Design and Prototyping of a Novel Triple Lumen Photo-Angioplasty Device: Lumi-Solve-T.

Purpose: A triple lumen iteration of the novel photo-angioplasty drug eluting balloon catheter (DEBc) Lumi-Solve may be compromised by guidewire shadow (GWS)-mediated attenuation of balloon surface drug activation. The current study aimed to design and evaluate a novel triple lumen prototype, designated Lumi-Solve-T, to circumvent these issues.

Methods: Effects of guidewire shadowing (GWS) on vascular smooth muscle cell (VSMC) proliferation was evaluated using the MTT assay.

Nerve guidance conduit development for primary treatment of peripheral nerve transection injuries: A commercial perspective.

Commercial nerve guidance conduits (NGCs) for repair of peripheral nerve discontinuities are of little use in gaps larger than 30 mm, and for smaller gaps they often fail to compete with the autografts that they are designed to replace. While recent research to develop new technologies for use in NGCs has produced many advanced designs with seemingly positive functional outcomes in animal models, these advances have not been translated into viable clinical products. While there have been many detailed reviews of the technologies available for creating NGCs, none of these have focussed on the requirements of the commercialisation process which are vital to ensure the translation of a technology from bench to clinic.

Design, Development, In Vitro and Preliminary In Vivo Evaluation of a Novel Photo-Angioplasty Device: Lumi-Solve.

Purpose: Paclitaxel (PTX)-coated drug eluting balloon catheters (DEBc) used in the management of neointimal hyperplasia (NIH) have been associated with safety concerns. Alternative coating agents and targeted delivery systems may improve safety and DEBc efficacy. Utilizing a multi-platform approach we designed, developed and evaluated Lumi-Solve, a novel DEBc, coated with ultraviolet (UV) 365 nm-activated caged metacept-3 (c-MCT-3), an epigenetic agent from the histone deacetylase inhibitor (HDACi) class.

Increased Cardiomyocyte Alignment and Intracellular Calcium Transients Using Micropatterned and Drug-Releasing Poly(Glycerol Sebacate) Elastomers.

Myocardial tissue engineering is a promising therapy for myocardial infarction recovery. The success of myocardial tissue engineering is likely to rely on the combination of cardiomyocytes, prosurvival regulatory signals, and a flexible biomaterial structure that can deliver them. In this study, poly(glycerol sebacate) (PGS), which exhibits stable elasticity under repeated tensile loading, was engineered to provide physical features that aligned cardiomyocytes in a similar manner to that seen in native cardiac tissue.

Controlling integrin-based adhesion to a degradable electrospun fibre scaffold via SI-ATRP.

While polycaprolactone (PCL) and similar polyesters are commonly used as degradable scaffold materials in tissue engineering and related applications, non-specific adsorption of environmental proteins typically precludes any control over the signalling pathways that are activated during cell adhesion to these materials. Here we describe the preparation of PCL-based fibres that facilitate cell adhesion through well-defined pathways while preventing adhesion via adsorbed proteins. Surface-initiated atom transfer radical polymerisation (SI-ATRP) was used to graft a protein-resistant polymer brush coating from the surface of fibres, which had been electrospun from a brominated PCL macroinitiator.

Low Fouling Electrospun Scaffolds with Clicked Bioactive Peptides for Specific Cell Attachment.

While electrospun fibers are of interest as scaffolds for tissue engineering applications, nonspecific surface interactions such as protein adsorption often prevent researchers from controlling the exact interactions between cells and the underlying material. In this study we prepared electrospun fibers from a polystyrene-based macroinitiator, which were then grafted with polymer brushes using surface-initiated atom transfer radical polymerization (SI-ATRP). These brush coatings incorporated a trimethylsilyl-protected PEG-alkyne monomer, allowing azide functional molecules to be covalently attached, while simultaneously reducing nonspecific protein adsorption on the fibers.

Optimization of Aqueous SI-ATRP Grafting of Poly(Oligo(Ethylene Glycol) Methacrylate) Brushes from Benzyl Chloride Macroinitiator Surfaces.

Poly(oligo(ethylene glycol) methacrylate) (pOEGMA) brushes were grafted via surface-initiated atom transfer radical polymerization (SI-ATRP) from a poly(styrene-co-vinylbenzyl chloride) macroinitiator. While bromoisobutyryl initiator groups are most commonly used for this purpose, benzyl chloride initiators may be advantageous for some applications due to superior stability. Water-only graft solutions produced thicker brush coatings with superior low fouling properties (low protein adsorption and cell adhesion) versus mixed water/alcohol solutions.

Surface grafting of electrospun fibers using ATRP and RAFT for the control of biointerfacial interactions.

Background: The ability to present signalling molecules within a low fouling 3D environment that mimics the extracellular matrix is an important goal for a range of biomedical applications, both in vitro and in vivo. Cell responses can be triggered by non-specific protein interactions occurring on the surface of a biomaterial, which is an undesirable process when studying specific receptor-ligand interactions. It is therefore useful to present specific ligands of interest to cell surface receptors in a 3D environment that minimizes non-specific interactions with biomolecules, such as proteins.

Mitochondrial DNA haplotypes define gene expression patterns in pluripotent and differentiating embryonic stem cells.

Mitochondrial DNA haplotypes are associated with various phenotypes, such as altered susceptibility to disease, environmental adaptations, and aging. Accumulating evidence suggests that mitochondrial DNA is essential for cell differentiation and the cell phenotype. However, the effects of different mitochondrial DNA haplotypes on differentiation and development remain to be determined.

Implantation of functionalized thermally gelling xyloglucan hydrogel within the brain: associated neurite infiltration and inflammatory response.

To develop neural tissue engineering strategies that are useful for repairing damaged neural pathways in the central nervous system, it is essential to control and optimise neurone and neurite interactions with functional scaffolds. In this study, the suitability of thermally gelling xyloglucan hydrogels, along with xyloglucan-graft-poly-D-lysine (PDL) hydrogels, was assessed through their implantation within the caudate putamen of adult rats. The ability of the hydrogel scaffolds to encourage the infiltration of axons in a controlled manner was investigated, as was the inflammatory response associated with the implantation.

Neurite infiltration and cellular response to electrospun polycaprolactone scaffolds implanted into the brain.

Assessment of axonal infiltration and guidance within neural tissue engineering scaffolds, along with the characterisation of the inflammatory response, is critical in determining these scaffolds' potential for facilitating neural repair. In this study, the extent of microglial and astrocytic response was measured following implantation of electrospun poly(epsilon-caprolactone) (PCL) scaffolds into the caudate putamen of the adult rat brain. The inflammation peaked at around 4 days (microglia) and 7 days (astrocytes) and subsided to homeostatic levels by 60 days.

Surface and bulk characterisation of electrospun membranes: problems and improvements.

Electrospun membranes are used in a variety of applications, including filtration systems and sensors for chemical detection, and have attracted increased interest in the field of tissue engineering and regenerative medicine. Successful integration of these materials into a specific technology will require understanding of the fibres' surface, bulk and architectural properties. Detailed characterisation of these properties is frequently overlooked, particularly in specialised interdisciplinary fields such as tissue engineering.