TY - JOUR
T1 - Role of thermo-responsiveness and poly(ethylene glycol) diacrylate cross-link density on protein release from poly(N-isopropylacrylamide) hydrogels
AU - Drapala, Pawel W.
AU - Brey, Eric M.
AU - Mieler, William F.
AU - Venerus, David C.
AU - Kang Derwent, Jennifer J.
AU - Pérez-Luna, Victor H.
N1 - Funding Information:
We would like to thank research assistants Diana Gutierrez and Alexa L. Beaver for help with protein release and hydrogel swelling experiments, and Prof. Sandra Bishnoi for facilitating the use of the Raman Microscope. This research was made possible through the funding provided by The Lincy Foundation, The Macula Foundation, the Veteran’s Administration and the National Science Foundation (Grant No. 0852048).
PY - 2011/1/1
Y1 - 2011/1/1
N2 - 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.
AB - 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.
KW - Thermo-responsive hydrogel
KW - drug delivery
KW - poly(N-isopropylacrylamide)
KW - poly(ethylene glycol)
KW - protein release
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U2 - 10.1163/092050609X12578498952315
DO - 10.1163/092050609X12578498952315
M3 - Article
C2 - 20540835
AN - SCOPUS:78649910389
SN - 0920-5063
VL - 22
SP - 59
EP - 75
JO - Journal of Biomaterials Science, Polymer Edition
JF - Journal of Biomaterials Science, Polymer Edition
IS - 1-3
ER -