Here you can find a summary of the stuff that I’m working on at the moment. My work is highly collaborative, and many of these projects involve other groups. For papers relating to these projects, please see my publications page.

Diffusiophoresis

autophoresis

Diffusiophoresis is a process whereby differential chemical reaction rates across a particle’s surface generate effective slip flows in a very thin surface boundary layer, propelling the particle through the fluid. Thus, the trajectories of diffusiophoretic particles arise from highly-coupled physics; complex solute-environment-hydrodynamic interactions that require modelling to fully-understand. Diffusiophoretic particles have the potential to create materials with novel properties, and to perform intricate microfluidics tasks such as cargo transport and microstructure assembly. My current interest in diffusiophoresis lies in improving theoretical and numerical techniques in order to model realistic systems with greater accuracy.

Microrobots

nelson_website

Biomedical microrobots are novel devices being developed to perform tasks within the human body, such as 1) removal of material, eg ectopic pregnancy, 2) targeted drug delivery, and 3) remote monitoring of unreachable areas of the body. Microrobots are a minimally invasive solution compared with many traditional alternatives, they treat only the affected area, which can reduce patient recovery time, infection risks and post-operative pain. To perform such tasks, microrobots would need to actively self-propel and navigate with precision. However, the human body is a diverse, unpredictable environment, filled with branching vessels, sticky fluids and pulsing flow. My research lies in understanding the effects of boundaries, ambient flow and complex fluid rheology on the ways a microscopic swimmers progress through environments.

Microbiofluiddynamics

microboifluids
Fluid interactions are ubiquitous in the natural world; all organisms must find strategies to generate, utilise or resist flow in order to be successful. This strand of research is focused on developing mathematical and computational tools to understand microscopic biological flows. The work is highly interdisciplinary, drawing from mathematics, statistical physics, biology and continuum mechanics. I am particularly interested in external flows, for instance flow driven by beating filaments such as cilia and flagella, their fluid structure interaction, and the resultant behaviour of flagellated swimmers such as sperm and algae.

Vertebrate symmetry-breaking

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Left-right symmetry breaking in vertebrates is a fundamental embryonic process determining the organisation of internal organs. In the developing zebrafish embryo, symmetry breaking is dependent upon Kupffer’s vesicle; a scalene ellipsoidal structure of cells filled with fluid. Hair-like organelles known as cilia protrude from these cells, whirling in order to generate a fluid flow, which is associated with symmetry-breaking. This work is being performed in collaboration with David Smith and Susana Lopes’ experimental laboratory in Lisbon. We have used detailed three-dimensional numerical simulations combined with flow analysis from videomicroscopy to examine the roles of cilium number and placement on left-right situs. We are currently using these techniques to probe the mechanisms through which fluid flow in a closed cavity breaks symmetry.

Growth of plant embryos

plant_growth

In collaboration with George Bassel’s and Richard Smith’s groups, I have developed 3DCellAtlas, a plugin for the open source MorphographX software that analyses the three-dimensional single-cell morphology of plant organs. Using morphology data, the software generates a digital cell atlas of the organ with no lower than 98% accuracy. Using this approach, we have quantified the cell-type specific anisotropies that drive Arabidopsis hypocotyl elongation. The approach can also quantify reporter abundance in specific cells, allowing us to better understand the effects of growth hormones. A version of the software which can be applied to plant Meristems is currently in development.