- Trabbic-Carlson, Kimberly and Setton, Lori A. and Chilkoti, Ashutosch, Swelling and mechanical behaviors of chemically cross-linked hydrogels of elastin-like polypeptides,
Biomacromolecules, vol. 4 no. 3
pp. 572 - 580 [bm025671z] .
(last updated on 2007/04/10)
Genetically engineered elastin-like polypeptides consisting of Val-Pro-Gly-X-Gly repeats, where X was chosen to be Lys every 7 or 17 pentapeptides (otherwise X was Val), were synthesized and expressed in E. coli, purified, and chemically cross-linked using tris-succinimidyl aminotriacetate to produce hydrogels. Swelling experiments indicate hydrogel mass decreases by 80-90% gradually over an approximate 50 °C temperature range. Gels ranged in stiffness from 0.24 to 3.7 kPa at 7 °C and from 1.6 to 15 kPa at 37 °C depending on protein concentration, lysine content, and molecular weight. Changes in gel stiffness and loss angle with cross-linking formulation suggest a low-temperature gel structure that is nearly completely elastic, where force is transmitted almost exclusively through fully extended polypeptide chains and chemical crosslinks, and a high-temperature gel structure, where ELP chains are contracted and force is transmitted through chemical cross-links as well as frictional contact between polypeptide chains.
Hydrogels;Crosslinking;Synthesis (chemical);Stiffness;Molecular weight;