David Liu

Graduate Student, Ph.D. Program

The City College of New York, CUNY, New York, NY.
B.E. in Chemical Engineering, 2011

Research Interest:
Solute partitioning and diffusion in hydrogels






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Hydrogels, hydrophilic polymeric networks swollen in aqueous media, are of interest in a wide variety of applications including chromatographic separations, membrane separations and encapsulation of cells for tissue engineering. Due to their biocompatibility, hydrogels are extensively used in pharmaceutics and for delivery of bioactive agents. Contact lenses, a widespread application of hydrogels, can be employed as delivery vehicles for drugs and for comfort/wetting agents to the eye.

One major challenge in developing delivery systems is controlling the amount and rate of bioactive agent uptake and release. Hydrogels are especially important because: (1) they provide protection from harmful environments and (2) undergo swelling/deswelling as a response to external stimuli, allowing for controlled release in specific physiological conditions. If successfully employed, controlled and targeted release using hydrogels can significantly impact clinical treatment of disorders and diseases such as in administering insulin in diabetes. Likewise, in soft-contact lenses, surfactant and polymeric agents can potentially be delivered through the lens to prevent adhesion to the eye, to protect against bacterial adhesion, and to provide comfort. In both applications, cross-linking degree determines hydrogel mesh size—the average spacing between cross-links (ξ) —and can be used to regulate solute uptake and release.

Solute partitioning and diffusion in the hydrogel network govern the amount of agent uptake and rate of release respectively. Current models, however, are typically semi-empirical and often oversimplify the physical phenomena. Thus, they do not completely describe solute transport and thermodynamics in hydrogels, especially proteins, polymers and surfactants where solute size and mesh size are comparable. In spite of the importance of hydrogels in biomedical applications, their structure/property relationships are still not well understood. The primary goal of my work is to develop physicals model to predict equilibrium partitioning and diffusion of prototypical solutes in hydrogels.


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