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PubMed1998

Surface characteristics and biocompatibility of lactide-based poly(ethylene glycol) scaffolds for tissue engineering.

Novel lactide-based poly(ethylene glycol) (PEG) polymer networks (GL9-PEGs) were prepared by UV copolymerization of a glycerol-lactide triacrylate (GL9-Ac) with PEG monoacrylate (PEG-Ac) to use as scaffolds in tissue engineering, and the surface properties and biocompatibility of these networks were investigated as a function of PEG molecular weight and content. Analysis by ATR-FTIR and ESCA revealed that PEG was incorporated well within the GL9-PEG polymer networks and was enriched at the surfaces. From the results of SEM, AFM, and contact angle analyses, GL9-PEG networks showed relatively rough and irregular surfaces compared to GL9 network, but the mobile PEG chains coupled at their termini were readily exposed toward the aqueous environment when contacting water such that the surfaces became smoother and more hydrophilic. This reorientation and increase in hydrophilicity were more extensive with increasing PEG molecular weight and content. As compared to GL9 network lacking PEG, protein adsorption as well as platelet and S. epidermidis adhesion to GL9-PEG networks were significantly reduced as the molecular weight and content of PEG was increased, indicating that GL9-PEG networks are more biocompatible than the GL9 network due to PEG's passivity. Based on the physical and biological characterization reported, the GL9-PEG materials would appear to be interesting candidates as matrices for tissue engineering.

Bacterial Adhesion↗

PubMed2004

Considerations on surface and structural biocompatibility as prerequisite for long-term stability of neural prostheses.

Neural prostheses are technical systems that partially substitute neural functions of the body after traumatic lesions or neurological disorders. Using biomedical microsystems, complex implants can be designed and fabricated in very small dimensions. However, miniaturization of neural prostheses for long-term implantation is very challenging. Implants not only have to be biosafe and biostable in terms of cytotoxicity and degradation, they also have to cope with the biological requirements of structural biocompatibility. In this paper, examples of biomedical microimplants for neural prostheses use are introduced. Results from basic biocompatibility investigations regarding the cytotoxicity are reported, as well as aspects of the interaction between surface structure and cell behaviour. A detailed outlook addresses possible approaches to use nanosciences to ensure long-term stability of thin technical layers within the body and create surfaces for selective and specified functional reactions at the interface between the artificial implant and the biological environment.

Biocompatible Materials↗

PubMedDate not supplied

Uptake and biocompatibility of functionalized poly(vinylalcohol) coated superparamagnetic maghemite nanoparticles by synoviocytes in vitro.

Superparamagnetic iron oxide nanoparticles (SPION) were coated with either Polyvinyl alcohol (PVA) or Vinyl alcohol/vinyl amine copolymer and further functionalized with the fluorochromes Cy3.5 or Texas Red. A colloidally stable suspension of nanoparticles was incubated on sheep synovial cells in vitro for 3, 24, 72, and 120 hours. Nanoparticle internalization into synoviocytes as well as biocompatibility was visualized using light, fluorescence and confocal microscopy and fluorochrome labeled cells were quantified by flow cytometry. Data were analyzed by ANOVA factorial tests. Amino-PVA-SPION alone was detectable in cytoplasmic endosome-like structures after 3 hours of incubation but resulted in early cell death after 24 hours. Although amino-PVA-Cy3.5-SPION and PVA-TexasRed-SPION were taken up more slowly and less intensely, both labeled more than 80% of the cells in culture, but did not significantly change cell morphology or vitality at any time of evaluation in comparison to control cells. Results indicate that functionalized amino PVA-coated SPION are biocompatible, were successfully internalized by synoviocytes and hold promise for future biomedical applications utilizing magnetic drug targeting in joint disease.

Animals↗

PubMed1984

Use of biocompatible orthopaedic polymer for fracture treatment and reconstructive orthopaedic procedures.

For many years attempts have been made to develop materials for use in the surgical treatment of fractures. So far only metal implants have been used. Soviet research has now succeeded in developing a copolymer of polyvinyl-pyrrolidone and methyl methacrylate reinforced by polyamide fibres and calcium gluconate which is reported to have comparable strength of metal implants but superior flexibility. It can be trimmed and shaped at the time of surgery, has no irritative reactions or release of toxic components, and above all is biocompatible. Clinical studies have been going on for 10 years in various Soviet medical centres and the total number of cases treated with the biocompatible polymer implants is well over 1000. In no case was a repeat operation necessary to remove the implant. Control X-rays (as well as animal data) showed that biodestruction of the implants is complete within 1.5 to 3 years depending on their sizes. The first operations outside the Soviet Union have been recently performed in Belgium. In the Soviet Union this material has also been used to treat pathologic fractures and in reconstructive surgical procedures such as leg lengthening.

Adolescent↗

PubMed2003

In vitro biocompatibility of titanium oxide for prosthetic devices nanostructured by low pressure metal-organic chemical vapor deposition.

Metal-Organic Chemical Vapor Deposition (MOCVD) has recently been proposed to coat orthopedic and dental prostheses with metal nanostructured oxide films through the decomposition of oxygenated compounds (single-source precursors) or the reaction of oxygen-free metal compounds with oxygenating agents. The present study was carried out to assess the in vitro biocompatibility in terms of cell proliferation and activation, of commercially pure Ti (control material: TI/MA) coated with nanostructured TiO2 film by MOCVD (Ti/MOCVD) using osteoblast-like cell cultures (MG-63). Evaluations were performed at 3, 7 and 14 days. Cell proliferation showed a similar trend for Ti/MA and TilMOCVD compared to polystyrene; cell number increased with time from seeding to day 7 (p < 0.005), and then decreased progressively until day 14 (ranging from -14% to -47%). The ALP level and OC production showed no significant differences between Ti/MOCVD and Ti/MA at each experimental time. Significantly higher ALP levels were found in Ti/MA at 3 days and in Ti/MOCVD at 7 and 14 days when compared to the polystyrene group. OC production decreased over time and the highest values were observed at 3 days, when it was significantly higher in the Ti/MA than in the polystyrene group (50%, p < 0.05). CICP synthesis was positively affected by the presence of Ti/MOCVD and was higher in Ti/MOCVD than in the polystyrene group. No significant differences were found between Ti/MOCVD and Ti/MA in terms of IL-6 and TGF-beta1 synthesis at any experimental time. In conclusion, the current findings demonstrate that the nanostructured TiO2 coating positively affects the osteoblast-like cell behavior in terms of cell proliferation and activity, thus confirming its high level of in vitro biocompatibility in accordance with expectations.

Biocompatible Materials↗

PubMed2006

Biocompatibility of supercritical CO2-treated titanium implants in a rat model.

Supercritical phase CO2 is a promising method for sterilizing implantable devices and tissue grafts. The goal of this study is to evaluate the biocompatibility of titanium implants sterilized by supercritical phase CO2 in a rat subcutaneous implantation model. At 5 weeks post implantation titanium implants sterilized by supercritical phase CO2 produce a soft tissue reaction that is comparable to other methods of sterilization (steam autoclave, ultraviolet light radiation, ethylene oxide gas, and radio-frequency glow-discharge), as indicated by the thickness and density of the foreign body capsule, although there were some differences on the capillary density. Overall the soft tissue response to the implants was similar among all methods of sterilization, indicating supercritical phase CO2 treatment did not compromise the biocompatibility of the titanium implant.

Alloys↗

PubMed2006

Microcirculation as a novel marker of membrane biocompatibility.

BACKGROUND: It is possible to consider microcirculation as a kind of OwitnessO of the complex biological reactions triggered by the dialytic treatment. The reactivity of microcirculation to the dialytic stress may represent a measure of the overall biocompatibility of the membrane. In this study we tested the hypothesis that different synthetic membranes may have different biological effects, particularly related to microcirculation. SUBJECTS AND METHODS: In this crossover study, we observed 16 chronically hemodialyzed patients. All patients were treated with the EVAL membrane; we recorded the TcPO2 during the second treatment of the week. All patients were then switched to the hf-PS membrane. During the study observation we did not change the dialytic prescription or the pharmacologic treatment. RESULTS: From the beginning of the session until 90O, the behavior of TcPO2 is similar for both the membranes. From 120O to the end of the treatment in sessions with the EVAL membrane, the TcPO2 values come back to the starting level, whereas in the treatments with hf-PS the TcPO2, the values remain at a lower level; there was a significant difference between EVAL and hf-PS in the values recorded. Arterial blood gas values of paO2 and paCO2 are quite similar in the treatments with both the membranes, without any significant difference. CONCLUSIONS: The analysis of microcirculation by means of TcPO2 measurement is a useful tool to obtain a OclinicalO measure of biocompatibility of the dialytic treatment and different membranes may have different impacts on TcPO2.

Aged↗

PubMed2005

Biocompatibility of Poly(epsilon-caprolactone) scaffold modified by chitosan--the fibroblasts proliferation in vitro.

In this study, the surface of poly(epsilon-caprolactone) (PCL) scaffold was modified by chitosan (CS) in order to enhance its cell affinity and biocompatibility. It is demonstrated by scanning electronic microscopy (SEM) that when 0.5-2.0 wt% chitosan solutions are used to modify the PCL scaffold, the amount of adhesion of the fibroblasts on the chitosan-modified PCL scaffolds dramatically increase when compared to the control after 7 days cell culture. The results indicate that the chitosan-modified PCL scaffolds are more favorable for cell proliferation by improving the scaffold biocompatibility. The improvement may be helpful for the extensive applications of PCL scaffold in heart valve and blood vessel tissue engineering.

Cell Adhesion↗

PubMed1997

Hematological aspects of biocompatibility--review article.

The development and improvement of medical devices and artificial organs is critically dependent on the realisation of the importance of the interactions between materials and body tissues. In this regard, the evaluation of biocompatibility assumes paramount importance. This paper reviews the hematological aspects of biocompatibility--the responses evoked by the material as well as the methods for their detection. The paper also mentions a few methods of improvement of material compatibility.

Animals↗

PubMedDate not supplied

Biocompatibility of poly (DL-lactide-co-glycolide) microspheres implanted into the brain.

The delivery of therapeutic molecules to the brain has been limited in part due to the presence of the blood-brain barrier. One potential solution is the implantation of biodegradable polymers with sustained release of drugs. Poly (DL-lactide-co-glycolide) (PLG) is a bioerodible polymer with a long and successful history of use as a suture material. More recently, PLG has been investigated for localized and sustained delivery of molecules into both peripheral sites and the brain. Despite its well-defined safety profile for parenteral applications, little information exists concerning the safety of PLG when implanted into the brain. To further characterize the biocompatibility of PLG in the brain, we examined the gliotic response following implants of PLG into the brains of rats. As a control, each animal received an injection of the suspension medium into the contralateral hemisphere. Following implantation, PLG was well tolerated. GFAP-positive astrocytes were observed throughout the cerebral cortex and striatum on both the implanted and control sides, with the reaction being greatest within the heavily myelinated fiber tracts of the corpus callosum. Quantitative analyses revealed that this reaction occurred within 1 h postsurgery, reached its peak at 1 week following surgery, and then decreased markedly by 1 month postsurgery. A minimal gliotic reaction was still present 1 year postsurgery but was localized to the needle tract. No differences in GFAP reactivity were seen between the polymer-implanted and control sides at any time point. Histological analysis determined that the majority of the PLG disappeared between 1 and 4 weeks. A set of parallel studies in which PLG samples were retrieved from the brain at various time points corroborated these findings and determined that the majority of PLG degraded within 2 weeks following implantation. Together, these results demonstrate that PLG is well tolerated following implantation into the CNS and that the astrocytic response to PLG is largely a consequence of the mechanical trauma that occurs during surgery. The biocompatibility of PLG implanted into the CNS provides further support for its use in a wide range of new therapeutic applications for sustained and localized drug delivery to the brain.

Animals↗

PubMed2004

BIOKID: randomized controlled trial comparing bicarbonate and lactate buffer in biocompatible peritoneal dialysis solutions in children [ISRCTN81137991].

BACKGROUND: Peritoneal dialysis (PD) is the preferred dialysis modality in children. Its major drawback is the limited technique survival due to infections and progressive ultrafiltration failure. Conventional PD solutions exert marked acute and chronic toxicity to local tissues. Prolonged exposure is associated with severe histopathological alterations including vasculopathy, neoangiogenesis, submesothelial fibrosis and a gradual loss of the mesothelial cell layer. Recently, more biocompatible PD solutions containing reduced amounts of toxic glucose degradation products (GDPs) and buffered at neutral pH have been introduced into clinical practice. These solutions contain lactate, bicarbonate or a combination of both as buffer substance. Increasing evidence from clinical trials in adults and children suggests that the new PD fluids may allow for better long-term preservation of peritoneal morphology and function. However, the relative importance of the buffer in neutral-pH, low-GDP fluids is still unclear. In vitro, lactate is cytotoxic and vasoactive at the concentrations used in PD fluids. The BIOKID trial is designed to clarify the clinical significance of the buffer choice in biocompatible PD fluids. METHODS/DESIGN: The objective of the study is to test the hypothesis that bicarbonate based PD solutions may allow for a better preservation of peritoneal transport characteristics in children than solutions containing lactate buffer. Secondary objectives are to assess any impact of the buffer system on acid-base status, peritoneal tissue integrity and the incidence and severity of peritonitis. After a run-in period of 2 months during which a targeted cohort of 60 patients is treated with a conventional, lactate buffered, acidic, GDP containing PD fluid, patients will be stratified according to residual renal function and type of phosphate binding medication and randomized to receive either the lactate-containing Balance solution or the bicarbonate-buffered Bicavera solution for a period of 10 months. Patients will be monitored by monthly physical and laboratory examinations. Peritoneal equilibration tests, 24-h dialysate and urine collections will be performed 4 times. Peritoneal biopsies will be obtained on occasion of intraabdominal surgery. Changes in small solute transport rates, markers of peritoneal tissue turnover in the effluent, acid-base status and peritonitis rates and severity will be analyzed.

Adolescent↗

PubMed2005

Calcium alginate gel as a biocompatible material for endovascular arteriovenous malformation embolization: six-month results in an animal model.

OBJECTIVE: We sought to expand our assessment of calcium alginate as an embolic agent in an animal model of a cerebral arteriovenous malformation (AVM). The objective of this study was to assess the long-term biocompatibility and stability of calcium alginate in AVM swine models that survived from 1 to 6 months. METHODS: The swine model included a carotid-jugular anastomosis to redirect flow to the rete mirabile (RM), thereby simulating flow to an AVM. Alginate and the reactive component, calcium chloride, were injected from double-lumen or concentric-tube microcatheters to form an occlusion of the RM feeding vessel and the inferior portion of the RM. RESULTS: Angiography and histology verified complete occlusion of the RM feeding vessel for up to 6 months in eight of nine swine. Blood flow remained open to the superior portion of the RM and the circle of Willis. No evidence of downstream calcium alginate gel was seen in the follow-up angiograms or the histological preparations of the circle of Willis. A minor bioactive response to the alginate gel was noted at 1 month, yet no degenerative or inflammatory response was seen. At 6 months, there was moderate fibrous tissue around the alginate, which further sealed off flow to the embolized areas of the RM. CONCLUSION: Over a period of 6 months, calcium alginate was an effective endovascular occlusion material that blocked blood flow to the inferior portion of the RM. The chronic AVM model verified the long-term stability and biocompatibility of calcium alginate.

Alginates↗

PubMed2005

[Electrochemical properties of biocompatible material hardness modifications on titanium and steel under mechanical loads].

Friction corrosion may appear between different implant components or between implant and hard tissue. The sliding micro movements induce fretting wear corrosion and have been recently reported as a cause of joint prostheses failure. A surface coating is desirable, that retains the mechanical properties of the substrate, offers good biocompatibility and improves the fretting corrosion resistance. In this study it could be demonstrated that tantalum and niobium coatings fulfill the requirements. On titanium substrates the coating decreases the abrasion against PMMA, an orthopedic relevant material. Furthermore, in the case of medical steel substrates the biocompatibility and the corrosion properties are improved. The better abrasion-resistance is minimizing the release of allergological critical particles like nickel and chromium.

Coated Materials, Biocompatible↗

PubMed1993

[Evaluation of the biocompatibility of implant materials with human bone marrow cell cultures].

A cell culture biocompatibility test for implant materials is described. For the first time, the human bone marrow cells that actually come into direct contact with the implanted biomaterial can be employed. The usefulness of this method is shown for materials which have long been used in the clinical situation (hydroxyapatite, commercially pure titanium and ultra-high molecular weight polyethylene). After two weeks in culture, light- and fluorescence-microscopic and SEM studies revealed significant differences in cell growth. Maximum compatibility was shown by the hydroxyapatite specimen. In the case of commercially pure titanium we found somewhat decreased biocompatibility. Polyethylene was associated with distinct signs of cytotoxicity. These results are compatible with those of animal experiments and clinical experience. Our system would thus appear to be a useful screening test for some implantation materials, and may help reduce the need for animal tests.

Biocompatible Materials↗

PubMed2003

[A new coating method for cemented femur shaft implants--biocompatibility, stability during sterlization and adhesive strength].

The main cause of aseptic loosening of cemented stems in total hip arthroplasty is the hydrolytic degradation of the metal-cement interface. In order to prevent this debonding a new multilayer method of coating the implant surface involving the use of a silica-/silane technique to create a durable adhesive bond between metal stem and bone cement has been developed. The biocompatibility of all the elements of the multilayer system was confirmed using a human osteoblast cell culture test. For sterilization purposes, gamma irradiation with a 25 kGy effective dose proved to be the method of choice. The proven biocompatibility and successful sterilization of the coated implants are the main prerequisites for in-vivo usage. On the technical side, the bonding effectiveness of the multilayer coating system was demonstrated by the tensile test, which revealed a significant improvement in the adhesive strength of the cement-metal bond under prolonged moist conditions similar to those met with in the human body.

Bone Cements↗

PubMed2005

Molecular determinants of biocompatibility.

The biocompatibility of medical implants dictates the fate of almost all medical devices. It is well established that medical devices trigger a variety of adverse tissue responses, such as inflammation, fibrosis, infection and thrombosis. However, the mechanisms involved in biomaterial-mediated tissue responses remain largely unknown. The lack of such knowledge hinders the development of biomaterials with better biocompatibility and safety. The aim of this review is to summarize our current understanding of the processes governing foreign body reactions to tissue-contact devices. Obviously, this information is urgently needed for assisting the rational design of materials or medical devices to minimize undesirable tissue reactions upon implantation and, in addition, to promote the wound healing process.

Biocompatible Materials↗

PubMed2006

Physico-chemical characterization and biocompatibility evaluation of hydroxyapatites.

The aim of this study was to evaluate the physico-chemical and biocompatibility characteristics of two different hydroxyapatites. Physical and chemical properties were analyzed using granulometric analysis, scanning electron microscopy (SEM), X-ray energy-dispersion (EDX), X-ray fuorescence (XRF) and X-ray diffraction (XRD). Biomaterials were implanted into the subcutaneous tissue on the dorsum of 36 Wistar rats, divided into the following groups: Group 1 - Gen-Ox (natural); Group 2 - HA-U (synthetic) and Group 3 - Control (Sham). After 15 and 30 days, 6 animals/period were sacrificed and the subcutaneous tissue was taken for histological and histometric analysis, giving consideration to inflammatory reaction and granule area. The granulometric test results showed a mean granule diameter of 161.6 microm (min = 19.0 microm; max = 498.0 microm) and 48.7 microm (min = 7.0 microm; max = 256.0 microm) for groups 1 and 2 respectively. Analysis with SEM demonstrated irregular and sharp-edge particles in group 1 (3332.8 +/- 274.3 microm(2)) and irregular and rounded particles in group 2 (1320.8 +/- 83.0 microm(2)) (P < 0.0001; Student's t test). EDX and XRF revealed calcium, carbon, oxygen, sodium and phosphorus in both groups. XRD indicated that both biomaterials were pure and crystalline. There was a statistically significant difference in granule area between the two groups after 15 days (P = 0.022; Student's t-test). After 15 days, an increased inflammatory response was seen in group 2 (P < 0.0001; ANOVA and Tukey's post hoc test) whereas it was more pronounced in group 1 after 30 days (P < 0.0001; ANOVA and Tukey's post hoc test). It was concluded that these biomaterials have similar physical, chemical and biocompatibility characteristics.

Analysis of Variance↗

PubMed2003

Biocompatibility of three-dimensional chondrocyte grafts in large tibial defects of rabbits.

OBJECTIVE: To evaluate biocompatibility and effects of implantation of 3-dimensional chondrocyte-agarose autografts in tibial defects in rabbits and to compare in vitro and in vivo chondrocyte-agarose constructs with respect to cell viability, differentiation, and matrix production. ANIMALS: 24 adult New Zealand White rabbits. PROCEDURE: Three-dimensional constructs with (grafted group) or without (control group) autogenous chondrocytes were implanted into tibial defects of rabbits and cultured in vitro. During an 8-week period, defects were evaluated radiographically, grossly, histologically, biochemically, and immunohistochemically. In vitro constructs were evaluated histologically, biochemically, and immunohistochemically. RESULTS: Tibial defects had significantly higher radiographic densitometry values at 4 and 6 weeks after implantation in grafted group rabbits, compared with control group rabbits. Number of observed centers of endochondral ossification was significantly greater in defects of grafted group rabbits, compared with control group rabbits. On day 14, glycosaminoglycan concentration was significantly higher in tibial defects of grafted group rabbits, compared to defects of control group rabbits or in vitro constructs. At weeks 2, 4, and 8, glycosaminoglycan concentrations were significantly lower in the in vitro control constructs, compared with other groups. Collagen type I was present in bone and bony callous in defects of grafted and control group rabbits. Collagen type II was identified in cartilaginous tissues of grafted and control group rabbits. Collagen type X was associated with hypertrophic chondrocytes. Only type II collagen was found in the in vitro chondrocyte constructs. CONCLUSIONS AND CLINICAL RELEVANCE: Chondrocyte-agarose grafts are biocompatible in large tibial defects and appear to provide a cell source for augmenting endochondral ossification.

Animals↗