Development of biomimetic photo-responsive artificial carriers for the transmembrane chloride transport

Abstract

Thesis Abstract: Title: Development of biomimetic photo-responsive artificial carriers for the transmembrane chloride transport The transport of ions across the cell membrane through naturally occurring ion carriers and ion channels is crucial for multiple physiological functions. In particular, the transport of chloride ions is known to induce chloride-mediated apoptosis inside the cancer cells. Traditional transporters lack ion selectivity and hence can damage the normal healthy tissues. Stimuli such as voltage, pH, enzymes, ligands, light, etc., have been employed for activating ion transporters inside the cancer cells. Light-responsive ion transport systems, in particular, are important systems because of their spatiotemporal control, remote addressability, and less cytotoxicity. Herein, we developed several light-responsive synthetic ion carriers, which were manifestly controlled utilizing the external electromagnetic radiations. Initially, the most widely used azobenzene photoswitch was used to generate the light-responsive ion transport systems, and efficient “OFF-ON” photoreguatory ion transport activity was achieved. Acylhydrazone-based photoswitches were employed to enhance the exciting state thermal stability. The reversibly-gated ion transport activity was achieved utilizing light and catalytic acid, respectively, as the external stimuli. Phenylhydrazone-based photoswitches were utilized to enhance the excitation wavelength. These photoswitches function comparatively at higher wavelengths compared to that of acylhydrazone switches. Eventually, we demonstrated an onitrobenzyl-based photocaged ion transport system could be selectively activated inside the cancer cells to induce chloride-mediated apoptosis utilizing the external electromagnetic radiations.