480248 Electrochemical Compaction of Chondroitin Sulfate Incorporated Collagen Matrices for Corneal Applications

Monday, November 14, 2016
Grand Ballroom B (Hilton San Francisco Union Square)
Kori Watkins and Vipuil Kishore, Chemical Engineering, Florida Institute of Technology, Melbourne, FL

Corneal disease is a leading cause of blindness that affects over 10 million people. Transplantation of allogenic cornea for the treatment of corneal disease is associated with limitations that include short supply and immune-related complications. Therefore, there is a need for an alternative method that circumvents the current challenges with donor corneas for the treatment of corneal disease. Corneal tissue engineering via the development of a scaffold that mimics the physicochemical properties of native cornea is a promising approach. We have recently shown that electrochemical compaction of collagen yields highly transparent and stable collagen matrices. In an effort to better mimic the compositional properties of native cornea, chondroitin sulfate (CS) was incorporated within electrochemically compacted collagen (ECC) matrices and the effect of chondroitin sulfate incorporation on the transparency, swelling ratio, and mechanical properties of ECC matrices was investigated. Electrochemical compaction relies on the principles of isoelectric focusing and triggers the self-assembly of collagen molecules by inducing the formation of a pH gradient between the electrodes. CS incorporated ECC matrices were synthesized by mixing CS with dialyzed collagen solution (2% CS w/w) and applying an electric field of 3V for 45 min. ECC matrices without CS were used as control. CS incorporation within ECC matrices was confirmed via 1,9-dimethylmethylene blue (DMMB) staining. Light transmission measurements were performed to measure the transparency of CS incorporated ECC matrices. Swelling ratio was determined by measuring the dry weight and wet weight (after 24 hours hydration) of the CS incorporated ECC matrices and taking the ratio of the difference in weights to the wet weight. Finally, monotonic tensile tests were performed to assess the effect of CS incorporation on the mechanical properties of ECC matrices. Results from DMMB staining showed that CS can be incorporated uniformly throughout the ECC matrices. Further, light transmission measurements showed that the transparency of ECC matrices decreased significantly upon CS incorporation. However, the transparency of CS incorporated ECC matrix was on par with native cornea. Results from the swelling studies showed that CS incorporation increased the swelling ratio of ECC matrices. Mechanical testing results showed that the ultimate tensile stress and tensile modulus of CS incorporated ECC matrices were significantly lower than ECC matrices without CS. Ultimate strain was comparable with and without CS incorporation. Future work will assess the merit of CS incorporation by investigating corneal cell response (i.e., corneal epithelial cells, keratocytes). Overall, the applicability of CS incorporated ECC matrices for corneal tissue engineering warrants further investigation.

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