bluuebunny/crossref_metadata_2025_split huggingface dataset:
Engineered cellular response to scaffold architecture in a rabbit trephine defect
Authors: Simon Joshua L. , Roy Tithi Dutta , Parsons J. Russell , Rekow E. Dianne , Thompson Van P. , Kemnitzer John , Ricci John L. 
Published: July 2003

AbstractTight control of pore architecture in porous scaffolds for bone repair is critical for a fully elucidated tissue response. Solid freeform fabrication (SFF) enables construction of scaffolds with tightly controlled pore architecture. Four types of porous scaffolds were constructed using SFF and evaluated in an 8‐mm rabbit trephine defect at 8 and 16 weeks (n = 6): a lactide/glycolide (50:50) copolymer scaffold with 20% w/w tri‐calcium phosphate and random porous architecture (Group 1); another identical design made from poly(desaminotyrosyl‐tyrosine ethyl ester carbonate) [poly(DTE carbonate)], a tyrosine‐derived pseudo‐polyamino acid (Group 2); and two poly(DTE carbonate) scaffolds containing 500 μm pores separated by 500‐μm thick walls, one type with solid walls (Group 3), and one type with microporous walls (Group 4). A commercially available coralline scaffold (Interpore) with a 486‐μm average pore size and empty defects were used as controls. There was no significant difference in the overall amount of bone ingrowth in any of the devices, as found by radiographic analysis, but patterns of bone formation matched the morphology of the scaffold. These results suggest that controlled scaffold architecture can be superimposed on biomaterial composition to design and construct scaffolds with improved fill time. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 275–282, 2003
Electrochemical preparation of chitosan/hydroxyapatite composite coatings on titanium substrates
Authors: Redepenning Jody , Venkataraman Guhanand , Chen Jun , Stafford Nathan 
Published: July 2003

AbstractComposite coatings containing brushite (CaHPO4 · 2H2O) and chitosan were prepared by electrochemical deposition. The brushite/chitosan composites were converted to hydroxyapatite/chitosan composites in aqueous solutions of sodium hydroxide. The coatings ranged from ≈1 to 15% chitosan by weight. Qualitative assessment of the coatings showed adhesion significantly improved over that observed for electrodeposited coatings of pure HA. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 411–416, 2003
Compatibility in vitro of albumin‐heme (O2 carrier) with blood cell components
Authors: Huang Yubin , Komatsu Teruyuki , Nakagawa Akito , Tsuchida Eishun , Kobayashi Shū 
Published: July 2003

AbstractRecombinant human serum albumin including 2‐[8‐{N‐(2‐methylimidazolyl)}octanoyloxymethyl]‐5,10,15,20‐tetrakis(α,α,α,α‐o‐pivaloylamino)phenylporphinatoiron(II) (albumin‐heme; rHSA‐FeP) is a synthetic hemoprotein that has sufficient capability to reversibly bind and release O2 under physiological conditions (pH 7.3, 37°C) similar to hemoglobin and myoglobin. In order to use this albumin‐based O2 carrier as a new class of red blood cell substitutes, its compatibility with blood cell components carefully was investigated in vitro. After the addition of the rHSA‐FeP solution into whole blood at 10, 20, and 44 vol %, the FeP concentration in the plasma phase remained constant for 6 h at 37°C in each group, and no significant time dependence was observed in the numbers of red blood cells, white blood cells, or platelets. The microscopic observations clearly showed that the shapes of the red blood cells had not been deformed during the measurement period. With respect to the blood coagulation parameters (prothrombin time and activated partial thromboplastin time), the coexistence of rHSA‐FeP had only a negligibly small influence. Also the blood compatibility under dynamic flow conditions was evaluated using a microchannel array flow analyzer. All these results suggest that the albumin‐heme has no effect on the morphology of blood cell components in vitro. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 292–297, 2003
Long‐term craniofacial osteoblast culture on a sodium phosphate and a calcium/sodium phosphate glass
Authors: Gough J. E. , Christian P. , Scotchford C. A. , Jones I. A. 
Published: July 2003

AbstractThe aim of this study was to determine the characteristics of human craniofacial osteoblasts cultured on sodium phosphate glass and calcium–sodium phosphate glass in a long‐term culture of up to 28 days. The characteristics studied were attachment, proliferation, alkaline phosphatase activity, collagen‐1 production, and mineralization. A comparison of the degradation rate, measured by mass loss of the glasses, which are intended for use as a component of a novel degradable composite for craniofacial bone repair, was also performed. It was our hypothesis that the glass would be degradable with a change in degradation rate observed by calcium addition and support osteoblast proliferation and expression of the above characteristics. The inclusion of calcium into the reaction mixture significantly decreased the degradation rate, and it is suggested that the slower degradation is the result of pseudo crosslinking (ionic crosslinks rather than covalent bonding) of the polyphosphate chains by the calcium ions. Therefore, twice as many PO bonds will need to be hydrolyzed for dissolution of the metal phosphate to occur, therefore greatly reducing the rate of hydrolysis. Osteoblasts were able to attach, spread, and proliferate in a manner comparable with the positive control, as shown by analysis of variance. Formation of a collagen‐rich mineralized matrix was also observed. The results presented here suggest that a biocompatible soluble glass has been produced, which has potential to be included in a novel biodegradable craniofacial implant. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 233–240, 2003
Native extracellular matrix coating on Ti surfaces
Authors: Pham Minh T. , Reuther Helfried , Maitz Manfred F. 
Published: July 2003

AbstractOsteoblast‐like SAOS‐2 cells were allowed to synthesize and assemble their extracellular matrix (ECM) on titanium surfaces. After the selective removal of cells, Ti coated with a native ECM was obtained (ECM‐Ti). The responses of SAOS‐2 cells to ECM−Ti compared with those to peptide sequence RGDS‐ or fibronectin‐immobilized Ti were examined, demonstrating the compositional and structural effects needed to trigger the native cell behavior. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 310–316, 2003
In vitro bioactivity of silicon‐substituted hydroxyapatites
Authors: Balas F. , Pérez‐Pariente J. , Vallet‐Regí M. 
Published: July 2003

AbstractSilicon‐containing hydroxyapatites were synthesized by the controlled crystallization method. Chemical analysis, N2 adsorption, Hg porosimetry, X‐ray diffraction, scanning electron microscopy‐energy‐dispersive X‐ray spectroscopy, and X‐ray photoelectron spectroscopy (XPS) were used to characterize the hydroxyapatite and to monitor the development of a calcium phosphate layer onto the surface of the substrate immersed in a simulated body fluid, that is, in vitro bioactivity tests. The influence of the silicon content and the nature of the starting calcium and phosphorus sources on the in vitro bioactivity of the resulting materials were studied. A sample of silicocarnotite, whose structure is related to that of hydroxyapatite and contains isolated SiO44− anions that isomorphically substitute some PO43− anions, was prepared and used as reference material for XPS studies. An increase of the unit cell parameters with the Si content was observed, which indicated that SiO44− units are present in lattice positions, replacing some PO43− groups. By using XPS it was possible to assess the presence of monomeric SiO44− units in the surface of apatite samples containing 0.8 wt % of silicon, regardless the nature of the starting raw materials, either Ca(NO3)2/(NH4)2HPO4/Si(OCOCH3)4 or Ca(OH)2/H3PO4/Si(OCOCH3)4. However, an increase of the silicon content up to 1.6 wt % leads to the polymerization of the silicate species at the surface. This technique shows silicon enrichment at the surface of the three samples. The in vitro bioactivity assays showed that the formation of an apatite‐like layer onto the surface of silicon‐containing substrates is strongly enhanced as compared with pure silicon‐free hydroxyapatite. The samples containing monomeric silicate species showed higher in vitro bioactivity than that of silicon‐rich sample containing polymeric silicate species. The use of calcium and phosphate salts as precursors lead to materials with higher bioactivity. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 364–375, 2003
Performance of degradable composite bone repair products made via three‐dimensional fabrication techniques
Authors: Roy Tithi Dutta , Simon Joshua L. , Ricci John L. , Rekow E. Dianne , Thompson Van P. , Parsons J. Russell 
Published: July 2003

AbstractThis study analyzed the in vivo performance of composite degradable bone repair products fabricated using the TheriForm™ process, a solid freeform fabrication (SFF) technique, in a rabbit calvarial defect model at 8 weeks. Scaffolds were composed of polylactic‐co‐glycolic acid (PLGA) polymer with 20% w/w β‐tricalcium phosphate (β‐TCP) ceramic with engineered macroscopic channels, a controlled porosity gradient, and a controlled pore size for promotion of new bone ingrowth. Scaffolds with engineered macroscopic channels and a porosity gradient had higher percentages of new bone area compared to scaffolds without engineered channels. These scaffolds also had higher percentages of new bone area compared to unfilled control defects, suggesting that scaffold material and design combinations could be tailored to facilitate filling of bony defects. This proof‐of‐concept study demonstrated that channel size, porosity, and pore size can be controlled and used to influence new bone formation and calvarial defect healing. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 283–291, 2003
Development of a novel method for synthesis of a polymeric ultrasound contrast agent
Authors: El‐Sherif Dalia M. , Wheatley Margaret A. 
Published: July 2003

AbstractMedical ultrasound is a highly valuable diagnostic tool, especially when compared with other imaging modalities. It is a noninvasive, real‐time, portable, extremely safe method compared with X‐ray and inexpensive relative to magnetic resonance imaging. However, ultrasound is limited in its ability to distinguish between diseased and normal tissue. This limitation has led to the development of contrast agents. We have produced novel poly (lactic‐co‐glycolic) acid air‐filled microcapsules that work well as ultrasound contrast agents, giving up to 24 and 25 dB enhancement when insonated in the medical imaging range at 5 and 7.5 MHz, respectively. The capsules were fabricated by modifying a double emulsion method to encapsulate camphor in the oil phase and ammonium carbonate in the aqueous phase, and later sublime the encapsulated material, leaving voids capable of being filled with a gas in their place. The role of the surfactant, poly vinyl alcohol, solution temperature, was studied and found to play an important role in the morphology of the capsules, altering their acoustic response. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 347–355, 2003
Preparation, characterization, and in vitro degradation of bioresorbable and bioactive composites based on Bioglass®‐filled polylactide foams
Authors: Maquet V. , Boccaccini A. R. , Pravata L. , Notingher I. , Jérôme R. 
Published: July 2003

AbstractHighly porous poly(D,L‐lactide)/Bioglass® composites scaffolds were prepared by thermally induced phase separation process of polymer solutions and subsequent solvent sublimation. A series of composite foams with different polymer/Bioglass® weight ratios was prepared to study the influence of Bioglass® content on the foam characteristics such as porous structure, density, and pore volume. The pore volume was decreased from 9.5 to 5.7 cm3/g when the Bioglass® content was increased up to 40 wt %, but the overall pore morphology was not affected very much by changing the polymer/glass composition ratio. The composites foams were then incubated in phosphate‐buffered saline at 37°C to study the in vitro degradation of the polymer and to detect hydroxyapatite (HA) formation as an indication of their bioactivity. The addition of Bioglass® to polymer foams increased the water absorption and weight loss as compared with pure polymer foams. However, the polymer molecular weight, determined by size exclusion chromatography, was found to decrease more rapidly and to a larger extent in absence of Bioglass®. This delayed degradation rate in the composite foams was probably caused by the dissolution of alkaline ions from the Bioglass®, resulting in a buffering effect of the incubation medium. After incubation for 7 days, HA was detected by X‐ray diffractometry and Raman spectroscopy and confirmed by environmental scanning electron microscopy and energy‐dispersive X‐ray analysis. The porous composites developed here are promising materials for bone regeneration applications because the formation of HA on the surface of the pore walls should provide good environment for the adhesion and proliferation of osteoblasts and osteoprogenitor cells. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 335–346, 2003
Ultraviolet light‐induced modification of crosslinked hyaluronan gels
Authors: Ramamurthi Anand , Vesely Ivan 
Published: July 2003

AbstractHyaluronan (HA) gels (hylans) crosslinked with divinyl sulfone (DVS) are highly biocompatible and can be structurally modified to obtain desired mechanical properties that are attractive for their use as tissue‐engineering scaffolds. However, unmodified hylan gels are not good substrates for cell attachment or infiltration, likely as a result of their smooth surface and the highly anionic nature of HA. This study investigated whether the cell‐adhering characteristics of hylan gels could be enhanced by irradiation with ultraviolet (UV) light, with or without prior dehydration. The attachment and proliferation of neonatal rat smooth muscle cells atop these gels was compared with that on unmodified (control; C) or dehydrated (D) gels. UV‐induced changes to gel structure and chemistry were characterized by confocal and electron microscopy, and fluorphore‐assisted carbohydrate electrophoresis (FACE). Cell attachment was sparse on both unmodified (C) and dehydrated (D) gels. Significantly higher levels of cell attachment were observed on the surface of irradiated (UV) and dehydrated‐irradiated (DUV) gels, likely because of texturing of the gel surface by UV light. In addition, dehydration of gels before UV irradiation created irregular pore‐like structures through which cells appeared to migrate into the interior. FACE assays demonstrated that UV‐irradiation alters the chemistry of HA, causing limited breakdown of HA chains and DVS crosslinks within gel and possibly creating new crosslinks that have not yet been identified. Because the hylan gels are altered structurally and chemically, binding of cells to the material is likely to be more permanent than possible by other approaches, such as coating of cell‐adhesive matrix factors on the gel surface, described previously. The significance of this work is that we have developed a technique for the modification of DVS‐crosslinked HA (hylans) to enhance their performance as a cellular scaffold for tissue‐engineering applications. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 317–329, 2003
Electrostatic spray deposition (ESD) of calcium phosphate coatings
Authors: Leeuwenburgh S. , Wolke J. , Schoonman J. , Jansen J. 
Published: July 2003

AbstractUsing electrostatic spray deposition (ESD), thin calcium phosphate layers were deposited onto commercially pure cp‐Ti substrates. ESD is a thin‐film technique that enables the deposition of inorganic thin films onto metallic substrates using a simple and cheap experimental set‐up. The results show that coating structure and morphology can be tailored by choosing the appropriate combination of deposition parameters. Scanning electron microscopy revealed that various surface morphologies, ranging from dense to very porous coatings, can be obtained. Particularly interesting was a unique reticular coating morphology characterized by a three‐dimensionally interconnected pore network. X‐ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR) analyses showed that crystalline carbonate apatite coatings were formed after heat treatment of as‐deposited ESD coatings. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 330–334, 2003
Seeding cells into needled felt scaffolds for tissue engineering applications
Authors: Unsworth J. M. , Rose F. R. A. J. , Wright E. , Scotchford C. A. , Shakesheff K. M. 
Published: July 2003

AbstractTissue engineering methods are under development that will enable the repair or replacement of a variety of tissues, including articular cartilage and bone. To engineer functional tissue it is necessary that scaffolds initially be seeded with a large number of cells distributed evenly throughout the scaffold structure. It previously has been shown that, compared to static seeding conditions, seeding scaffolds under dynamic conditions facilitates high seeding densities and even distributions of cells (Li et al., Biotechnology Progress 2001;17:935–944). The efficiency of seeding HOSTE85 cells and bovine chondrocytes into needled felt scaffolds following agitation at different speeds was determined. Seeding efficiency was determined using the Hoechst 33258 assay, and cell viability was assessed using the Alamar Blue™ assay. The distribution of cells within the scaffolds was imaged using scanning electron microscopy. It was found that the optimum seeding conditions varied for HOSTE85 cells and bovine chondrocytes, with different agitation speeds leading to different seeding efficiencies, cell viabilities, and distributions of cells within scaffolds. The optimum agitation speeds for seeding a high number of viable cells into scaffolds so that they were arranged evenly were 300 rpm for HOSTE85 cells and 200 rpm for bovine chondrocytes. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 425–431, 2003
Tailored delivery of active keratinocyte growth factor from biodegradable polymer formulations
Authors: Cho Eun Jeong , Tao Zunyu , Tang Ying , Tehan Elizabeth C. , Bright Frank V. , Hicks Wesley L. , Gardella Joseph A. , Hard Robert 
Published: July 2003

AbstractWe report the results of a high throughput screening campaign that is aimed to develop a biodegradable polymer‐based formulation to deliver active keratinocyte growth factor (KGF) and provide a means to tune the KGF delivery rate. A statistical design strategy was used to prepare and screen a series of polymer blends that were composed of poly(lactic acid) (PLA), poly(glycolic acid) (PGA), and the surfactant sodium bis(ethylhexyl)sulfosuccinate (Aerosol‐OT, AOT). Chloroform was the solvent. Our high throughput screening method used a two‐tiered assessment strategy. At Level 1, we identified “lead” KFG‐loaded formulations that exhibited KGF emission spectra that were the most similar to the native KGF spectrum recorded in buffer. At Level 2, we used steady‐state emission and a homogeneous polarization immunoassay strategy to determine the concentration of total and active KGF, respectively, liberated from the lead formulations during biodegradation. After preparing and screening 2500 formulations, we identified several viable, lead formulations. An analysis of the data showed that the combination of PLA, PGA, and AOT were important to yield a high fraction of active KGF upon release from the formulation; no combination of any two together produced an effect as good as the ternary formulation. The optimum formulations that yielded the highest fraction of active KGF upon release had the following general features: PLA/PGA (w/w) near unity, AOT loading of 100–200 mM, water/AOT mole ratio of 10–20, and a pH between 6 and 8. PLA alone cast from chloroform delivered KGF, but that KGF did not bind to anti‐KGF antibodies (i.e., it was inactive). We can tune the KGF release kinetics by more than two orders of magnitude while maintaining the KGF activity upon liberation from the formulation by adjusting the PLA molecular weight. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 417–424, 2003
Heparin inhibits lipopolysaccharide (LPS) binding to leukocytes and LPS‐induced cytokine production
Authors: Anastase‐Ravion Sylvie , Blondin Catherine , Cholley Béatrice , Haeffner‐Cavaillon Nicole , Castellot John J. , Letourneur Didier 
Published: July 2003

AbstractThe glycosaminoglycan heparin is known to exhibit anti‐inflammatory properties unrelated to its anticoagulant activity. However, in a generalized inflammatory response with implanted or extracorporeal devices, the beneficial effect of heparin coating and/or systemic administration is still unclear as well as the precise mechanisms of action. In the present study, we have first studied the effect of heparin on lipopolysaccharide (LPS)‐induced cytokine production by human blood monocytes. Our results indicated that the production of interleukin‐1α, tumor necrosis factor‐α, and interleukin‐8 was significantly decreased when heparin was simultaneously incubated with Escherichia coli LPS. Because the modulation of heparin on monocyte activation could be mediated by its binding via CD14, the main LPS receptor on monocytes, we then studied the binding of LPS and heparin to leukocytes from human blood and to Chinese hamster ovary cells transfected with the human CD14 gene. The data by flow cytometry showed the binding of biotinylated heparin to leukocytes. Moreover, the experiments performed on leukocytes and on CD14‐positive Chinese hamster ovary cells indicated that heparin inhibited LPS binding. From our results, we conclude that: 1. heparin is an effective inhibitor of LPS‐induced monocyte activation, and 2. heparin inhibits the binding of LPS to cells via a CD14‐independent pathway. This study suggests a potentially important therapeutic application for heparin or heparin analogs to prevent inflammation with biomaterials. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 66A: 376–384, 2003