueous medium. DBC non-wovens were incorporated into 5-methylpyrrolidinone chitosan solution and submitted to freeze-drying to produce a reinforced wound dressing material. The latter was tested in vivo in full thickness wounds in rats. The insertion of 4x4 mm pieces did not promote any adverse effect on the healing process, as shown histologically. DBC is therefore suitable for contacting intact and wounded human tissues.

Amylases↗

PubMed2005

Nano-composite of poly(L-lactide) and surface grafted hydroxyapatite: mechanical properties and biocompatibility.

In order to improve the bonding between hydroxyapatite (HAP) particles and poly(L-lactide) (PLLA), and hence to increase mechanical properties of the PLLA/HAP composite as potential bone substitute material, the HAP nano-particles were surface-grafted with PLLA and further blended with PLLA. The structure and properties of the composites were subsequently investigated by the mechanical property testing, the differential scanning calorimeter measurements (DSC), the scanning electron microscopy (SEM), the polarized optical microscopy (POM), and the cell culture. The PLLA molecules grafted on the HAP surfaces, as inter-tying molecules, played an important role in improving the adhesive strength between the particles and the polymer matrix. At a low content (approximately 4 wt%) of surface grafted-HAP (g-HAP), the PLLA/g-HAP nano-composites exhibited higher bending strength and impact energy than the pristine PLLA, and at a higher g-HAP content (e.g., 20 wt%), the modulus was remarkably increased. It implied that PLLA could be strengthened as well as toughened by g-HAP nano-particles. The results of biocompatibility test showed that the g-HAP existing in the PLLA composite facilitated both adhesion and proliferation of chondrocytes on the PLLA/g-HAP composite film.

Bone Substitutes↗

PubMed2005

Surface engineering of stainless steel materials by covalent collagen immobilization to improve implant biocompatibility.

It was shown recently that the deposition of thin films of tantalum and tantalum oxide enhanced the long-term biocompatibility of stainless steel biomaterials due to an increase in their corrosion resistance. In this study, we used this tantalum oxide coating as a basis for covalent immobilization of a collagen layer, which should result in a further improvement of implant tissue integration. Because of the high degradation rate of natural collagen in vivo, covalent immobilization as well as carbodiimide induced cross-linking of the protein was performed. It was found that the combination of the silane-coupling agent aminopropyl triethoxysilane and the linker molecule N,N'-disulphosuccinimidyl suberate was a very effective system for collagen immobilizing. Mechanical and enzymatic stability testing revealed a higher stability of covalent bound collagen layers compared to physically adsorbed collagen layers. The biological response induced by the surface modifications was evaluated by in vitro cell culture with human mesenchymal stem cells as well as by in vivo subcutaneous implantation into nude mice. The presence of collagen clearly improved the cytocompatibility of the stainless steel implants which, nevertheless, significantly depended on the cross-linking degree of the collagen layer.

Adsorption↗

PubMed2005

Assessing the in vitro biocompatibility of a novel carbon device for the treatment of sepsis.

The aim of the present study was to conduct a preliminary investigation into the blood biocompatibility of a novel, uncoated carbon for use in a filtration/adsorption device for the treatment of sepsis. Carbon well prototypes were manufactured from phenol-formaldehyde-aniline-based pyrolysed carbons using monolithic polymer technology. Inflammatory blood cell and plasma protein mediation of the inflammatory response were evaluated using the novel carbon prototypes and compared with dialyser membrane and tissue culture plate controls. Assays determining monocyte and granulocyte adhesion, platelet adhesion and activation, granulocyte activation and complement activation were performed. Preliminary findings suggest an adsorptive but passivating carbon surface. Moderate levels of monocyte and granulocytes adhesion were seen in conjunction with adsorption of plasma proteins to the carbon surface. Activation of granulocyte and adherent platelets was not detected and the complement cascade was not activated by the carbons, indicating a surface compatible with blood contact. The results support the further development of the proposed carbon-based device for the treatment of sepsis.

Biocompatible Materials↗

PubMed2005

Approaches to improving the biocompatibility of porous perfluoropolyethers for ophthalmic applications.

Porous perfluoropolyether (PFPE) membranes for ophthalmic applications were prepared with a zwitterion monomer, 3-[[2-(methacryloxy) ethyl](N,N-dimethyl)ammonio]-propane-1-sulphonate, copolymerized in weight ratios of 0-10%. The polymer samples were assessed for a range of physical properties, including equilibrium water content, bovine serum albumin permeability, transparency, refractive index and the ability to support corneal epithelial cell and tissue attachment, growth and migration. In vitro assessment of the polymers using bovine corneal epithelial cells and tissue showed that a zwitterion incorporation level of between 0% and 6% in the PFPE membranes supported the migration of an intact sheet of epithelial tissue without compromising epithelial cell attachment and growth, with 4-6% being the optimal level for these properties. Binding patterns of the cell adhesion glycoprotein fibronectin were also found to reflect the cell and tissue response. Effective nutrient permeability, refractive index and optical transparency were also maintained by the porous PFPE polymers containing this concentration of zwitterionic monomer. The presence of amounts of zwitterion greater than 6% was inhibitory to both tissue migration and cell growth and was associated with increased optical haze. These results demonstrated that it is possible to achieve the potential for increased biocompatibility in zwitterion-containing PFPE polymers without compromising existing beneficial characteristics.

Animals↗