Paper Number
PO57 

Session
Poster Session

Title
Modulating the rheology of collagen-based hydrogels using morphology-controlled tannic acid particles

Presentation Date and Time
October 13, 2021 (Wednesday) 6:30

Track / Room
Poster Session / Ballroom 1-2-3-4

Authors (Click on name to view author profile)

1. Sarker, Prottasha (North Carolina State University, Chemical and Biomolecular Engineering)
2. Rojas, Orlando J. (University of British Columbia, Chemical and Biological Engineering)
3. Khan, Saad A. (North Carolina State University, Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Prottasha Sarker¹, Orlando J. Rojas² and Saad A. Khan^1
1Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC; ²Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia, Canada

Speaker / Presenter 
Sarker, Prottasha

Keywords
experimental methods; biological materials; gels; rheology methods

Text of Abstract
Hydrogels are porous three-dimensional structures with polymeric cross-linked networks which has the provision for sufficient water and nutrient flow for cell proliferation to stimulate the regeneration of defective tissues. Compared to surgical scaffold implantation, injectable hydrogels can be easily applied by minimal invasive techniques to form a self-standing hydrogel. Naturally derived polymer, collagen has been widely employed as injectable hydrogel since it inherits the structural and functional cursors to accelerate tissue formation, however it shows poor mechanical properties. The use of biodegradable tannic acid particles provides a useful approach to improve the rheology of these systems while its inherent antibacterial and anticarcinogenic nature adding to the gel functionality. Polyphenolic tannic acid particles could potentially interact with collagen through their hydroxyl and carboxyl groups allowing us to modulate the rheology. In this study we examine how liquid as well as particulate tannic acids impact the rheological properties of collagen-based hydrogels. Liquid and tannic acid particles of different shapes are synthesized and incorporated into collagen in this regard. While samples exhibit solution-like features at storage conditions (4^οC), they transform into gels under physiological temperatures (37^οC). The sol-gel transition in terms of temperature and time are monitored as a function of tannic acid concentration and morphology. Interestingly, particulate tannic acid incorporation exhibits the largest increase in elastic modulus with shape playing a secondary factor. Measurement of yield stress using the elastic stress method also reveals a similar trend. These results are interpreted in terms of the underlying interactions of the tannic acid with collagen, as examined using other analytic approaches.