bluuebunny/crossref_metadata_2025_split huggingface dataset:
Orthopedic nano diamond coatings: Control of surface properties and their impact on osteoblast adhesion and proliferation
Authors: Yang Lei , Sheldon Brian W. , Webster Thomas J. 
Published: November 2008

AbstractThe superior mechanical and tribological properties of diamond coatings suggest their promise for improving current orthopedic implants. Therefore, understanding and controlling biological responses on diamond coatings are important and necessary for their advancement in orthopedics. For this reason, the objective of the present study was to correlate surface properties of diamond coatings with osteoblast (OB) adhesion and proliferation. Diamond coatings on silicon of variable surface features (specifically, grain size, surface roughness and surface chemistry) were fabricated by microwave plasma enhanced chemical‐vapor‐deposition (MPCVD). Scanning electron microscopy (SEM) as well as atomic force microscopy (AFM) was applied for topographical characterization and contact angles were measured to assess surface wettability. Results revealed that the grain size, surface roughness and wettability of diamond coatings can be controlled by adjusting H2 plasma in the MPCVD process. Further, results showed enhanced OB adhesion on nanocrystalline diamond (ND) with grain sizes less than 100 nm whereas nanostructured diamond/amorphous carbon coatings (NDp) and microcrystalline diamond (MD) inhibited OB adhesion. H2 plasma treated ND (NDH) also promoted OB adhesion. Similarly, OB proliferated to a greater extent on ND and NDH compared with MD and uncoated silicon controls. In summary, surface properties (including topography and chemistry) of diamond coatings can be controlled to either promote or inhibit OB functions, which implies that various forms of diamond coatings can be used to either support or inhibit bone growth in different regions of an orthopedic implant. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Calcium phosphate surface treatment of bioactive glass causes a delay in early osteogenic differentiation of adipose stem cells
Authors: Haimi Suvi , Moimas Loredana , Pirhonen Eija , Lindroos Bettina , Huhtala Heini , Räty Sari , Kuokkanen Hannu , Sándor George K. , Miettinen Susanna , Suuronen Riitta 
Published: November 2008

AbstractHuman adipose stem cells (ASCs) combined with osteostimulative material provide an attractive approach for clinical bone regeneration. The effect of calcium phosphate (Ca‐P) surface treatment of three‐dimensional bioactive glass scaffolds on the attachment, proliferation, and osteogenic differentiation of ASCs was studied. Three types of bioactive glass scaffolds (nontreated, thick and thin Ca‐P treated) were compared. All scaffold types supported ASC attachment, spreading, and proliferation equally as detected by scanning electron microscopy, fluorescence staining, and DNA measurement. Indices of osteogenic differentiation including the expression of osteopontin and alkaline phosphatise (ALP) were consistently higher in the nontreated and thin Ca‐P‐treated scaffolds when compared with thick Ca‐P‐treated scaffolds at 2 weeks. ASCs cultured on nontreated bioactive glass scaffolds showed significantly higher ALP activity when compared with both thin and thick Ca‐P‐treated scaffolds after 1 week in culture, but these differences equalized between the three scaffolds by the 2‐week time point. In conclusion, osteogenic differentiation appears to be delayed on the Ca‐P surface‐treated scaffolds. This delay is more pronounced with thick Ca‐P treatment of the scaffolds. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
In vivoanalysis of biocompatibility and vascularization of the synthetic bone grafting substitute NanoBone®
Authors: Abshagen K. , Schrodi I. , Gerber T. , Vollmar B. 
Published: November 2008

AbstractOne of the major challenges in the application of bone substitutes is adequate vascularization and biocompatibility of the implant. Thus, the temporal course of neovascularization and the microvascular inflammatory response of implants of NanoBone® (fully synthetic nanocrystalline bone grafting material) were studiedin vivoby using the mouse dorsal skinfold chamber model. Angiogenesis, microhemodynamics, and leukocyte‐endothelial cell interaction were analyzed repetitively after implantation in the center and in the border zone of the implant up to 15 days. Both NanoBone® granules and plates exhibited high biocompatibility comparable to that of cancellous bone, as indicated by a lack of venular leukocyte activation after implantation. In both synthetic NanoBone® groups, signs of angiogenesis could be observed even at day 5 after implantation, whereas granules showed higher functional vessel density compared with NanoBone® plates. The angiogenic response of the cancellous bone was markedly accelerated in the center of the implant tissue. Histologically, implant tissue showed an ingrowth of vascularized fibrous tissue into the material combined with an increased number of foreign‐body giant cells. In conclusion, NanoBone®, particularly in granular form, showed high biocompatibility and high angiogenic response, thus improving the healing of bone defects. Our results underline that, beside the composition and nanostructure, the macrostructure is also of importance for the incorporation of the biomaterial by the host tissue. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Soluble factors from neocortical astrocytes enhance neuronal differentiation of neural progenitor cells from adult rat hippocampus on micropatterned polymer substrates
Authors: Oh Jisun , Recknor Jennifer B. , Recknor Justin C. , Mallapragada Surya K. , Sakaguchi Donald S. 
Published: November 2008

AbstractRat adult hippocampal progenitor cells (AHPCs) are self‐renewing, multipotent neural progenitors that have the ability to differentiate into neurons and glia. Previously, we demonstrated that coculture of AHPCs with postnatal day 2, type 1 cortical astrocytes on laminin‐coated micropatterned polymer substrates facilitates selective neuronal differentiation of the AHPCs (Recknor et al., Biomaterials 2006;27:4098–4108). Under this condition, multidimensional cell–cell and/or cell–extracellular matrix interactions, as well as possible soluble factors released from astrocytes provided spatial and temporal control selectively enhancing neuronal differentiation and neurite alignment on topographically different regions of the same substrate. To investigate the potential role of astrocyte‐derived soluble factors as cues involved in neuronal differentiation, a noncontact coculture system was used. Under control conditions, ∼14% of the AHPCs were immunoreactive (IR) for the neuronal marker, class III β‐tubulin (TUJ1‐IR). When cocultured in physical contact with astrocytes, neuronal differentiation increased significantly to about 25%, consistent with our previous results. Moreover, under noncontact coculture conditions using Transwell® insert cultures, neuronal differentiation was dramatically increased to ∼64%. Furthermore, neurite outgrowth from neuronal cell bodies was considerably greater on the patterned substrate when compared with the nonpatterned planar substrate under noncontact coculture conditions. Taken together, our results demonstrate that astrocyte‐derived soluble factors provide cues for specific neuronal differentiation of AHPCs cultured on micropatterned substrates. In addition, a suppressive influence on neuronal differentiation appears to be mediated by contact with cocultured astrocytes. These results provide important insights into mechanisms for controlling neural progenitor/stem cell differentiation and facilitate development of strategies for CNS repair. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Self‐setting collagen‐calcium phosphate bone cement: Mechanical and cellular properties
Authors: Moreau Jennifer L. , Weir Michael D. , Xu Hockin H. K. 
Published: November 2008

AbstractCalcium phosphate cement (CPC) can conform to complex bone cavities and set in‐situ to form bioresorbable hydroxyapatite. The aim of this study was to develop a CPC‐collagen composite with improved fracture resistance, and to investigate the effects of collagen on mechanical and cellular properties. A type‐I bovine‐collagen was incorporated into CPC. MC3T3‐E1 osteoblasts were cultured. At CPC powder/liquid mass ratio of 3, the work‐of‐fracture (mean ± sd; n = 6) was increased from (22 ± 4) J/m2 at 0% collagen, to (381 ± 119) J/m2 at 5% collagen (p ≤ 0.05). At 2.5–5% of collagen, the flexural strength at powder/liquid ratios of 3 and 3.5 was 8–10 MPa. They matched the previously reported 2–11 MPa of sintered porous hydroxyapatite implants. SEM revealed that the collagen fibers were covered with nano‐apatite crystals and bonded to the CPC matrix. Higher collagen content increased the osteoblast cell attachment (p ≤ 0.05). The number of live cells per specimen area was (382 ± 99) cells/mm2 on CPC containing 5% collagen, higher than (173 ± 42) cells/mm2 at 0% collagen (p ≤ 0.05). The cytoplasmic extensions of the cells anchored to the nano‐apatite crystals of the CPC matrix. In summary, collagen was incorporated into in situ‐setting, nano‐apatitic CPC, achieving a 10‐fold increase in work‐of‐fracture (toughness) and two‐fold increase in osteoblast cell attachment. This moldable/injectable, mechanically strong, nano‐apatite‐collagen composite may enhance bone regeneration in moderate stress‐bearing applications. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Bone augmentation by bone marrow mesenchymal stem cells cultured in three‐dimensional biodegradable polymer scaffolds
Authors: Tanaka Toshimitsu , Hirose Motohiro , Kotobuki Noriko , Tadokoro Mika , Ohgushi Hajime , Fukuchi Takeshi , Sato Junichi , Seto Kanichi 
Published: November 2008

AbstractPoly‐lactic‐glycolic acid (PLGA) is a biocompatible as well as biodegradable polymer and used in various medical applications. In this study, we evaluated efficiency of the specially designed three‐dimensional porous PLGA as a scaffold for bone augmentation. First, cell attachment/proliferation, differentiation, and mineralization of Fisher 344 rat marrow mesenchymal stem cells (MSCs) cultured on the PLGA scaffold were analyzed. Viable MSCs were impregnated into pore areas of the scaffold and a moderate increase of DNA contents was seen. High alkaline phosphatase, osteocalcin content, and calcium content of MSCs in PLGA scaffolds under osteogenic differentiation conditions were seen after 14 or 21 days of culture. Subsequently, we implanted the PLGA/MSCs composites on rat calvaria bone for 30 days. Newly formed bone was seen in only the composite PLGA/MSCs implantation group, which had been precultured under osteogenic condition. We also demonstrated that the newly formed bone originated from the donor composites. These results demonstrate that the three‐dimensional PLGA scaffold can support osteogenic differentiation of MSCs, and the scaffold combined with osteogenic MSCs can be used for in vivo bone tissue augmentation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Assessing the binding selectivity of molecularly imprinted polymer artificial antibodies by mass spectrometry‐based profiling system
Authors: Liao Pao‐Chi , Tyan Yu‐Chang , Wang Chung‐Yao , Hsu Jing‐Fang , Chou Tse‐Chuan , Lin Hsin‐Yi 
Published: November 2008

AbstractMolecularly imprinted polymer (MIP) is a technique for generating polymer‐bearing biomimetic receptors. It offers several advantages to the research such as analysis, sensors, extraction, or preconcentration of components. Myoglobin is known to be an important biological index for the diagnosis of cardiac diseases. The purpose of this research was to optimize the formation of myoglobin‐imprinted polymer (Myo‐MIP) and develop a mass spectrometry‐based profiling system for assessing the binding selectivity of artificial antibodies formed by Myo‐MIP. Experimental results showed that myoglobin and albumin were bound/absorbed onto Myo‐MIP chips and not to nonimprinted polymer (NIP) chips. Other proteins, such as histidine‐rich glycoprotein, immunoglobulins, proapolipoprotein, and leech‐derived tryptase inhibitor, were also observed but with less reproducibility from the chips. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
In vitro growth factor release from injectable calcium phosphate cements containing gelatin microspheres
Authors: Habraken W. J. E. M. , Boerman O. C. , Wolke J. G. C. , Mikos A. G. , Jansen J. A. 
Published: November 2008

AbstractTo improve the in vivo resorption of an injectable calcium phosphate cement (CPC) for bone tissue engineering purposes, in previous experiments macroporosity was introduced by the in situ degradation of incorporated gelatin microspheres. Gelatin microspheres are also suitable carriers for osteoinductive drugs/growth factors, where release occurs concomitantly with degradation of the hydrogel. Introduction of these microspheres into CPC can alter the release pattern of the cement, which usually shows a marginal release of incorporated drugs. The goal of this study was to determine the in vitro release characteristics of gelatin microsphere CPC. For this, recombinant human TGF‐β1, bFGF, and BMP‐2 were labeled with 125I and loaded onto gelatin type A (porcine, pI = 7.0–9.0)/type B (bovine, pI = 4.5–5.0) microspheres for a short (instant) and longer (prolonged) time before mixing them with the cement. Radioactivity of the resulting 5 or 10 wt % gelatin microsphere CPC composites was monitored for 6 weeks when subjected to proteolytic medium. Drug‐loaded CPC was used as control. Results showed that release pattern/efficiency of gelatin microsphere CPCs and CPC controls was highly dependent on the type of growth factor but unaffected by the amount of growth factor. With gelatin microsphere CPC, release was also dependent on the type of gelatin, total volume of incorporated microspheres, and loading method. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Generation and characterization of a human acellular meniscus scaffold for tissue engineering
Authors: Sandmann G. H. , Eichhorn S. , Vogt S. , Adamczyk C. , Aryee S. , Hoberg M. , Milz S. , Imhoff A. B. , Tischer T. 
Published: November 2008

AbstractMeniscus tears are frequent indications for arthroscopic evaluation which can result in partial or total meniscectomy. Allografts or synthetic meniscus scaffolds have been used with varying success to prevent early degenerative joint disease in these cases. Problems related to reduced initial and long‐term stability, as well as immunological reactions prevent widespread clinical use so far. Therefore, the aim of this study was to develop a new construct for tissue engineering of the human meniscus based on an acellular meniscus allograft. Human menisci (n = 16) were collected and acellularized using the detergent sodium dodecyl sulfate as the main ingredient or left untreated as control group. These acellularized menisci were characterized biomechanically using a repetitive ball indentation test (Stiffness N/mm, residual force N, relative compression force N) and by histological (hematoxylin‐eosin, phase‐contrast) as well as immunohistochemical (collagen I, II, VI) investigation. The processed menisci histologically appeared cell‐free and had biomechanical properties similar to the intact meniscus samples (p > 0.05). The collagen fiber arrangement was not altered, according to phase‐contrast microscopy and immunohistochemical labeling. The removal of the immunogenic cell components combined with the preservation of the mechanically relevant parts of the extracellular matrix could make these scaffolds ideal implants for future tissue engineering of the meniscus. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009
Transforming growth factor β‐3 bound with sulfate polysaccharide in synthetic extracellular matrix enhanced the biological activities for neocartilage formation in vivo
Authors: Park Ji Sun , Woo Dae Gyun , Yang Han Na , Na Kun , Park Keun‐Hong 
Published: November 2008

AbstractThe thermoreversible hydrogel of poly(N‐isopropylacrylamide‐co‐acrylic acid) [p(NiPAAm‐co‐AAc)] was utilized in an injectable protein (growth factor) delivery system for use in tissue regeneration protocols. The transforming growth factor β (TGF β) proteins, which have been shown to bind to heparin, have been well established to induce chondrogenic differentiation in chondrocytes. In this study, we assessed the effects of heparin on the TGF β‐3 activities in rabbit chondrocytes embedded in thermoreversible hydrogel. The hydrogels embedded with chondrocytes and heparin‐bound TGF β‐3 were injected subcutaneously into nude mice, which were monitored for up to 8 weeks after injection. P(NiPAAm‐co‐AAc) hydrogels with TGF β‐3 were compared with the hydrogels with heparin bound to TGF β‐3 for the assessment of the effects of heparin binding on chondrogenic differentiation. To monitor the release of growth factor via in vivo analysis, we assessed the Cy5.5‐NHS‐conjugated growth factors via the bioimaging method. In terms of the release of growth factors, the release of heparin‐binding growth factor was slower than that of the growth factor itself. Additionally, the proliferation rate and cartilage‐specific ECM production were both found to be significantly higher in the presence of heparin binding than was observed with the controls. The quantity of cartilage‐associated ECM proteins was assessed via immunohistochemical staining (collagen type II) and safranin‐O staining. These data indicate the potential use of heparin‐binding TGF β‐3 for the reconstruction of neocartilage formation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Antimicrobial modification of polyester by admicellar polymerization
Authors: Ren Xuehong , Kou Lei , Kocer Hasan B. , Worley S. D. , Broughton R. M. , Tzou Y. M. , Huang T. S. 
Published: November 2008

AbstractThe N‐halamine monomer 3‐(4′‐vinylbenzyl)‐5,5‐dimethylhydantoin (VBDMH) was synthesized and employed to form thin films on the surfaces of polyester fibers by surface polymerization with the aid of a cationic surfactant. The coated samples were characterized by FTIR and SEM. The thin film coatings could be rendered biocidal by exposure to dilute sodium hypochlorite. The antimicrobial polyesters were challenged with Staphylococcus aureus and Escherichia coli O157:H7. Complete inactivation of S. aureus and E. coli O157:H7 was observed within 10 and 30 min of contact time, respectively. The chlorine bonded to the coatings was very stable under standard washing tests and UVA irradiation tests, and much of the lost chlorine could be regenerated by rechlorination. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Assessment in vitro of the active hemostatic properties of wound dressings
Authors: Jesty Jolyon , Wieland Martin , Niemiec Jack 
Published: November 2008

AbstractThe development of actively hemostatic wound dressings for use in severe trauma remains a major public‐health and military goal. But, although some manufacturers claim that existing dressings activate platelets and/or blood coagulation, mechanistic evidence is often lacking. We describe a method for assessing the active hemostatic properties of dressings in vitro, entailing measurement of the flow of recalcified platelet‐rich plasma (PRP) through a dressing sample. If the dressing is hemostatically active, flow is reduced. This flow is then compared with the flow‐through of PRP in which both platelet and coagulation function are blocked with EDTA. The ratio of the two generates a hemostatic index that ranges from 1.0 (no active hemostasis) to 0 (highly potent). The method is applicable to porous or semiporous dressings, whether fabric, sponge, fleece, or granules. For an active dressing, the test is easily modified to differentiate between the contributions of platelet and coagulation to overall hemostasis. The method is illustrated for fabrics, over‐the‐counter gauze and sponge dressings, collagen‐based sheets, and an absorbent granule dressing. One active collagen dressing is used to illustrate discrimination between platelet and coagulation function. The ability to assess hemostatic properties may significantly enhance the development of advanced active dressings. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Surface characterization and force relaxation of retrieved silk sutures
Authors: Zinelis S. , Eliades T. , Dimitrakopoulos I. , Silikas N. , Eliades G. 
Published: November 2008

AbstractAim:To investigate the relaxation of as‐received and retrieved silk sutures and characterize the compositional and structural changes occurred during service.Materials and Methods:Silk sutures were tested in three conditions: (a) as‐received, (b) retrieved from the oral cavity of patients, and (c) retrieved from extraoral sites of patients following 4 days. Specimens of the first group were fabricated by tying a knot on a plastic cable of 5 mm diameter. Specimens (n = 6) of groups (b) and (c) were placed in the appropriate surgical site and retrieved. Specimens were subjected to Fourier transform infrared spectroscopy for the characterization of molecular composition; low vacuum scanning electron microscopy (LV‐SEM) to investigate the morphological variation; and energy dispersive X‐ray microanalysis to assess the elemental composition of integuments formed onto the materials. To investigate the stress relaxation of elastics, a portable test assembly was developed to monitor the force exerted by a stretched suture for a period of 4 days.Results:Retrieved specimens demonstrated absorption of proteinaceous matter comprising of amide I and II and alcohol, as well as precipitation of Mg, Si, Cl, and Ca for the extraorally aged specimens and additional K and P for the intraorally exposed sutures. Aged specimens showed swelling and disorganization and rupture of suture bundles. Stress relaxation data were indicative of no difference between the three groups, which relaxed at 30% of the initial value, whereas the curves showed similar slopes.Significance:Significant relaxation was found for silk sutures, which seems to be independent of surgical site. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Development of a bioresorbable self‐hardening bone adhesive based on a composite consisting of polylactide methacrylates and β‐tricalcium phosphate
Authors: Heiss C. , Kraus R. , Peters F. , Henn W. , Schnabelrauch M. , Berg A. , Pautzsch T. , Weisser J. , Schnettler R. 
Published: November 2008

AbstractIn this work, a novel bioresorbable bone adhesive based on radically polymerizable polylactide with methacrylate endgroups known from polymethylmethacrylate (PMMA) cements and varying amounts of bioresorbable/biodegradable lactide moieties was developed. The swelling and degradation properties as well as the hardening time, viscosity, and adhesion properties (tension and shear resistance) were subsequently measured in vitro and optimized. For a broad use in surgery the handling properties, the shelf life and the storage temperature are important issues. The finally developed material consists of three substances that have to be mixed to start the reaction: a highly viscous mixture of oligomers and two β‐tricalcium phosphate (β‐TCP, Cerasorb®) powders with the radical starter and the promoter. The material has a processing time of 2 min and is completely cured after another minute. The tension and shear resistance of the material is 3.1–13.9 MPa that will decrease by storing the substance in a humid atmosphere. Degradation experiments showed a mass loss of 20–35% during the first 5 weeks. Tests with MC3T3‐E1 cells showed an increase of the alkaline phosphatase activity over a period of 14 days. The mechanical and handling properties and the in vitro data are showing a promising biomaterial for bone regeneration. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009