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Comparative study of the viscoelastic mechanical behavior of agarose and poly(ethylene glycol) hydrogels
Author(s) -
Roberts Justine J.,
Earnshaw Audrey,
Ferguson Virginia L.,
Bryant Stephanie J.
Publication year - 2011
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.31883
Subject(s) - self healing hydrogels , materials science , agarose , viscoelasticity , ethylene glycol , peg ratio , swelling , chemical engineering , dynamic mechanical analysis , porosity , elastic modulus , stress relaxation , relaxation (psychology) , tissue engineering , composite material , polymer chemistry , polymer , biomedical engineering , chromatography , chemistry , creep , medicine , psychology , social psychology , finance , engineering , economics
This study presents a comparative investigation into differences in the mechanical properties between two hydrogels commonly used in cartilage tissue engineering [agarose vs. poly(ethylene glycol) (PEG)], but which are formed through distinctly different crosslinking mechanisms (physical vs. covalent, respectively). The effects of hydrogel chemistry, precursor concentration, platen type (nonporous vs. porous) used in compression bioreactors, and degradation (for PEG) on the swelling properties and static and dynamic mechanical properties were examined. An increase in precursor concentration resulted in decreased equilibrium mass swelling ratios but increased equilibrium moduli and storage moduli for both hydrogels ( p < 0.05). Agarose displayed large stress relaxations and a frequency dependence indicating its viscoelastic properties. Contrarily, PEG hydrogels displayed largely elastic behavior with minimal stress relaxation and frequency dependence. In biodegradable PEG hydrogels, the largely elastic behavior was retained during degradation. The type of platen did not affect static mechanical properties, but porous platens led to a reduced storage modulus for both hydrogels implicating fluid flow. In summary, agarose and PEG exhibit vastly different mechanical behaviors; a finding largely attributed to differences in their chemistries and fluid movement. Taken together, these design choices (hydrogel chemistry/structure, loading conditions) will likely have a profound effect on the tissue engineering outcome. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.