bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of dense polylactic acid/beta‐tricalcium phosphate scaffolds for bone tissue engineering
Authors: Yanoso‐Scholl Laura , Jacobson Justin A. , Bradica Gino , Lerner Amy L. , O'Keefe Regis J. , Schwarz Edward M. , Zuscik Michael J. , Awad Hani A. 
Published: August 2010

AbstractAdvances in biomaterial fabrication have introduced numerous innovations in designing scaffolds for bone tissue engineering. Often, the focus has been on fabricating scaffolds with high and interconnected porosity that would allow for cellular seeding and tissue ingrowth. However, such scaffolds typically lack the mechanical strength to sustain in vivo ambulatory stresses in models of load bearing cortical bone reconstruction. In this study, we investigated the microstructural and mechanical properties of dense PLA and PLA/beta‐TCP (85:15) scaffolds fabricated using a rapid volume expansion phase separation technique, which embeds uncoated beta‐TCP particles within the porous polymer. PLA scaffolds had a volumetric porosity in the range of 30 to 40%. With the embedding of beta‐TCP mineral particles, the porosity of the scaffolds was reduced in half, whereas the ultimate compressive and torsional strength were significantly increased. We also investigated the properties of the scaffolds as delivery vehicles for growth factors in vitro and in vivo. The low‐surface porosity resulted in sub optimal retention efficiency of the growth factors, and burst release kinetics reflecting surface coating rather than volumetric entrapment, regardless of the scaffold used. When loaded with BMP2 and VEGF and implanted in the quadriceps muscle, PLA/beta‐TCP scaffolds did not induce ectopic mineralization but induced a significant 1.8‐fold increase in neo vessel formation. In conclusion, dense PLA/beta‐TCP scaffolds can be engineered with enhanced mechanical properties and potentially be exploited for localized therapeutic factor delivery. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Cartilage regeneration by bone marrow cells‐seeded scaffolds
Authors: Wegener Bernd , Schrimpf Florian M. , Bergschmidt Philipp , Pietschmann Mathias F. , Utzschneider Sandra , Milz Stefan , Jansson Volkmar , Müller Peter E. 
Published: August 2010

AbstractDifferent approaches exist for the treatment of small articular cartilage defects. Several studies show comparable results for autologous chondrocyte implantation (ACI) and microfracture. Unfortunately, the fibrocartilage resulting from microfracture has neither the structure nor the mechanical properties of hyaline cartilage, even though the adult mesenchymal stem cells, which immigrate into the defect, are supposed to differentiate into chondrocytes. This study was performed to examine the capacity of a resorbable implant made from polylactide‐co‐glycolide acid (PGLA)‐fleece combined with autologous bone marrow cells fixed with a fibrin/thrombin‐clot in the weight‐bearing area of the femoral condyle of mature sheep. For this study, six defects were treated with either the PGLA‐implant alone or with a combination of the implant with added fibrin glue or were left untreated to serve as controls. The animals were sacrificed after 12 weeks; the operated knees were removed and examined by measuring the covering of the defect with cartilaginous tissue and according to the score of O'Driscoll. Additional criteria such as immunolabeling for collagen II and aggrecan were included. Results showed that no improvement of the tissue quantity or quality could be achieved by increasing the cell load of the implant with cells fixed by fibrin glue. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Biomimetic organic–inorganic nanocomposite coatings for titanium implants. In vitro and in vivo biological testing
Authors: Schade R. , Sikirić M. Dutour , Lamolle S. , Ronold H. J. , Lyngstadass S. P. , Liefeith K. , Cuisinier F. , Füredi‐Milhofer H. 
Published: August 2010

AbstractRecently described organic–inorganic nanocomposite coatings of the chemical composition: (PLL/PGA)10CaP[(PLL/PGA)5CaP]4 (coating A) and (PLL/PGA)10CaP[(PLL/PGA)5CaP]4(PLL/PGA)5 (coating B), applied to chemically etched titanium plates, have been tested by extensive cell culture tests and in vivo biological experiments, with uncoated titanium plates serving as controls. Before testing, coated samples were stored for extended periods of time (from 2 weeks to 8 months) under dry, sterile conditions. Cells of the cell‐lines MC3T3‐E1 and/or SAOS‐2 were used for the following cell culture tests: initial adhesion (4 h) and proliferation (up to 21 days), cell activity (XTT test), morphology, synthesis of collagen type I and alkaline phosphatase activity (all incubation up to 21 days). In addition, coating B was tested against uncoated control in a validated in vivo pull‐out model in rabbit tibia. The results of both in vitro and in vivo experiments show excellent biological properties of chemically etched titanium which are even surpassed by surfaces covered with coating B. Thus, after 8 weeks of healing the implants coated with B were significantly better attached to the cortical bone of rabbit thibiae than uncoated titanium controls with more than twice the force needed to detach coated implants. However, coating A (top crystal layer) had an adverse effect on both cell proliferation and activity, which is explained by morphological observations, showing inhibited spreading of the cells on its rough surfaces. The results also show the remarkable stability of the coatings when shelved under dry and sterile conditions. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
In vitro evaluation of polyester‐based scaffolds seeded with adipose derived stem cells for peripheral nerve regeneration
Authors: Tse Kai‐Hei , Sun Mingzhu , Mantovani Cristina , Terenghi Giorgio , Downes Sandra , Kingham Paul J. 
Published: August 2010

AbstractTo overcome the disadvantages of autografts for peripheral nerve repair, different methods such as artificial nerve conduits have been investigated for an alternative approach. This study demonstrated that solvent casting is a simple but efficient method to create thin polyester‐based scaffolds for stem cell delivery. Using poly (ε‐caprolactone) and poly (D,L‐lactic acid), we produced scaffold films containing heterogenous depressions (pits) on the air surface with a size ranging from 0.5 to 30 μm2. These scaffolds were moderately hydrophobic; however, they supported the differentiation of adipose derived stem cells (ADSC) into a Schwann cell‐like phenotype. The differentiated ADSC (dADSC) expressed S100 protein and glial fibrillary acidic protein and readily adhered to the films and proliferated at a similar rate to those cultured on tissue culture polystyrene. Cells were also positive for proliferating cell nuclear antigen. Furthermore, dADSC retained functional activity and significantly enhanced neurite outgrowth from dorsal root ganglia neurons. This study suggests polymer scaffolds combined with dADSCs could be a promising therapy for peripheral nerve injuries. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
UV‐killed Staphylococcus aureus enhances adhesion and differentiation of osteoblasts on bone‐associated biomaterials
Authors: Somayaji Shankari N. , Huet Yvette M. , Gruber Helen E. , Hudson Michael C. 
Published: August 2010

AbstractTitanium alloys (Ti) are the preferred material for orthopedic applications. However, very often, these metallic implants loosen over a long period and mandate revision surgery. For implant success, osteoblasts must adhere to the implant surface and deposit a mineralized extracellular matrix (ECM). Here, we utilized UV‐killed Staphylococcus aureus as a novel osteoconductive coating for Ti surfaces. S. aureus expresses surface adhesins capable of binding to bone and biomaterials directly. Furthermore, interaction of S. aureus with osteoblasts activates growth factor‐related pathways that potentiate osteogenesis. Although UV‐killed S. aureus cells retain their bone‐adhesive ability, they do not stimulate significant immune modulator expression. All of the abovementioned properties were utilized for a novel implant coating so as to promote osteoblast recruitment and subsequent cell functions on the bone‐implant interface. In this study, osteoblast adhesion, proliferation, and mineralized ECM synthesis were measured on Ti surfaces coated with fibronectin with and without UV‐killed bacteria. Osteoblast adhesion was enhanced on Ti alloy surfaces coated with bacteria compared to uncoated surfaces, while cell proliferation was sustained comparably on both surfaces. Osteoblast markers such as collagen, osteocalcin, alkaline phosphatase activity, and mineralized nodule formation were increased on Ti alloy coated with bacteria compared to uncoated surfaces. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Enhancement of osteoblast differentiation that is inhibited by titanium particles through inactivation of NFATc1 by VIVIT peptide
Authors: Maoqiang Li , Zhenan Zhu , Fengxiang Liu , Gang Wang , Yuanqing Mao , Ming Liu , Xin Zhao , Tingting Tang 
Published: August 2010

AbstractBone formation, which is inhibited by particulate wear debris, is a pathological factor that contributes to periprosthetic osteolysis. Although the nuclear factor of activated T cells c1 (NFATc1) is known to be involved in osteoblast differentiation, and its effect on osteoblasts in response to wear particles remains unclear. In this study, we investigated the role of NFATc1 in the regulation of osteoblastic differentiation of rat calvaria (RC) cells (a cell‐culture model comprising many osteoprogenitors) that were challenged with titanium (Ti) particles. The results showed that the Ti particles inhibited osteoblastic differentiation and mineralization of RC cells. NFATc1 plays a critical role in the Ti‐particle inhibition process of the osteoblastic differentiation in RC cells. Inactivation of NFATc1 by the 11R‐VIVIT peptide potently enhanced osteoblast differentiation and mineralization inhibition by the Ti particles. The 11R‐VIVIT peptide does not have a toxic effect on the RC cells. On the basis of these data, we conclude that inactivation of NFATc1 by the 11R‐VIVIT peptide may provide a promising therapeutic target for the treatment of periprosthetic osteolysis by increasing bone formation. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Biomaterial topography alters healing in vivo and monocyte/macrophage activation in vitro
Authors: Bota Paige C. S. , Collie Angela M. B. , Puolakkainen Pauli , Vernon Robert B. , Sage E. Helene , Ratner Buddy D. , Stayton Patrick S. 
Published: August 2010

AbstractThe effect of biomaterial topography on healing in vivo and monocyte/macrophage stimulation in vitro was assessed. A series of expanded polytetrafluoroethylene (ePTFE) materials were characterized by increasing average intranodal distance of 1.2 μm (1.2‐ePTFE), 3.0 μm (3.0‐ePTFE), and 4.4 μm (4.4‐ePTFE), but presented consistent surface chemistry with nonporous PTFE (np‐PTFE). Subcutaneous implantation of 4.4‐ePTFE into mice resulted in a statistically thinner capsule that appeared less organized and less dense than the np‐PTFE response. In vitro, isolated monocytes/macrophages cultured on np‐PTFE produced low levels of interleukin 1‐beta (IL‐1β), 1.2‐ePTFE and 3.0‐ePTFE stimulated intermediate levels, and 4.4‐ePTFE stimulated a 15‐fold increase over np‐PTFE. Analysis of cDNA microarrays demonstrated that additional proinflammatory cytokines and chemokines, including IL‐1β, interleukin 6, tumor necrosis factor alpha, monocyte chemotactic protein 1, and macrophage inflammatory protein 1‐beta, were expressed at higher levels by monocytes/macrophages cultured on 4.4‐ePTFE at 4 and 24 h, respectively. Expression ratios for several genes were quantified by RT‐PCR and were consistent with those from the cDNA array results. These results demonstrate the effect of biomaterial topography on early proinflammatory cytokine production and gene transcription by monocytes/macrophages in vitro and decreased fibrous capsule thickness in vivo. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Mono‐dispersed bioactive glass nanospheres: Preparation and effects on biomechanics of mammalian cells
Authors: Hong Zhongkui , Luz Gisela M. , Hampel Paul J. , Jin Minshan , Liu Aixue , Chen Xuesi , Mano João F. 
Published: August 2010

AbstractMono‐dispersed SiO2‐CaO bioactive glass nanospheres (BGNS) were prepared by a two step sol‐gel method in the absence of surfactant. The size of BGNS ranged from 200 to 350 nm in diameter and exhibited a rough surface texture. In vitro biomineralization tests showed that BGNS could rapidly induce the deposition of an apatite layer in simulated body fluid (SBF). The effect of bioactive glass on the biomechanical properties of various mammalian cells was first reported in this paper. Atomic force microscopy (AFM) was used for measuring the biomechanical properties of mammalian cells. The result showed that BGNS‐medium could significantly decrease the plasma membrane stiffness of bone marrow stem cells (BMSCs) by ∼50% and stimulate BMSCs spreading. The effect of BGNS on biomechanical properties of bovine aortic endothelial cells (BAECs) was opposite to that on BMSCs. BGNS increased the BAECs' stiffness and stimulated the elongation of endothelial cells and the formation of endothelial networks, which might potentially facilitate the vascularization of implanted BGNS‐based biomaterials in tissue engineering as a scaffold or as an injectable system. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.
Synthesis and characterization of injectable composites of poly[D,L‐lactide‐co‐(ε‐caprolactone)] reinforced with β‐TCP and CaCO3 for intervertebral disk augmentation
Authors: López Alejandro , Persson Cecilia , Hilborn Jöns , Engqvist Håkan 
Published: August 2010

AbstractDegeneration of the intervertebral disk constitutes one of the major causes of low back pain in adults aged 20–50 years old. In this study, injectable, in situ setting, degradable composites aimed for intervertebral disk replacement were prepared. β‐TCP and calcium carbonate particles were mixed into acrylic‐terminated oligo[D,L‐lactide‐co‐(ε‐caprolactone)], which were crosslinked at room temperature. The structure of the oligomers was confirmed by 1H‐NMR spectroscopy. The composites were examined via SEM, and the mechanical properties of the crosslinked networks were determined. The porous β‐TCP particles showed good mechanical anchorage to the matrix due to polymer penetration into the pores. In vitro degradation tests showed that the composites containing β‐TCP slowly degraded, whereas the composites containing CaCO3 exhibited apatite formation capacity. It was concluded that the surface area, morphology, and solubility of the fillers might be used to control the degradation properties. The incorporation of fillers also increased both the elastic modulus and the maximum compression strength of the composites, properties that were similar to those of the physiological disk. These materials have potential for long‐term intervertebral disk replacement and regenerative scaffolds because of their low degradation rates, bioactivity, and mechanical properties. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Silk hydrogel for cartilage tissue engineering
Authors: Chao Pen‐Hsiu Grace , Yodmuang Supansa , Wang Xiaoqin , Sun Lin , Kaplan David L. , Vunjak‐Novakovic Gordana 
Published: August 2010

AbstractCartilage tissue engineering based on cultivation of immature chondrocytes in agarose hydrogel can yield tissue constructs with biomechanical properties comparable to native cartilage. However, agarose is immunogenic and nondegradable, and our capability to modify the structure, composition, and mechanical properties of this material is rather limited. In contrast, silk hydrogel is biocompatible and biodegradable, and it can be produced using a water‐based method without organic solvents that enables precise control of structural and mechanical properties in a range of interest for cartilage tissue engineering. We observed that one particular preparation of silk hydrogel yielded cartilaginous constructs with biochemical content and mechanical properties matching constructs based on agarose. This finding and the possibility to vary the properties of silk hydrogel motivated this study of the factors underlying the suitability of hydrogels for cartilage tissue engineering. We present data resulting from a systematic variation of silk hydrogel properties, silk extraction method, gel concentration, and gel structure. Data suggest that silk hydrogel can be used as a tool for studies of the hydrogel‐related factors and mechanisms involved in cartilage formation, as well as a tailorable and fully degradable scaffold for cartilage tissue engineering. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Hyaluronic acid hydrogel modified with nogo‐66 receptor antibody and poly‐L‐lysine to promote axon regrowth after spinal cord injury
Authors: Wei Yue‐Teng , He Yu , Xu Chang‐Lei , Wang Ying , Liu Bing‐Fang , Wang Xiu‐Mei , Sun Xiao‐Dan , Cui Fu‐Zhai , Xu Qun‐Yuan 
Published: August 2010

AbstractThe biomaterials used for central nervous system injury require not only interacting with specific cell adhesion but also specific growth factor receptors to promote nerve regeneration. In this study, hyaluronic acid (HA)‐based hydrogels modified with poly‐L‐lysine (PLL) and nogo‐66 receptor antibody (antiNgR) (HA‐PLL/antiNgR) were administered to rats after lateral hemisection of the spinal cord. Anti‐neurofilament positive axons were found to extend into the HA‐PLL/antiNgR hydrogel at 8 weeks after implantation, which shows significant difference compared with HA‐PLL or blank control group. Electron micrographs of implanted hydrogels showed that there were more cells and normal axons with myelin in the HA‐PLL/antiNgR implant than that of HA‐PLL hydrogel. The antiNgR grafted on HA hydrogels could be detected for 8 weeks after transplantation in vivo. All of these properties may facilitate HA‐PLL/antiNgR hydrogels to become a promising scaffold for repairing spinal cord injury. Nevertheless, both two kinds of modified hydrogels (HA‐PLL/antiNgR and HA‐PLL) showed remarkable advantages in supporting angiogenesis, and simultaneously inhibiting the formation of glial scar. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Use of textile dyeing technology to create an infection‐resistant functionalized polyester biomaterial
Authors: Aggarwal Puja , Sousa Kerry A. , LoGerfo Frank W. , Bide Martin J. , Phaneuf Matthew D. 
Published: August 2010

AbstractInfection is a major complication when utilizing implantable devices. The purpose of this study was to create a functionalized polyethylene terephthalate (polyester) biomaterial with sustained antimicrobial properties using textile‐dyeing technology. Polyester was hydrolyzed via exposure to sodium hydroxide (NaOH) to provide two functional sites within the polymeric backbone. A modified textile dyeing technique known as thermofixation or pad‐heating (pad‐heat) in conjunction with autoclaving was employed to directly incorporate the fluoroquinolone antibiotic Ciprofloxacin (Cipro) into polyester fibers. Woven polyester segments were placed into various concentrations of boiling NaOH solutions to create carboxylic acid and hydroxyl groups (HYD). The segments were then sprayed (padded) with a 5 mg mL−1 Cipro solution and dried overnight, followed by exposure to intense heat and autoclaving. Untreated HYD, Cipro‐dipped, and pad‐heat‐treated HYD segments were then washed under stringent conditions. The antimicrobial activity of the each material was determined via zone of inhibition. Untreated HYD controls had no antimicrobial activity at any of the time periods examined. Cipro‐dipped HYD segments had no antimicrobial activity after 1 h. In contrast, antimicrobial activity for autoclaved, pad‐heat‐treated HYD segments persisted for 80 days (length of study). Autoclave usage prior to plating affected antimicrobial activity substantially. Additionally, varying hydrolysis concentrations did not significantly affect overall Cipro release. Thus, Cipro application to HYD polyester via thermofixation resulted in controlled, sustained antibiotic release over an extended period of time. The long‐term infection resistance provided by this technique may address major problems of infection from which implantable devices suffer. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Guided bone regeneration: Dynamic procedures versus static shielding in an animal model
Authors: Lethaus Bernd , Tudor Christian , Bumiller Lars , Birkholz Torsten , Wiltfang Jörg , Kessler Peter 
Published: August 2010

AbstractDue to its osteoinductive potential, the periosteum plays a crucial role in the process of neoosteogenesis. Therefore, periosteal elevation can lead to new bone formation in an artificially created space. In this study, we compared dynamic periosteal elevation with static shielding in an animal experiment. Different elevation/shielding heights of 5, 10, and 15 mm were tested with regard to various consolidation periods. Histological analysis, histomorphometry, and microradiography were used to measure the quantity and quality of the newly formed bone. No significant differences regarding bone quantity or quality were found between the two techniques. The cumulative results for the bone regeneration in the space created by distraction/elevation were about 66% in the dynamic and 67% in static procedure. The main advantages of both techniques are minimal invasion and low morbidity. In terms of clinical applications, periosteal elevation could be applied in cranio‐maxillofacial surgery, in pre‐implant augmentation and in reconstructive surgery. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010.
Cognitive impairment in Parkinson's disease without dementia
Authors: Rodríguez‐Ferreiro Javier , Cuetos Fernando , Herrera Elena , Menéndez Manuel , Ribacoba Renée 
Published: August 2010

AbstractSome degree of cognitive impairment appears frequently in Parkinson's disease (PD) patients, even at the onset of the disease. However, due to the heterogeneity of the patients and the lack of standardized assessment batteries, it remains unclear which capacities are primarily affected by this disease. Fifty PD patients were assessed with 15 tests including executive functions, attention, temporal and spatial orientation, memory, and language tasks. Their results were compared with those of 42 age‐ and education‐matched healthy seniors. Semantic fluency, along with visual search appeared to be the most discriminant tasks, followed by temporal orientation and face naming, as well as action naming and immediate recall. PD patients studied showed an impairment of frontal‐ to posterior‐dependent capacities. Executive functions, attention, and recall tasks appeared to be significantly impaired in the patients. Nevertheless, significantly poor scores in tasks like action and face naming, as well as semantic fluency, also reveal a mainly semantic deficit. © 2010 Movement Disorder Society