Med-Tech Innovation Materials


rather than shear, which requires thicker samples in order to retain stiffness.


• DMSO has the effect of increasing crystallinity within the hydrogels. Prior literature indicates that crystallinity can be attributed to the interaction between DMSO and water, which has the effect of isolating the PVA hydroxyl groups.5


Expanding potential of hydrogels


The study demonstrates the potential of physically cross- linked hydrogels to replicate the physical dimensions of blood vessels and the mechanical properties of venous tissue. The results clearly show the effect of varying formulations on parameters, and provide insight for further manipulation of material characteristics. It was observed that higher concentrations of DMSO


were found to increase transparency. This is an important point considering the advantage of good visual feedback for in vitro simulation. The research serves as an addendum to the work carried out by CTRG in constructing a mock circulatory system, as described in the previous article.1


It is an


incremental step towards the development of a fully integrated, low-cost platform for cardiovascular evaluation and training.


A laboratory-engineered future Research is now ongoing by the group into the use of hydrogels for vascular biomodelling. With the simulation of venous blood vessels accomplished, attention is focused on accurately mimicking the properties of arterial tissue using laboratory-engineered hydrogels. The potential of hydrogels in biomedical applications extends beyond vascular modelling to seemingly infi nite possibilities, and undoubtedly they will continue to provoke interest among the research community for many years to come.


Although hydrogels are naturally occurring, the synthesis of hydrogels in a laboratory setting is a feat of materials science that has been translated into forward momentum in the biomedical sphere. This inter- disciplinary convergence is helping to create innovative solutions to a host of existing health issues – an evolution that is the very cornerstone of convergent technologies research.


References


1. A. Coffey, P. Walsh, N. Murphy, S. Hanley, Mock Circulatory Loops for Device Testing, Med-Tech Innovation, 12–16, 15, July/August (2013).


2. A. Coffey et al., “Freeze-thawed hydrogels for modelling blood vessels,” Plastics Research Online, 10.1002/spepro.003334 (2010).


3. K. Kosukegawa et al., “Measurements of dynamic viscoelasticity of poly (vinyl alcohol) hydrogel for the development of blood vessel biomodeling,” Journal of Fluid Science and Technology, 3, 533–543 (2008).


4. M. Ohta, et al., “Poly-vinyl alcohol hydrogel vascular models for in vitro aneurysm simulations: The key to low friction surfaces,” Technology & Health Care, 12, 225–233 (2004).


5. C. Hassan and N. Peppas, “Structure and applications of poly (vinyl alcohol) hydrogels produced by conventional crosslinking


www.med-techinnovation.com September/October 2013 ¦ 15


Sian Hanley is a Research Engineer with the CTRG at WIT. Waterford Institute of Technology, Cork Road, Waterford, Ireland, tel. +353 51 302 090 e-mail: acoffey@wit.ie, www.wit.ie


or by freezing/thawing methods,” Biopolymers PVA Hydrogels, Anionic Polymerisation Nanocomposites, 37–65 (2000).


6. M.J.D. Nugent and C.L. Higginbotham, “Investigation of the infl uence of freeze-thaw processing on the properties of polyvinyl alcohol/polyacrylic acid complexes,” Journal of Materials Science, 41, 2393–2404 (2006).


Dr Austin Coffey is Principal Investigator with the Convergent Technologies Research Group and is Programme Director of the award winning M.Sc. in Innovative Technology Engineering at WIT. He is also the current Chair and Councillor of the European Medical Polymers Division of the Society of Plastics Engineers.


Philip Walsh is the Technical Lead with the CTRG and is programme director of M.Eng. in Electronic Engineering at WIT.


Niall Murphy is a Senior Researcher and lecturer in the Department of Engineering Technology at WIT.


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