Glyconanotubes to direct stem cell behaviour

• Main Author: Tillotson, Donna
• Other Authors: Merry, Catherine; Kinloch, Ian
• Published: University of Manchester 2013
• Subjects: 620
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607000

Carbon nanotubes (CNTs) are high aspect ratio, super hydrophobic, cylindrical carbon tubes with a diameter < 10 nm. These unique structure related properties have led to their use as nano-carriers for nucleic acids, small molecules and proteins. Here, we have developed the use of CNTs as a delivery vehicle for sulphated polysaccharides such as heparan sulphate (HS) ready for interactions at the cell surface. HS is essential for development and has been shown to be a key regulator in many embryonic stem (ES) cell biochemical events including self-renewal, proliferation and differentiation. Differentiation of ES cells to their lineage-specific progeny has proven to be a useful model system in which the role of glycosaminoglycans in general and HS in particular can be determined and characterised. We hypothesise that the functionalisation of CNTs with biologically active oligosaccharides will provide a novel way to probe the interactions HS during differentiation. Here we demonstrate that heparin and HS can non-covalently interact with CNTs to produce stable CNT dispersions in a manner that is dependent on the presence of sulphated groups. In the presence of CNTs mES cells show a normal phenotype where they are able to attach to gelatin coated tissue culture plastic, form tightly packed rounded colonies and show normal proliferation rates. Heparin delivered via CNTs remains biologically active, as determined by its ability to rescue neural and mesodermal specification in a HS deficient mES cell line. Interestingly, heparin delivered via CNTs is able to direct neural differentiation more strongly than the addition of soluble heparin alone. Heparin delivered by a CNT may be able to interact with a key signalling molecule, the FGFs, to increase its stability in the cell culture environment and to mediate its signalling more effectively than soluble heparin alone. This could allow us to deliver potent HS oligosaccharides to the cell surface which are able to drive lineage specific differentiation.