CAREER: Structure-Function Relationships of Photoswitchable Rotaxanes in Membrane Remodeling, Ion Transport, and Memristive Behavior.

In this CAREER project, Professor Víctor García-López of the Department of Chemistry at Louisiana State University will develop new classes of light-responsive molecules that reversibly modulate the physical and electrical properties of cell-like membranes. By using light to dynamically alter the membrane environment, the project aims to control ion movement across membranes with high spatial and temporal precision and to generate adaptive electrical behaviors inspired by biological neuronal synapses. Understanding how dynamic changes in soft membranes regulate voltage-dependent ion transport and electrical signaling may enable new approaches to soft bioinspired electronics and brain-inspired computing technologies. The project also aims to strengthen STEM engagement across multiple educational stages and to contribute to the development of a highly skilled scientific and engineering workforce. It provides interdisciplinary training for undergraduate and graduate students in synthetic chemistry, spectroscopy, and membrane biophysics. Outreach activities will broaden participation in STEM by organizing the regional You Be The Solution Challenge for middle school students and by developing educational modules for pre-engineering students. Mechanically interlocked rotaxanes are highly modular, structurally tunable molecules that enable systematic control over their interactions with lipid bilayers. Their light-driven conformational changes can induce distinct modifications in membrane structure and permeability, depending on molecular design, thereby enabling programmable electrical behavior at soft interfaces. Furthermore, their photoreversibility may enable switching between different neuromorphic-like membrane responses. This project will synthesize a family of photoswitchable rotaxanes to establish how molecular structure governs membrane function and electrical behavior. Specifically, the work will (1) determine how rotaxane topology influences photoswitching and intramolecular dynamics, (2) assess how membrane environments affect photoswitching efficiency, (3) map how spatially localized photoswitching alters bilayer properties, and (4) identify structural features that enable efficient ion transport and tunable memristive behavior. Together, these studies will establish design principles for rotaxanes that can precisely and reversibly control membrane structure and function. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.