James Flewellen

I commenced doctoral studies under Dr Richard Berry in October 2008. The aim of my research project is to investigate indirect methods of detecting baterial motion. This has involved using optical methods to detect the hydrodynamically coupled signal of microspheres held in optical traps near a moving cell. More recently, I have been developing holographic microscopy techniques for full three-dimensional imaging of swimming bacteria.

Funding for my research comes from an EPSRC Basic Technology Studentship and the Sims Scholarship via my alma mater, the University of Canterbury, New Zealand.

I am a member of Lincoln College. Outside of my research I have been involved the Lincoln MCR Committee, rowing, choral singing and blind wine tasting.

Holographic Microscopy

I am currently exploring high-speed, high-magnification holographic microscopy to study the behaviour of swimming bacteria.

A conventional image is a record of the amplitude of the light reflected from (or transmitted through) an object. Holography uses the interference properties of light to generate images (holograms) from which both the amplitude and phase of the object can be reconstructed.

Holographic imaging has the advantage over conventional microscopy in that you are not limited by typical depth of field restrictions. This allows for a full, isotropic 3D volume to be imaged at a framerate limited only by your camera. A 3D approach is crucial for understanding the swimming behaviour of microorganisms, which, of course, exist in a 3D world.

I am working with Irwin Zaid on this project. We are currently comparing both inline and off-axis approaches to holographic microscopy.

Hydrodynamic Sensing of Bacteria

An earlier project, in collaboration with the Padgett Group at the University of Glasgow, sought to investigate the use of hydrodynamic interactions between swimming bacteria and optically trapped microspheres to remotely detect bacteria. The aim is to develop an indirect sensor for swimming microorganisms via hydrodynamic coupling between the moving cell and a (series of) optically trapped microsphere(s).