Synthesis of Temperature-Sensitive Poly(N-isopropylacrylamide) Hydrogel with Improved Surface Property

Zhang, Xian‐Zheng; Zhuo, Ren‐Xi

doi:10.1006/jcis.1999.6654

Cited by 92 publications

(72 citation statements)

References 19 publications

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“…Zhang and coworkers also reported that a large content of starch could weaken the aggregation of the hydrophobic groups of hydrogels. 25 The equilibrium swelling ratio (SR) and swelling kinetics of semi-IPN gels…”

Section: Resultsmentioning

confidence: 99%

pH‐responsive semi‐interpenetrating networks hydrogels of poly(acrylic acid‐acrylamide‐methacrylate) and amylose. I. Synthesis and characterization

Yang

et al. 2007

J of Applied Polymer Sci

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The semi-interpenetrating networks gels of hydrophobically-modified poly(acrylic acid-acrylamidemethacrylate) and amylose were prepared using 4,4 0 -bis(methacryloylamino) azobenzene as a crosslinker. Investigation of mechanical strength of gels showed that the equilibrium elastic modulus G changed from 12.4 to 32.9 g/cm 2 with increasing the contents of amylose in the case of low content of crosslinker. The swelling behavior of gels indicated that the aggregation of the hydrophobic groups of hydrogels could be destroyed by expanded amylose and the electrostatic repulsion between the charged À ÀCOO À groups because of the ionization of the carboxylic groups in pH 7.4 buffer solutions. The hydrophobicity and flexibility of the side chain, the entanglement extent of the amylose, and the ionization of carboxyl groups in the gels greatly affected the swelling rates and swelling ratios. Investigations of swelling/deswelling periodically in pH 2.2 and 7.4 media indicated that the semi-IPN gel was more pH-sensitive than the nonsemi-IPN gel.

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Section: Resultsmentioning

confidence: 99%

pH‐responsive semi‐interpenetrating networks hydrogels of poly(acrylic acid‐acrylamide‐methacrylate) and amylose. I. Synthesis and characterization

Yang

et al. 2007

J of Applied Polymer Sci

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“…To achieve the porous structure, various gel preparation methods have been investigated. 4,5,14,15 However, as far as we know, there is no report on creating macroporous structure by salt effect during the polymerization in sodium chloride solution. In the present study, we attempted to prepare hydrogels with highly porous structures to facilitate the protein loading and release.…”

Section: Introductionmentioning

confidence: 93%

“…At a so-called lower critical solution temperature (LCST), it exhibits a temperatureinduced volume phase transition, during which the gel changes from a swollen phase at a low temperature (below 32-33°C) to a collapsed state at a high temperature (above 32-33°C). 1,[3][4][5] This unique property of PNIPA hydrogel has been utilized in biomedical and many other fields including drug controlled release, 6 enzyme immobilization, 7 and absorbent recycling. 8 Although the explosive development of protein drugs provides new therapies for diseases, the effective delivery of the proteins still cannot be achieved satisfactorily because of the low bioactivity and rapid clearance after oral administration.…”

Section: Introductionmentioning

confidence: 99%

Macroporous poly(N‐isopropylacrylamide) hydrogels with fast response rates and improved protein release properties

Cheng

Zhang

Zhuo

2003

J Biomedical Materials Res

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A series of temperature-sensitive poly(N-isopropylacrylamide) (PNIPA) hydrogels with large pore size and fast response were prepared by carrying out polymerizations in aqueous sodium chloride solutions with different concentrations. In comparison with conventional PNIPA hydrogels, the PNIPA gels thus prepared have remarkably larger swelling ratios below their lower critical solution temperature (LCST), and exhibit much faster response rates as the temperature is raised above their LCST. The improved properties are due to the presence of inorganic salt, NaCl, which leads the phase separation and formation of a heterogeneous porous structure during the polymerizations. The study on the drug release properties shows the macroporous hydrogels exhibit modulated release in response to temperature. The model protein, bovine serum albumin (BSA), can be released completely from the porous hydrogels at the temperature lower than the LCST because the pore size of the hydrogels is larger than the protein molecules. However, the release of BSA from the gels almost stops after a "burst" release in the initial stage at the temperature higher than the LCST because the pores are closed at the high temperature.

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“…The LCST of IPN hydrogels based on 2 and 3 wt % of alginate are close to 37 C, which is not in well agreement with the DSC results, since the different methods of measurement can give changes in this temperature of even 4 C. 37 Obtained swelling profiles confirms known property of pure PNIPAAm hydrogels to have weaker response to temperature variations, as a result of the formation of a skin layer. 38,39 This dense skin layer hinders the diffusion of water molecules out of the gel during the deswelling process at higher temperatures (>LCST). Addition of alginate as a hydrophilic component, primarily because of hydroxyl groups, reduces hydrophobic aggregation in the surface layer of hydrogel and formation of the skin layer.…”

Section: Swelling Behaviormentioning

confidence: 99%

Development and characterization of thermosensitive hydrogels based on poly(N‐isopropylacrylamide) and calcium alginate

Petruš̆̌̌̌ić

Lewandowski

Giraud

et al. 2011

J of Applied Polymer Sci

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This work refers to the synthesis and characterization of thermosensitive hydrogels based on interpenetrating polymer networks (IPNs) of poly(N-isopropylacrylamide) (PNIPAAm) and calcium alginate in the form of films. The influence of the crosslinking degree of PNIPAAm and alginate content on thermal, swelling, mechanical, and morphological properties of hydrogels is investigated in detail. Characterization of pure PNIPAAm hydrogels and IPN hydrogels was performed by FTIR, DSC, DMA, and SEM. In addition, the studies of equilibrium swelling behavior as well as swelling, deswelling, and reswelling kinetics are performed.The results obtained imply the benefits of synthesizing IPNs based on PNIPAAm and calcium alginate over pure PNIPAAm hydrogels. The presence of calcium alginate contributes to the improvement of mechanical properties, the deswelling rate of hydrogels, and the network porosity, without altering the thermosensitivity of PNIPAAm significantly.

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Synthesis of Temperature-Sensitive Poly(N-isopropylacrylamide) Hydrogel with Improved Surface Property

Cited by 92 publications

References 19 publications

pH‐responsive semi‐interpenetrating networks hydrogels of poly(acrylic acid‐acrylamide‐methacrylate) and amylose. I. Synthesis and characterization

pH‐responsive semi‐interpenetrating networks hydrogels of poly(acrylic acid‐acrylamide‐methacrylate) and amylose. I. Synthesis and characterization

Macroporous poly(N‐isopropylacrylamide) hydrogels with fast response rates and improved protein release properties

Development and characterization of thermosensitive hydrogels based on poly(N‐isopropylacrylamide) and calcium alginate

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