The development of a tissue-engineered tracheobronchial epithelial model using a bilayered collagen-hyaluronate scaffold.

Today, chronic respiratory disease is one of the leading causes of mortality globally. Epithelial dysfunction can play a central role in its pathophysiology. The development of physiologically-representative in vitro model systems using tissue-engineered constructs might improve our understanding of epithelial tissue and disease.

Multi-layered collagen-based scaffolds for osteochondral defect repair in rabbits.

Introduction: Identification of a suitable treatment for osteochondral repair presents a major challenge due to existing limitations and an urgent clinical need remains for an off-the-shelf, low cost, one-step approach. A biomimetic approach, where the biomaterial itself encourages cellular infiltration from the underlying bone marrow and provides physical and chemical cues to direct these cells to regenerate the damaged tissue, provides a potential solution. To meet this need, a multi-layer collagen-based osteochondral defect repair scaffold has been developed in our group.

Insoluble elastin reduces collagen scaffold stiffness, improves viscoelastic properties, and induces a contractile phenotype in smooth muscle cells.

Biomaterials with the capacity to innately guide cell behaviour while also displaying suitable mechanical properties remain a challenge in tissue engineering. Our approach to this has been to utilise insoluble elastin in combination with collagen as the basis of a biomimetic scaffold for cardiovascular tissue engineering. Elastin was found to markedly alter the mechanical and biological response of these collagen-based scaffolds.

The pre-vascularisation of a collagen-chondroitin sulphate scaffold using human amniotic fluid-derived stem cells to enhance and stabilise endothelial cell-mediated vessel formation.

Unlabelled: 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.

Incorporation of fibrin into a collagen-glycosaminoglycan matrix results in a scaffold with improved mechanical properties and enhanced capacity to resist cell-mediated contraction.

Unlabelled: Fibrin has many uses as a tissue engineering scaffold, however many in vivo studies have shown a reduction in function resulting from the susceptibility of fibrin to cell-mediated contraction. The overall aim of the present study was to develop and characterise a reinforced natural scaffold using fibrin, collagen and glycosaminoglycan (FCG), and to examine the cell-mediated contraction of this scaffold in comparison to fibrin gels. Through the use of an injection loading technique, a homogenous FCG scaffold was developed.

Development of a gene-activated scaffold platform for tissue engineering applications using chitosan-pDNA nanoparticles on collagen-based scaffolds.

Biomaterial scaffolds that support cell infiltration and tissue formation can also function as platforms for the delivery of therapeutics such as drugs, proteins, and genes. As burst release of supraphysiological quantities of recombinant proteins can result in adverse side effects, the objective of this study was to explore the potential of a series of collagen-based scaffolds, developed in our laboratory, as gene-activated scaffold platforms with potential in a range of tissue engineering applications. The potential of chitosan, a biocompatible material derived from the shells of crustaceans, as a gene delivery vector was assessed using mesenchymal stem cells (MSCs).

Hypoxia-mimicking bioactive glass/collagen glycosaminoglycan composite scaffolds to enhance angiogenesis and bone repair.

One of the biggest challenges in regenerative medicine is promoting sufficient vascularisation of tissue-engineered constructs. One approach to overcome this challenge is to target the cellular hypoxia inducible factor (HIF-1α) pathway, which responds to low oxygen concentration (hypoxia) and results in the activation of numerous pro-angiogenic genes including vascular endothelial growth factor (VEGF). Cobalt ions are known to mimic hypoxia by artificially stabilising the HIF-1α transcription factor.

A novel collagen-nanohydroxyapatite microRNA-activated scaffold for tissue engineering applications capable of efficient delivery of both miR-mimics and antagomiRs to human mesenchymal stem cells.

Manipulation of gene expression through the use of microRNAs (miRNAs) offers tremendous potential for the field of tissue engineering. However, the lack of sufficient site-specific and bioactive delivery systems has severely hampered the clinical translation of miRNA-based therapies. In this study, we developed a novel non-viral bioactive delivery platform for miRNA mimics and antagomiRs to allow for a vast range of therapeutic applications.

Development of collagen-hydroxyapatite scaffolds incorporating PLGA and alginate microparticles for the controlled delivery of rhBMP-2 for bone tissue engineering.

The spatiotemporally controlled delivery of the pro-osteogenic factor rhBMP-2 would overcome most of the severe secondary effects linked to the products delivering this protein for bone regeneration. With this in mind, the aim of the present work was to develop a controlled rhBMP-2 release system using collagen-hydroxyapatite (CHA) scaffolds, which had been previously optimized for bone regeneration, as delivery platforms to produce a device with enhanced capacity for bone repair. Spray-drying and emulsion techniques were used to encapsulate bioactive rhBMP-2 in alginate and PLGA microparticles, with a high encapsulation efficiency.

Thermally triggered release of a pro-osteogenic peptide from a functionalized collagen-based scaffold using thermosensitive liposomes.

Collagen is one of the most attractive materials for the development of matrices for tissue engineering, due to its excellent biocompatibility and non-toxic bioresorption. The present work describes a collagen-based externally controlled drug-eluting scaffold which consists of drug encapsulated thermoresponsive liposomes covalently attached to the surface of a functionalized collagen-based scaffold. The model drug used in this work was PTHrP 107-111, a pentapeptide with pro-osteogenic and antiosteoclastic activity.

A biomimetic multi-layered collagen-based scaffold for osteochondral repair.

Cartilage and osteochondral defects pose a significant challenge in orthopedics. Tissue engineering has shown promise as a potential method for the treatment of such defects; however, a long-lasting repair strategy has yet to be realized. This study focuses on the development of a layered construct for osteochondral repair, fabricated through a novel "iterative layering" freeze-drying technique.