Search results for "tissue engineering"

A Standardised Approach to the Biomechanical Evaluation of Tracheal Grafts

2021

[EN] The ideal tracheal substitute must have biomechanical properties comparable to the native trachea, but currently there is no standardised approach to evaluating these properties. Here we propose a novel method for evaluating and comparing the properties of tracheal substitutes, thus systematising both measurement and data curation. This system was tested by comparing native rabbit tracheas to frozen and decellularised specimens and determining the histological characteristics of those specimens. We performed radial compression tests on the anteroposterior tracheal axis and longitudinal axial tensile tests with the specimens anastomosed to the jaw connected to a measuring system. All ca…

Nanocarbons in electrospun polymeric nanomats for tissue engineering: A review

2017

Electrospinning is a versatile process technology, exploited for the production of fibers with varying diameters, ranging from nano- to micro-scale, particularly useful for a wide range of applications. Among these, tissue engineering is particularly relevant to this technology since electrospun fibers offer topological structure features similar to the native extracellular matrix, thus providing an excellent environment for the growth of cells and tissues. Recently, nanocarbons have been emerging as promising fillers for biopolymeric nanofibrous scaffolds. In fact, they offer interesting physicochemical properties due to their small size, large surface area, high electrical conductivity an…

3D Bioprinting for Vascularized Tissue-Engineered Bone Fabrication

2020

Vascularization in bone tissues is essential for the distribution of nutrients and oxygen, as well as the removal of waste products. Fabrication of tissue-engineered bone constructs with functional vascular networks has great potential for biomimicking nature bone tissue in vitro and enhancing bone regeneration in vivo. Over the past decades, many approaches have been applied to fabricate biomimetic vascularized tissue-engineered bone constructs. However, traditional tissue-engineered methods based on seeding cells into scaffolds are unable to control the spatial architecture and the encapsulated cell distribution precisely, which posed a significant challenge in constructing complex vascul…

Polycaprolactone/gelatin-based scaffolds with tailored performance: in vitro and in vivo validation

2019

Abstract Nanofibrous scaffolds composed of polycaprolactone (PCL) and gelatin (Ge) were obtained through a hydrolytic assisted electrospinning process. The PCL-to-Ge proportion (100/0 to 20/80), as well as the dissolution time (24, 48, 72, 96, 120 h) into a 1:1 formic/acetic acid solvent before electrospinning were modified to obtain the different samples. A strong influence of these factors on the physicochemical properties of the scaffolds was observed. Higher Ge percentage reduced crystallinity, allowed a uniform morphology and increased water contact angle. The increase in the dissolution time considerably reduced the molar mass and, subsequently, fibre diameter and crystallinity were a…

Porous gelatin cryogels as cell delivery tool in tissue engineering.

2007

Bioengineered human bone tissue using autogenous osteoblasts cultured on different biomatrices

2003

Surgical treatment of critical-size posttraumatic bone defects is still a challenging problem, even in modern bone and joint surgery. Progress in cellular and molecular biology during the last decade now permits novel approaches in bone engineering. Recent conceptual and technical advances have enabled the use of mitotically expanded, bone-derived cells as a therapeutic approach for tissue repair. Using three different tissue carrier systems, we successfully cultivated human osteoblasts in a newly developed perfusion chamber. We studied cell proliferation and the expression of osteocalcin, osteopontin, bone morphogenetic protein-2A, alkaline phosphatase, and vascular endothelial growth fact…

Bi-layer PCL/PLA scaffold prepared by melt for interface tissue engineering

2017

The development of porous multilayer devices allow controlling chemical, physical and mechanical properties by tuning the properties of each single layer. For instance, this feature is of main concern for the production of porous devices designed to regenerate diseased zones at the interface of tissue presenting intrinsic anisotropic structures that gradually change from one tissue to another. In this context, synthetic biodegradable polymers commonly used biomedical applications include polylactic acid (PLA) and polycaprolactone (PCL). In this work, a novel bi-layered multiphasic scaffold (BLS) is presented. It is composed by a PLA-layer presenting pore size in the range of 90-110 μm while…

In-vitro regulation of odontogenic gene expression in human embryonic tooth cells and SHED cells

2012

The bud-to-cap stage transition during early tooth development is a time when the tooth-inducing potential becomes restricted to the mesenchyme. Several key genes, expressed in the mesenchyme at this stage, are an absolute requirement for the progression of tooth development. These include the transcription factors Msx1 and Pax9. The inductive potential of tooth mesenchyme cells is a key requisite for whole-tooth bioengineering and thus identification of cells that can retain this property following expansion in culture is an important as yet unresolved, goal. We show here that in-vitro culture of embryonic human tooth mesenchyme cells and SHED cells express low levels of PAX9 and MSX1 and …

Contribution of outgrowth endothelial cells from human peripheral blood on in vivo vascularization of bone tissue engineered constructs based on star…

2009

In the present study we assessed the potential of human outgrowth endothelial cells (OEC), a subpopulation within endothelial progenitor cell cultures, to support the vascularization of a complex tissue engineered construct for bone. OEC cultured on starch polycaprolactone fiber meshes (SPCL) in monoculture retained their endothelial functionality and responded to angiogenic stimulation by VEGF (vascular endothelial growth factor) in fibrin gel-assays in vitro. Co-culture of OEC with human primary osteoblasts (pOB) on SPCL, induced an angiogenic activation of OEC towards microvessel-like structures achieved without additional supplementation with angiogenic growth factors. Effects of co-cul…

Computational modeling and experimental characterization of fluid dynamics in micro-CT scanned scaffolds within a multiple-sample airlift perfusion b…

2023

The perfusion of flow during cell culture induces cell proliferation and enhances cellular activity. Perfusion bioreactors offer a controlled dynamic environment for reliable in vitro applications in the tissue engineering field. In this work, to evaluate the effects of the operating parameters of a custom-made bioreactor, numerical simulations were performed to solve the fluid velocity profile inside the bioreactor containing multi-grid support that allows allocating of multiple seeded scaffolds at the same time. The perfusion system exhibited a uniform distribution of liquid velocities within the regions, suitable for cell growth on seeded scaffolds. The effects of the porous microstructu…