Search results for "tissue engineering."

Macromolecular engineering of hydrogels: from macro to nano scalar materials for different levels of biointeraction

2009

Designed biodegradable hydrogel structures prepared by stereolithography using poly(ethylene glycol)/poly(D,L-lactide)-based resins

2010

Designed three-dimensional biodegradable poly(ethylene glycol)/poly(D,L-lactide) hydrogel structures were prepared for the first time by stereolithography at high resolutions. A photo-polymerisable aqueous resin comprising PDLLA-PEG-PDLLA-based macromer, visible light photo-initiator, dye and inhibitor in DMSO/water was used to build the structures. Porous and non-porous hydrogels with well-defined architectures and good mechanical properties were prepared. Porous hydrogel structures with a gyroid pore network architecture showed narrow pore size distributions, excellent pore interconnectivity and good mechanical properties. The structures showed good cell seeding characteristics, and human…

A novel approach to fully characterize fiber network morphology of planar fibrous tissues and scaffolds

2010

Understanding how scaffold structure influences cell morphology, metabolism, phenotypic expression, and predicting mechanical behaviors have increasingly become crucial goals in the development of engineered tissue scaffolds. A novel image-based analysis algorithm that provides an automatic tool to characterize engineered tissue fiber network topology is presented. Micro architectural descriptors that unambiguously define the fiber network topology were detected, which include fiber orientation distribution, connectivity, intersection spatial density, and diameter. Algorithm performance was tested using actual sample scanning electron microscopy (SEM) images of (1) electrospun poly(ester ur…

Tissue response and biomaterial integration: the efficacy of in vitro methods

2002

Implantation involves tissue trauma, which evokes an inflammatory response, coupled to a wound healing reaction, involving angiogenesis, fibroblast activation and matrix remodelling. Until now the type and extent of such reactions to give optimal integration of various biomaterials are practically unknown. Three principal fields of research can yield useful data to understand these phenomena better: studies on explanted biomaterials, animal models and relevant in vitro techniques. This paper will present examples of the latter field and the application of endothelial cell (EC) culture systems to study the effects of important tissue (e.g. pro-inflammatory cytokines, chemokines) and material…

Timing effect of intramyocardial hydrogel injection for positively impacting left ventricular remodeling after myocardial infarction

2015

Intramyocardial injection of various injectable hydrogel materials has shown benefit in positively impacting the course of left ventricular (LV) remodeling after myocardial infarction (MI). However, since LV remodeling is a complex, time dependent process, the most efficacious time of hydrogel injection is not clear. In this study, we injected a relatively stiff, thermoresponsive and bioabsorbable hydrogel in rat hearts at 3 different time points - immediately after MI (IM), 3 d post-MI (3D), and 2 w post-MI (2W), corresponding to the beginnings of the necrotic, fibrotic and chronic remodeling phases. The employed left anterior descending coronary artery ligation model showed expected infar…

Functionality of endothelial cells on silk fibroin nets: Comparative study of micro- and nanometric fibre size

2007

Biomimetic material design, such as mimicking nanostructured components of the extracellular matrix, is an actual challenge for biomaterial research with a high impact on tissue engineering and regenerative medicine. Thus, understanding the cellular response at the cell biological and molecular level and the consequences of various chemically or physically modified biomaterials is highly important. In the present study we assessed the response of human umbilical vein endothelial cells (HUVEC) and outgrowth endothelial cells (OEC) from endothelial progenitor cells to different variants of nanofibrous silk fibroin nets in comparison to microfibrous silk fibroin scaffolds with regard to cellul…

Use of a collagen/elastin-membrane for the tissue engineering of dermis.

1999

In an experimental model in rats, xenogeneic membranes consisting of processed native collagen and elastin were grafted to serve as a template for the formation of a neo-dermis, while in vitro-cultured autogeneic keratinocytes were applied on top of this to restore an epidermis. The process of tissue reconstruction and the digestion of the grafted membrane components were analysed by histological and immunohistochemical methods as well as electron microscopy. Approximately 3 weeks post grafting the membranes were completely vascularised and colonized by different types of cells. After 6 weeks, the collagenous fibres of the graft were mostly replaced by newly formed collagenous texture, wher…

Medium-term Culture of Normal Human Oral Mucosa: A Novel Three-dimensional Model to Study the Effectiveness of Drugs Administration

2012

Tissue-engineered oral mucosal equivalents have been developed for in vitro studies for a few years now. However, the usefulness of currently available models is still limited by many factors, mainly the lack of a physiological extracellular matrix (ECM) and the use of cell populations that do not reflect the properly differentiated cytotypes of the mucosa of the oral cavity. For this reason, we have developed a novel three-dimensional culture model reflecting the normal architecture of the human oral mucosa, with the main aim of creating a better in vitro model where to test cellular responses to drugs administration. This novel 3D cell culture model (3D outgrowth) was set up using an arti…

Development of an lbuprofen-Releasing Biodegradable PLA/PGA Electrospun Scaffold for Tissue Regeneration

2009

Our aim was to develop a biodegradable fibrous dressing to act as a tissue guide for in situ wound repair while releasing Ibuprofen to reduce inflammation in wounds and reduce pain for patients on dressing changes. Dissolving the acid form of Ibuprofen (from 1% to 10% by weight) in the same solvent as 75% polylactide, 25% polyglycolide (PLGA) polymers gave uniformly loaded electrospun fibers which gave rapid release of drug within the first 8 h and then slower release over several days. Scaffolds with 10% Ibuprofen degraded within 6 days. The Ibuprofen released from these scaffolds significantly reduced the response of fibroblasts to major pro-inflammatory stimulators. Fibroblast attachment…

Use of cultured human epithelium for coverage: a defect of radial forearm free flap donor site

2010

The radial forearm free flap has been popular in many areas of reconstructive surgery. Despite the many attributes of this flap in maxillofacial reconstruction, one of the disadvantages has been the morbidity of the donor site. Allogeneic cultured epidermis has been successfully applied on large second degree burns and on chronic leg ulcers. Autologous human keratinocytes and fibroblast equivalents can be cultured in-vitro from a small skin sample in order to produce a sufficient amount of epithelial autografts to cover the large defects of third-degree burn wounds. Interestingly, transplanted cultured epidermis retains characteristics of the original donor site. We report a case of a patie…