ORCID Profile
0000-0001-6640-8840
Current Organisation
University of Nottingham
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Publisher: SPIE
Date: 10-02-2011
DOI: 10.1117/12.873365
Publisher: SPIE-Intl Soc Optical Eng
Date: 2012
Publisher: Elsevier BV
Date: 04-2021
Publisher: Elsevier BV
Date: 12-2013
DOI: 10.1016/J.MSEC.2013.07.046
Abstract: The aim of this work is to demonstrate that the structural and fluidic properties of polymer foam tissue scaffolds, post-fabrication but prior to the introduction of cells, can be engineered via exposure to high power ultrasound. Our analysis is supported by measurements of fluid uptake during insonification and imaging of the scaffold microstructure via X-ray computed tomography, scanning electron microscopy and acoustic microscopy. The ultrasonic treatment is performed with a frequency of 30 kHz, average intensities up to 80,000 Wm(-2) and exposure times up to 20 h. The treatment is found to increase the mean pore size by over 10%. More striking is the improvement in fluid uptake: for scaffolds with only 40% water uptake via standard immersion techniques, we can routinely achieve full saturation of the scaffold over approximately one hour of exposure. These desirable modifications occur with negligible loss of scaffold integrity and mass, and are optimized when the ultrasound treatment is coupled to a pre-wetting stage with ethanol. Our findings suggest that high power ultrasound is highly targeted towards flow obstructions in the scaffold architecture, thereby providing an efficient means to promote pore interconnectivity and fluid transport in thick foam tissue scaffolds.
Publisher: American Chemical Society (ACS)
Date: 20-06-2019
Abstract: Surface-functionalized microparticles are relevant to fields spanning engineering and biomedicine, with uses ranging from cell culture to advanced cell delivery. Varying topographies of biomaterial surfaces are also being investigated as mediators of cell-material interactions and subsequent cell fate. To investigate competing or synergistic effects of chemistry and topography in three-dimensional cell cultures, methods are required to introduce these onto microparticles without modification of their underlying morphology or bulk properties. In this study, a new approach for surface functionalization of poly(lactic acid) (PLA) microparticles is reported that allows decoration of the outer shell of the polyesters with additional polymers via aqueous atom transfer radical polymerization routes. PLA microparticles with smooth or dimpled surfaces were functionalized with poly(poly(ethylene glycol) methacrylate) and poly[
Publisher: SPIE
Date: 10-02-2011
DOI: 10.1117/12.873302
Publisher: IOP Publishing
Date: 06-2012
DOI: 10.1088/1748-6041/7/4/045011
Abstract: The amniotic membrane (AM) is considered as a natural cell culture substrate and has occasionally been exploited in regenerative medicine especially for ocular surface reconstruction and dermal wound healing applications. However, its use is limited by its relatively weak mechanical strength, difficulty during manual handling and susceptibility to proteolytic degradation in vivo. Therefore, in this study we aimed to enhance the mechanical and biological characteristics of the AM by enzymatically cross-linking it using tissue transglutaminase (TG)-a calcium-dependent enzyme capable of forming stable ε(γ-glutamyl)lysine cross-linkages. Using a biological catalyst such as TG does not only prevent denaturation during s le preparation but also minimizes the potential of residual chemical cross-linking agents compared to alternative methodologies. Human AM, sourced from elective caesarean sectioning, were treated with TG, bovine serum albumin and/or a no-treatment control. S les were then compared in terms of their physical and (scanning electron microscopy (SEM), transparency, mechanical strength, susceptibility to proteolytic degradation) biological characteristics (in vitro cell culture, activation of dendritic cells (DC)) and their in vivo biocompatibility/angiogenic capacity (chick chorioallantoic membrane assay). TG-treated AM exhibited enhanced mechanical strength and greater resistance to proteolytic/collagenase degradation compared to the control(s). SEM imaging of the TG-treated membrane summarized a significantly closer association and greater interconnectivity of in idual collagen fibres yet it had no effect on the overall transparency of the AM. In vitro cell culture demonstrated no detrimental effect of TG-treatment on the AM in terms of cell attachment, spreading, proliferation and differentiation. Moreover, an 'immune response' was not elicited based on extended in vitro culture with human-monocyte-derived DC. Interestingly, the TG-treated AM still allowed angiogenesis to occur and in some instances, demonstrated an enhancement compared to the control (n = 5). We hereby demonstrate that treating the AM with the cross-linking enzyme, TG, results in a novel biomaterial with enhanced mechanical and biological characteristics. Above all, this modified membrane demonstrates greater strength, maintains in vitro cell growth, retains optical transparency and allows angiogenesis to occur without inducing an immune response. Altogether, this study demonstrates the feasibility of TG as an alternate cross-linking treatment for the production of novel biomaterials and suggests that TG-treated AM may now be more commonly exploited as a therapeutic dressing for ocular or wound applications.
Publisher: Wiley
Date: 24-05-2005
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2010
End Date: 2016
Funder: Engineering and Physical Sciences Research Council
View Funded ActivityStart Date: 2008
End Date: 2011
Funder: Biotechnology and Biological Sciences Research Council
View Funded Activity