A rapid method for determining protein diffusion through hydrogels for regenerative medicine applications.

• Authors: Marian H. Hettiaratchi, Georgia Institute of Technology; Alex Schudel, Georgia Institute of Technology; Tel Rouse, Georgia Institute of Technology; Andres J. García, Georgia Institute of Technology; Susan N. Thomas, Georgia Institute of Technology; Robert E. Guldberg, Emory University; Todd C. McDevitt, University of California San Francisco
• Journal Title: APL Bioengineering
• Volume: Volume 2, Number 2
• Publisher: AIP Publishing LLC | 2018-06, Pages 026110-026110
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1063/1.4999925
• Subjects: Engineering, Biomedical; Health Sciences, Rehabilitation and Therapy
• Keywords: Immune system; Proteins; Computational models; Tissue engineering; Biomaterials; Capillary flows; Chemical elements; Fluorescein; Therapeutics; Diffusion rate

Abstract

Hydrogels present versatile platforms for the encapsulation and delivery of proteins and cells for regenerative medicine applications. However, differences in hydrogel cross-linking density, polymer weight content, and affinity for proteins all contribute to diverse diffusion rates of proteins through hydrogel networks. Here, we describe a simple method to accurately measure protein diffusion through hydrogels, within a few hours and without the use of large amounts of protein. We tracked the diffusion of several proteins of varying molecular weights along the axial direction of capillary tubes filled with alginate, collagen, or poly(ethylene glycol) hydrogels. The rate of protein diffusion decreased with increasing molecular weight. A computational model of protein diffusion through capillary tubes was also created to predict and verify experimental protein diffusion coefficients. This in vitro capillary tube-based method of measuring protein diffusion represents a simple strategy to interrogate protein diffusion through natural and synthetic hydrogels and aid in the design of better biomaterial-based delivery vehicles that can effectively modulate protein release.