A temperature-responsive poly(vinyl alcohol) gel for controlling fluidity of an inorganic phase change material

Karimineghlani, Parvin; Emmons, Emily; Green, Micah J.; Shamberger, Patrick J.; Sukhishvili, Svetlana A.

doi:10.1039/c7ta02897k

Cited by 43 publications

(29 citation statements)

References 70 publications

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“…The tube was set to cool for 3 hours in a chamber set at 15 and then inverted for one hour at room temperature 22,23 . After the inversion, the absence of flow indicated the formation of a gel, assuming that the sample formed the cross-linked network that prevents the flow of liquid trapped in the matrix 24 . The nanogels were also analyzed using this test.…”

Section: Assessment Of Gel Formationmentioning

confidence: 99%

Anti-inflammatory Activity of Curcumin in Gel Carriers on Mice with Atrial Edema

et al. 2020

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A bioactive compound is a product that provides health benefits when consumed, that may include anti-inflammatory, antioxidant activity, ROS and RNS scavenging, specific cytotoxicity, among others. These properties may aid in the prevention and/or mitigation of some chronic diseases 4. Curcumin, known as the Indian gold , has been used to alleviate arrhythmia, and as an aid in the treatment of various illnesses including Alzheimer s, asthma, liver disease, and also as antioxidant, anti-inflammatory, cardioprotective, anticarcinogenic and chemopreventive agent 5 7. Curcumin has been reported to interfere in several mechanisms that control inflammatory responses, among which are: modulation of arachidonic acid metabolism 8 , inhibition of cyclooxygenase 2 COX-2 and lipoxygenase LOX , two enzymes involved in inflammation. COX-2 induces cyto-Abstract: Curcumin is a bioactive compound with proven antioxidant and anti-inflammatory activities, but has low water solubility and dermal absorption. The inflammatory process is considered as the biological response to damage induced by various stimuli. If this process fails to self-regulate, it becomes a potential risk of cancer. The objective of this work was to evaluate the anti-inflammatory activity of curcumin administered to mice with induced atrial edema using two topical vehicles: organogels and O/W-type nanogels at pH 7, Organogels and O/W-type nanogels at pH 7 were prepared, characterized and the antiinflammatory activity was assessed. A histopathological analysis of mouse ears was performed and two gel formulations were selected. Thermograms of organogels indicated that increasing the gelling agent improved the stability of the system. Deformation sweeps confirmed a viscoelastic behavior characteristic of gels in both systems. During the anti-inflammatory activity evaluations, the nanogels demonstrated greater activity (61.8 %) than organogels; Diclofenac ® (2-(2,6-dichloranilino) phenylacetic acid), used as a control medication achieved the highest inhibition (85.4%); however, the drug produced the death of 2 (40%) of the study subjects caused by secondary adverse events. Histopathological analysis confirmed the data.

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Section: Assessment Of Gel Formationmentioning

confidence: 99%

Anti-inflammatory Activity of Curcumin in Gel Carriers on Mice with Atrial Edema

et al. 2020

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“…While there is a sizable body of literature on the rheology‐based studies of the flow activation energy, only a few studies assessed the activation energy of dissociation of physical networks from the temperature dependence of the DLS slow mode . This study aims to explore the role of the hydrogen‐bonding crosslinkers of varied functionality on gelation of a new family of physical gels—phase change salogels, recently developed in our group . The specific focus is on making a head‐to‐head comparison of the flow activation energies in these systems as independently determined by rheology and DLS.…”

Section: Introductionmentioning

confidence: 99%

“…The specific focus is on making a head‐to‐head comparison of the flow activation energies in these systems as independently determined by rheology and DLS. Phase change salogels are formed by a physically crosslinked polymer, that is, polyvinyl alcohol (PVA), which shape stabilizes a liquid inorganic phase change material (PCM)—lithium nitrate trihydrate (LNH) . Salogel networks can be strengthened by the use of a physical crosslinker whose amine groups form hydrogen bonds with OH groups of PVA .…”

Section: Introductionmentioning

confidence: 99%

“…[41][42][43] This study aims to explore the role of the hydrogen-bonding crosslinkers of varied functionality on gelation of a new family of physical gels-phase change salogels, recently developed in our group. [44,45] The specific focus is on making a head-to-head comparison of the flow activation energies in these systems as independently determined by rheology and DLS. Phase change salogels are formed by a physically crosslinked polymer, that is, polyvinyl alcohol (PVA), which shape stabilizes a liquid inorganic phase change material (PCM)-lithium nitrate trihydrate (LNH).…”

Section: Introductionmentioning

confidence: 99%

“…Phase change salogels are formed by a physically crosslinked polymer, that is, polyvinyl alcohol (PVA), which shape stabilizes a liquid inorganic phase change material (PCM)-lithium nitrate trihydrate (LNH). [44,45] Salogel networks can be strengthened by the use of a physical crosslinker whose amine groups form hydrogen bonds with OH groups of PVA. [44] In LNH, hydration of PVA chains was suppressed and OH groups were available for hydrogen bonding with a crosslinker.…”

Section: Introductionmentioning

confidence: 99%

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Activation Energy for Dissociation of Hydrogen‐Bonding Crosslinkers in Phase‐Change Salogels: Dynamic Light Scattering versus Rheological Studies

Karimineghlani

Sukhishvili

2019

Macro Chemistry & Physics

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Dissociation energy of dynamic bonds in thermoresponsive phase‐change salogels is explored using rheology and dynamic light scattering (DLS). The salogels are formed by polyvinyl alcohol (PVA) reversibly crosslinked by hydrogen‐bonding amine‐terminated molecules in an inorganic phase‐change material—lithium nitrate trihydrate (LNH) salt—as a solvent. The crosslinker geometry (linear vs branched) has a strong effect on both the gelation temperature (Tgel) and the crosslinker to polymer ratio at which the gelation occurs. Due to their higher functionality, dendritic crosslinkers are more efficient gelators as compared to their linear counterparts, inducing PVA gelation at a lower concentration of a crosslinker and resulting in salogels with higher Tgel. Both stress relaxation and DLS data can be fitted by the exponential functions with temperature‐independent exponents of ≈0.5 and 2, respectively. For the first time, it is reported that the crosslinker dissociation activation energy determined from the rheological stress relaxation time and DLS slow mode decay time are in very good agreement, comprising ≈130–140 kJ mol−1 for salogels with both linear and dendritic crosslinkers.

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3‐Dimensional Printing of Hydrogel‐Based Nanocomposites: A Comprehensive Review on the Technology Description, Properties, and Applications

et al. 2021

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Hydrogels are notable biomaterials in bioengineering and biotechnology due to their outstanding biocompatibility, good permeability to water-soluble metabolites, and the high swelling ratio. [1] Hydrogels are extensively used in regenerative medicine and tissue engineering, such as biomarker detection, [2] stem cell research, [3] and organ-on-a-chip (OOC) applications. Hydrogels are chemically or physically cross-linked natural or synthetic threedimensional (3D) networks that can form into various shapes and hold large amounts of water, which could be up to 4000% by dry weight, while they are hardly dissolved in water. [4] Their water retention properties are primarily because of the existence of hydrophilic groups in polymer chains such as amido, amino, carboxyl, and hydroxyl. The degree of swelling depends on the composition of the polymer, the density, and the Increasing demand for customized implants and tissue scaffolds requires advanced biomaterials and fabricating processes for fabricating three-dimensional (3D) structures that resemble the complexity of the extracellular matrix (ECM). Lately, biofabrication approaches such as cell-laden (soft) hydrogel 3D printing (3DP) have been of increasing interest in the development of 3D functional environments similar to natural tissues and organs. Hydrogels that resemble biological ECMs can provide mechanical support and signaling cues to cells to control their behavior. Although the capability of hydrogels to produce artificial ECMs can regulate cellular behavior, one of the major drawbacks of working with hydrogels is their inferior mechanical properties. Therefore, keeping and enhancing the mechanical integrity of fabricated scaffolds has become an essential matter for 3D hydrogel structures. Herein, 3D-printed hydrogel-based nanocomposites (NCs) are evaluated systematically in terms of introducing novel techniques for 3DP of hydrogel-based materials, properties, and biomedical applications.

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A temperature-responsive poly(vinyl alcohol) gel for controlling fluidity of an inorganic phase change material

Abstract: A temperature-responsive PVA gel is achieved that reversibly holds fluid lithium nitrate trihydrate and releases it in response to temperature for easy gelling in-place and later removal from heat-exchange modules.

Cited by 43 publications

References 70 publications

Anti-inflammatory Activity of Curcumin in Gel Carriers on Mice with Atrial Edema

Anti-inflammatory Activity of Curcumin in Gel Carriers on Mice with Atrial Edema

Activation Energy for Dissociation of Hydrogen‐Bonding Crosslinkers in Phase‐Change Salogels: Dynamic Light Scattering versus Rheological Studies

3‐Dimensional Printing of Hydrogel‐Based Nanocomposites: A Comprehensive Review on the Technology Description, Properties, and Applications

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