Oligo-α-hydroxy ester cross-linkers: Impact of cross-linker structure on biodegradable hydrogel networks


Journal Article

We describe the synthesis of a series of biodegradable oligo-α-hydroxy ester cross-linkers and evaluate their impact on the degradation kinetics and macromolecule diffusion from a hydrogel network. By changing the steric and electronic environment at the site of degradation in the cross-linker, we were able to modulate the degradation, swelling kinetics, and corresponding release profiles of macromolecules from poly(HPMA) hydrogel networks under physiologically relevant conditions. As the steric hindrance and electron demand at the site of hydrolysis for three different cross-linkers was increased, the total time for the hydrogel network to completely dissolve increased from 2 to over 30 days while incubated in pH 7 buffer. As the number of hydrolyzable sites and the electron demand at the side of hydrolysis decreased, the time to completely dissolve decreased from weeks to several days. Increasing the cross-linking density for one of the degradable cross-linkers (1.5% to 3.0% feed ratio) increased the degradation time by several weeks. Burst release was absent for high molecular weight solutes because the release rate depended on controlled degradation of the polymer network and an increase in average network mesh size. The synthetically adaptable cross-linkers described herein offer a new approach for controlling the rate and extent of release from biodegradable hydrogel networks. © 2005 American Chemical Society.

Full Text

Duke Authors

Cited Authors

  • Eichenbaum, KD; Thomas, AA; Eichenbaum, GM; Gibney, BR; Needham, D; Kiser, PF

Published Date

  • December 27, 2005

Published In

Volume / Issue

  • 38 / 26

Start / End Page

  • 10757 - 10762

International Standard Serial Number (ISSN)

  • 0024-9297

Digital Object Identifier (DOI)

  • 10.1021/ma0518306

Citation Source

  • Scopus