Chemical modulation of thermosensitive poly(N-isopropylacrylamide) microsphere swelling: a new strategy for chemical sensing

Oktar, O.; Caglar, Perihan; Seitz, W. Rudolf

doi:10.1016/j.snb.2004.04.033

Cited by 39 publications

(21 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The development of thermoresponsive hydrogels with combined stiffness and strength could greatly broaden the utility of hydrogels for applications such as actuators [1] , soft robotics [2] , biosensors [3] , drug delivery [4] and tissue engineering [5] . Thermoresponsive hydrogels are 3-dimensional, water swollen polymer networks with the ability to undergo a thermally-triggered, reversible volume change.…”

Section: Introductionmentioning

confidence: 99%

Thermoresponsive Double Network Hydrogels with Exceptional Compressive Mechanical Properties

Means

Ehrhardt

Whitney

et al. 2017

Macromol. Rapid Commun.

View full text Add to dashboard Cite

The utility of thermoresponsive hydrogels, such as those based on poly(N-isopropylacrylamide) (PNIPAAm), is severely limited by their deficient mechanical properties. In particular, the simultaneous achievement of high strength and stiffness remains unreported. In this work, a thermoresponsive hydrogel is prepared having the unique combination of ultra-high compressive strength (~23 MPa) and excellent compressive modulus (~1.5 MPa). This is accomplished by employing a double network (DN) design comprised of a tightly crosslinked, highly negatively charged 1st network based on poly(2-acrylamido-2-methylpropane sulfonic acid (PAMPS) and a loosely crosslinked, zwitterionic 2nd network based on a copolymer of thermoresponsive NIPAAm and zwitterionic 2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (MEDSAH). Comparison to other DN designs reveals that this PAMPS/P(NIPAAm-co-MEDSAH) DN hydrogel’s remarkable properties stem from the intra- and inter-network ionic interactions of the two networks. Finally, this mechanically robust hydrogel retains the desirable thermosensitivity of PNIPAAm hydrogels, exhibiting a volume phase transition temperature (VPTT) of ~35 °C.

show abstract

Section: Introductionmentioning

confidence: 99%

Thermoresponsive Double Network Hydrogels with Exceptional Compressive Mechanical Properties

Means

Ehrhardt

Whitney

et al. 2017

Macromol. Rapid Commun.

View full text Add to dashboard Cite

show abstract

“…The solvent diffusion depends on the gel size, and therefore the smaller is the size of the hydrogel, the faster is the response rate 24, 25. Methods for the preparation of small microspheres from monomers with a relative fast swelling/collapsing rate have been reported previously 26, 27. Thermoresponsive microspheres from preformed polymers are prepared by dropping a polymer solution into a liquid at a temperature above the LCST 28, 29.…”

Section: Introductionmentioning

confidence: 99%

Conditional activation of β‐catenin signaling in mice leads to severe defects in intervertebral disc tissue

Wang

Tang

Shu

et al. 2012

Arthritis & Rheumatism

100

125

View full text Add to dashboard Cite

Objective The incidence of low back pain is extremely high and is often linked to intervertebral disc (IVD) degeneration. The mechanism of this disease is currently unknown. In this study, we have investigated the role of β-catenin signaling in IVD tissue function. Methods β-catenin protein levels were measured in disc samples derived from patients with disc degeneration and normal subjects by immunohistochemistry (IHC). To generate β-catenin conditional activation (cAct) mice, Col2a1-CreERT2 transgenic mice were bred with β-cateninfx(Ex3)/fx(Ex3) mice. Changes in disc tissue morphology and function were analyzed by micro-CT, histology and real-time PCR assays. Results We found that β-catenin protein was up-regulated in disc tissues from patients with disc degeneration. To assess the effects of increased β-catenin on disc tissue we generated β-catenin cAct mice. Overexpression of β-catenin in disc cells led to extensive osteophyte formation in 3- and 6-month-old β-catenin cAct mice which were associated with significant changes in the cells and extracellular matrix of disc tissues and growth plate. Gene expression analysis demonstrated that activation of β-catenin could enhance Runx2-dependent Mmp13 and Adamts5 expression. Moreover, genetic ablation of the Mmp13 or Adamts5 under β-catenin cAct background, or treatment of β-catenin cAct mice with a specific MMP13 inhibitor, ameliorated the mutant phenotype. Conclusions β-catenin signaling pathway plays a critical role in disc tissue function.

show abstract

“…It is important for a hydrogel to display rapid response to stimuli, and miniaturization of domain size is one means to achieve this. [8][9][10][11][12] Poly(N-isopropylacrylamide-co-acrylic acid) [poly(NIPAM-co-AAc)] has emerged as a promising material for use in a variety of applications, including drug delivery, [13,14] sensing, [15] microlenses, [16,17] and microfluidic devices. [8,18,19] In this work, we present the fabrication and characterization of poly(NIPAM-co-AAc)/porous silica (porous SiO 2 ) hybrids.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of a pH‐ and Thermally Responsive Poly(N‐isopropylacrylamide‐co‐acrylic acid)/Porous SiO₂ Hybrid

Perel'man

Moore

Singelyn

et al. 2010

Adv Funct Materials

View full text Add to dashboard Cite

A multifunctional nanohybrid composed of a pH- and thermoresponsive hydrogel, poly(N-isopropylacrylamide-co-acrylic acid), poly(NIPAM-co-AAc) is synthesized in-situ within the mesopores of an oxidized porous Si template. The hybrid is characterized by electron microscopy and by thin film optical interference spectroscopy. The optical reflectivity spectrum of the hybrid displays Fabry-Pérot fringes characteristic of thin film optical interference, enabling direct, real-time observation of the pH- induced swelling and volume phase transitions associated with the confined poly(NIPAM-co-AAc) hydrogel. The optical response correlates to the percentage of AAc contained within the hydrogel, with a maximum change observed for samples containing 20% AAc. The swelling kinetics of the hydrogel are significantly altered due to the nanoscale confinement; displaying a more rapid response to pH or heating stimuli relative to bulk polymer films. The inclusion of AAc dramatically alters the thermoresponsiveness of the hybrid at pH 7, effectively eliminating the lower critical solution temperature (LCST). The observed changes in the optical reflectivity spectrum are interpreted in terms of changes in the dielectric composition and morphology of the hybrids.

show abstract

Chemical modulation of thermosensitive poly(N-isopropylacrylamide) microsphere swelling: a new strategy for chemical sensing

Cited by 39 publications

References 20 publications

Thermoresponsive Double Network Hydrogels with Exceptional Compressive Mechanical Properties

Thermoresponsive Double Network Hydrogels with Exceptional Compressive Mechanical Properties

Conditional activation of β‐catenin signaling in mice leads to severe defects in intervertebral disc tissue

Preparation and Characterization of a pH‐ and Thermally Responsive Poly(N‐isopropylacrylamide‐co‐acrylic acid)/Porous SiO₂ Hybrid

Contact Info

Product

Resources

About

Chemical modulation of thermosensitive poly(N-isopropylacrylamide) microsphere swelling: a new strategy for chemical sensing

Cited by 39 publications

References 20 publications

Thermoresponsive Double Network Hydrogels with Exceptional Compressive Mechanical Properties

Thermoresponsive Double Network Hydrogels with Exceptional Compressive Mechanical Properties

Conditional activation of β‐catenin signaling in mice leads to severe defects in intervertebral disc tissue

Preparation and Characterization of a pH‐ and Thermally Responsive Poly(N‐isopropylacrylamide‐co‐acrylic acid)/Porous SiO2 Hybrid

Contact Info

Product

Resources

About

Preparation and Characterization of a pH‐ and Thermally Responsive Poly(N‐isopropylacrylamide‐co‐acrylic acid)/Porous SiO₂ Hybrid