bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro cytocompatibility assessment of amorphous carbon structures using neuroblastoma and Schwann cells
Authors: Jain Shilpee , Sharma Ashutosh , Basu Bikramjit 
Published: January 2013

AbstractThe development of scaffolds for neural tissue engineering application requires an understanding of cell adhesion, proliferation, and migration of neuronal cells. Considering the potential application of carbon as scaffold materials and the lack of understanding of compatibility of amorphous carbon with neuronal cells, the carbon‐based materials in the forms of carbon films and continuous electrospun carbon nanofibers having average diameter of ∼200 nm are being investigated with or without ultraviolet (UV) and oxy‐plasma (OP) treatments for cytocompatibility property using mouse Neuroblastoma (N2a) and rat Schwann cells (RT4‐D6P2T). The use of Raman spectroscopy in combination with Fourier transform infrared (FTIR) and X‐ray diffraction establishes the amorphous nature and surface‐bonding characteristics of the studied carbon materials. Although both UV and OP treatments make carbon surfaces more hydrophilic, the cell viability of N2a cells is statistically more significant on OP treated fibers/films compared to UV fiber/film substrates after 4 days in culture. The electrospun carbon fibrous substrate provides the physical guidance to the cultured Schwann cells. Overall, the experimental results of this study demonstrate that the electrospun amorphous carbon nanofibrous scaffolds can be used as a suitable biomaterial substrate for supporting cell adhesion and proliferation of neuronal cells in the context of their applications as artificial nerve implants. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Fabrication of crosslinked carboxymethylchitosan microspheres and their incorporation into composite scaffolds for enhanced bone regeneration
Authors: Reves Benjamin T. , Bumgardner Joel D. , Haggard Warren O. 
Published: January 2013

AbstractCarboxymethylchitosan (CMCS) microspheres were prepared by the carboxymethylation of chitosan (CS) beads using monochloroacetic acid. The CMCS microspheres were crosslinked using two different methods: the amine‐amine crosslinker genipin and carbodiimide chemistry, yielding Gen‐X CMCS and X‐CMCS beads, respectively. The Gen‐X CMCS beads were found to have poor degradation and drug release profiles. The X‐CMCS microspheres displayed good potential for use in tissue engineering applications in which degradation and local drug delivery are desired. The X‐CMCS beads displayed enzymatic degradation of 82.7 ± 1.2% in 100 μg/mL lysozyme after 1 month. An extended release of rhBMP‐2 for at least 45 days was also observed with the X‐CMCS microspheres. Scaffolds were formed by fusing beads together, and the X‐CMCS beads were successfully incorporated into composite X‐CMCS/CS scaffolds. The composite scaffolds had increased degradation of 14.5 ± 6.6% compared to 0.5 ± 0.4% for CS‐only scaffolds, and the X‐CMCS/CS scaffolds released more rhBMP‐2 at all timepoints. The composite scaffolds also supported the attachment and proliferation of SAOS‐2 cells. The addition of X‐CMCS beads resulted in fabrication of scaffolds with improved properties for use in bone tissue engineering. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Porous TiO2 surface formed on nickel‐titanium alloy by plasma electrolytic oxidation: A prospective polymer‐free reservoir for drug eluting stent applications
Authors: Huan Zhiguang , Fratila‐Apachitei Lidy E. , Apachitei Iulian , Duszczyk Jurek 
Published: January 2013

AbstractIn this study, a porous oxide layer was formed on the surface of nickel‐titanium alloy (NiTi) by plasma electrolytic oxidation (PEO) with the aim to produce a polymer‐free drug carrier for drug eluting stent (DES) applications. The oxidation was performed galvanostatically in concentrated phosphoric acid electrolyte at low temperature. It was found that the response of NiTi substrate during the PEO process was different from that of bulk Ti, since the presence of large amount of Ni delayed the initial formation of a compact oxide layer that is essential for the PEO to take place. Under optimized PEO conditions, the resultant surface showed porosity, pore density and oxide layer thickness of 14.11%, 2.40 × 105 pores/mm2 and 0.8 μm, respectively. It was additionally noted that surface roughness after PEO did not significantly increase as compared with that of original NiTi substrate and the EDS analyses revealed a decrease in Ni/Ti ratio on the surface after PEO. The cross‐section morphology showed no discontinuity between the PEO layer and the NiTi substrate. Furthermore, wettability and surface free energy of the NiTi substrate increased significantly after PEO treatment. The PEO process could be successfully translated to NiTi stent configuration proving for the first time its feasibility for such a medical device and offering potential for development of alternative, polymer‐free drug carriers for NiTi DES. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
In vitro response of preosteoblastic MG63 cells on Ni‐free Ti shape memory substrates
Authors: Arciniegas M. , Peña J. , Gil F. J. , Manero J. M. 
Published: January 2013

AbstractNi‐free Ti alloys are a potential strategy to overcome the risk of Ni‐adverse reactions and rigidity mismatch for implant materials. Here, we report the biological behavior induced for two promising candidate alloys—Ti19.1Nb8.8Zr (MS temperature of 46°C and elastic modulus of 74 GPa) and Ti41.2Nb6.1Zr (elastic modulus of 67 GPa)—on cultured MG63 cells, as well as their physical and chemical properties. Contact angle results revealed the hydrophobic character of the former alloy (59.02° ± 2.35°) attributed to the presence of the martensitic phase, while the latter one presented a hydrophilic response (67.77° ± 2.78°). Results showed also that the cell adhesion response (after 4 and 8 h of incubation) in both substrates was not statistically different to that obtained in the cp Ti as control material. These surfaces induced well spread cell morphology with cytoplasmic extension like filopodia of up to 100 μm even at short culture times and presented an uninterrupted proliferation after longer incubation times (9 days). A decrement in the proliferation rate was appreciated from the Ti19.1Nb8.8Zr surface at that time, which was attributed to an earlier activation of the cell differentiation stage, as confirmed by the twofold increment of alkaline phosphatase activity. The results also evidenced that the presence of a 2 nm thick layer of amorphous Nb2O5, which was detected on both alloys, has a significant effect on cell behavior favoring the cell adhesion and morphology response of the new alloys studied. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Prediction of mechanical properties of multilayer gradient hydroxyapatite reinforced poly(vinyl alcohol) gel biomaterial
Authors: Yusong Pan , Qianqian Shen , Chengling Pan , Jing Wang 
Published: January 2013

AbstractFunctional graded materials provided us one new concept for artificial articular cartilage design with graded component and graded structure. In this article, a novel functional material design was proposed by functionalizing hydroxyapatite (HA) particles in poly(vinyl alcohol) (PVA) hydrogel. The goal of the present study was to fabricate a multilayer gradient HA/PVA gel biocomposites through layer‐by‐layer casting method combining with freeze/thaw cycle technology and establish a mechanical model to predict the compressive mechanical properties of multilayer gradient gel biocomposites. The results showed that the compressive strength of the multilayer gradient gel biocomposites increased with the rise of HA content, but it presented decreasing trend with the rise of interlayer gradient concentration of HA particles. Furthermore, the compressive strength of multilayer gradient biocomposites would be approximately predicted by the established mechanical model. The maximum error between theoretical compressive strength predicted by the model and the experimental strength is less than 7%. On the other hand, the compressive mechanical properties of multilayer gradient composites could be designed and controlled by the mechanical model as established in this study. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Self‐activated mesh device using shape memory alloy for periosteal expansion osteogenesis
Authors: Yamauchi Kensuke , Takahashi Tetsu , Tanaka Kenko , Nogami Shinnosuke , Kaneuji Takeshi , Kanetaka Hiroyasu , Miyazaki Toshiki , Lethaus Bernd , Kessler Peter 
Published: January 2013

AbstractThe present study evaluated the use of this self‐activated shape memory alloy (SMA) device, with a focus on its effects in the region under the periosteum. Twelve Japanese white rabbits were used in this study. The device was inserted under the periosteum at the forehead. In the experimental group, the device was pushed, bent, and attached to the bone surface and fixed with a titanium screw. In control group, the device was only inserted under the periosteum. After 14 days, the screw was removed and the mesh was activated in the experimental group. Rabbits were sacrificed 5 and 8 weeks after the operation and newly formed bone was histologically and radiographically evaluated. The quantitative data by the area and the occupation of newly formed bone indicated that the experimental group had a higher volume of new bone than the control group at each consolidation period. Histologically, some newly formed bone was observed and most of the subperiosteal space underneath the device was filled with fibrous tissue, and a thin layer of immature bone was observed in the control group. In the experimental group, multiple dome‐shaped bones, outlined by thin and scattered trabeculae, were clearly observed under the SMA mesh device. The use of self‐activated devices for the periosteal expansion technique may make it possible to avoid donor site morbidity, trans‐skin activation rods, any bone‐cutting procedure, and the following intermittent activation procedure. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Effects of density of anisotropic microstamped silica thin films on guided bone tissue regeneration—In vitrostudy
Authors: Pelaez‐Vargas Alejandro , Gallego‐Perez Daniel , Carvalho Angela , Fernandes Maria H. , Hansford Derek J. , Monteiro Fernando J. 
Published: January 2013

AbstractThe growing demand for better implant aesthetics has led to increased research on the development of all‐ceramic dental implants. The use of microtextured coatings with enhanced properties has been presented as a viable way to improve tissue integrability of all‐ceramic implants. The aim of this study was to evaluate the effects of different densities of anisotropic microtextured silica thin films, which served as a model coating, on the behavior of human osteoblast‐like cells. The differential responses of human osteoblast‐like cells to anisotropic silica microtextures with varying densities, produced via a combination of sol–gel and soft lithography processing, were evaluated in terms of alignment, elongation (using fluorescence microscopy), overall cellular activity, and the expression/activity levels of alkaline phosphatase (ALP). Statistical analysis was conducted using one‐way ANOVA/Tukey HSDpost hoctest. The thin films were thoroughly characterized via scanning electron microscopy/energy dispersive spectroscopy, Fourier transform infrared, and contact angle measurements. Thin film characterization revealed increased nanoscale roughness and reduced wettability on the micropatterned surfaces. Cell culture experiments indicated that the microtextures induced cell alignment, elongation, and guided colonization on the surface. Cells cultured on denser micropatterns exhibited increased metabolic activity (t= 14–21 days). The early expression/activity levels of ALP released into the medium were found to be significantly higher only on the least dense micropattern. These results suggest the possibility that microstructured silica thin films could be used to guide and enhance peri‐implant cell/tissue responses, potentially improving tissue integration for metallic and all‐ceramic dental implants. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Crevice corrosion of biomedical alloys: A novel method of assessing the effects of bone cement and its chemistry
Authors: Bryant Michael , Hu Xinming , Farrar Richard , Brummitt Ken , Freeman Robert , Neville Anne 
Published: January 2013

AbstractIn this study, five commercially available poly(methyl methacrylate) PMMA bone cements were tested to investigate the effects of antibiotics on the severity of crevice corrosion. Bone cements with varying chemistry were also tested. A test method was developed in part reference to ASTM F746‐04. Cylindrical specimens were fitted with a bone cement tapered collar, creating consistent crevice conditions. Crevice corrosion was then studied using potentiodynamic polarization techniques in 0.9% NaCl solution (pH7.4) at 37°C. Surface analyses using a light microscope and scanning electron microscopy were also conducted to investigate the surface morphology after accelerated electrochemical testing. Initial testing of commercially available bone cements indicated that different PMMA bone cements can affect the initiation and propagation mechanism of crevice corrosion. Further studies, utilising electrochemical and mass spectroscopy techniques, have identified that the addition of radiopaque agent and antibiotics affect the initiation mechanisms of 316L stainless steel, whilst significantly increasing the extent of propagation in CoCrMo alloys. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Effect of fabrication and processing technology on the biodegradability of magnesium nanocomposites
Authors: Ma Chao , Chen Lianyi , Xu Jiaquan , Fehrenbacher Axel , Li Yan , Pfefferkorn Frank E. , Duffie Neil A. , Zheng Jing , Li Xiaochun 
Published: January 2013

AbstractMagnesium and its alloys have gained significant attention recently as potential alternatives for biodegradable materials due to their unique biodegradability, biocompatibility, and mechanical properties. However, magnesium alloys tend to have high corrosion rates in biological liquids, thus presenting a potential problem if a magnesium implant/device needs to maintain mechanical integrity for a sufficient period under practical physiological conditions. In this study, hydroxyapatite nanoparticles were used to form magnesium based metal matrix nanocomposites (MMNC) through two processes: friction stir processing (FSP) and a two‐state nanoprocessing (TSnP) combining liquid state ultrasonic processing and solid state FSP. In addition, laser surface melting (LSM) was carried out for further surface treatment. In vitro immersion tests indicated that the corrosion rate of MMNC decreased by 52% compared with pure Mg through FSP. Potentiodynamic polarization tests showed that the corrosion current of MMNC decreased by 71% and 30%, respectively, by TSnP and LSM when compared with pure Mg or untreated counterparts. This study suggests that fabrication of MMNC and further processing through FSP and LSM can robustly enhance the corrosion resistance of magnesium, which will boost its potential for biological applications. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
Evaluation of the flexural strength of dual‐cure composite resin cements
Authors: Duymus Zeynep Yesil , Yanikoğlu Nuran Dinckal , Alkurt Murat 
Published: January 2013

AbstractThe aim of this study was to evaluate of flexural strength of some adhesive resin cements. Three dual‐cure composite resin cements (Nexus 3; Variolink II, Panavia F) were prepared. The manufacturer's mixing directions for the cements were followed. Adhesive resin cement was mixed, placed in the rectangular portion of the mold. Fifteen specimens were prepared for each cements. The cements were light‐activated with light lamp for 40 s on both and top and bottom surfaces. The each cement specimens were divided into three groups according to time of storage and stored in distilled water for 24 h, 15, and 30 days. Total 45 specimens were stored at 37°C (98.6 0F) in distilled water for 24 h, 15, and 30 days prior to tests. The flexural strength was tested wıth a universal testing machine at a crosshead speed of 0.5 mm/min (0.02 in.) The maximum load was recorded as MPa. The results were analyzed by Analysis of Variance and Duncan test. The Panavia F resin cements content Bisphenol A was showed the highest flexural strength (80.80 MPa) (11.71 ksi) for 24 h. The lowest flexural strength was observed in Nexus 3 (51.00 MPa) (7.39 ksi). It was found significant interaction of material and time (p < 0.05). The types of cement and time of storage was statistically significant on the flexural strengths (p < 0.001). © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2013.
CT-measured bone attenuation in patients with chronic obstructive pulmonary disease: Relation to clinical features and outcomes
Authors: Romme Elisabeth APM , Murchison John T , Edwards Lisa D , JR van Beek Edwin , Murchison David M , Rutten Erica PA , Smeenk Frank WJM , Williams Michelle C , Wouters Emiel FM , MacNee William ,   on behalf of the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints (ECLIPSE) study investigators
Published: January 2013

ABSTRACT

Osteoporosis is highly prevalent in chronic obstructive pulmonary disease (COPD) patients and has been related to several clinical features. However, most studies have been in relatively small COPD cohorts. Therefore, the objectives of this study were to compare bone attenuation measured on low-dose chest computed tomography (CT) between COPD subjects and smoker and nonsmoker controls, and to relate bone attenuation to clinical parameters, inflammatory biomarkers, and outcomes in a large, well-characterized COPD cohort. We studied 1634 COPD subjects, 259 smoker controls, and 186 nonsmoker controls who participated in a large longitudinal study (ECLIPSE). We measured bone attenuation, extent of emphysema, and coronary artery calcification (Agatston score) on baseline CT scans, and clinical parameters, inflammatory biomarkers, and outcomes. Bone attenuation was lower in COPD subjects compared with smoker and nonsmoker controls (164.9 ± 49.5 Hounsfield units [HU] versus 183.8 ± 46.1 HU versus 212.1 ± 54.4 HU, p &lt; 0.001). Bone attenuation was not significantly different between COPD subjects and smoker controls after adjustment for age, sex, and pack-years of smoking. In the COPD subjects, bone attenuation correlated positively with forced expiratory volume in 1 second (FEV1, r = 0.062, p = 0.014), FEV1/forced vital capacity (FVC) ratio (r = 0.102, p &lt; 0.001), body mass index (r = 0.243, p &lt; 0.001), fat-free mass index (FFMI, r = 0.265, p &lt; 0.001), and C-reactive protein (r = 0.104, p &lt; 0.001), and correlated negatively with extent of emphysema (r = −0.090, p &lt; 0.001), Agatston score (r = −0.177, p &lt; 0.001), and interleukin-8 (r = −0.054, p = 0.035). In a multiple regression model, older age, lower FFMI and higher Agatston score were associated with lower bone attenuation. Lower bone attenuation was associated with higher exacerbation (r = −0.057, p = 0.022) and hospitalization (r = −0.078, p = 0.002) rates but was not associated with all-cause mortality. In conclusion, CT-measured bone attenuation was lower in COPD subjects compared with nonsmoker controls but not compared with smoker controls, after adjustment for age, sex, and pack-years of smoking. In the COPD subjects, bone attenuation was associated with age, body composition, and coronary artery calcification but was not associated with all-cause mortality.
Delineating breast cancer cell interactions with engineered bone microenvironments
Authors: Taubenberger Anna V , Quent Verena M , Thibaudeau Laure , Clements Judith A , Hutmacher Dietmar W 
Published: January 2013

Abstract

The mechanisms leading to colonization of metastatic breast cancer cells (BCa) in the skeleton are still not fully understood. Here, we demonstrate that mineralized extracellular matrices secreted by primary human osteoblasts (hOBM) modulate cellular processes associated with BCa colonization of bone. A panel of four BCa cell lines of different bone-metastatic potential (T47D, SUM1315, MDA-MB-231, and the bone-seeking subline MDA-MB-231BO) was cultured on hOBM. After 3 days, the metastatic BCa cells had undergone morphological changes on hOBM and were aligned along the hOBM's collagen type I fibrils that were decorated with bone-specific proteins. In contrast, nonmetastatic BCa cells showed a random orientation on hOBM. Atomic force microscopy-based single-cell force spectroscopy revealed that the metastatic cell lines adhered more strongly to hOBM compared with nonmetastatic cells. Function-blocking experiments indicated that β1-integrins mediated cell adhesion to hOBM. In addition, metastatic BCa cells migrated directionally and invaded hOBM, which was accompanied by enhanced MMP-2 and -9 secretion. Furthermore, we observed gene expression changes associated with osteomimickry in BCa cultured on hOBM. As such, osteopontin mRNA levels were significantly increased in SUM1315 and MDA-MB-231BO cells in a β1-integrin–dependent manner after growing for 3 days on hOBM compared with tissue culture plastic. In conclusion, our results show that extracellular matrices derived from human osteoblasts represent a powerful experimental platform to dissect mechanisms underlying critical steps in the development of bone metastases.
Real‐time Raman spectroscopy measurements to study the uniaxial tension of isotactic polypropylene: a global overview of microstructural deformation mechanisms
Authors: Martin J. , Ponçot M. , Hiver J.M. , Bourson P. , Dahoun A. 
Published: January 2013

ABSTRACTMicro‐Raman spectroscopy was used to investigate the main deformation micromechanisms of isotactic polypropylene uniaxially stretched at constant temperature (T = 30 °C) under a constant true strain rate ( = 5.10−3 s−1). To accurate measurements namely to be free of the recovering phenomenon which causes in most of the cases interference during post‐mortem analysis, we introduced a new experimental setup combining a Raman spectrometer with a tensile machine piloted by the VidéoTraction™ system. Microstructure is described by essential parameters such as the crystallinity index, the macromolecular orientation both in the crystalline and the amorphous phase, and distribution of the internal stress at the chemical bonds scale. For each, a well‐tried Raman spectral criterion was used. Cross‐checking of these results, obtained with a minimum of tensile tests, allows a more complete understanding of the deformation micromechanisms of semi‐crystalline polymer. Copyright © 2013 John Wiley & Sons, Ltd.
Amphiphilic Unimolecular Nanoparticles Based on a Hyperbranched Polyacrylate Core and a PNIPAm Shell: Synthesis via ATRP and Properties
Authors: Cai Yong , Liu Yu‐Yang 
Published: January 2013

AbstractA novel amphiphilic unimolecular nanoparticle, multi‐HPBPEA‐g‐PNIPAm, for encapsulation and release of hydrophobic guest molecules, is developed. The polymer shows core–shell architecture and is synthesized from inimer 2‐((2‐bromopropionyl)oxy)ethyl acrylate (BPEA) by atom transfer radical polymerization (ATRP) in three steps. The hydrophobic core (multi‐HPBPEA) is composed of hyperbranched poly(2‐((2‐bromopropionyl)oxy)ethyl acrylate) (HPBPEA), which is synthesized by self‐condensing vinyl polymerization (SCVP) of BPEA. Multi‐HPBPEA‐g‐PNIPAm is obtained by multi‐HPBPEA core initiating ATRP of N‐isopropylacrylamide (NIPAm). The encapsulation behavior of the core of multi‐HPBPEA‐g‐PNIPAm in an aqueous solution is investigated by fluorescent spectra. It is found that multi‐HPBPEA‐g‐PNIPAm can efficiently encapsulate and release a hydrophobic drug like nifedipine.magnified image