Paper Number
BB26 

Session
Biomaterials and Biological Systems

Title
Characterization of aqueous alginate solutions at high concentrations with neutron scattering and rheology

Presentation Date and Time
October 7, 2014 (Tuesday) 4:00

Track / Room
Track 2 / Commonwealth B

Authors (Click on name to view author profile)

1. Eral, Huseyin B. (Massachusetts Institute of Technology)
2. Bavand, Keshavarz (Massachusetts Institute of Technology, Mechanical Engineering)
3. McKinley, Gareth H. (Massachusetts Institute of Technology, Department of Mechanical Engineering)
4. Doyle, Patrick S. (Massachusetts Institute of Technology)

Author and Affiliation Lines (in printed abstract book)
Huseyin B. Eral¹, Keshavarz Bavand², Gareth H. McKinley², and Patrick S. Doyle^1
1Massachusetts Institute of Technology, Cambridge, MA 02139; ²Mechanical Engineering, Massachusetts Institute of Technology, cambridge, MA 02139

Speaker / Presenter 
Eral, Huseyin B.

Text of Abstract
Alginate (ALG) is a polysaccharide that is commonly used in the food and pharmaceutical industry as a filling material. Due its ability to ionically crosslink with divalent ions, it also finds applications in biomedical industry as a biocompatible hydrogel in wound dressings, for encapsulating active ingredients for controlled release and most recently in pharmaceutical production. Therefore, characterization of its rheological characteristics is critical for developing optimal continuous manufacturing processes. Combining neutron scattering and rheological measurement, we have investigated both uncrosslinked ALG solutions and crosslinked gels at varying ALG concentrations. At low ALG concentrations (i.e. less than 4% weight/ volume), small amplitude oscillatory shear tests of uncrosslinked aqueous ALG solutions show Maxwell-like behavior with one dominant timescale for both loss and storage modulus. However, at high concentrations (>4% weight/ volume), power law behavior is observed for both moduli which is a signature of the existence of a weak fractal network. We investigated the underling physical mechanism responsible for the power law behavior at high ALG concentrations. Our preliminary results indicate that the existence of Hydrogen-bonding groups along the alginate backbone are important in the formation of this weak elastic network. Understanding and controlling the strength of this percolated network facilitates the design of more efficient flow-based manufacturing processes for ALG-containing biomaterials of interest to the pharmaceutical industry.