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Composite Scaffold (composite + scaffold)
Selected AbstractsHydrogel-Perfluorocarbon Composite Scaffold Promotes Oxygen Transport to Immobilized CellsBIOTECHNOLOGY PROGRESS, Issue 2 2008Kyuongsik Chin Cell encapsulation provides cells a three-dimensional structure to mimic physiological conditions and improve cell signaling, proliferation, and tissue organization as compared to monolayer culture. Encapsulation devices often encounter poor mass transport, especially for oxygen, where critical dissolved levels must be met to ensure both cell survival and functionality. To enhance oxygen transport, we utilized perfluorocarbon (PFC) oxygen vectors, specifically perfluorooctyl bromide (PFOB) immobilized in an alginate matrix. Metabolic activity of HepG2 liver cells encapsulated in 1% alginate/10% PFOB composite system was 47,104% higher than alginate systems lacking PFOB. A cubic model was developed to understand the oxygen transport mechanism in the alginate/PFOB composite system. The theoretical flux enhancement in alginate systems containing 10% PFOB was 18% higher than in alginate-only systems. Oxygen uptake rates (OURs) of HepG2 cells were enhanced with 10% PFOB addition under both 20% and 5% O2 boundary conditions, by 8% and 15%, respectively. Model predictions were qualitatively and quantitatively verified with direct experimental OUR measurements using both a perfusion reactor and oxygen sensing plate, demonstrating a greater OUR enhancement under physiological O2 boundary conditions (i.e., 5% O2). Inclusion of PFCs in an encapsulation matrix is a useful strategy for overcoming oxygen limitations and ensuring cell viability and functionality both for large devices (>1 mm) and over extended time periods. Although our results specifically indicate positive enhancements in metabolic activity using the model HepG2 liver system encapsulated in alginate, PFCs could be useful for improving/stabilizing oxygen supply in a wide range of cell types and hydrogels. [source] Stem Cell Aligned Growth Induced by CeO2 Nanoparticles in PLGA Scaffolds with Improved Bioactivity for Regenerative MedicineADVANCED FUNCTIONAL MATERIALS, Issue 10 2010Corrado Mandoli Abstract Hybrid 2D polymeric,ceramic biosupports are fabricated by mixing a nanostructured CeO2 powder with 85:15 poly(D,L -lactic- co -glycolic acid) (PLGA)/dichloromethane solutions at specific concentrations, followed by solvent casting onto pre-patterned molds. The mold patterning allows the orientation of ceramic nanoparticles into parallel lines within the composite scaffold. The ability of the produced films to host and address cell growth is evaluated after 1, 3, and 6 days of culturing with murine derived cardiac and mesenchymal stem cells (CSCs and MSCs), and compared with PLGA films without ceramics and loaded with nanostructured TiO2. Aligned cell growth is observed only for scaffolds that incorporate oriented ceramic nanoparticles, attributed to the nanoceramic ability to modulate the roughness pitch, thus improving cell sensitivity towards the host surface features. Better CSC and MSC proliferative activity is observed for CeO2 composites with respect to either TiO2 -added or unfilled PLGA films. This evidence may be related to the nanostructured CeO2 antioxidative properties. [source] Electrospun polylactide/silk fibroin,gelatin composite tubular scaffolds for small-diameter tissue engineering blood vesselsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009Shudong Wang Abstract Many synthetic scaffolds have been used as vascular substitutes for clinical use. However, many of these scaffolds may not show suitable properties when they are exposed to physiologic vascular environments, and they may fail eventually because of some unexpected conditions. Electrospinning technology offers the potential for controlling the composition, structure, and mechanical properties of scaffolds. In this study, a tubular scaffold (inner diameter = 4.5 mm) composed of a polylactide (PLA) fiber outside layer and a silk fibroin (SF),gelatin fiber inner layer (PLA/SF,gelatin) was fabricated by electrospinning. The morphological, biomechanical, and biological properties of the composite scaffold were examined. The PLA/SF,gelatin composite tubular scaffold possessed a porous structure; the porosity of the scaffold reached 82 ± 2%. The composite scaffold achieved the appropriate breaking strength (1.28 ± 0.21 MPa) and adequate pliability (elasticity up to 41.11 ± 2.17% strain) and possessed a fine suture retention strength (1.07 ± 0.07 N). The burst pressure of the composite scaffold was 111.4 ± 2.6 kPa, which was much higher than the native vessels. A mitochondrial metabolic assay and scanning electron microscopy observations indicated that both 3T3 mouse fibroblasts and human umbilical vein endothelial cells grew and proliferated well on the composite scaffold in vitro after they were cultured for some days. The PLA/SF,gelatin composite tubular scaffolds presented appropriate characteristics to be considered as candidate scaffolds for blood vessel tissue engineering. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Polysaccharide-based artificial extracellular matrix: Preparation and characterization of three-dimensional, macroporous chitosan, and heparin composite scaffoldJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Shu-Huei Yu Abstract Scaffold-guided tissue engineering based on synthetic and natural occurring polymers has gained many interests in recent year. In this study, the development of a chitosan-heparin artificial extracellular matrix (AECM) is reported. Three-dimensional, macroporous composite AECMs composed of heparin (Hep) and chitosan (Chito) were prepared by an interpolyelectrolyte complex/lyophilization method. The Chito-Hep composite AECMs were, respectively, crosslinked with glutaraldehyde, as well as cocrosslinked with N,N -(3-dimethylaminopropyl)- N,-ethyl carbodiimide (EDC/NHS) and N -hydroxysuccinimide (NHS). The crosslinking reactions were examined by FT-IR analysis. In physiological buffer solution (PBS), the EDC/NHS-crosslinked Chito-Hep composite AECM showed a relative lower water retention ratio than its glutaraldehyde-crosslinked counterparts. The EDC/NHS-crosslinked Chito-Hep composite AECMs showed excellent biocompatibility, according to the results of the in vitro cytotoxic test. This result suggested that the EDC/NHS-crosslinked Chito-Hep composite AECMs might be a potential biomaterial for scaffold-guided tissue engineering applications. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Lyophilization to improve drug delivery for chitosan-calcium phosphate bone scaffold construct: A preliminary investigationJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2009Benjamin T. Reves Abstract Lyophilization was evaluated in chitosan-calcium phosphate microspheres and scaffolds to improve drug delivery of growth factors and antibiotics for orthopedic applications. The dual delivery of an antibiotic and a growth factor from a composite scaffold would be beneficial for treatment of complex fracture sites, such as comminuted fractures and segmental bone defects. The aim of this investigation was to increase the loading capacity of the composite by taking advantage of the increased porosity, due to lyophilization, and to produce an extended elution profile using a secondary chitosan-bead coating. The physiochemical properties of the composite were investigated, and loading and elution studies were performed with alkaline phosphatase (ALP), bone morphogenetic protein-2 (BMP-2), and amikacin. Lyophilization was found to increase the surface area of scaffolds by over 400% and the porosity of scaffolds by 50%. Using ALP as a model protein, the loading capacity was increased by lyophilization from 4.3 ± 2.5 to 24.6 ± 3.6 ,g ALP/mg microspheres, and the elution profile was extended by a supplemental chitosan coating. The loading capacity of BMP-2 for composite microspheres was increased from 74.4 ± 3.7 to 102.1 ± 8.0 ,g BMP-2/g microspheres with lyophilization compared with nonlyophilized microspheres. The elution profiles of BMP-2 and the antibiotic amikacin were not extended with the supplemental coating. Additional investigations are planned to improve these elution characteristics for growth factors and antibiotics. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source] Self-hardening calcium phosphate composite scaffold for bone tissue engineering,JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2004Hockin H. K. Xu Abstract Calcium phosphate cement (CPC) sets in situ to form solid hydroxyapatite, can conform to complex cavity shapes without machining, has excellent osteoconductivity, and is able to be resorbed and replaced by new bone. Therefore, CPC is promising for craniofacial and orthopaedic repairs. However, its low strength and lack of macroporosity limit its use. This study investigated CPC reinforcement with absorbable fibers, the effects of fiber volume fraction on mechanical properties and macroporosity, and the cytotoxicity of CPC,fiber composite. The rationale was that large-diameter absorbable fibers would initially strengthen the CPC graft, then dissolve to form long cylindrical macropores for colonization by osteoblasts. Flexural strength, work-of-fracture (toughness), and elastic modulus were measured vs. fiber volume fraction from 0% (CPC Control without fibers) to 60%. Cell culture was performed with osteoblast-like cells, and cell viability was quantified using an enzymatic assay. Flexural strength (mean ± SD; n == 6) of CPC with 60% fibers was 13.5 ± 4.4 MPa, three times higher than 3.9 ± 0.5 MPa of CPC Control. Work-of-fracture was increased by 182 times. Long cylindrical macropores 293 ± 46 ,m in diameter were created in CPC after fiber dissolution, and the CPC,fiber scaffold reached a macroporosity of 55% and a total porosity of 81%. The new CPC,fiber formulation supported cell adhesion, proliferation and viability. The method of using large-diameter absorbable fibers in bone graft for mechanical properties and formation of long cylindrical macropores for bone ingrowth may be applicable to other tissue engineering materials. Published by Elsevier Ltd. on behalf of Orthopuedic Research Society. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] A Study on Biomineralization Behavior of N -Methylene Phosphochitosan ScaffoldsMACROMOLECULAR BIOSCIENCE, Issue 10 2004Yu Ji Yin Abstract Summary: Biomimetic growth of calcium phosphate over natural polymer may be an effective approach to constituting an organic/inorganic composite scaffold for bone tissue engineering. In this work, N -methylene phosphochitosan (NMPCS) was prepared via formaldehyde addition and condensation with phosphoric acid in a step that allowed homogeneous modification without obvious deterioration in chitosan (CS) properties. The NMPCS obtained was characterized by using FT-IR and elemental analysis. The macroporous scaffolds were fabricated through a freeze-drying technique. A comparative study on NMPCS and CS scaffold biomimetic mineralization was carried out in different media, i.e, a simulated body fluid (SBF) or alternative CaCl2 and Na2HPO4 solutions respectively. Apatite formation within NMPCS and CS scaffolds was identified with FT-IR, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and X-ray diffractometery (XRD). The results revealed alternate soaking of the scaffolds in CaCl2 and Na2HPO4 solutions was better than soaking in SBF solution alone in relation to apatite deposition on the scaffold pore walls. Biomineralization provides an approach to improve nature derived materials, e.g., chitosan derivative NMPCS properties e.g., compressive modulus, etc. SEM image of a NMPCS/apatite composite scaffold. [source] Electrospun Composite Mats of Poly[(D,L -lactide) -co- glycolide] and Collagen with High Porosity as Potential Scaffolds for Skin Tissue EngineeringMACROMOLECULAR MATERIALS & ENGINEERING, Issue 9 2009Ye Yang Abstract Electrospun composite mats of poly[(D,L -lactide) -co- glycolide] and collagen with high porosities of 85,90% and extended pore sizes of 90,130,µm were prepared to mimic the ECM morphologically and chemically. The existence of collagen molecules on the fiber surface was confirmed, enabling the cells to find enhanced binding sites for their integrin receptors. The mechanical data for the blended fibrous mats indicated that they were sufficiently durable for dermal tissue engineering. Fibroblasts derived from GFP transgenic C57BL/6 mice were used to directly observe cell proliferation, and the inoculation of collagen enhanced cell attachment, proliferation and extracellular matrix secretion, which were found to be dependent on the amount of collagen in the composite scaffold. [source] Designing a Three-dimensional Expanded Polytetrafluoroethylene,Poly(lactic-co-glycolic acid) Scaffold for Tissue EngineeringARTIFICIAL ORGANS, Issue 4 2009Hung-Jen Shao Abstract:, The purpose of this study was to design a three-dimensional expanded polytetrafluoroethylene (ePTFE),poly(lactic-co-glycolic acid) (PLGA) scaffold for tissue engineering. To test the feasibility of this composite scaffold, a series of two-dimensional culture experiments were performed to investigate the behavior of anterior cruciate ligament (ACL) cells on the ePTFE and PLGA membranes. It was found PLGA provided a cell-favorable substrate for cell adhesion, migration, and growth, indicating PLGA is an ACL cell-conductive material. Conversely, poor adhesion and proliferation of ACL cells were observed on the ePTFE, even on the collagen-coated ePTFE. Therefore, the scaffold was not fabricated by coating PLGA on the ePTFE surface because it is difficult to coat anything on the extremely hydrophobic ePTFE surface. Instead, the ePTFE embedded in the PLGA matrix was prepared by immersing ePTFE scrim yarns into the PLGA solution, and then precipitating PLGA to form a three-dimensional construction with porous morphology. The role of ePTFE is regarded as a reinforcing constituent to improve the mechanical strength of porous PLGA matrix to provide early repair strength for tissue healing. However, porous PLGA matrix acts as a supportive environment for allowing cell adhesion, migration, and growth to guide the repair and regeneration of ligament tissue. To test this assumption, a preliminary animal experiment of rabbit ACL wound healing with this three-dimensional ePTFE,PLGA scaffold was performed. These results are very encouraging because such a new scaffold made of ePTFE scrim yarns embedded in PLGA may serve as ACL prostheses in the ligament tissue engineering. [source] Three-dimensional fibrous PLGA/HAp composite scaffold for BMP-2 deliveryBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2008Hemin Nie Abstract A protein loaded three-dimensional scaffold can be used for protein delivery and bone tissue regeneration. The main objective of this project was to develop recombinant human bone morphogenetic protein-2 (rhBMP-2) loaded poly(D,L -lactide-co-glycolide)/hydroxylapatite (PLGA/HAp) composite fibrous scaffolds through a promising fabrication technique, electrospinning. In vitro release of BMP-2 from these scaffolds, and the attachment ability and viability of marrow derived messenchymal stem cells (MSCs) in the presence of the scaffolds were investigated. The PLGA/HAp composite scaffolds developed in this study exhibit good morphology and it was observed that HAp nanoparticles were homogeneously dispersed inside PLGA matrix within the scaffold. The composite scaffolds allowed sustained (2,8 weeks) release of BMP-2 whose release rate was accelerated with increasing HAp content. It was also shown that BMP-2 protein successfully maintained its integrity and natural conformations after undergoing the process of electrospinning. Cell culture experiments showed that the encapsulation of HAp could enhance cell attachment to scaffolds and lower cytotoxicity. Biotechnol. Bioeng. 2008;99: 223,234. © 2007 Wiley Periodicals, Inc. [source] Matrix Assisted Pulsed Laser Evaporation (MAPLE) of Poly(D,L lactide) (PDLLA) on Three Dimensional Bioglass® StructuresADVANCED ENGINEERING MATERIALS, Issue 8 2009Valeria Califano Matrix assisted pulsed laser evaporation (MAPLE) was used to coat Bioglass-based tissue engineering scaffolds with poly(D,L lactide). The polymer penetrated to some extent from the surface producing a graded porous composite material. This structure can be beneficial for application in osteochondral tissue engineering, where composite scaffolds are required exhibiting two distinct regions, one for cartilage integration (biopolymer) and the other one for bone contact (bioactive glass). [source] Novel Rice-shaped Bioactive Ceramic Nanoparticles (Adv. Eng.ADVANCED ENGINEERING MATERIALS, Issue 5 2009Mater. The cover of Advanced Biomaterials shows Rice-shaped bioactive ceramic nanoparticles with 70 nm in average diameter and around 200 nm in length were produced by an improved sol-gel method. In comparison to most traditional bioactive glass/ceramic materials this novel bioactive ceramic contains a significant lower quantity of silicon and higher content of phosphorous. In vitro bioactivity test showed that this new class of materials can induce the deposition of an apatite layer from SBF solution, having potential to be used in both conventional orthopedic applications or in bone tissue engineering when incorporated in composite scaffolds. More information can be found in the article of J. F. Mano et al. on page B25. [source] Novel Rice-shaped Bioactive Ceramic Nanoparticles,ADVANCED ENGINEERING MATERIALS, Issue 5 2009Zhongkui Hong Rice-shaped bioactive ceramic nanoparticles of 70 nm average diameter and around 200 nm length were produced by an improved sol-gel method. In comparison to most traditional bioactive glass/ceramic materials, this novel bioactive ceramic contains a significant lower quantity of silicon and higher content of phosphorous. In vitro bioactivity tests showed that this new class of materials can induce the deposition of an apatite layer from simulated body fluid, having the potential to be used in both conventional orthopedic applications or in bone tissue engineering when incorporated in composite scaffolds. [source] Three-Dimensional Bioactive and Biodegradable Scaffolds Fabricated by Surface-Selective Laser Sintering ,ADVANCED MATERIALS, Issue 3 2005N. Antonov Surface-selective laser sintering (SSLS) has been developed for fabrication of three-dimensional polymer composite scaffolds with precise dimensions and intricate structure (see Figure), which are bioactive and biodegradable. SSLS allows sintering of polymer powders by melting only the surface layers of particles, which prevents overheating of internal domains, allowing incorporation of bioactive molecules into the structures. [source] | |||||||||||||||||||||||||