Search results for "Biomaterials"
showing 10 items of 1265 documents
From single fiber to macro-level mechanics: A structural finite-element model for elastomeric fibrous biomaterials
2014
In the present work, we demonstrate that the mesoscopic in-plane mechanical behavior of membrane elastomeric scaffolds can be simulated by replication of actual quantified fibrous geometries. Elastomeric electrospun polyurethane (ES-PEUU) scaffolds, with and without particulate inclusions, were utilized. Simulations were developed from experimentally-derived fiber network geometries, based on a range of scaffold isotropic and anisotropic behaviors. These were chosen to evaluate the effects on macro-mechanics based on measurable geometric parameters such as fiber intersections, connectivity, orientation, and diameter. Simulations were conducted with only the fiber material model parameters a…
Non-cross-linked porcine-based collagen I-III membranes do not require high vascularization rates for their integration within the implantation bed: …
2012
There are conflicting reports concerning the tissue reaction of small animals to porcine-based, non-cross-linked collagen I-III membranes/matrices for use in guided tissue/bone regeneration. The fast degradation of these membranes/matrices combined with transmembrane vascularization within 4 weeks has been observed in rats compared with the slow vascularization and continuous integration observed in mice. The aim of the present study was to analyze the tissue reaction to a porcine-based non-cross-linked collagen I-III membrane in mice. Using a subcutaneous implantation model, the membrane was implanted subcutaneously in mice for up to 60 days. The extent of scaffold vascularization, tissue …
A self-sterilizing fluorescent Nanocomposite as versatile material with broad-spectrum Antibiofilm features
2020
Abstract Hematogenous spread of infections from colonized central intravenous catheters or central lines is a long-recognized problem with infection rates of 2 and 6.8 per 1000 days, respectively. Besides, removal of severe microbial colonization of implanted biomaterials is still a challenge and usually requires invasive operations. Hence, on demand self-sterilizing materials are required to avoid explant of colonized biomaterials and improve patient compliance. Moreover, photoluminescence is needed to make trackable biomaterials, which can be easily monitored upon implanting them in the body. Here, we propose the incorporation of near infrared (NIR) sensitive red-emitting carbon nanodot (…
The pre-vascularisation of a collagen-chondroitin sulphate scaffold using human amniotic fluid-derived stem cells to enhance and stabilise endothelia…
2015
Abstract A major problem in tissue engineering (TE) is graft failure in vivo due to core degradation in in vitro engineered constructs designed to regenerate thick tissues such as bone. The integration of constructs post-implantation relies on the rapid formation of functional vasculature. A recent approach to overcome core degradation focuses on the creation of cell-based, pre-engineered vasculature formed within the TE construct in vitro , prior to implantation in vivo . The primary objective of this study was to investigate whether an amniotic fluid-derived stem cell (AFSC)–human umbilical vein endothelial cell (HUVEC) co-culture could be used to engineer in vitro vasculature in a collag…
Response of micro- and macrovascular endothelial cells to starch-based fiber meshes for bone tissue engineering.
2006
The establishment of a functional vasculature is as yet an unrealized milestone in bone reconstruction therapy. For this study, fiber-mesh scaffolds obtained from a blend of starch and poly(caprolactone) (SPCL), that have previously been shown to be an excellent material for the proliferation and differentiation of bone marrow cells and thereby represent great potential as constructs for bone regeneration, were examined for endothelial cell (EC) compatibility. To be successfully applied in vivo, this tissue engineered construct should also be able to support the growth of ECs in order to facilitate vascularization and therefore assure the viability of the construct upon implantation. The ma…
The role of the silicatein-alpha interactor silintaphin-1 in biomimetic biomineralization.
2008
Biosilicification in sponges is initiated by formation of proteinaceous filaments, predominantly consisting of silicateins. Silicateins enzymatically catalyze condensation of silica nanospheres, resulting in symmetric skeletal elements (spicules). In order to create tailored biosilica structures in biomimetic approaches it is mandatory to elucidate proteins that are fundamental for the assembly of filaments. Silintaphin-1 is a core component of modularized filaments and also part of a spicule-enfolding layer. It bears no resemblance to other proteins, except for the presence of an interaction domain that is fundamental for its function as scaffold/template. In the presence of silicatein sil…
Endothelial cell colonization and angiogenic potential of combined nano- and micro-fibrous scaffolds for bone tissue engineering
2008
Presently the majority of tissue engineering approaches aimed at regenerating bone relies only on postimplantation vascularization. Strategies that include seeding endothelial cells (ECs) on biomaterials and promoting their adhesion, migration and functionality might be a solution for the formation of vascularized bone. Nano/micro-fiber-combined scaffolds have an innovative structure, inspired by extracellular matrix (ECM) that combines a nano-network, aimed to promote cell adhesion, with a micro-fiber mesh that provides the mechanical support. In this work we addressed the influence of this nano-network on growth pattern, morphology, inflammatory expression profile, expression of structura…
The chemical composition of synthetic bone substitutes influences tissue reactions in vivo : histological and histomorphometrical analysis of the cel…
2012
Bone substitute material properties such as granule size, macroporosity, microporosity and shape have been shown to influence the cellular inflammatory response to a bone substitute material. Keeping these parameters constant, the present study analyzed the in vivo tissue reaction to three bone substitute materials (granules) with different chemical compositions (hydroxyapatite (HA), beta-tricalcium phosphate (TCP) and a mixture of both with a HA/TCP ratio of 60/40 wt%). Using a subcutaneous implantation model in Wistar rats for up to 30 days, tissue reactions, including the induction of multinucleated giant cells and the extent of implantation bed vascularization, were assessed using histo…
Covalent RGD modification of the inner pore surface of polycaprolactone scaffolds
2011
Scaffold production for tissue engineering was demonstrated by means of a hot compression molding technique and subsequent particulate leaching. The utilization of spherical salt particles as the pore-forming agent ensured complete interconnectivity of the porous structure. This method obviated the use of potentially toxic organic solvents. To overcome the inherent non-cell-adhesive properties of the hydrophobic polymer polycaprolactone (PCL) surface activation with a diamine was performed, followed by the covalent immobilization of the adhesion-promoting RGD-peptide. The wet-chemical approach was performed to guarantee modification throughout the entire scaffold structure. The treatment wa…
Microstructural manipulation of electrospun scaffolds for specific bending stiffness for heart valve tissue engineering
2012
Biodegradable thermoplastic elastomers are attractive for application in cardiovascular tissue construct development due to their amenability to a wide range of physical property tuning. For heart valve leaflets, while low flexural stiffness is a key design feature, control of this parameter has been largely neglected in the scaffold literature where electrospinning is being utilized. This study evaluated the effect of processing variables and secondary fiber populations on the microstructure, tensile and bending mechanics of electrospun biodegradable polyurethane scaffolds for heart valve tissue engineering. Scaffolds were fabricated from poly(ester urethane) urea (PEUU) and the deposition…