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Biocompatible
Terms modified by Biocompatible Selected AbstractsBiocompatible, Luminescent Silver@Phenol Formaldehyde Resin Core/Shell Nanospheres: Large-Scale Synthesis and Application for In Vivo Bioimaging,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2008Shi-Rui Guo Abstract Biocompatible and green luminescent monodisperse silver/phenol formaldehyde resin core/shell spheres with controllable sizes, in the range of 180 to 1000 nm, and interesting architectures (centric, eccentric, and coenocytic core/shell spheres) have been synthesized by a facile one-step hydrothermal approach. These spheres can be used as bioimaging labels for human lung cancer H1299 cells. The results demonstrate that the nanoparticles can be internalized into cells and exhibit no cytotoxic effects, showing that such novel biocompatible core/shell structures can potentially be used as in vivo bioimaging labels. This facile one-pot polymerization and encapsulation technique may provide a useful tool to synthesize other core/shell particles that have potential application in biotechnology. [source] Biocompatibility evaluation of alendronate paste in rat's subcutaneous tissueDENTAL TRAUMATOLOGY, Issue 2 2009Graziela Garrido Mori Therefore, this study aimed to investigate the biocompatibility of experimental alendronate paste in subcutaneous tissue of rats, for utilization in teeth susceptible to root resorption. The study was conducted on 15 male rats, weighing ,180,200 grams. The rats' dorsal regions were submitted to one incision on the median region and, laterally to the incision, the subcutaneous tissue was raised and gently dissected for introduction of two tubes, in each rat. The tubes were sealed at one end with gutta-percha and taken as control. The tubes were filled with experimental alendronate paste. The animals were killed at 7, 15 and 45 days after surgery and the specimens were processed in laboratory. The histological sections were stained with hematoxylin-eosin and analyzed by light microscopy. Scores were assigned to the inflammatory process and statistically compared by the Tukey test (P < 0.05). Alendronate paste promoted severe inflammation process at 7 days, with statistically significant difference compared to the control (P < 0.05%). However, at 15 days, there was a regression of inflammation and the presence of connective tissue with collagen fibers, fibroblasts and blood vessels was observed. After 45 days, it was observed the presence of well-organized connective tissue, with collagen fibers and fibroblasts, and few inflammatory cells. No statistical difference was observed between the control and experimental paste at 15 and 45 days. The experimental alendronate paste was considered biocompatible with subcutaneous tissue of rat. [source] Cationic and anionic lipid-based nanoparticles in CEC for protein separationELECTROPHORESIS, Issue 11 2010Christian Nilsson Abstract The development of new separation techniques is an important task in protein science. Herein, we describe how anionic and cationic lipid-based liquid crystalline nanoparticles can be used for protein separation. The potential of the suggested separation methods is demonstrated on green fluorescent protein (GFP) samples for future use on more complex samples. Three different CEC-LIF approaches for protein separation are described. (i) GFP and GFP N212Y, which are equally charged, were separated with high resolution by using anionic nanoparticles suspended in the electrolyte and adsorbed to the capillary wall. (ii) High efficiency (800,000 plates/m) and peak capacity were demonstrated separating GFP samples from Escherichia coli with cationic nanoparticles suspended in the electrolyte and adsorbed to the capillary wall. (iii) Three single amino-acid-substituted GFP variants were separated with high resolution using an approach based on a physical attached double-layer coating of cationic and anionic nanoparticles combined with anionic lipid nanoparticles suspended in the electrolyte. The soft and porous lipid-based nanoparticles were synthesized by a one-step procedure based on the self-assembly of lipids, and were biocompatible with a large surface-to-volume ratio. The methodology is still under development and the optimization of the nanoparticle chemistry and separation conditions can further improve the separation system. In contrast to conventional LC, a new interaction phase is introduced for every analysis, which minimizes carry-over and time-consuming column regeneration. [source] Fabrication and Evaluation of Chitin-Based Nerve Guidance Conduits Used to Promote Peripheral Nerve Regeneration,ADVANCED ENGINEERING MATERIALS, Issue 11 2009Yumin Yang Chitin product was prepared from the chitosan counterpart and both were found to be equally biocompatible with cultured Schwann cells. Chitin- and chitosan-based nerve guidance conduits (NGCs) were surgically implanted to bridge 10-mm-long neural defects in rat sciatic nerves. The regenerative outcome provided positive evidence that chitin- and chitosan-based NGCs produce the similar beneficial effects on peripheral nerve regeneration. [source] Physical and Biological Properties of a Novel Hydrogel Composite Based on Oxidized Alginate, Gelatin and Tricalcium Phosphate for Bone Tissue Engineering,ADVANCED ENGINEERING MATERIALS, Issue 12 2007K. Cai A novel hydrogel composite is reported in this study, which was derived from oxidized alginate, gelatin and tricalcium phosphate (TCP). The physical and biological properties of these hydrogel composites prepared with oxidized sodium alginate with different oxidation degrees were investigated. The drug delivery potential of this hydrogel composite as a carrier was evaluated by using Vitamin B2 as a model drug as well. An in vitro investigation with encapsulation of osteoblast revealed that these composites were biocompatible. This hydrogel composite presented here may be utilized for the fabrication of potential injectable systems for tissue engineering, drug delivery and other medical applications. [source] Silica-Coated Manganese Oxide Nanoparticles as a Platform for Targeted Magnetic Resonance and Fluorescence Imaging of Cancer CellsADVANCED FUNCTIONAL MATERIALS, Issue 11 2010Hong Yang Abstract Monodisperse silica-coated manganese oxide nanoparticles (NPs) with a diameter of ,35,nm are synthesized and are aminated through silanization. The amine-functionalized core,shell NPs enable the covalent conjugation of a fluorescent dye, Rhodamine B isothiocyanate (RBITC), and folate (FA) onto their surface. The formed Mn3O4@SiO2(RBITC),FA core,shell nanocomposites are water-dispersible, stable, and biocompatible when the Mn concentration is below 50,µg mL,1 as confirmed by a cytotoxicity assay. Relaxivity measurements show that the core,shell NPs have a T1 relaxivity (r1) of 0.50,mM,1,s,1 on the 0.5 T scanner and 0.47,mM,1,s,1 on the 3.0 T scanner, suggesting the possibility of using the particles as a T1 contrast agent. Combined flow cytometry, confocal microscopy, and magnetic resonance imaging studies show that the Mn3O4@SiO2(RBITC),FA nanocomposites can specifically target cancer cells overexpressing FA receptors (FARs). Findings from this study suggest that the silica-coated Mn3O4 core,shell NPs could be used as a platform for bimodal imaging (both magnetic resonance and fluorescence) in various biological systems. [source] Flexible Silk,Inorganic Nanocomposites: From Transparent to Highly ReflectiveADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Eugenia Kharlampieva Abstract A novel type of all-natural, biocompatible, and very robust nanoscale free-standing biohybrids are reported. They are obtained by integrating a silk fibroin matrix with functional inorganic nanoplatelets using a spin-assisted layer-by-layer assembly. The organized assembly of the silk fibroin with clay (montmorillonite) nanosheets results in highly transparent nanoscale films with significantly enhanced mechanical properties, including strength, toughness, and elastic modulus, as compared to those for the pristine silk nanomaterials. Moreover, replacing clay nanoplatelets with a highly reflective Langmuir monolayer of densely packed silver nanoplates causes a similar enhancement of the mechanical properties, but in contrast to the materials above, highly reflective, mirror-like, nanoscale flexible films are created. This strategy offers a new perspective for the fabrication of robust all-natural flexible nanocomposites with exceptional mechanical properties important for biomedical applications, such as reinforced tissue engineering. On the other hand, the ability to convert silk-based nanoscale films into mirror-like biocompatible flexible films can be intriguing for prospective photonics and optical exploitation of these nanobiohybrids. [source] Cell Imaging: (Generic Strategy of Preparing Fluorescent Conjugated-Polymer-Loaded Poly(DL -lactide- co -Glycolide) Nanoparticles for Targeted Cell Imaging) Adv.ADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Funct. A generic strategy for the fabrication of highly fluorescent poly(DL -lactide- co -glycolide) nanoparticles loaded with conjugated polymers is reported by B. Liu et al. This method may serve to produce a new generation of biocompatible, surface-functionalizable probes for targeted cancer cell imaging and diagnostics, as described on page 3535. [source] Generic Strategy of Preparing Fluorescent Conjugated-Polymer-Loaded Poly(DL -lactide- co -Glycolide) Nanoparticles for Targeted Cell ImagingADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Kai Li Abstract A general strategy for the preparation of highly fluorescent poly(DL-lactide- co -glycolide) (PLGA) nanoparticles (NPs) loaded with conjugated polymers (CPs) is reported. The process involves encapsulation of organic-soluble CPs with PLGA using a modified solvent extraction/evaporation technique. The obtained NPs are stable in aqueous media with biocompatible and functionalizable surfaces. In addition, fluorescent properties of the CP-loaded PLGA NPs (CPL NPs) could be fine-tuned by loading different types of CPs into the PLGA matrix. Four types of CPL NPs are prepared with a volume-average hydrodynamic diameter ranging from 243 to 272,nm. The application of CPL NPs for bio-imaging is demonstrated through incubation with MCF-7 breast cancer cells. Confocal laser scanning microscopy studies reveal that the CPL NPs are internalized in cytoplasm around the nuclei with intense fluorescence. After conjugation with folic acid, cellular uptake of the surface-functionalized CPL NPs is greatly enhanced via receptor-mediated endocytosis by MCF-7 breast cancer cells, as compared to that for NIH/3T3 fibroblast cells, which indicates a selective targeting effect of the folate-functionalized CPL NPs in cellular imaging. The merits of CPL NPs, such as low cytotoxicity, high fluorescence, good photostability, and feasible surface functionalization, will inspire extensive study of CPL NPs as a new generation of probes for specific biological imaging and detection. [source] Adhesive, Flexible, and Robust Polysaccharide Nanosheets Integrated for Tissue-Defect RepairADVANCED FUNCTIONAL MATERIALS, Issue 16 2009Toshinori Fujie Abstract Recent developments in nanotechnology have led to a method for producing free-standing polymer nanosheets as a macromolecular organization. Compared with bulk films, the large aspect ratio of such nanosheets leads to unique physical properties, such as transparency, noncovalent adhesion, and high flexibility. Here, a biomedical application of polymer nanosheets consisting of biocompatible and biodegradable polysaccharides is reported. Micro-scratch and bulge tests indicate that the nanosheets with a thickness of tens of nanometers have sufficient physical adhesiveness and mechanical strength for clinical use. A nanosheet of 75,nm thickness, a critical load of 9.1,×,104,N m,1, and an elastic modulus of 9.6,GPa is used for the minimally invasive repair of a visceral pleural defect in beagle dogs without any pleural adhesion caused by wound repair. For the first time, clinical benefits of sheet-type nano-biomaterials based on molecular organization are demonstrated, suggesting that novel therapeutic tools for overlapping tissue wounds will be possible without the need for conventional surgical interventions. [source] A Smart Nanoprobe Based On Fluorescence-Quenching PEGylated Nanogels Containing Gold Nanoparticles for Monitoring the Response to Cancer TherapyADVANCED FUNCTIONAL MATERIALS, Issue 6 2009Motoi Oishi Abstract A biocompatible, caspase-3-responsive, and fluorescence-quenching smart apoptosis nanoprobe based on a PEGylated nanogel that contains gold nanoparticles (GNPs) (fluorescence quenchers) in the cross-linked polyamine gel core and fluorescein isothiocyanate (FITC)-labeled DEVD peptides at the tethered PEG chain ends is prepared for monitoring the cancer response to therapy. FITC,DEVD,nanogel,GNP shows very little fluorescence in the absence of activated caspase-3 (normal cells) through the fluorescence resonance energy transfer (FRET) process between the GNPs and the FITC molecules, while pronounced fluorescence signals are observed in apoptotic cells because of the cleavage of the DEVD peptide by activated caspase-3 present in the cells, which results in the release of FITC molecules. Thus, remarkable quenching and dequenching of fluorescence signals in response to activated caspase-3 is observed. Apoptotic cells are detected in human hepatocyte (HuH-7) multicellular tumor spheroids (MCTSs), a commonly used three-dimensional in vitro model mimicking the in vivo biology of tumors, as early as one day post-treatment with staurosporine, an apoptosis-inducing agent; while growth inhibition (i.e., change in size) of the HuH-7 MCTSs is only observed after a delay of three days (i.e., on day 4). This demonstrates the effectiveness of the FITC,DEVD,nanogel,GNP probe as a smart nanoprobe for real-time monitoring as well as a more rapid assessment of the early response to cancer therapy. [source] Acute Postdialysis Changes in Plasma ICAM-1 and IL-1 Levels in Hemodialysis PatientsHEMODIALYSIS INTERNATIONAL, Issue 1 2003S EL-Hefeni Fifty subjects: 20 controls and 30 hemodialysis patients were included in the study. The acute changes in plasma ICAM-1 and IL-1, levels immediately after dialysis were evaluated using two types of membranes and two types of dialysate. The predialysis ICAM-1 level in the whole patients was significantly higher than controls, while that of IL-1, was significantly lower. The postdialysis ICAM-1 showed insignificant higher level than the predialysis one, while that of IL-1, showed significant higher level than both the predialysis and control levels. Both postdialysis ICAM-1 and IL-1, levels in patients using cuprophane membrane (bioincompatible) showed insignificant higher levels than in those using polysulfone one (biocompatible). The percent increase in ICAM-1 level did not significantly differ in these two subgroups, while the percent increase in IL-1, level showed significantly higher value in those using bioincompatible membrane (108%) than that in those using biocompatible membrane (44%). No significant difference in the levels of either ICAM-1 or IL-1, were found between patients using acetate and bicarbonate dialysate. Conclusion: the bioincompatibility of the membrane is the important factor in the occurrence of the acute reaction during hemodialysis. [source] Cytotoxicity of substances leached or dissolved from pulp capping materialsINTERNATIONAL ENDODONTIC JOURNAL, Issue 8 2005B. N. Cavalcanti Abstract Aim, To evaluate the cytotoxic effects of substances leached or dissolved from pulp capping materials on human pulp fibroblasts. Methodology, The substances were applied to cell cultures in conditioned media. The experimental groups were: GI (control; n = 24) , cultures treated with fresh medium; GII (n = 24) , cultures treated with calcium hydroxide cement; GIII (n = 24) , cultures treated with adhesive resin and GIV (n = 24) , cultures treated with 37% orthophosphoric acid. The media were conditioned by placing the crude materials in contact with fresh culture medium for 1 h. The cytotoxicity analysis was performed using the Trypan blue dye exclusion assay at times of 0, 6, 12 and 24 h for cell viability assay, and at 1, 3, 5 and 7 days for survival assay. Data were treated by anova (P < 0.05) and Tukey's test (P < 0.05). Results, GI and II presented similar cell viability and cell growth. GIII and IV exhibited statistically significant lower percentages of cell viability: GIV only at the 0 h experimental time, whereas in GIII this viability markedly diminished reaching values of 10% by 12 h. Cell growth was impaired only in cultures of GIII. Conclusions, Substances dissolved from the adhesive system tested were cytotoxic for human dental pulp fibroblasts in culture, whilst substances leached from calcium hydroxide were biocompatible. [source] A comparative histological evaluation of the biocompatibility of materials used in apical surgeryINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2004C. J. A. Sousa Abstract Aim, To evaluate the biological properties of a variety of materials that could be used in apical surgery. Methodology, The intraosseous implant technique recommended by the FDI (1980) and ADA (1982) was used to test the following materials: zinc oxide-eugenol (ZOE), mineral trioxide aggregate (MTA), and Z-100 light-cured composite resin. Thirty guinea-pigs, 10 for each material, divided into experimental periods of 4 and 12 weeks, received one implant on each side of the lower jaw symphysis. The connective tissue response alongside the lateral wall outside the cup served as a negative control for the technique. At the end of the observation periods, the animals were killed and the specimens prepared for routine histological examination to evaluate their biocompatibility. Results, The reaction of the tissue to the materials diminished with time. The ZOE cement was highly toxic during the 4-week experimental period, but this profile changed significantly after 12 weeks, when it showed biocompatible characteristics. MTA and Z-100 showed biocompatibility in this test model at both time periods. Conclusions, MTA and Z-100 composite were biocompatible at 4 and 12 weeks in this experimental model. [source] Biomedical Materials: Nanoporous Biodegradable Elastomers (Adv. Mater.ADVANCED MATERIALS, Issue 2 20092/2009) The mechanical properties and degradation rate of elastomers can be tailored with nanoporosity. The elastomers described in this study by Guillermo Ameer and co-workers (p. 188) are based on citric acid and are biocompatible. The nanopores also facilitate the entrapment and slow release of macromolecular therapeutics. The inside cover depicts the nano- and microarchitecture of the elastomer prior to pore collapse. [source] Cell Proliferation of Human Fibroblasts on Alumina and Hydroxyapatite-Based Ceramics with Different Surface Treatments,INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 2 2010Juliana Marchi Biocompatibility is an important characteristic of dental implant material, and in vitro tests are required to elucidate the interaction between these materials and human tissues. Cell proliferation assays were done with fibroblasts plated on the surface of alumina and hydroxyapatite sintered samples, each with a different surface treatment (sintered, rectified, or polished). After 1, 2, and three days, the samples were prepared for scanning electron microscopy observations. The data were compared by analysis of variance followed by Tukey's test. It was concluded that neither the hydroxyapatite or alumina substrate is cytotoxic, and hydroxyapatite is more biocompatible than alumina. [source] Biodegradable Xylitol-Based Polymers,ADVANCED MATERIALS, Issue 10 2008Joost P. Bruggeman Synthetic polymers composed of metabolites endogenous to the mammalian organism are designed. The design is based on the monomer xylitol, which possesses a wide range of physical properties that are biologically relevant. Xylitol-based hydrogels and elastomers are biocompatible in vitro and in vivo, compared to the prevalent synthetic polymer poly(L-lactic- co - glycolic acid) (PLGA). It furthermore provides a platform to tune mechanical properties, degradation profiles, and cell attachment. [source] Gold Nanocages for Biomedical Applications,ADVANCED MATERIALS, Issue 20 2007E. Skrabalak Abstract Nanostructured materials provide a promising platform for early cancer detection and treatment. Here we highlight recent advances in the synthesis and use of Au nanocages for such biomedical applications. Gold nanocages represent a novel class of nanostructures, which can be prepared via a remarkably simple route based on the galvanic replacement reaction between Ag nanocubes and HAuCl4. The Au nanocages have a tunable surface plasmon resonance peak that extends into the near-infrared, where the optical attenuation caused by blood and soft tissue is essentially negligible. They are also biocompatible and present a well-established surface for easy functionalization. We have tailored the scattering and absorption cross-sections of Au nanocages for use in optical coherence tomography and photothermal treatment, respectively. Our preliminary studies show greatly improved spectroscopic image contrast for tissue phantoms containing Au nanocages. Our most recent results also demonstrate the photothermal destruction of breast cancer cells in vitro by using immuno-targeted Au nanocages as an effective photo-thermal transducer. These experiments suggest that Au nanocages may be a new class of nanometer-sized agents for cancer diagnosis and therapy. [source] Magnetite-Loaded Polymeric Micelles as Ultrasensitive Magnetic-Resonance Probes,ADVANCED MATERIALS, Issue 16 2005H. Ai Increased contrast in magnetic resonance imaging (MRI) is accomplished using polymeric micelles loaded with superparamagnetic iron oxide (SPIO) nanoparticles encapsulated in biocompatible, biodegradable poly(,-caprolactone)- b -poly(ethylene glycol) (PCL- b -PEG) copolymers (see Figure). The loaded micelles show significantly improved T2 relaxivities and remarkable MRI detection sensitivity. [source] Oxycellulose: Significant characteristics in relation to its pharmaceutical and medical applicationsADVANCES IN POLYMER TECHNOLOGY, Issue 3 2009Bajerová Martina Abstract As a biomaterial, cellulose can be converted into a wide range of derivatives with desired properties for a variety of medical, biomedical, and pharmaceutical applications. The oxidation of cellulose yields oxidized cellulose (OC, oxycellulose, 6-carboxycellulose). OC represents an important class of biocompatible and bioresorbable polymers. In vivo bioabsorption of OC occurs via chemical depolymerization and enzymatic hydrolysis. Despite the fact OC is well established as a hemostatic agent and is widely used in a clinical practice, it still attracts a great interest and its new applications, especially pharmaceutical, are investigated. The present review is focused on characterization of OC's physical and chemical properties. Its synthesis and mechanisms involved in its in vivo and in vitro biodegradation are discussed. Medical and biomedical applications of OC are summarized, and especially its hemostatic, enterosorbent, and wound-healing properties are described. In addition to these applications, OC could be used as a pharmaceutical excipient in solid (e.g., tablets, microparticles), semisolid (e.g., gels), as well as liquid (e.g., suspensions) dosage forms. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:199,208, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20161 [source] Cryostructuring of polymer systems.JOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008XXIX. Abstract Supermacroporous (spongy) agarose-based cryogels were prepared by a two-step freezing procedure (freezing at ,30°C followed by incubation at a warmer subzero temperature) and subsequent thawing. The cryogels were formed as cylinders in plastic syringes and as platelike samples in flat metal molds. The characteristic feature of the gel matrices thus obtained was their heterogeneous spongelike morphology with a system of interconnected gross (50,250-,m and larger) pores. The influence of the cryogenic processing regimes on the properties and porous morphology of such agarose cryogels was explored by flow-through analysis, optical microscopy, thermometry, and high-sensitivity differential scanning calorimetry. These biocompatible, spongelike matrices were used as three-dimensional scaffolds for culturing insulin-producing rat insulinoma cells self-assembled in multicellular spherical aggregates (pseudoislets). The cell morphology and functional activity of such pseudoislets indicate that supermacroporous agarose-based cryogels can be useful as a tool for engineering biohybrid insulin-producing tissue. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Structure and mechanical properties of cellulose derivatives/soy protein isolate blendsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Ziyan Zhou Abstract Biodegradable and biocompatible composites based on soy protein isolate (SPI) and various cellulose derivatives have been prepared, and the dependence of structures and mechanical properties on the content and species of cellulose derivatives for the composites were investigated by X-ray diffraction, differential scanning calorimetry, scanning electron microscope, and tensile test. The selected cellulose derivatives, such as methyl cellulose (MC), hydroxyethyl cellulose (HEC), and hydroxypropyl cellulose, were miscible with SPI when the content of cellulose derivatives was low, and then the isolated crystalline domains, shown as the structures of network and great aggregate, formed with an increase of cellulose derivative content. The miscible blends could produce the higher strength, and even result in the simultaneous enhancement of strength and elongation for the HEC/SPI and MC/SPI blends. Meanwhile, the moderate content of great MC domains also reinforced the materials. However, the damage of original ordered structure in SPI gave the decreased modulus. Since all the components, i.e., cellulose derivatives and soy protein, are biocompatible, the resultant composites are not only used as environment-friendly material, but the biomedical application can be expected, especially for the tissue engineering scaffold. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Mechanochemical modification of silica with poly(1-vinyl-2-pyrrolidone) by grinding in a stirred media millJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007Voronov A. Abstract The polymerization of 1-vinyl-2-pyrrolidone (VP) mechanochemically initiated by grinding silica was investigated in a wet stirred media mill. The polymerization itself proceeds from the silica grinding without any additional initiator. We have found that the amount of grafted polymer increases with an increase in total ground silica surface. The suspension of polymer-modified silica nanoparticles showed high colloidal stability in water because of the appearance of grafted hydrophilic PVP on the surface during the reactive grinding. Because the nanoparticles SiO2 - graft -PVP are biocompatible, the developed polymer nanocomposite material can be of particular interest for the performance of membranes and for the fabrication of biocompatible hydrogels with enhanced mechanical properties and porosity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3708,3714, 2007 [source] Rietveld structure and in vitro analysis on the influence of magnesium in biphasic (hydroxyapatite and ,-tricalcium phosphate) mixturesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2009S. Kannan Abstract The structure of two different Mg-substituted biphasic (HAP and ,-TCP) mixtures along with the biphasic mixtures without substituted Mg2+ was investigated using Rietveld refinement technique. The substituted Mg2+ was found in the ,-TCP phase and its influence on the composition has led to an increase in HAP content of Mg-containing biphasic mixtures when compared with the HAP content detected in pure biphasic mixtures. The refined structural parameters of Ca10(PO4)6(OH)2 and ,-Ca3(PO4)2 confirmed that all the investigated compositions have crystallized in the corresponding hexagonal (space group P63/m) and rhombohedral (space group R3c) structures. The substitution of lower sized magnesium was found preferentially incorporated at the sixfold-coordinated Ca (5) site of ,-TCP, which is due to the strong Ca (5)·O interaction among all the five different Ca sites of ,-Ca3(PO4)2. The in vitro tests using primary culture of osteoblasts showed that all the tested samples are biocompatible and promising materials for in vivo studies. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Controlling the biodegradation rate of magnesium using biomimetic apatite coatingJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2009Yajing Zhang Abstract Magnesium is light, biocompatible and has similar mechanical properties to natural bone, so it has the potential to be used as a biodegradable material for orthopedic applications. However, pure magnesium severely corrodes in a physiological environment, which may result in fracture prior to substantial tissue healing. Hydroxyapatite (HA) is the main composition of natural bone. It has excellent bioactivity and osteoconductivity. In this study, HA coating with two different thicknesses was applied onto the surface of pure magnesium substrates using a biomimetic technique. The corrosion rate of the surface-treated substrates was tested. It was found that both types of coatings substantially slowed down the corrosion of the substrate, and the dual coating was more effective than the single coating in hindering the degradation of the substrate. Thus, the corrosion rate of magnesium implants can be closely tailored by adjusting apatite coating thickness and thereby monitoring the release of magnesium ions into the body. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Influences of passivating elements on the corrosion and biocompatibility of super stainless steelsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008Young-Ran Yoo Abstract Biometals need high corrosion resistance since metallic implants in the body should be biocompatible and metal ion release should be minimized. In this work, we designed three kinds of super stainless steel and adjusted the alloying elements to obtain different microstructures. Super stainless steels contain larger amounts of Cr, Mo, W, and N than commercial alloys. These elements play a very important role in localized corrosion and, thus, their effects can be represented by the "pitting resistance equivalent number (PREN)." This work focused on the behavior which can arise when the bare surface of an implant in the body is exposed during walking, heavy exercise, and so on. Among the experimental alloys examined herein, Alloy Al and 316L stainless steels were mildly cytotoxic, whereas the other super austenitic, duplex, and ferritic stainless steels were noncytotoxic. This behavior is primarily related to the passive current and pitting resistance of the alloys. When the PREN value was increased, the passivation behavior in simulated body solution was totally different from that in acidic chloride solution and, thus, the Cr2O3/Cr(OH)3 and [Metal oxide]/[Metal + Metal oxide] ratios of the passive film in the simulated body solution were larger than those in acidic chloride solution. Also, the critical current density in simulated body solution increased and, thus, active dissolution may induce metal ion release into the body when the PREN value and Ni content are increased. This behavior was closely related to the presence of EDTA in the simulated body solution. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] TC -tuned biocompatible suspension of La0.73Sr0.27MnO3 for magnetic hyperthermiaJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008N. K. Prasad Abstract La1,xSrxMnO3, a ferromagnet with high magnetization and Curie temperature TC below 70°C, enables its use for magnetic hyperthermia treatment of cancer with a possibility of in vivo temperature control. We found that La0.73Sr0.27MnO3 particles of size range 20,100 nm showed saturation magnetization around 38 emu/g at 20 kOe and a TC value of 45°C. Aqueous suspension of these nanoparticles was prepared using a polymer, acrypol 934, and the biocompatibility of the suspension was examined using HeLa cells. A good heating ability of the magnetic suspension was obtained in the presence of AC magnetic field, and it was found to increase with the amplitude of field. The suspension having concentration of 0.66 mg/mL (e.g., 0.66 mg of nanoparticles with acropyl per milliliter of culture media) was observed to be biocompatible even after 96 h of treatment, as estimated by sulforhodamine B and trypan blue dye exclusion assays. Further, the treatment with the aforementioned concentration did not alter the microtubule cytoskeleton or the nucleus of the cells. However, the bare particles (concentration of 0.66 mg of nanoparticles per milliliter of culture media, but without acropyl) decreased the viability of cell significantly. Our in vitro studies suggest that the suspension (concentration of 0.66 mg/mL) may further be analyzed for in vivo studies. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] UV-embossed microchannel in biocompatible polymeric film: Application to control of cell shape and orientation of muscle cellsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2006Jin-Ye Shen Abstract This article shows that ultra violet (UV) micro-embossing can be successfully used for fabricating biocompatible micropatterned films with microchannels separated by high aspect ratio microwalls. Eight series of micropatterns were investigated; the width of the microwall was either 10 or 25 ,m and that of the microchannel either 40, 80, 120, or 160 ,m. The material investigated was principally polyurethane diacrylate. The UV-embossed micropattern was extracted with methanol, converting the micropatterns from cytotoxic to biocompatible. The typical UV embossing method was modified by using a marginally adhesive polyester substrate, which facilitates demolding but is removable before methanol extraction to avoid fragmentation of the embossed micropatterns. The effect of the micropatterns on A7r5 smooth muscle cells and C2C12 skeletal muscle cells was investigated. The dimensions of both channel and wall have significant effects on the elongation of both muscle cells. In the narrower 40-,m channel, the C2C12 cells merged together to form myofibers. These results indicate that UV-embossed micropatterns may present a useful scaffold for in vitro cell shape and orientation control needed in vascular and muscle tissue engineering. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Periodontal growth factors and tissue carriers: Biocompatibility and mitogenic efficacy in vitroJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2006Claudio Cesari Clinical research has long been testing techniques of integrating biomaterials with many external factors, such as simple proteins or more complicated devices, in order to achieve the restitutio ad integrum of periodontium. This study assessed the in vitro effectiveness of platelet derivate growth factor-BB (PDGF) and insulin growth factor I (IGF); the biocompatibility of materials like Paroguide, Oclastim membranes, Gingistat sponges, Surgiplaster, and Capset; and their efficacy as carriers for the platelet derivate growth factor-BB (PDGF) and insulin growth factor I (IGF). Fibroblasts from the human periodontal ligament were incubated with growth factors free or vehiculated. Mitogenic effect was evaluated by measuring the growth rate and biocompatibility by observing cell morphology at SEM. PDGF was the most effective in stimulating cell proliferation both in solution (p < 0.001) and vehiculated (p < 0.01). Surgiplaster and Capset were more biocompatible; however, final analysis to assess their efficacy as carriers failed to disclose significant differences between experimental findings and control. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source] Tissue reaction and biodegradation of implanted cross-linked high amylose starch in ratsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 6 2002Cyril Désévaux Abstract The biocompatibility and degradation characteristics of cross-linked high amylose starch (Contramid®) were investigated in rats over 4 months. Contramid® pellets (3-mm diameter and thickness) obtained by direct compression, were implanted subcutaneously and intramuscularly. On sequential time points, macroscopic observations of implantation sites were performed and tissue samples were removed, fixed, and histologically evaluated. No macroscopic inflammatory reaction was observed with Contramid®. Upon histologic examination, inflammatory reaction produced by Contramid® was moderate and restricted to implantation sites. The sequence of inflammatory events with Contramid® was similar regardless of implantation site. Degradation of Contramid® pellets was characterized by fragmentation with formation of fibrovascular septa and phagocytosis by macrophages. Finally Contramid® was mostly absorbed by the end of the 4-month period and substituted by adipocytes. It has been demonstrated that Contramid® is a biocompatible and absorbable material. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 772,779, 2002 [source] | ||||||||||||||||||||||||||||||||||