Research Projects

The retina of the eye contains all the necessary machinery for converting light into a rich array of electrical signals that the brain processes to create internal representations of the location and qualities of visual features in the environment. The basic architecture of the five layers in the retina: three layers of cells and two layers of synaptic connections (plexiform layers) are universally observed across species. The neuronal-cell layer closest to the lens are retinal ganglion cells (RGCs); RGC axons form the optic nerve, that connects the brain. The electrical signals carried by these RGC axons establish the link between the outside world and our internal perception of sight. There are several features such as motion-direction sensitive aspects at single pixel (neuron) level; colour contrast mechanisms; and gaze stabilization for the visual scenes incident embedded within the mammalian retina, all features that help in navigation-adjustment and decision processing. It will be valuable to incorporate elements of the features in real-world scenarios such as robotics, autonomous vehicles, and solutions for the visually challenged. The proposal covers two broad aspects related to the sensory vision system: (i) Develop devices and components that captures visual features using variety of processes to obtain temporal and spatial scales similar to that in a retina. Processes and architecture inspired by retina in primate and non-primate species offer interesting options that can be utilized for sensory input in many applications. The significant advancement in molecular/nanostructured materials and processes will be utilized for this purpose. Specific features in terms of color recognition, direction-motion sensing, and polarization sensitive devices will be envisaged and implemented. (ii) Exploration of active materials for Retinal Disorder: Retinitis pigmentosa (RP) and age-related macular degeneration (AMD) where there is a major degeneration of photoreceptors take major share of the adult eye diseases component that particularly affects the neurovascular retina. The prevalence of RP is significantly in India is appreciably higher than the global average. In this regard, specific molecular and polymeric semiconductors offer combination of optoelectronic and mechanical properties for sensing and stimulating neuronal activity and evoking response in retinal ganglion cells. This possibility of triggering neuronal signals in a blind retina has opened up a route for utilizing these (intelligent) substrates as a prosthetic element. Sub-retinal prosthesis, utilizing the relatively undamaged inner retinal network circuitry, is a promising option for restoring vision. Recent results from our laboratory, where semiconducting polymer blend films are utilized as photoreceptors in blind avian-retina, reveal promising trends that require a deeper understanding to explore a route for vision restoration