Nanoparticle Dynamics in Polymer Solutions and Melts

University Of Texas At Austin, Austin TX

Investigators

Abstract

NONTECHNICAL SUMMARY This award supports theoretical and computational research and education on the motion of small particles, drug molecules and proteins in environments crowded with polymers, long chain-like molecules, such as may be realized in cell interiors and tissue networks. Increasing evidence suggests that the influence of cell crowding on the motion of small particles and proteins indirectly influences a number of biomolecular phenomena, including protein stability and aggregation, and enzymatic reactions. Unfortunately, the typical cell environment consists of a soup of a vast number of different components, such as long-chain polymers, genomic DNA, and metabolites, rendering it difficult to quantify the features responsible for protein or particle motion in such matrices. This research is aimed to develop and use computer simulations to study the motion of small particles in a model, representative system of polymeric solutions, to identify the influence of (a) crowding, as quantified by the relative size of the particle/protein to environmental dimensions; and (b) the interactions between the particle/protein and the environment. The understanding derived in this project can have impact on both fundamental understanding of cellular processes and the design of new nanoparticle therapies. The project will include opportunities for graduate, undergraduates and high school students to pursue research in an area at the crossroads of biology and polymer physics. The outcomes of the research will also be used to develop computer-based educational modules to illustrate the physics accompanying motion of small probes and proteins in crowded environments. TECHNICAL SUMMARY This award supports theoretical and computation research and education on the fundamental physics underlying the movement of nanoparticles in polymeric fluids. Recently, sophisticated experimental studies have accessed the dynamics of particles whose sizes are comparable to the polymer solution correlation lengths, and have unearthed a number of intriguing behaviors which are distinct from the continuum characteristics exhibited by colloidal particles. The PI aims to develop and use coarse-grained computer simulation methodologies to identify the fundamental physics governing the mobility and rheological properties of nanoparticles in polymer solutions ranging from dilute to concentrated conditions. More specifically, this research will use computer simulations and models to address two broad issues: (i) The influence of noncontinuum, scale-dependent rheological properties of the matrix upon the dynamics and rheological properties of nanoparticle suspensions in polymer matrices; (ii) The influence of polymer-nanoparticle interactions upon the mobilities and suspension rheologies. This project will include: research opportunities for graduate, undergraduates and high school students; development of new simulation and educational modules targeting undergraduate, graduate courses and K-12 outreach activities; and synergistic activities involving the organization of colloquia designed to serve as a forum for confluence of research in polymer physics and continuum mechanics.