Session: 16-01-01: Government Agency Student Poster Competition

Paper Number: 142773

142773 - Strain-Programmable Particle Diffusion in Stretchable Hydrogels 

Particle diffusion, a movement of particles transport from a higher concentration area to a lower concentration region, is a fundamental phenomenon playing a critical role in both life science and multiple engineering applications. For instance, particle transport contributes to the survival of living organisms, facilitating essential processes such as intracellular transport, mucus clearance, and cytoplasmic streaming. Additionally, the technologies to modulate particle transport with high efficiency, superior controllability, and desirable adaptability enable higher performance in drug delivery, chemical catalysis, water treatment, and biosensing. Therefore, exploring and leveraging effective methods to program particle transport is important to enhance the potential of diffusion-involved technologies.

Conventional approaches to tune the particle transport primarily involve medium viscosity manipulation based on the Stokes-Einstein equation. However, relying solely on the viscosity adjustment to control the diffusivity of particles has several significant limitations. Firstly, adjusting the viscosity of a medium often necessitates external environmental variation such as the manipulation of temperature and pressure, making the real-time and on-demand transport modulation challenging. Secondly, the viscosity is typically an intrinsic property of the medium, requiring considerable effort to effect relatively minor changes, thus limiting the tuning space of the viscosity and thus the transport efficiency. Moreover, although recent existing efforts reveal that manipulating the particles with external fields such as static electric field, magnetic field, or light intensity gradient show desirable controllability in particle transport, the responsive particles are not universally applicable in most application scenarios.

In this work, we exploit mechanical deformation as a new design space to program particle transport in the stretchable soft hydrogel medium, with high efficiency, superior controllability, and desirable adaptability. Specifically, we develop a theory-guided approach to employ strain-engineering techniques to tune the hopping diffusion process of the gold nanoparticles within hydrogels. By applying the macroscopic deformation to the stretchable polymeric hydrogel medium, the polymer networks vary the mesh size on the molecular scale, thereby reducing the energy barriers experienced by the nanoparticles during diffusion. Through a customized loading platform, the polymeric hydrogel mediums are under static stretches with different stretch ratios, multiple stretching rates, and various shear strains, and the nanoparticle's diffusion profiles are observed. Remarkably, the results show that the nanoparticle diffusivity manifests a 12-fold increase under a 4-fold stretch of the hydrogel medium. Additionally, it can be observed that the diffusivity of the nanoparticles varies with the adjustable loading rates and the stress states in different patterns. Moreover, a deformation-sensitive drug delivery system is constructed based on this mechanism, demonstrating its potential for on-demand drug release applications. This work not only advances the fundamental understanding of the particle transport mechanism in polymeric stretchable soft materials but also opens up the horizons with strain-programmable diffusion modulation which was inaccessible in previous research.

Presenting Author: Chuwei Ye Michigan State University

Presenting Author Biography: Chuwei Ye is currently a PhD student in Mechanical Engineering at MSU, co-supervised by Dr. Shaoting Lin and Dr. Zhaojian Li. He received his Master's degree and Bachelor's degree in Mechanical Engineering from Zhejiang University in 2020 and 2017, respectively. His research interests include particle transport in stretchable hydrogels, solid mechanics of soft materials, and system integration.

Authors:

Chuwei Ye Michigan State University
Tsz Hung Wong Michigan State Univerisity
Jiabin Liu Michigan State Univerisity
Congjie Wei Texas A&M University
Xinyue Liu Michigan State Univerisity
Ziyou Song National University of Singapore
Chenglin Wu Texas A&M University
Zhaojian Li Michigan State Univerisity
Shaoting Lin Michigan State Univerisity