Scaffold fabrication

We are involved in synthesising novel biodegradable and biomimetic materials for tissue regeneration. These materials are used to generate scaffolds that support cell and tissue growth. We are currently developing methods of fabricating controlled drug delivery devices within these scaffolds, such that drugs and growth factors may be released during tissue development.

Biomimetic polymers: surface modification

It is generally proposed that the regeneration of artificial organs from specific cell lines is best approached with the aid of a supportive scaffold device. Such a material should closely mimic the natural environment in which cell growth occurs and should therefore be capable of interacting with, and maintaining the differentiated functions of, cell populations.

This approach combines tissue engineering with state-of-the-art surface analysis techniques. We have demonstrated that cell behaviour on scaffolds can be controlled by engineering the scaffold surface to promote specific cell adhesion (such as the tripeptide sequence RGD). Using surface specific tecniques including Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS), Differential Scanning Calorimetry (DSC) and Scanning Thermal Microscopy, we are currently investigating the influence of scaffold chemical structure on surface morphology and behaviour. In addition to promoting cell adhesion, we are also investigating ways to prevent unwanted bacteria/protein/platelet adhesion to our biomaterials, which lead to unfavourable events such as attachment of unwanted cell types and thrombus formation. Poly(ethylene glycol) has already proved to be of value in such instances.

It is hoped that this research will lead to the development of stable polymeric surfaces suitable for tissue engineering.

Supercritical Fluid Scaffolds

Supercritical fluids are highly compressed gases that possess properties of both a gas and a liquid. Supercritical CO2 (scCO2) can be used as an environmentally acceptable alternative to conventional solvents for reaction chemistry, so called "Clean Technology". Supercritical CO2 mixing can be used to generate porous scaffolds of biodegradable polymers, such as poly(D,L lactic acid), which has a low glass transition temperature and is already approved for medical applications. Supercritical CO2 lowers the glass transition temperature of the polymer further to physiological temperatures and therefore allows the incorporation of growth factors and mammalian cells into the polymer during the processing stage, without the loss of protein activity or significant cell viability. These scaffolds are currently being used to regenerate a number of tissues including liver and cartilage.