2011 Paterson Medal and Prize

Dr Jochen Guck

University of Cambridge

For his invention of the optical stretcher, together with other novel physical probes to elucidate cellular mechanical and optical properties, their role in biological function and their potential in medical diagnostics.

Jochen Guck is a leader in developing innovative photonic tools to test the relevance of living cell mechanical and optical properties for biological function and ultimately to impact clinical practice in improved disease diagnosis and regenerative medicine. His 'optical stretcher' is a key laser tool to trap and deform individual cells through the forces arising from momentum transfer of light to their surface. Changing the laser power induces deformation, revealing the response of the cytoskeleton, which is important for physiological and diagnostic for pathological changes. The aim is to develop a label-free, high-throughput cell analysis method for cancer diagnosis, infections and stem cell sorting. Preclinical tests of this approach for oral carcinomas have already been successful.

Another optical tool for marker-free characterization of cellular processes under development is single-cell refractive index tomography. A digital holographic microscope, used for interferometric imaging of phase differences in cells, combined with a contact-free optical cell rotator, reveals 3D distributions of refractive index within living cells at resolution well below Abbé’s diffraction limit. This allows the marker-free study of chromatin density inside living cells, which is linked to the epigenetic regulation of transcription.

This novel technique combines the advantages of electron microscopy (high resolution) with those of light microscopy (live cell imaging), e.g. to identify stem cells from differentiated cells. Both photonic tools were also used to shed new light on vertebrate vision. Individual elongated glial cells in the retina were explored using a modified optical stretcher and refractive index measurements. Guck showed that these Müller cells act as living optical fibres. More recently, the Guck and colleagues showed that even the photoreceptor nuclei in the retina uniquely invert their chromatin structure becoming microlenses for improved light transport to the photoreceptor segments – finally resolving the enigma of the inverted retina.