Dr Aimee Sweeney

Retina cells demonstrate the amazing capability of single-photon detection, pointing at the ability of biological photoreceptors to exhibit quantum mechanical properties at room temperature and normal atmospheric pressure, in a ‘noisy’ biological environment. In the human retina, photo transduction is an enormously efficient process, involving multi-wavelength photon absorption by different rod and cone cells and signal transfer through neurons towards the optical nerve.  Several quantum processes have been suggested as mechanisms, contributing to the remarkable speed and efficiency of photoisomerization and subsequent signal transduction, including quantum coherence, superposition, and tunnelling in retina cells. Mimicking these processes with bio-compatible, synthetic organic molecular systems will provide pathways for a deeper understanding.

This project studies the use of naturally occurring chromophores isolated from the juice of different fruits and vegetables, for studies of their photoresponses in stimulated bio-environments when their peak absorption matches that of human eye rods and cones. A simplified model of the eye is being used to investigate is such chromophores can induce depolarisation effects to stimulate retina neuron depolarisation. The construction of a full colour response prosthetic retina ultra-flexible device will be attempted to investigate the feasibility of vision restoration. The study will also suggest strategies for the fabrication of single-photon bio-inspired molecular detectors that could help to increase the efficiency of solar cells.