Synthesis of macroporous hydrogels with rapid swelling and deswelling properties for delivery of macromolecules

Yan, Qi; Hoffman, Allan S.

doi:10.1016/0032-3861(95)93123-4

Cited by 108 publications

(73 citation statements)

References 2 publications

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“…[20,35,[62][63][64] Taking advantage of the diffusion length scale, Yan and Hoffman have shown that polymerizing pNIPAm gels at temperatures higher than the LCST of the polymer results in gels that have large pore sizes, which in turn have faster swelling rates. [65] Reporting all the properties of hydrogels is beyond the scope of this Review; hence we have mentioned just a few important properties, and some others will be discussed in the later Sections.…”

Section: Swelling Properties Of Hydrogelsmentioning

confidence: 99%

Soft Nanotechnology with Soft Nanoparticles

2005

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The last decade of research in the physical sciences has seen a dramatic increase in the study of nanoscale materials. Today, "nanoscience" has emerged as a multidisciplinary effort, wherein obtaining a fundamental understanding of the optical, electrical, magnetic, and mechanical properties of nanostructures promises to deliver the next generation of functional materials for a wide range of applications. While this range of efforts is extremely broad, much of the work has focused on "hard" materials, such as Buckyballs, carbon nanotubes, metals, semiconductors, and organic or inorganic dielectrics. Meanwhile, the soft materials of current interest typically include conducting or emissive polymers for "plastic electronics" applications. Despite the continued interest in these established areas of nanoscience, new classes of soft nanomaterials are being developed from more traditional polymeric constructs. Specifically, nanostructured hydrogels are emerging as a promising group of materials for multiple biotechnology applications as the need for advanced materials in the post-genomic era grows. This review will present some of the recent advances in the marriage between water-swellable networks and nanoscience.

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Section: Swelling Properties Of Hydrogelsmentioning

confidence: 99%

Soft Nanotechnology with Soft Nanoparticles

2005

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“…However, the responding time was longer than that (about 30 s) addressed in a later article. 30 It is suspected that the interference of the nonwoven with the hydrogel and the presence of PHEMA in the gel might delay the responding process. Further investigation may be of interest to identify the factors that determine the response kinetics of swelling and de-swelling in such gels.…”

Section: Temperature-responsive Swelling Properties Of the Membranesmentioning

confidence: 99%

Preparation and characterization of ?-amylase-immobilized thermal-responsive composite hydrogel membranes

Sun

Chen

Chu

1999

J. Biomed. Mater. Res.

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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.

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“…For instance, the degree of swelling (DS) and the LCST values can be altered by cross-linking NIPAAm in the presence of comonomers of various degrees of hydrophilicity 10 -12 or by changing the medium properties through the addition of cosolvents, 13 salts, 14 or surfactants. 15 The response rate can be enhanced by preparing hydrogels with a porous structure, 16,17 containing dangling chains, 18 or, finally, by copolymerizing NIPAAm with suitable monomers. 19 Recently, thermoresponsive composite materials were synthesized by incorporating montmorillonite into pNIPAAm gels.…”

Section: Introductionmentioning

confidence: 99%

Effect of montmorillonite on the properties of thermosensitive poly(N‐isopropylacrylamide) composite hydrogels

Bignotti

Sartore

Penco

et al. 2004

J of Applied Polymer Sci

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Thermosensitive composite hydrogels containing various amounts of sodium montmorillonite (NaMM) and poly(N-isopropylacrylamide) (pNIPAAm) were synthesized. Their equilibrium degree of swelling (DS) was measured in NaCl solutions of different ionic strength and at various temperatures. The DS decreased when increasing the clay content and no substantial shift in the phase transition temperature was noticed. The composite hydrogels investigated had a NaMM content ranging between 1.0 and 5.7 wt % (in 0.1M NaCl at 25°C). A considerable enhancement in the response to thermal stimuli was observed for NaMM contents Ͼ2-3 wt %. It is suggested that when the NaMM concentration approaches a critical value, the clay platelets can inhibit the formation of the hydrophobic skin layer that hinders shrinking in conventional pNIPAAm hydrogels. The effect of montmorillonite on the mechanical properties of the hydrogels was investigated by uniaxial compression tests, which showed that the modulus increases with the NaMM content.

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Synthesis of macroporous hydrogels with rapid swelling and deswelling properties for delivery of macromolecules

Cited by 108 publications

References 2 publications

Soft Nanotechnology with Soft Nanoparticles

Soft Nanotechnology with Soft Nanoparticles

Preparation and characterization of ?-amylase-immobilized thermal-responsive composite hydrogel membranes

Effect of montmorillonite on the properties of thermosensitive poly(N‐isopropylacrylamide) composite hydrogels

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