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Tissue Scaffolds (tissue + scaffold)
Selected AbstractsPreparation and properties of ,-chitin-whisker-reinforced hyaluronan,gelatin nanocomposite scaffoldsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Parintorn Hariraksapitak Abstract Tissue scaffolds made of naturally derived polymers present poor mechanical properties, which may limit their actual utilization in certain areas where high strength is a key criterion. This study was aimed at developing tissue scaffolds from a 50 : 50 w/w blend of hyaluronan (HA) and gelatin (Gel) that contained different amounts of acid-hydrolyzed ,-chitin whiskers (CWs) by a freeze-drying method. The weight ratios of the CWs to the blend were 0,30%. These scaffolds were characterized for their physical, physicochemical, mechanical, and biological properties. Regardless of the CW content, the average pore size of the scaffolds ranged between 139 and 166 ,m. The incorporation of 2% CWs in the HA,Gel scaffolds increased their tensile strength by about two times compared to those of the other groups of the scaffolds. Although the addition of 20,30% CWs in the scaffolds improved their thermal stability and resistance to biodegradation, the scaffolds with 10% CWs were the best for supporting the proliferation of cultured human osteosarcoma cells (SaOS-2). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] A New Biological Matrix for Septal OcclusionJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2003CHRISTIAN JUX, M.D. The ideal septal occluder scaffold should promote the healthiest and most complete healing response possible while eventually facilitating the full resorption of the material, leaving "native" tissue behind. An excellent biocompatibility of the scaffold tissue is a prerequisite for quick, complete, and firm ingrowth of the device, optimizing outcomes and minimizing the potential for complications. Intestinal collagen layer (ICL) is a highly purified (acellular) bioengineered type-1 collagen derived from porcine submucosa. It is gradually resorbed by the host organism and subsequently replaced by the host tissue. CardioSEAL® occluders were modified by substituting the conventional polyester fabric for an intestinal collagen layer (ICL). Percutaneous transcatheter closure of interventionally created atrial septal defects was performed in lambs using these modified occluders. A complete pathomorphological investigation including histology was carried out after 2, 4, and 12 weeks follow-up. Standard CardioSEAL implants served as a control group. After 2 weeks in vivo the devices were already covered completely by neo-endothelium. Compared with the conventional synthetic scaffold, ICL devices showed a quicker endothelialization, decreased thrombogenicity, and superior biocompatibility with no significant cellular infiltration observed in the histology of explants with ICL fabrics. After 3 months in vivo the collagen layer remained mechanically intact, but began to show the first histological signs of mild disintegration, gradual resorption, and remodeling. In conclusion, short-term results from preliminary in vivo experiments using a bioengineered collagen matrix as the occluder tissue scaffold showed excellent biocompatibility. This resulted in superior overall results: quicker endothelialization, a decreased thrombogenicity, and decreased immunological host response. (J Interven Cardiol 2003;16:149,152) [source] Artificial Vasculature: Rapid Fabrication of Bio-inspired 3D Microfluidic Vascular Networks (Adv. Mater.ADVANCED MATERIALS, Issue 35 200935/2009) The cover depicts a 3D microchannel network embedded inside an acrylic polymer substrate. The network is created using an electrostatic discharge method that instantaneously vaporizes and fractures the substrate, leaving behind a tree-like fractal arrangement of microchannels bearing a remarkable similarity to naturally occurring vasculature. The ability to rapidly construct microchannel networks incorporating a wide range of diameters (,10,500 µm) may help enable production of organ-sized engineered tissue scaffolds containing embedded vasculature, as reported by Arul Jayaraman, Victor Ugaz, and co-workers on p. 3567. [source] Rapid Fabrication of Bio-inspired 3D Microfluidic Vascular NetworksADVANCED MATERIALS, Issue 35 2009Jen-Huang Huang A new method to embed branched 3D microvascular fluidic networks inside plastic substrates by harnessing electrostatic discharge phenomena is introduced. This nearly instantaneous process reproducibly generates highly branched tree-like microchannel architectures that bear remarkable similarity to naturally occurring vasculature. This method can be applied to a variety of polymers, and may help enable production of organ-sized tissue scaffolds containing embedded vasculature. [source] Preparation and properties of ,-chitin-whisker-reinforced hyaluronan,gelatin nanocomposite scaffoldsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Parintorn Hariraksapitak Abstract Tissue scaffolds made of naturally derived polymers present poor mechanical properties, which may limit their actual utilization in certain areas where high strength is a key criterion. This study was aimed at developing tissue scaffolds from a 50 : 50 w/w blend of hyaluronan (HA) and gelatin (Gel) that contained different amounts of acid-hydrolyzed ,-chitin whiskers (CWs) by a freeze-drying method. The weight ratios of the CWs to the blend were 0,30%. These scaffolds were characterized for their physical, physicochemical, mechanical, and biological properties. Regardless of the CW content, the average pore size of the scaffolds ranged between 139 and 166 ,m. The incorporation of 2% CWs in the HA,Gel scaffolds increased their tensile strength by about two times compared to those of the other groups of the scaffolds. Although the addition of 20,30% CWs in the scaffolds improved their thermal stability and resistance to biodegradation, the scaffolds with 10% CWs were the best for supporting the proliferation of cultured human osteosarcoma cells (SaOS-2). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Nerve regeneration along bioengineered scaffoldsMICROSURGERY, Issue 5 2007S. Geuna M.D. Tissue engineering has recently seen great advancements in many medical fields, including peripheral nerve reconstruction. In the rat median nerve model, we investigated nerve repair by means of bioengineered tissue scaffolds (muscle-vein-combined tubes) focusing on changes in the neuregulin-1/ErbB-receptor system which represents one of the main regulatory systems of axo-glial interaction in peripheral nerves. Repaired nerves were withdrawn at 5, 15, and 30 days postoperative and processed for morphological and retro-transcriptase polymerase chain reaction (RT-PCR) analysis. Results revealed an early and progressive increase in the expression of NRG1, isoform only, while the appearance of the , isoform of NRG1, which is normally present in peripheral nerves, was delayed. In regards to ErbB2 and ErbB3 receptors, their expression increased progressively inside the muscle-vein-combined scaffolds, though with different kinetics. Taken together, these results suggest that variations in neuregulin-1/ErbB system activation play a key role in peripheral nerve regeneration along bioengineered muscle-vein-combined scaffolds. Since similar variations are also detectable in denervated skeletal muscles, it can be hypothesized that the existence of a NRG1's autocrine/paracrine trophic loop shared by both glial and muscle fibers could be responsible for the effectiveness of muscle-vein-combined conduits for repairing nerve defects. © 2007 Wiley-Liss, Inc. Microsurgery, 2007. [source] Cartilage Regeneration in the Rabbit Nasal Septum,THE LARYNGOSCOPE, Issue 10 2006Meghann L. Kaiser MD Abstract Objective: Rhinoplasty frequently includes harvesting of nasal septal cartilage. The objective of this prospective basic investigation is to determine whether cartilage can regenerate after submucosal resection (SMR) of the nasal septum in the rabbit. Neocartilage formation has not heretofore been described in this model. Methods: By lateral rhinotomy, SMR was performed on 17 rabbits followed by reapproximation of the perichondrium. After 7 months, septi were fixed, sectioned, and examined histologically. Findings were photographed and data tabulated according to location and extent. Results: Sites of matrix-secreting isogenous chondrocyte islands were identified between the perichondrial flaps of every animal, principally in the anterior inferior septum. The width of the islands averaged 190 ,m, and the mean neocartilage height was found to be 840 ,m. The newly formed cartilage consisted of chondrocytes within chondrons and was comparable in shape and structure to native septal cartilage. Conclusions: After SMR, rabbit cartilage tissue can regenerate and form matrix within the potential space created by surgery. The surrounding stem cell-rich perichondrium may be the site of origin for these chondrocytes. These findings suggest that after SMR of the human nasal septum, it may be possible for new cartilage tissue to develop provided the mucosa is well approximated. This biologic effect may be enhanced by insertion of cytokine-rich tissue scaffolds that exploit the native ability of septal perichondrium to regenerate and repair cartilage tissue. [source] Time-lapsed imaging for in-process evaluation of supercritical fluid processing of tissue engineering scaffoldsBIOTECHNOLOGY PROGRESS, Issue 4 2009Melissa L. Mather Abstract This article demonstrates the application of time-lapsed imaging and image processing to inform the supercritical processing of tissue scaffolds that are integral to many regenerative therapies. The methodology presented provides online quantitative evaluation of the complex process of scaffold formation in supercritical environments. The capabilities of the developed system are demonstrated through comparison of scaffolds formed from polymers with different molecular weight and with different venting times. Visual monitoring of scaffold fabrication enabled key events in the supercritical processing of the scaffolds to be identified including the onset of polymer plasticization, supercritical points and foam formation. Image processing of images acquired during the foaming process enabled quantitative tracking of the growing scaffold boundary that provided new insight into the nature of scaffold foaming. Further, this quantitative approach assisted in the comparison of different scaffold fabrication protocols. Observed differences in scaffold formation were found to persist, post-fabrication as evidenced by micro x-ray computed tomography (, x-ray CT) images. It is concluded that time-lapsed imaging in combination with image processing is a convenient and powerful tool to provide insight into the scaffold fabrication process. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] | |||||||||||||