Creating Materials to Deliver Stem Cell Products
Stem cell therapy holds immense potential as a treatment paradigm for a number of conditions. However, currently the therapeutic outcome is often limited by low cell survivability, poor integration within the host tissue of the stroke brain and non-sustained delivery over the period of treatment. Bioengineering strategies can be employed to try and overcome these limitations by specifically designing three-dimensional scaffolds that replicate the ECM environment. They can provide a protective platform to support the long-term growth and proliferation of cells, thereby significantly improving the in vivo viability of transplanted cells. Therefore, incorporation of multiple signals within the hydrogel matrix through simple modifications to the peptide monomers to best encapsulate and support the growth of stem cells is a project of interest going forward.
Whilst it is important to modulate biological signals to promote stem cell survival, the stiffness and porosity of the hydrogel are also of critical importance. The ability to control the stiffness and porosity of peptide-based materials has proved to be a major obstacle for many α-peptide-based systems. I have identified two separate methods by which the stiffness AND porosity of β-peptide hydrogels can be individually tailored to suit the end application. I have shown that different β-peptide monomers can co-assemble to provide fibres and gels with multiple functions. In this instance, hydrogels that are formed by the assembly of some specific β-peptides have pores that are far too small for the encapsulation of stem cells, however, other β-peptides form hydrogels with large pores that enable cell encapsulation. The combination of these peptides has the potential to tailor the pore size for the encapsulation and delivery of a variety of products. This represents a unique platform whereby the biological and mechanical parameters of the hydrogels can be individually modulated without perturbation to the self-assembly. Projects will include the modulation of pore size for the delivery of stem cells, exosomes and miRNA for the treatment of stroke, spinal cord injury and heart disease.