Enzyme immobilization on thermosensitive hydrogel microspheres

Shiroya, Toshifumi; Tamura, Nobuko; Yasui, Minami; Fujimoto, Keiji; Kawaguchi, Haruma

doi:10.1016/0927-7765(94)01177-7

Cited by 77 publications

(49 citation statements)

References 13 publications

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“…The phase separation on heating is believed as a phase behavior with the lower critical solution temperature (LCST) [3] which is common to all polymer solutions, although it is stilll controversial [4]. This phase transition of PNIPAM has been used in attempts to control the enzymatic activity [5][6][7][8][9], affinity precipitation separation [10,11] and protein recycling systems [12][13][14][15]. Another growing area in which this property has been exploited is a targeted delivery of drugs and chemical agents such as anticancer drugs.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and phase behavior of aqueous poly(N-isopropylacrylamide-co-acrylamide), poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) and poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate)

et al. 2006

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Poly(N-isopropylacrylamide) (PNIPAM) and random copolymers of Poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) (PNIPAM-HEMA), poly(N-isopropylacrylamide-co-acrylamide) (PNIPAM-AAm) and poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) (PNIPAM-DMAA) with various volume fractions of NIPAM , were synthesized by radical polymerization. The phase behavior of the polymers in water was investigated by means of optical transmittance and dynamic light scattering. With decreasing , the cloud point temperature T cp for PNIPAM-HEMA decreased whereas T cp for both PNIPAM-AAm and PNIPAM-DMAA increased. Increase of hydrodynamic radius around T cp resulted from the aggregation of the globules of each polymer was observed from dynamic light scattering. The relationships between the reciprocal of T cp of the polymer solutions and 1-were linear for the three copolymers in the experimental range of 0.65 < < 1. The results are discussed from the aspect of the interaction parameters of copolymer solutions.

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Section: Introductionmentioning

confidence: 99%

Synthesis and phase behavior of aqueous poly(N-isopropylacrylamide-co-acrylamide), poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) and poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate)

et al. 2006

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“…in response to temperature changes across the LCST. These unique features make PNIPAM particles desirable for numerous applications, including controlled drug delivery, 11,12 control of enzymatic activity, 13,14 tunable optics, 15,16 and bioseparation. 17 Colloidally stable PNIPAM particles were first prepared by precipitation polymerization of NIPAM with N,N 0 -methylenebisacryamide (MBAAm) as a cross-linking agent in an aqueous medium at 60 to 70 C. 18 The resulting particles showed a volume phase transition at the LCST around 32 C. In precipitation polymerization, the initial state of the reaction mixture is a homogeneous solution.…”

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confidence: 99%

Preparation and Characterization of Micrometer-Sized Poly(N-isopropylacrylamide) Hydrogel Particles

2009

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The present study deals with preparation and swelling properties of micrometer-sized poly(N-isopropylacrylamide) (PNIPAM) hydrogel particles. Aqueous precipitation polymerization of NIPAM with N,N 0 -methylenebisacrylamide (MBAAm) was performed with varying electrolyte concentrations in the polymerization media. Sodium chloride was used as an electrolyte. According to the particle size analysis by transmission electron microscope, the particle size increased in the range of 0.55 to 1.60 mm with an increase in the electrolyte concentration up to 1.6 wt %. The concentration is based on the NIPAM monomer weight. Dynamic light scattering data showed that swelling ratio of PNIPAM hydrogel particles in water varied from 10 to 40 as the electrolyte concentration at particle preparation increased from 0 to 1.6 wt %. Time-course analysis of particle size showed that an increase in particle size would be caused by aggregation of smaller particles. In conclusion, micrometer-sized PNIPAM particles with high swelling capacity can be obtained by the addition of an electrolyte in polymerization media. Thermosensitive hydrogel particles containing poly(N-isopropylacrylamide) (PNIPAM) moieties have attracted much attention because they exhibit sharp and reversible volume phase transition at the lower critical solution temperature (LCST).1,2 PNIPAM particles also show the dramatic change of their colloidal properties such as hydrophobicity, 3 particle size, 4 electrophoretic mobility, 5,6 colloidal stability, 7,8 rheology 9,10 etc. in response to temperature changes across the LCST. These unique features make PNIPAM particles desirable for numerous applications, including controlled drug delivery, 11,12 control of enzymatic activity, 13,14 tunable optics, 15,16 and bioseparation. 17 Colloidally stable PNIPAM particles were first prepared by precipitation polymerization of NIPAM with N,N 0 -methylenebisacryamide (MBAAm) as a cross-linking agent in an aqueous medium at 60 to 70 C. 18 The resulting particles showed a volume phase transition at the LCST around 32 C. In precipitation polymerization, the initial state of the reaction mixture is a homogeneous solution. When a water-soluble initiator is added to the mixture, initiation and propagation take place largely in the homogeneous medium, followed by phase separation of growing PNIPAM chains because PNIPAM is insoluble in the medium at the reaction temperature. This leads to continuous nucleation and coagulation of the resulting nuclei to form larger particles. Since the first report, various methods have been studied so far for preparation of PNIPAM hydrogel particles. Pelton and co-workers reported that addition of surfactant gave smaller and more uniform PNIPAM particles than those obtained without surfactant.19 Yi et al. reported that monodisperse thermosensitive poly(styrene-co-NIPAM) particles with diameters in the range of 100 to 130 nm could be prepared by emulsifier-free emulsion polymerization with microwave irradiation. 20 In addition, many researchers have focuse...

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“…This interesting characteristic may be used in a variety of applications. For instance, in proteinligand recognition, drug controlled release, recovered and cultured cells and immobilization enzymes [9][10][11][12][13]. But, the PNIPAAm homopolymeric hydrogel is not a suitable material for biomedical applications because of its transition temperature and rigid network structure.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of temperature-sensitive and biodegradable hydrogel based on N-isopropylacrylamide

Zhu

et al. 2010

Open Chemistry

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Based on a biodegradable cross-linker, N-maleyl chitosan (N-MACH), a series of Poly(N-isopropylacrylamide) (PNIPAAm) and Poly(N-isopropylacrylamide-co-acrylamide) [P(NIPAAm-co-Am)] hydrogels were prepared, and their lower critical solution temperature (LCST), swelling kinetics, equilibrium swelling ratio in NaCl solution, and enzymatic degradation behavior in simulated gastric fluids (SGF) were discussed. The LCST did not change with different cross-linker contents. By altering the NIPAAm/Am molar ratio of P(NIPAAm-co-Am) hydrogels, the LCST could be increased to 39°C. The LCST of the hydrogel was significantly influenced by the monomer ratio of the NIPAAm/Am but not by the cross-linker content. In the swelling kinetics, all the dry hydrogels exhibited fast swelling behavior, and the swelling ratios were influenced by the cross-linker content and NIPAAm/Am molar ratios. Equilibrium swelling ratio of all the hydrogels decreased with increasing NaCl solution concentration. In enzymatic degradation tests, the weight loss of hydrogels was dependent on the cross-linker contents and the enzyme concentration. © Versita Sp. z o.o.

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Enzyme immobilization on thermosensitive hydrogel microspheres

Cited by 77 publications

References 13 publications

Synthesis and phase behavior of aqueous poly(N-isopropylacrylamide-co-acrylamide), poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) and poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate)

Synthesis and phase behavior of aqueous poly(N-isopropylacrylamide-co-acrylamide), poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) and poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate)

Preparation and Characterization of Micrometer-Sized Poly(N-isopropylacrylamide) Hydrogel Particles

Synthesis and characterization of temperature-sensitive and biodegradable hydrogel based on N-isopropylacrylamide

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