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Metallic dental material biocompatibility in osteoblastlike cells: correlation with metal ion release.

Ions released from metallic dental materials used in orthodontic appliances could induce undesirable effects on cells and tissues. This study evaluates the biocompatibility of two of the most labile components of metallic dental alloys on osteoblastlike cells. The influence of protein and ions on metal dissolution properties is also investigated using different electrolyte solutions. Morphological alterations, cell growth, and differentiation of osteoblasts were assessed after exposure to pure metals (Ag, Cu, Pd, Au) and Ni-Ti alloy and correlated with the kinetics of elements released into the culture media. Results showed that Cu and Ag were the most cytotoxic elements and the other metals were biocompatible with the osteoblasts. The parameters of biocompatibility were correlated with the levels of ions detected into the culture media. Metal ions induced cell death through early mitosis arrest, apoptotic phenomena, and necrotic processes. Voltammograms showed that anions and proteins interfered in the corrosion process. Fetal bovine serum (FBS) strongly affected the electrochemical process, decreasing the oxidation rate of the metals. In conclusion, copper and silver ions showed a time-dependent low biocompatibility, which correlated with the concentration of released ions. The dissolution of the metallic materials was dependent on the composition of the simulated biological media.

Animals↗

Focal adhesion quantification - a new assay of material biocompatibility? Review.

The development of novel synthetic biomaterials is necessitated by the increasing demand for accelerated healing of tissues following surgical intervention. Strict testing of such materials is necessary before application. Currently, before any material can be marketed, approval by regulatory organisations such as the FDA is required. Presently, in vitro testing is performed as a prerequisite to in vivo evaluation. The in vitro techniques currently employed do not reflect the progress in our understanding of extra and intra-cellular processes, with far more sensitive in vitro evaluations now available. Obtaining quantifiable data is increasingly relevant to evaluating events occurring in vivo. Quantifying cell adhesion to surfaces provides some of this data as an initial assessment method. Major developments in this field are occurring but many investigators still use less than optimal methods for assessing biomaterials. The relevance of using cell adhesion assays to help determine biomaterial biocompatibility is reviewed. Additionally, current in vitro methods of evaluating biomaterials are discussed in the context of novel testing concepts developed by the authors.

Animals↗

Preliminary report on cell encapsulation in a hydrogel made of a biocompatible material, AN69, for the development of a bioartificial pancreas.

The occurrence of an inflammatory reaction represents the major obstacle to the development of any implantable system including micro and macroencapsulation. The purpose of this study was to describe an encapsulation method for cells using a membrane made of AN69, a copolymer of acrylonitrile which is considered as a reference in biocompatibility in the field of haemodialysis. The hydrogel of AN69 was obtained after a coagulation step at room temperature followed by a solvent/non-solvent (water) exchange phase. Microcapsules were obtained by co-extrusion of AN69 collodion and saline (with or without cells). The function of encapsulated cells was assessed in vitro, demonstrating cell survival after the microencapsulation procedure. These preliminary data are consistent with the potential interest for the development of the microencapsulation procedure aimed at realising a bioartificial pancreas.

Acrylic Resins↗

[Sterilization of biocompatible materials: which method to choose?].

Sterilization of biomaterials, in hospitals, must be considered as the re-sterilization (and not reuse) of devices: prostheses, implants, catheters... This practice is not allowed, according to the circular of may 14 th, 1986; however it is a necessity in various cases. It must be realised with an extreme care, after evaluation of the different methods of sterilization: steam, dry-heat, ethylene oxide, formaldehyde or ionizing radiations and of their effects on the behaviour of the biomaterial.

Biocompatible Materials↗

[The evolution of viscerosynthesis and its methodological implications: from manual sutures to biocompatible materials].

This study aims to provide an overview of the different suturing techniques used in surgery, paying special attention to cancer surgery which, compared to general surgery, has precise requirements correlated to the type of patient and form of exeresis used, which often tends to be extensive. In this panorama which manages to avoid any form of superficiality, the discussion ranges from mechanical automatic suturing devices to recent advances in so-called biological repair, without omitting an analysis of the gold standard of tissue repair, namely suture thread, which appears to have been overwhelmed by the enthusiasm for technological innovation, even in the literature.

Biocompatible Materials↗

Cellular micropatterns on biocompatible materials.

We present a method to produce micropatterns of cells on tissue culture substrates. A network of deep elastomeric microchannels defining the desired pattern is sealed onto the surface of interest, and a protein template is created by injecting sub-milliliter quantities of protein solution into the microchannels. Protein adsorbs only on the areas that were exposed to the microflow. After the channels are flushed and the elastomer is removed, cells attach only on the protein template. Micropatterns of collagen or fibronectin were used to selectively adhere cells on various biomedical polymers and on heterogeneous or microtextured substrates. Since the bare substrate areas remain apt for seeding other, more adhesive cell types such as fibroblasts, we were able to create micropatterned co-cultures. Our method allows for inexpensive patterning of a rich assortment of biomolecules, cells, and surfaces under physiological conditions.

Animals↗

[Detection of cytotoxicity of biocompatible materials in MRC-5, HeLa, and RC-IAL cell lines].

The sensitivity of diploid and heteroploid cell lines for detection of cytotoxicity using the agar diffusion method on cell culture, was tested with ascorbic acid solution of different concentrations. A total of 562 samples of 21 various materials were tested. The heteroploid cell line, RC-IAL, showed in relation to the MRC-5 and HeLa cell lines, greater sensitivity because it showed the presence of cytotoxic effect with the lowest concentration used (10 and 25 micrograms/ml) of ascorbic acid and showed greater diameter of cytotoxic halo in 15 samples and equal diameter in 16 of the 43 positive samples (7.6%). Out of 43 positive samples, the MRC-5 line did not show cytotoxicity in 3 sponge samples and 1 of acrylic resin. The PVC (polyvinylchloride) and polyethylene rarely showed positivity, while, the plastic, cotton and acrylic resin demonstrated cytotoxicity in about 5% of samples. We thus suggest the use of the RC-IAL and HeLa cell lines for continuation of this type of analysis at Adolfo Lutz Institute.

Animals↗

[Comparison of methods to test the "in vitro" cytotoxicity of biocompatible materials].

OBJECTIVE: A comparison of the sensitivity of the agar diffusion method with that of extraction using cell-lines RC-IAL (fibroblastic of rabbit kidney) and HeLa (epithelial carcinoma cells from the cervix uteri of the human uterus), in the in vitro evaluation of materials of medical and hospital. MATERIALS AND METHODS: Fifteen samples chosen at random, from among the already known positives and negatives in our stock, were tested and identified as cotton, form, latex, cellulose and acrylic. Besides the samples mentioned, many SDS (GIbco) concentrations were tested experimentally in RC-IAL and HeLa cell cultures. RESULTS: Of the 50 samples tested, 44(88%) were positive by both methods. However, when the SDS were compared by using the two methods, positive results were noted in the concentrations of from 0.5 to 0.05 microgram/ml in the agar diffusion ans extraction methods. A cytotoxic effect was only noted in the concentrations of up to 0.25 microgram/ml. CONCLUSION: When the SDS was used, differences favorable to the agar diffusion method were observed in the two cell lines, in two concentrations; that is, the sensitivity of this method was quantitatively greater on inspection than that of the extraction method, as well as being the simpler method to use.

Animals↗

Uterus-sparing vaginal surgery of genitourinary prolapse employing biocompatible material.

OBJECTIVE: The study presents an original uterus sparing technique for transvaginal repair of total genitourinary prolapse. The technique employs a synthetic mesh of mixed polypropylene and 910 polyglactin fibers. METHODS: The prosthesis creates a support for the cystocele, the cervix and the enterocele. It has four anchoring sites: two at the rear in the sacrospinous ligaments and two at the front in the arcus tendineous of the levator ani muscle. Between February 2001 and December 2004, 24 patients (mean age 66.9 years), presenting symptoms of uterine prolapse, cystocele and enterocele (POP-Q stage III-IV Aa associated to II-III-IV C), were treated with our procedure. Pre- and postoperative parameters were evaluated statistically. RESULTS: No patient had any serious complications. The mean follow-up was 31.1 months (range 6-52). 19 patients (79.1%) have shown excellent results and have been completely cured. In 5 other cases (20.8%), the cystocele was completely cured and there was a significant improvement in the hysterocele and the enterocele. One patient required surgical treatment for postoperative stress incontinence. Statistical analysis of data regarding the pre- and postoperative prolapse stage demonstrated a high degree of objective cure rates (p < 0.0001). CONCLUSIONS: While hysterectomy remains the habitual treatment for severe uterine prolapse, our technique provides a promising alternative solution. It is also significant that there were no complications of erosion or infection associated with the prosthesis.

Aged↗

Dendritic polyglycerol: a new versatile biocompatible-material.

Polyglycerol represents the first hyperbranched polymer that can be prepared in a controlled synthesis. It is characterized by the combination of a stable, biocompatible polyether scaffold, high-end group functionality and a compact, well-defined dendrimer-like architecture. These characteristics can be used to generate new materials properties and for biomedical applications to molecularly amplify or multiply effects or to create extremely high local concentrations of drugs, molecular labels, or probe moieties. Therefore, dendritic polyglycerols are expected to lead to new strategies for 'molecular medicine'. In this brief summary, the current state of the art in polyglycerol research is given, focusing on applications in life sciences.

Biocompatible Materials↗

[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↗

Titanium and glass-ionomer cement as ossicular replacement materials: biocompatibility results after implantation in the rabbit.

The middle ear poses unique challenges when finding suitable materials for ossicular reconstruction, primarily because of its link to the external environment via the eustachian tube, which leads to a greater potential for exposure to infectious agents. In this animal study, the biocompatibilities of titanium and glass-ionomer cement were assessed in the middle ear of the rabbit after being implanted as total ossicular replacement prostheses (TORPs) or as free pins. Animals were sacrificed after 28, 84, 168, 336, or 504 days or 2 years, and a cutting saw technique was used to prepare slides for light microscopy. Slides were examined for mucosal coverage and any sign of foreign body reaction. Both materials showed good acceptance in the middle ear. After 28 days, the TORPs were covered by middle ear mucosa. As expected, it took a longer time (up to 504 days) to cover the free implants. An interesting finding was the growth of new bone on both the surface of the titanium implants and the glass-ionomer prostheses. The results of this animal study indicate that both titanium and glass-ionomer cement are favorable materials for ossicular replacement prostheses.

Animals↗

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↗