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Macroporous Poly( N ‐isopropylacrylamide) Hydrogels with Adjustable Size “Cut‐off” for the Efficient and Reversible Immobilization of Biomacromolecules
Author(s) -
Fänger Christian,
Wack Holger,
Ulbricht Mathias
Publication year - 2006
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/mabi.200600027
Subject(s) - self healing hydrogels , swelling , poly(n isopropylacrylamide) , peg ratio , ethylene glycol , dextran , chemical engineering , polymer chemistry , bovine serum albumin , chemistry , polymer , macromolecule , materials science , copolymer , chromatography , organic chemistry , finance , economics , engineering , biochemistry
Abstract Summary: Poly( N ‐isopropylacrylamide) (PNIPA) hydrogels with varied degree of crosslinking (DC) were synthesized by using poly(ethylene glycol) (PEG) as an additive. A phase separated (“macroporous”) morphology was formed when using PEG contents of ≥20 wt.‐%. Temperature‐dependent degrees of swelling had been measured, and average mesh sizes of the swollen polymer network had been calculated. The loading of the hydrogels with labelled dextrans with various molar masses and bovine serum albumin (BSA)—via swelling of the shrunken gel in a cold solution—and their subsequent unloading—via immersion in hot water—were studied in detail. The loading efficiencies were close to zero for PNIPA prepared at PEG contents of ≤10 wt.‐%, and they increased sharply to about 100% for PNIPA prepared with PEG contents of ≥20 wt.‐%. A complete unloading was achieved as well. For macroporous PNIPA prepared at 40 wt.‐% PEG content, the loading efficiency was a function of the DC, and the “cut‐off” observed as a function of dextran or protein size correlated with the mesh size of the hydrogel. The function of these “smart” hydrogels can be explained by the temperature‐induced “pumping” of the solution into the gel bulk via the permanent pores, along with an uptake into the adjacent hydrogel network. Those materials could be used as matrices for the efficient and reversible immobilization of (bio)macromolecules.