Large-area alginate/PEO-PPO-PEO hydrogels with thermoreversible rheology at physiological temperatures
July 21-24, 2019
Alginate hydrogels have shown great promise for applications in wound dressings, drug delivery, and tissue engineering. Here, we report the fabrication, rheological properties, and dynamics of a multicomponent hydrogel consisting of alginate and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers, and the achievement of thick, castable gels with tunable, thermoreversible behavior at physiological temperatures (Figure 1). PEO-PPO-PEO triblock copolymers can form temperature-sensitive hydrogels that exist as liquids at low temperatures and soft solids at high temperatures. In this work, we have employed PEO-PPO-PEO triblock copolymers to impart thermoresponsive properties to alginate hydrogels in the form of a multicomponent hydrogel. These systems can transition between a weak gel and a stiff gel, with a corresponding increase in the viscoelastic moduli of approximately two orders of magnitude as temperature is increased. The temperatures corresponding to the upper and lower boundaries of the stiff gel region, as well as the storage modulus at physiological temperatures (e.g., 36 – 40 C), can be controlled through the PEO-PPO- PEO concentration. Additionally, we explore the properties of these materials under compression and large deformations, and describe how alginate and F127 concentration can be used to control the fracture stress and strain. Finally, we compare the results from bulk rheology to the structure and dynamics of the gels measured via small-angle X-ray scattering (SAXS) and X-ray photon correlation spectroscopy (XPCS) experiments.
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Surita Bhatia, Suan P. Quah, Dmytro Nykypanchuk, Andrei Fluerasu, and Yugang Zhang, "Large-area alginate/PEO-PPO-PEO hydrogels with thermoreversible rheology at physiological temperatures" in "Colloidal, Macromolecular and Biological Gels II", Samiul Amin, Manhattan College, USA Saad Khan, North Carolina State University, USA Srini Raghavan, University of Maryland College Park, USA Eds, ECI Symposium Series, (2019). https://dc.engconfintl.org/cmb_gels_ii/7