Degree
Doctor of Philosophy (PhD)
Department
Chemistry
Document Type
Dissertation
Abstract
Light-driven molecular motors based on overcrowded alkenes convert photonic energy into continuous, unidirectional rotary motion, which can be harnessed to produce mechanical work. This mechanical action has been exploited to disrupt cell membranes, thereby killing cancer cells, bacteria, and fungi, and to facilitate cargo delivery through biomimetic membranes. Despite these advances, the mechanisms governing motor rotation under membrane confinement and the influence of membrane composition and structure on motor behavior remain poorly understood. This dissertation addresses these gaps by synthesizing different motors and investigating the rate-determining step of the rotation cycle, the thermal helix inversion process, in various biomimetic membranes.
Chapter 2 examines the incorporation of molecular motors into the bilayer of polymersomes and compares their rotational kinetics to those observed in bulk organic solution. Remarkably, the motors retain their rotational properties inside the polymer bilayer, and in some cases the thermal helix inversion step is faster than in solution. These findings demonstrate that membrane confinement does not impede motor operation and can instead modulate, or even enhance, motor function.
Chapter 3 investigates motors bearing different electronic substituents in lipid nanodiscs. In bulk organic solution, the two motors display distinct thermal helix inversion half-lives. However, both motors exhibit comparable half-lives within the lipid nanodisc bilayer. These findings suggest that the lipid membrane environment can dominate over the solvation or electronic effects that govern rotation in solution, establishing the membrane as an active modulator of motor dynamics rather than a passive host.
Chapter 4 focuses on the development of a new generation of motorized systems in which three or four motors are interconnected to form a cavitand-like architecture. These systems are proposed to exhibit distinct membrane-modulating behavior and may also find application in molecular recognition and surface functionalization. This chapter explores various synthetic strategies for their preparation and approaches to structurally characterizing these large molecules using scanning tunneling microscopy.
Together, these findings provide mechanistic insights into how light-driven molecular motors operate in membranes of diverse structure and composition, with implications for their rational design and future application in therapeutic and material applications.
Date
7-13-2026
Recommended Citation
Dawn, Soumya Kanti, "SYNTHESIS AND INVESTIGATION OF LIGHT-ACTIVATED MOLECULAR MOTORS IN BIOMIMETIC MEMBRANES" (2026). LSU Doctoral Dissertations. 7162.
https://repository.lsu.edu/gradschool_dissertations/7162
Committee Chair
Garcia-Lopez, Victor
LSU Acknowledgement
1
LSU Accessibility Acknowledgment
1