Preparation and characterization of alpha-amylase-immobilized thermal-responsive composite hydrogel membranes.
Composite hydrogel membranes of crosslinked poly(N-isopropylacrylamide-co-N-acryloxysuccinimide-co-2-hydroxyet hyl methacrylate) [P(NIPAAm-NAS-HEMA)] with starch, as a macropore forming agent, on nonwoven polyester was prepared. The membranes could swell and de-swell around the characteristic lower critical solution temperature (LCST) of poly(N-isopropylacrylamide) (PNIPAAm). It was demonstrated that the presence of macropores in the membranes could improve the immobilization efficiency as well as lead to a short responding time upon temperature change across the LCST. Immobilized alpha-amylase could retain as high as 33% of the activity of the free enzyme with a loading level of 0.60-0.65 mg/cm2 when the membrane preparation and enzyme immobilization conditions were optimized. The half time (T0.5) for the swelling or de-swelling response of the gel phase within the membranes was less than 2 min, and the 90% time (T0.9) was less than 6 min. The permeability for maltose through the membranes could change as much as 4.9-fold when the temperature was raised above or reduced below the LCST.
Sun
Y M
YM
Department of Chemical Engineering, Yuan Ze University, Chung-Li, Taoyuan, Taiwan 320, Republic of China.
Chen
J P
JP
Chu
D H
DH
D000178:Acrylamides / Q000737:chemistry; D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006358:Hot Temperature; D020100:Hydrogels; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007118:Immunoassay; D007700:Kinetics; D008567:Membranes, Artificial; D008689:Methacrylates / Q000737:chemistry; D010539:Permeability; D013213:Starch / Q000737:chemistry; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry*
D000178:Acrylamides; D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized; D020100:Hydrogels; D008567:Membranes, Artificial; D008689:Methacrylates; C407035:poly(N-isopropylacrylamide-co-N-acryloxysuccinimide-co-2-hydroxyethyl methacrylate); D013213:Starch; D000516:alpha-Amylases