CAREER: Phoretic Transport of Membrane-Bound Biological Colloids in Complex Environments

Molecular solutes such as salts and sugars present in biological systems are rarely at equilibrium as their distribution, concentration, and composition change continuously via various biochemical processes that are important in sustaining life. This award aims to investigate how the non-uniform solute conditions, particularly under confinement, give rise to the motion of biological colloids. Understanding the dynamics of biological colloids can provide valuable insights into fundamental biotransport processes, such as chemotaxis, vesicle trafficking, and capillary exchange, and in developing novel strategies for biomedical and environmental applications, including drug delivery and wastewater treatment, which have a profound societal and economic impact. Various educational activities are directly integrated into the proposed research program. The educational plan specifically targets upper-level undergraduate and entry-level graduate students to foster an adaptive workforce and prepare for their success in higher education and beyond. The goal of this award is to investigate the transport of semi-permeable, deformable vesicles driven by chemical-gradient-induced phoretic processes in confined systems. The proposed research program will elucidate how the interaction of various migration processes and the mechanical environment surrounding the vesicles impact their dynamics. The experimental investigation of the phoretic migration of vesicles includes using a hydrogel-based microfluidic platform to characterize the individual and coupled vesicle mobility under confinement, and three-dimensional microscopy to visualize the vesicle deformation and the internal/external flow field upon migration. The proposed research will provide quantitative insights into the vesicle phoretic transport lacking in the literature, which will help establish an analytical framework for vesicle phoresis that accounts for the deformable interface under confinement. Several research tasks are integrated with an educational effort directed toward engineering students to motivate the study of soft matter physics. By providing research opportunities, the proposed educational activities will encourage undergraduate STEM students, particularly underrepresented students, to pursue higher degree education. These activities will also promote diversity and inclusion in STEM fields and help to address the underrepresentation of certain groups in engineering research. 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.