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Electrospun eri silk fibroin scaffold coated with hydroxyapatite for bone tissue engineering applications
Muthumanickkam Andiappan, Subramanian Sundaramoorthy, Niladrinath Panda, Gowri Meiyazhaban, Sofi Beaula Winfred, Ganesh Venkataraman and Pramanik Krishna
Progress in Biomaterials , 2013, DOI: 10.1186/2194-0517-2-6
Abstract: Natural biomaterials such as collagen, silk fibroin, and chitosan, and synthetic biopolymers such as polylactic acid, polycaprolactone, polyglycolic acid, and their copolymers are being used as scaffold for tissue engineering applications. In the present work, a fibrous mat was electrospun from eri silk fibroin (ESF). A composite of hydroxyapatite (Hap) and the ESF scaffold was prepared by soaking the ESF scaffold in a solution of calcium chloride and then in sodium diammonium phosphate. The average tensile stress of the pure ESF and hydroxyapatite-coated ESF scaffold (ESF-Hap) was found to be 1.84 and 0.378 MPa, respectively. Pure ESF and ESF-Hap scaffolds were evaluated for their characteristics by a themogravimetric analyzer and Fourier transform infrared spectroscope. The crystallinity and thermal stability of the ESF-Hap scaffold were found to be more than that of uncoated eri silk nanofiber scaffold. The water uptake of the pure ESF and ESF-Hap scaffolds was found to be 69% and 340%, respectively, in distilled water as well as phosphate buffer saline. The hemolysis percentage of both scaffolds was less than 5%, which indicate their good blood compatibility. The cytocompatibility studied by 3-(4,5-dimethyl) thiazol-2-yl-2,5-dimethyl tetrazolium bromide assay showed that the scaffold is biocompatible. To assess cell attachment and growth on the scaffold, human mesenchymal stem cells were cultured on the scaffolds. The results from scanning electron microscopy and fluorescent microscopy showed a notable cellular growth and favorable morphological features. Hence, the ESF-Hap scaffold is better suited for cell growth than the pure ESF scaffold.
Cytocompatibility evaluation of hydroxyapatite/collagen composites doped with Zn+2
Santos, Maria Helena;Shaimberg, Ana Paula M.;Valerio, Patricia;Goes, Alfredo M.;Leite, Maria de Fátima;Mansur, Herman S.;
Matéria (Rio de Janeiro) , 2007, DOI: 10.1590/S1517-70762007000200009
Abstract: the cytocompatibility of synthetic hydroxyapatite/collagen composites alone or doped with zn+2 was tested by using primary culture of osteoblasts. the hydroxyapatite (hap) was synthesized having calcium hydroxide and orthophosphoric acid as precursors. a new hap composite was developed adding 1.05 w% of zn(no3)2.6h2o forming hapzn. the pure type i collagen (col) was obtained from bovine pericardium by enzymatic digestion method. the hap/col and hapzn/col composites were developed and characterized by sem/eds. the cell viability and alkaline phosphatase activity in the presence of composites were evaluated by mtt assay and nbt-bcip assay, respectively, and compared to osteoblastic cells of the control. three individual experiments were accomplished in triplicates and submitted to the variance analysis and bonferroni?s post-test with statistically significant at p<0.05. the hapzn/col composite did not stimulate the proliferation and increasing of alkaline phosphatase activity of the osteoblastic cells. the tested composites did not alter the cellular viability neither caused alterations in the cellular morphology in 72 h showing adequate properties for biological applications.
Biomimetic three-dimensional nanocrystalline hydroxyapatite and magnetically synthesized single-walled carbon nanotube chitosan nanocomposite for bone regeneration
Im O, Li J, Wang M, Zhang LG, Keidar M
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S29743
Abstract: iomimetic three-dimensional nanocrystalline hydroxyapatite and magnetically synthesized single-walled carbon nanotube chitosan nanocomposite for bone regeneration Original Research (3652) Total Article Views Authors: Im O, Li J, Wang M, Zhang LG, Keidar M Published Date April 2012 Volume 2012:7 Pages 2087 - 2099 DOI: http://dx.doi.org/10.2147/IJN.S29743 Received: 06 January 2012 Accepted: 09 March 2012 Published: 24 April 2012 Owen Im1, Jian Li2, Mian Wang2, Lijie Grace Zhang2,3, Michael Keidar2,3 1Department of Biomedical Engineering, Duke University, Durham, NC; 2Department of Mechanical and Aerospace Engineering, 3Institute for Biomedical Engineering and Institute for Nanotechnology, The George Washington University, Washington, DC, USA Background: Many shortcomings exist in the traditional methods of treating bone defects, such as donor tissue shortages for autografts and disease transmission for allografts. The objective of this study was to design a novel three-dimensional nanostructured bone substitute based on magnetically synthesized single-walled carbon nanotubes (SWCNT), biomimetic hydrothermally treated nanocrystalline hydroxyapatite, and a biocompatible hydrogel (chitosan). Both nanocrystalline hydroxyapatite and SWCNT have a biomimetic nanostructure, excellent osteoconductivity, and high potential to improve the load-bearing capacity of hydrogels. Methods: Specifically, three-dimensional porous chitosan scaffolds with different concentrations of nanocrystalline hydroxyapatite and SWCNT were created to support the growth of human osteoblasts (bone-forming cells) using a lyophilization procedure. Two types of SWCNT were synthesized in an arc discharge with a magnetic field (B-SWCNT) and without a magnetic field (N-SWCNT) for improving bone regeneration. Results: Nanocomposites containing magnetically synthesized B-SWCNT had superior cytocompatibility properties when compared with nonmagnetically synthesized N-SWCNT. B-SWCNT have much smaller diameters and are twice as long as their nonmagnetically prepared counterparts, indicating that the dimensions of carbon nanotubes can have a substantial effect on osteoblast attachment. Conclusion: This study demonstrated that a chitosan nanocomposite with both B-SWCNT and 20% nanocrystalline hydroxyapatite could achieve a higher osteoblast density when compared with the other experimental groups, thus making this nanocomposite promising for further exploration for bone regeneration.
Incorporation of strontium up to 5 Mol. (%) to hydroxyapatite did not affect its cytocompatibility
Tavares, Débora dos Santos;Resende, Cristiane Xavier;Quitan, Maíra Paiva;Castro, Letícia de Oliveira;Granjeiro, José Mauro;Soares, Gloria de Almeida;
Materials Research , 2011, DOI: 10.1590/S1516-14392011005000073
Abstract: the aim of this work was to produce hydroxyapatite (ha) granules containing 0, 0.5, 1 and 5 mol. (%) of strontium (sr), evaluate the physico-chemical properties and also the cytotoxicity by three different parameters of cell viability (iso 10993-5, 10993-12). the physico-chemical characterization was carried out by using x-ray diffraction (xrd), fourier-transform infrared spectroscopy (ftir) and x-ray fluorescence (xrf). the xrd profile presented the main peaks of ha (jcpds 860740) and the absorption bands of ha were identified by ftir. the xrf results showed that the strontium concentration was close to the theoretical value. regarding the cytotoxicity assays, the incorporation of strontium up to 5 mol. (%) to the ha did not affected dehydrogenase activity (xtt, 2,3-bis[2-methyloxy-4-nitro-5-sulfophenyl]-2h-tetrazolium-5-carboxanilide), membrane integrity (neutral red uptake) or dna contend (incorporation of crystal violet), in relation to ha alone. in conclusion, hydroxyapatite containing from 0.5 to 5 mol. (%) of sr was successfully produced and presented no cytotoxicity.
Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA) Composites: Effect of Coupling Agent Mediated Interface  [PDF]
Muhammad Sami Hasan,Ifty Ahmed,Andrew Parsons,Gavin Walker,Colin Scotchford
Journal of Functional Biomaterials , 2012, DOI: 10.3390/jfb3040706
Abstract: In this study three chemical agents Amino-propyl-triethoxy-silane (APS), sorbitol ended PLA oligomer (SPLA) and Hexamethylene diisocyanate (HDI) were identified to be used as coupling agents to react with the phosphate glass fibre (PGF) reinforcement and the polylactic acid (PLA) polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ? = 20 μm) in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa) was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS) helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP) control, supporting the use of these materials as coupling agent’s within medical implant devices.
Preparation and Characterization of Fluorescence Probe from Assembly Hydroxyapatite Nanocomposite  [cached]
Zhang Min,Liu Jin-Ku,Miao Ran,Li Guang-Ming
Nanoscale Research Letters , 2010,
Abstract: A new nanocomposite fluorescence probe with thioglycolic acid (TA) functional layers embedded inside the hydroxyapatite nanoribbon spherulites has been synthesized. The fluorescence intensity of the novel probe is about 1.5–3.3-fold increase compared with the probe containing no TA. When used to detect cadmium ion, the most of original assembly nanoribbon spherulites structure in the novel probe is found to have been damaged to new flake structures. The mechanism of determining cadmium ion in alcohol solution has been studied. The present systematic study provides significant information on the effect of assembly nanostructure on the metal-enhanced fluorescence phenomenon.
Synthesis and Antimicrobial Activity of a Silver-Hydroxyapatite Nanocomposite  [PDF]
Marcos Díaz,Flora Barba,Miriam Miranda,Francisco Guitián,Ramón Torrecillas,José S. Moya
Journal of Nanomaterials , 2009, DOI: 10.1155/2009/498505
Abstract: A silver-hydroxyapatite nanocomposite has been obtained by a colloidal chemical route and subsequent reduction process in H2/Ar atmosphere at 350°C. This material has been characterized by TEM, XRD, and UV-Visible spectroscopy, showing the silver nanoparticles (~65 nm) supported onto the HA particles (~130 nm) surface without a high degree of agglomeration. The bactericidal effect against common Gram-positive and Gram-negative bacteria has been also investigated. The results indicated a high antimicrobial activity for Staphylococcus aureus, Pneumococcus and Escherichia coli, so this material can be a promising antimicrobial biomaterial for implant and reconstructive surgery applications.
A Study on Mechanical Properties of PMMA/Hydroxyapatite Nanocomposite  [PDF]
S. M. Zebarjad, S. A Sajjadi, T. Ebrahimi Sdrabadi, S. A Sajjadi, A Yaghmaei, B Naderi
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.38096
Abstract: This study is focused on the role of nano hydroxyapatite particles on the mechanical properties of PMMA/HA nanocomposites. In order to achieve a proper and homogeneous distribution of HA particles in the polymer matrix, mixer milling process was applied. Wear, compression and three-point bending tests were conducted. It was observed that wear rate decreased by increasing in HA content in both atmosphere and artificial saliva. The results of compression tests showed that the addition of 2.5 percent HA to PMMA promoted ultimate compressive strength, yield strength and modulus while caused to decrease elongation at break. Also it was elucidated that addition of HA more than 2.5 wt.% caused a decrease in both ultimate compressive strength and compression yield strength and an increase in elongation at break. The results of three-point bending tests on the PMMA cements containing 2.5 percent HA demonstrated the maximum bending strength value and modulus among all the HA containing formulations. However there was no direct proportionality between the results of bending tests and the HA content and the addition of HA to PMMA (up to 10 wt.%) did not change the bending properties significantly.
In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications  [PDF]
Bing Wang,Ping Huang,Caiwen Ou,Kaikai Li,Biao Yan,Wei Lu
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms141223614
Abstract: Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA) coating on ZK60 magnesium alloy substrates to mediate the rapid degradation of Mg while improving its cytocompatibility for orthopedic applications. A simple chemical conversion process was applied to prepare HA coating on ZK60 magnesium alloy. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The corrosion properties of samples were investigated by immersion test and electrochemical test. Murine fibroblast L-929 cells were harvested and cultured with coated and non-coated ZK60 samples to determine cytocompatibility. The degradation results suggested that the HA coatings decreased the degradation of ZK60 alloy. No significant deterioration in compression strength was observed for all the uncoated and coated samples after 2 and 4 weeks’ immersion in simulated body fluid (SBF). Cytotoxicity test indicated that the coatings, especially HA coating, improved cytocompatibility of ZK60 alloy for L929 cells.
Effect of Sintering Atmosphere on Phase Evolution of Hydroxyapatite Nanocomposite Powders  [cached]
Ebadzadeh T.,Salahi E.,Ebrahimi M.
Proceedings of the International Conference Nanomaterials : Applications and Properties , 2012,
Abstract: In the present work, pure hydroxyapatite, hydroxyapatite -20 wt% alumina and hydroxyapatite -20 wt% titanium mixtures were pressed and sintered in air, moist, and reduction atmospheres at 1200oC for 2 h. XRD investigations of sintered samples showed that, pure hydroxyapatite is stable in all three atmospheres. But, moist and reduction atmospheres were preferred to suppress the hydroxyapatite decomposition in hydroxyapatite -alumina and hydroxyapatite –titanium nanocomposites, respectively.
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