Diffusion in supramolecular gels for drug delivery
The development of novel drug-delivery vehicles, especially for biologics, is as important as that of novel drug entities and has to show tuneability to the patient and the disease state alike. Biologics are currently preferred to be administered by injection due to bioavailability restrictions, and sustained release is generally achieved by increasing the viscosity of the injectable, e.g. by gel formation. Macroscopic viscosity, though, is not directly connected to its microscopic counterpart, and solute molecules mainly experience hydrodynamic interactions governing diffusion on the nano-scale in viscous solutions. In this project, we will connect the microscopic diffusion and and macroscopic viscosity to allow for the tailoring of novel materials for bespoke sustained drug release.
By probing the self-diffusion of pharmaceutically interesting solute molecules in supramolecular gels as a function of solute size, fibre network density and fibre surface charge on various time/length scales using QENS, pulse-field gradient NMR, X-ray photon and fluorescence correlation spectroscopies, we will obtain information about the influence of fibre surface and confinement on the macroscopic viscosity. Related to the macroscopic diffusion of the solute out of the gel probed over hours to days, the outcomes of this research will enable the tailoring of low-viscosity injectables with sustained drug release.