Calcium-induced volume transition in polyacrylate hydrogels swollen in physiological salt solutions

Horkay, Ferenc; Basser, Peter J.; Hecht, Anne‐Marie; Geissler, Erik

doi:10.1002/1616-5195(200206)2:5<207::aid-mabi207>3.0.co;2-5

Cited by 18 publications

(23 citation statements)

References 23 publications

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“…Stimuli-responsive hydrogels known as smart materials are macromolecules that undergo reversible volume phase transition in response to a small change of external stimuli such as temperature [1][2][3][4][5][6][7][8][9], pH [9][10][11][12][13], light [14][15][16], electric current [17][18][19], ionic strength [20][21][22] or chemical species [23]. Researchers are showing much attention in these materials for their wide range of biomedical and pharmaceutical applications [24][25][26][27][28][29].…”

Section: Introductionsupporting

confidence: 39%

Evaluating a simple blending approach to prepare magnetic and stimuli-responsive composite hydrogel particles for application in biomedical field

Ahmad¹,

Sultana²,

Alam³

et al. 2016

Express Polym. Lett.

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Abstract. The inclusion of super paramagnetic iron oxide (Fe 3 O 4 ) nanoparticles in stimuli-responsive hydrogel is expected to enhance the application potential for cellular therapy in cell labeling, separation and purification, protein immobilization, contrasting enhancement in magnetic resonance imaging (MRI), localized therapeutic hyperthermia, biosensors etc. in biomedical field. In this investigation two different magnetic and stimuli-responsive composite hydrogel particles with variable surface property were prepared by simply blending Fe 3 O 4 /SiO 2 nanocomposite particles with stimuli-responsive hydrogel particles. Of the hydrogel particles prepared by free-radical precipitation polymerization poly(styrene-N-isopropylacrylamide-methyl methacrylate-polyethylene glycol methacrylate) or P(S-NIPAM-MMA-PEGMA) was temperature-sensitive and poly(S-NIPAM-methacrylic acid-PEGMA) or P(S-NIPAM-MAA-PEGMA) was both temperature-and pH-responsive. The morphological structure, size distributions and volume phase transitions of magnetic and stimuli-responsive composite hydrogel particles were analyzed. Temperature-responsive absorptions of biomolecules were observed on both magnetic and stimuli-responsive Fe 3 O 4 /SiO 2 /P(S-NIPAM-MMA-PEGMA) and Fe 3 O 4 /SiO 2 /P(S-NIPAM-MAA-PEGMA) composite hydrogel particles and separation of particles from the dispersion media could be achieved by applying magnetic field without time consuming centrifugation or decantation method.

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Section: Introductionsupporting

confidence: 39%

Evaluating a simple blending approach to prepare magnetic and stimuli-responsive composite hydrogel particles for application in biomedical field

Ahmad¹,

Sultana²,

Alam³

et al. 2016

Express Polym. Lett.

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“…Previous studies demonstrated that changes in the ionic environment are associated with changes in the osmotic swelling pressure 13,24,28. It was also shown that in near physiological ionic conditions the electrostatic contribution (third term in equation 8) is negligible, i.e., the osmotic pressure of the cross-linked polymer can be estimated from the equation

Π_{mix} = Π_{sw} + G

Using equation 12 we determined Π mix for PAA gels at constant pH (pH: 7, 5, 3 and 1), and CaCl 2 concentration (c CaCl2 : 0, 0.2, 0.5 and 0.8 mM in 100 mM NaCl solution).…”

Section: Resultsmentioning

confidence: 99%

“…It was found that in near physiological salt concentration the thermodynamics of gel swelling can be described by a formalism similar to that of neutral polymer gels 13. Anomalous small-angle X-ray scattering measurements revealed significant differences between the distribution of monovalent and divalent counterions in the ion cloud surrounding the charged macromolecules 17,18.…”

Section: Introductionmentioning

confidence: 99%

“…Previously we made systematic measurements on a variety of synthetic and biopolymer solutions and gels using an array of complementary experimental techniques to determine the effect of multivalent ions on the structure and dynamic properties over a wide range of length and time scales 13–17. It was found that in near physiological salt concentration the thermodynamics of gel swelling can be described by a formalism similar to that of neutral polymer gels 13.…”

Section: Introductionmentioning

confidence: 99%

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Ionic and pH effects on the osmotic properties and structure of polyelectrolyte gels

Horkay

Basser

2008

J Polym Sci B Polym Phys

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ABSTRACT:We investigate the effects of salt concentration and pH on neutralized poly(acrylic acid) (PAA) gels in near physiological salt solutions. Either adding calcium ions or decreasing the pH is found to induce reversible volume transitions but the nature of these transitions seems to be different. For example, the osmotic pressure exhibits a simple power law dependence on the concentration as the transition is approached in both systems, but the power law exponent n is substantially different in the two cases. On decreasing the pH the value of n gradually increases from 2.1 (at pH ¼ 7) to 3.2 (at pH ¼ 1). By contrast, n decreases with increasing calcium ion concentration from 2.1 (in 100 mM NaCl solution) to 1.6 (0.8 mM CaCl 2 in 100 mM NaCl solution). In both systems, a strong increase of the small-angle neutron scattering intensity (SANS) is observed near the volume transition. The SANS results reveal that calcium ions favor the formation of linearly aligned regions in PAA gels.

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“…Hydrogels are attractive soft materials which have been widely studied as scaffolds due to their biocompatibility and non‐adhesiveness to cells 1. In particular, great interest has been focused on hydrogels which have the capability to respond to small external stimulus changes such as temperature,2, 3 pH,4 salt solution,5 light,6 etc. Their unique properties are important in both theoretical studies and practical applications.…”

Section: Introductionmentioning

confidence: 99%

Structure and properties of cellulose/poly(N‐isopropylacrylamide) hydrogels prepared by IPN strategy

Chang

Han

Zhang

2011

Polymers for Advanced Techs

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Interpenetrating polymer network (IPN) strategy was developed to fabricate novel hydrogels composed of cellulose and poly(N‐isopropylacrylamide) (PNIPAAm) with high mechanical strength and adjustable thermosensitivity. Cellulose hydrogels were prepared by chemically cross‐linking cellulose in NaOH/urea aqueous solution, which were employed as the first network. The second network was subsequently obtained by in situ polymerization/cross‐linking of N‐isopropylacrylamide in the cellulose hydrogels. The results from FTIR and solid 13C NMR indicated that the two networks co‐existed in the IPN hydrogels, which exhibited uniform porous structure, as a result of good compatibility. The mechanical and swelling properties of IPN hydrogels were strongly dependent on the weight ratio of two networks. Their temperature‐sensitive behaviors and deswelling kinetics were also discussed. This work created double network hydrogels, which combined the advantages of natural polymer and synthesized PNIPAAm collectively in one system, leading to the controllable temperature response and improvement in the physical properties. Copyright © 2009 John Wiley & Sons, Ltd.

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Calcium-induced volume transition in polyacrylate hydrogels swollen in physiological salt solutions

Cited by 18 publications

References 23 publications

Evaluating a simple blending approach to prepare magnetic and stimuli-responsive composite hydrogel particles for application in biomedical field

Evaluating a simple blending approach to prepare magnetic and stimuli-responsive composite hydrogel particles for application in biomedical field

Ionic and pH effects on the osmotic properties and structure of polyelectrolyte gels

Structure and properties of cellulose/poly(N‐isopropylacrylamide) hydrogels prepared by IPN strategy

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