DUFFY2	Microscopic models of Surface Acoustic Wave Sensors (SAWS)
Type	Theoretical
#students	1
Orientation	Why is the scientific problem of interest at all? Surface acoustic waves in sensors are generated by the inverse piezoelectric effect; whereby application of an electric field induces a mechanical deformation, elastic or acoustic waves, in the sensor which are incredibly sensitive to physical perturbations. This sensitivity can be used to accurately determine and identify minute (picograms/ ml) concentrations of biomarkers (such as antigens). These sensors are thus ideal candidates for diagnosis of infectious diseases such as HIV, Hepatitis C and influenza strains, which is of immediate interest, and of course importance in today's world.
How	How is the research going to shed light on the given problem? Exactly which physical effects most perturb the acoustic wave are unknown. Identification of the biomarker may be a function of changes in mass, viscosity, conductivity, permittivity (or combinations of these and other effects) induced as the sample is added to the sensor. Understanding the dominant physical effects will allow exploitation of them for the most reliable and accurate functionalization of the sensor for specific diagnostic purposes.
What	What is the specific thing that the student will do, and how does it fit inside the overall project? Functionalizing the sensors for specific applications depends on understanding the molecular detail as the biolayers are applied for detection. The student would be modelling the interactions between the sensor surface where the piezoelectric material of the sensor meets the biolayers. For example; the interactions between quartz : gold : solvent : antibody-antigen pairs : nanoparticles. This atomistic detail would then be used in molecular dynamics simulations to investigate how the layers of materials may bind and pack, change in density, viscosity, and electrical properties. This will elucidate how the acoustic waves on the surface may be best perturbed for the most sensitive detection, thus these simulations will help to tailor designing of the sensors for various applications.
Special Knowledge	Some programming experience (any language) and an interest in materials modelling are essential
Supervisor	Dr Dorothy Duffy d.duffy@ucl.ac.uk