2005 IRISH SCIENTIST YEAR BOOK

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Athlone Institute of Technology
Athlone Institute of Technology
New generation "smart" materials at Athlone IT


The term hydrogel is used to describe materials that are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids. They are best considered as polymeric materials, which are able to swell in water and retain a significant fraction of water within their structure, but do not completely dissolve. Hydrogels are becoming increasingly important materials for pharmaceutical applications. They are used in a variety of applications including diagnostic, therapeutic, and implantable devices for example, controlled release drug delivery systems which have been studied extensively, contact lenses and tissue engineering. Hydrogels have been widely used in such applications because of their biocompatibility with the human body and also because they resemble natural living tissue more than any other class of synthetic biomaterials. This is due to their high water content and soft consistency which makes them similar in characteristics to natural tissue.


Illustration 1: Biomedical Research Group at Athlone IT, l- r: Jean-Marie Bocquel, Michael Nugent, Luke Geever, Declan Devine, James Kennedy, Olivier Coubrun, Sean Lyons, Mark Hallinan and Dr. Clement Higginbotham

Hydrogels may be composed of homopolymers or copolymers and are insoluble in water due to the presence of chemical crosslinks (covalent bonding) or physical crosslinks, such as entanglements or crystallites. Their mechanical properties are very important for pharmaceutical applications, for example, the integrity of the drug device during the lifetime of the application is vital in obtaining 'food and drugs administration' (FDA) approval, unless the device is designed as a biodegradable system. A drug delivery system designed to protect a sensitive therapeutic agent, such as a protein, must maintain its integrity to be able to protect the protein until it is released out of the system.

Changing the degree of crosslinking has been utilised to achieve the desired mechanical properties of the hydrogels. Increasing the degree of crosslinking of the system will result in a stronger gel. However, a higher degree of crosslinking creates a more brittle structure. Hence, there is an optimum degree of crosslinking at which a relatively strong and yet elastic hydrogel, exists. Copolymerisation has also been utilized to achieve the desired mechanical properties of hydrogels. Incorporating a co-monomer that will contribute to hydrogen bonding can increase the strength of the hydrogel.


Illustration 2: The picture shows a TA 1000 Rheometer with an environmental chamber, which allows the thermal and mechanical properties of hydrogels to be examined

Smart materials are currently being synthesised for the following applications in the Centre for Biopolymer and Biomolecular Research (CBBR) at Athlone Institute of Technology.


* Drug Delivery

The focus of this research is to develop drug delivery systems based on stimuli sensitive polymers. The stimuli in which we are interested, include change in pH, change in temperature and change in glucose concentration. The latter has significant consequences in the treatment of diabetes.

* Coatings

The aim of this research is to develop methods for producing and applying lubricious hydrophilic coatings. These are coatings which, when applied to medical devices, such as catheters, become slippery when wet so that they can be inserted into the human body with ease.

* Coatings for drug delivery

This research combines the coatings research and the drug delivery research. The aim is to develop a coating into which a drug can be incorporated. The drug can then be released slowly over a specified period of time.

* Biomaterials for tissue engineering

This research is aimed at developing new biodegradable polymeric materials, or modifying existing polymeric materials, suitable for reconstructive surgery applications. For these applications it is essential that a high level of spontaneous tissue growth through the pore structure of the polymer be achieved, as part of the inflammatory response.
Contact: Dr. Clement L. Higginbotham; E-mail: [email protected] ;
Michael Nugent; E-mail: [email protected] ;
Centre for Biopolymer and Biomolecular Research,
Athlone Institute of Technology, Dublin Road, Athlone, Co. Westmeath;
Tel: 353 (0) 90 6424400