The influence of spatial scaffold properties on the interaction between cells and embedded growth factors

While modern-day healthcare continues to improve in terms of available treatments and life expectancy in many countries, increasing costs of providing medical services to aging populations place these systems under increasingly severe pressure. With continuing increases in chronic afflictions and ailments related to old age, more cost-efficient and long-term solutions are needed to meet these challenges.

Regenerative medicine offers the potential for more effective long-term treatments, but is hindered by the high cost of the desired treatments in terms of development and implementation, owing to the complexity of the living materials used for such therapies.

The work described in this thesis focuses on improving the level of control over the local cellular environment in order to reduce the need for costly materials (especially growth factors). Both surface topology and immobilization of growth factors have previously been shown to have an impact, and this research investigates potential interaction between these aspects. Patterning and immobilization of bio-active compounds are combined for the culture of human mesenchymal stem cells on surfaces with differently scaled patterns and concentrations of immobilized TGF-β1.

Initial work focused on the creation of patterned surfaces with feature sizes ranging from 1 to 50 µm. Patterns were successfully produced in Poly (Ethylene Glycol), Polystyrene and Polycaprolactone surfaces using a microparticle-based moulding process.

Further work resulted in the successful immobilization of TGF-β1 onto chemically modified surfaces, chiefly Polycaprolactone. Proteins were successfully immobilized onto Polycaprolactone surfaces at concentrations up to 4 pmol/cm2, with exact concentrations dependent on the parameters of the immobilization process.

Finally, the developed methods were combined in a hybrid experiment using both patterned surfaces and growth factor immobilization. Results demonstrated a probable link between surface patterning and the effectiveness of immobilized growth factors, although further work is needed to more accurately describe any underlying processes.