Prof. O'Brien heads the RCSI Tissue Engineering Research Group which collaborates closely with the Trinity Centre for Bioengineering and the Centre of Research on Adaptive Nanostructures and Nanodevices in TCD. The developing field of tissue engineering aims to regenerate damaged tissues by combining cells from the body with highly porous scaffold biomaterials, that act as templates for tissue regeneration, to guide the growth of new tissue. Tissue engineering uses a combination of: (i) the scaffold (ii) cells and (iii) signalling mechanisms (such as growth factors or mechanical stimuli) to restore the function of damaged or degenerated tissue in vivo or to culture tissue in vitro which can be used for subsequent implantation. The research carried out in our laboratory investigates each of these three areas with target applications in bone, cartilage, cardiovascular and other tissues. We have developed a series of porous collagen-based scaffolds with the optimal composition, pore structure and stiffness to promote tissue regeneration. A number of these technologies have been patented resulting in the recent formation of a spin out campus company, SurgaColl Technologies, which is focussed on the design and manufacture of innovative degradable regenerative technologies. In the cellular area, we are investigating the therapeutic potential of stem cells in combination with these scaffolds and we have a particular interest in using biophysical stimuli (applied by bioreactors or controlled by scaffold stiffness) to regulate stem cell differentiation. Ongoing research focuses on the use of these scaffolds as therapeutic bioactive platforms for the delivery of growth factors or as gene-activated matrices to promote enhanced tissue repair. In the latter area we focus on the development of non-viral nano-particulate systems for gene delivery in combination with these collagen-based scaffolds.