Regulating stem cell behaviour using bioengineered culture substrates

• Main Author: Hill, C. J.
• Published: University of Liverpool 2017
• Subjects: 616.02
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.722037

Stem cells hold enormous potential for the treatment of injuries and degenerative diseases. In the pursuit of stem cell therapies, a plethora of biomaterials have been developed to induce lineage-specific differentiation or support cell propagation for research and clinical applications. However, the use of stem cells is hindered by the cost of scale-up and risk of zoonotic transmissions from animalderived culture components. Here, we utilise a recombinant protein scaffold composed of self-assembling nanofibres, termed ZT, and assess the systems adaptability for in vitro applications. Protein-based scaffolds offer distinct advantages over conventional materials such as the display of peptidic motifs with near-native stoichiometries and control of the spatial density and nanotopographical distribution of genetically-encoded bioactivities. Herein, the functionalisation potential of the ZT system is explored via the generation of chimeric protein building blocks that exhibit the integrin-binding RGD motif. Specific sites within the building blocks were found to tolerate diversification, in the form of exogenous peptides or a fused protein domain, without structural perturbation or inhibition of assembly. The bioactivity of functionalised ZT nanofibres was assessed using murine mesenchymal stem cells (mMSCs), which recognised the integrin-binding moieties. The ability of one ZT nanofibre variant to induce mMSC chondrogenesis was investigated, which proved unsuccessful in the current context. A second generation of ZT variants were generated by the incorporation of chondroinductive motifs for future applications in cartilage tissue engineering. Additionally, the capacity of functionalised ZT nanofibres to act as culture substrates for human embryonic stem cell (hESC) self-renewal was explored.