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.
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 -