Role of thermo-responsiveness and poly(ethylene glycol) diacrylate cross-link density on protein release from poly(N-isopropylacrylamide) hydrogels

Pawel W. Drapala, Eric M. Brey, William F. Mieler, David C. Venerus, Jennifer J. Kang Derwent, Victor H. Pérez-Luna

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Thermo-responsive hydrogels have shown promise as injectable materials for local drug delivery. However, the phase-induced changes in polymer properties of N-isopropylacrylamide (NIPAAm) can pose additional challenges for achieving controlled protein release. In this work, thermo-responsive hydrogels derived from NIPAAm and cross-linked with poly(ethylene glycol) diacrylate (PEG-DA) were synthesized via free radical polymerization. The volume phase transition temperature (VPTT) of the hydrogels ranged from 32.9°C to 35.9°C. Below the VPTT, swelling ratios of the hydrogels decreased with cross-linker concentration, and showed a sharp drop (at least 4-fold) upon phase change. Protein encapsulation efficiency was high (84-90%) and decreased with cross-linker concentration. Release of bovine serum albumin, a model protein, at body temperature was significantly higher than at room temperature (67% at 37°C compared to 44% at 23°C after 48 h). The release kinetics of proteins from the hydrogels were initially expected to be a function of cross-link density. However, at the hydrogel compositions explored in this work, protein release did not change significantly with cross-linker mol fraction. The thermo-responsive hydrogels offer a promising platform for the localized delivery of proteins.

Original languageEnglish (US)
Pages (from-to)59-75
Number of pages17
JournalJournal of Biomaterials Science, Polymer Edition
Volume22
Issue number1-3
DOIs
StatePublished - Jan 1 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Bioengineering
  • Biomaterials
  • Biomedical Engineering

Keywords

  • Thermo-responsive hydrogel
  • drug delivery
  • poly(N-isopropylacrylamide)
  • poly(ethylene glycol)
  • protein release

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