Opportunities

We are interested in numerous applications where understanding how biological molecules interact with non-biological materials. Whether it be in designing nanoparticles for drug delivery, bioimaging or biosensing, it is important to know how biological molecules interact with these particles as it can change their ability to successfully deliver their payload or it might change their fluorescent behaviour.  Therefore we aim to understand how functionalising these nanoparticles affect the amount of interaction with their biological environment. We are also interested in understanding how biological molecules respond to be adsorbed to polymeric substrates.

We are interested in polymeric, peptide-based and lipid-based drug delivery vehicles and understanding the interactions which govern their ability to self assemble and encapsulate the therapeutic agent they are deliver.  We are also interested in investigating the molecular scale detail of their interaction with realistic model membranes when they reach their target.  Finally, we are interested in the molecular mechanisms that result in the delivery of the payload once they have reached their target.  Currently we are investigating, lipid nanoparticles (both solid & liquid), surfactant micelles, polymeric micelles and self-assembled peptide-based nanoparticles which mimic virions as anti-bacterial and anti-cancer agents. Moving forward we are increasingly interested in investigating nanoparticles which consist of a mixture of these types of molecules.

With a coefficient of friction on the order of 10^-4, synovial fluid currently outperforms all artificial lubricants and is effective up to loads of at least 20 MPa and over a wide range of shear rates.  Understanding precisely how this is achieved is essential in order to address one of the significant issues faced in an ageing population, osteoarthritis.  Currently, in vitro testing of artificial lubricants for joint implants
produces much higher levels of lubricity than seen in vivo, meaning that the lifetime of such joint replacements is much less than predicted and required. Current steel implants do not encourage adsorption of lubricating macromolecules onto their surfaces, and those that do absorb are very non-uniform.  These molecules, which include hyaluronan, lubricin, and surface-active phospholipids, are considered essential in lubricating the joints under boundary lubrication conditions characterised by high loads and low shear rates.

It has recently been found that it is the surface active phospholipids that are the primary source of lubrication in synovial joints subjected to high loads, and that friction dissipation occurs through viscous losses of the hydration shells of their headgroups.  Hyaluronan and lubricin are now understtod to be involved in the attachment of the lipid bilayers to the articular cartilage surface rather than directly contributing to the lubricity of the joints.  Many questions remain unanswered, both in relation to the precise hydration lubrication mechanism of adsorbed lipids, and the synergistic interactions between hyaluronan, lubricin and the surface active phospholipids.

We are interested in numerous challenging problems within the field of lipid biophysics including the effect of asymmetric lipids on the structural and dynamic properties of model and realistic lipid bilayers.  Also we are interested in the effect of oxidised lipid species, which result from aging and disease, effect the lipid membranes in which they reside.