scholarly journals Thermally responsive polymeric hydrogel brushes: synthesis, physical properties and use for the culture of chondrocytes

2006 ◽  
Vol 4 (12) ◽  
pp. 117-126 ◽  
Author(s):  
John Collett ◽  
Aileen Crawford ◽  
Paul V Hatton ◽  
Mark Geoghegan ◽  
Stephen Rimmer
Keyword(s):  
Crosslink Density ◽  
Cell Attachment ◽  
Viable Cell ◽  
Contact Angles ◽  
Polymer Chains ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Thermally Responsive ◽  
Isopropyl Acrylamide ◽  
Responsive Polymer

Hydrogel brushes are materials composed of a water-swollen network, which contains polymer chains that are grafted with another polymer. Using a thermally responsive polymer, poly( N -isopropyl acrylamide) (polyNIPAM), as the graft component we are able to maintain the critical solution temperature ( T crit ), independent of the overall composition of the material, at approximately 32°C. The change in swelling at T crit is a function of the amount of polyNIPAM in the system. However, there is a much smaller change in the surface contact angles at T crit . PolyNIPAM-based materials have generated considerable interest, as ‘smart’ substrates for the culture of cells and here, we show the utility of hydrogel brushes in cell culture. Chondrocytes attached to the hydrogel brushes and yielded viable cell cultures. Moreover, the chondrocytes could be released from the hydrogel brushes without the use of proteases by reducing the temperature of the cultures to below T crit to induce a change in the conformation of the polyNIPAM chain at T crit . The importance of the crosslink hydrogel component is illustrated by significant changes in cell attachment/cell viability as the crosslink density is changed.

Green Preparation of an Environment-Responsive Polymer

2013 ◽  
Vol 750-752 ◽  
pp. 1235-1238
Author(s):  
Qian Hou ◽  
Zhao Zhang ◽  
Ting Ting Yang ◽  
Yan Zhang
Keyword(s):  
Preparation Method ◽  
Reaction System ◽  
Functional Materials ◽  
Transformation Property ◽  
Solution Temperature ◽  
Smart Polymers ◽  
Critical Solution Temperature ◽  
Isopropyl Acrylamide ◽  
Responsive Polymer ◽  
Chemical Constitution

Smart polymers are very important in many fields, such as biochemistry, fine chemicals and functional materials, etc. In this paper, poly (N-isopropyl acrylamide) (PNIPAm) was prepared by ultrasonics sonochemistry. In the reaction system, the monomer is N-isopropyl acrylamide (NIPAm), the crosslinker is N,N'-methylenebisacrylamide (BIS) and the solvent is tetrahydrofuran (THF). FTIR and UV-Vis were used to investigate the chemical constitution and phase transformation property of PNIPAm. The results show that it is successful to obtain PNIPAm. It has thermosensitivity. And its lower critical solution temperature is found to be 34°C. Therefore, a green preparation method for environment-responsive polymer is presented.

scholarly journals Upper critical solution temperature thermo-responsive polymer brushes and a mechanism for controlled cell attachment

2017 ◽  
Vol 5 (25) ◽  
pp. 4926-4933 ◽  
Author(s):  
Xuan Xue ◽  
Lalitha Thiagarajan ◽  
Shwana Braim ◽  
Brian R Saunders ◽  
Kevin M Shakesheff ◽  
...  
Keyword(s):  
Polymer Brushes ◽  
Cell Attachment ◽  
Control Cell ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Upper Critical Solution Temperature ◽  
Responsive Polymer

We report the synthesis of thermo-responsive polymer brushes with Upper Critical Solution Temperature (UCST)-type behaviour on glass to provide a new means to control cell attachment.

Thermosensitive Nanocontainers Prepared from Poly(N-isopropylacrylamide-co-N-(hydroxylmethyl)acrylamide)-g-Poly(lactide)

2006 ◽  
Vol 6 (9) ◽  
pp. 2896-2901 ◽  
Author(s):  
Yan Zhang ◽  
Wuli Yang ◽  
Changchun Wang ◽  
Wei Wu ◽  
Shoukuan Fu
Keyword(s):  
Self Assembly ◽  
Solution Temperature ◽  
Temperature Sensitive ◽  
Critical Solution Temperature ◽  
Spherical Structure ◽  
Thermally Responsive ◽  
Transmission Electron ◽  
Isopropyl Acrylamide ◽  
Fundamental Research ◽  
Spatial Specificity

Thermally-responsive graft copolymer of poly(N-isopropylacrylamide-co-N-(hydroxylmethyl)acrylamide)-g-poly(lactide) was synthesized by ring-opening polymerization of D,L-lactide (LA). The polymerization was initiated by the hydroxy group of poly(N-isopropyl acrylamide-co-N-(hydroxylmethyl)acrylamide), using stannous octoate as catalyst. The resulting polymer was temperature-sensitive and the lower critical solution temperature (LCST) was affected by their composition. The chemical structure and physical properties of the grafted copolymers were investigated by various methods. Nanocontainers formed from the self-assembly of poly(N-isopropylacrylamide-co-N-(hydroxylmethyl) acrylamide)-g-poly(lactide) were characterized by transmission electron microscopy (TEM), and a spherical structure was observed. Dynamic light scattering (DLS) results indicate that the particle size increased with the increase of polylactide content in the copolymer. The properties of this polymer are interesting for both industrial application and fundamental research. In particular it will combine a spatial specificity in a passive manner and a temperature-responsive active targeting mechanism for drug delivery system.

Crystallization driving thermoresponsive transition of a liquid crystalline polymer

2021 ◽  
Author(s):  
Yuewen Yu ◽  
Guangran Shao ◽  
Wangqing Zhang
Keyword(s):  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Polymer Chains ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Upper Critical Solution Temperature ◽  
Responsive Polymer ◽  
Solvent Molecules

For a general responsive polymer exhibiting thermoresponsive transition in a solvent at the upper critical solution temperature (UCST), the interaction between polymer chains and solvent molecules and the interaction among...

scholarly journals Effects of the Hydrophilic–Lipophilic Balance of Alternating Peptides on Self-Assembly and Thermo-Responsive Behaviors

2019 ◽  
Vol 20 (18) ◽  
pp. 4604 ◽  
Author(s):  
Ihsan ◽  
Nargis ◽  
Koyama
Keyword(s):  
Aqueous Solutions ◽  
Self Assembly ◽  
Polymer Chains ◽  
Systematic Evaluation ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Hydrophilic Lipophilic Balance ◽  
Upper Critical Solution Temperature ◽  
Cloud Points ◽  
Micellization Behavior

A series of N-substituted poly(Gly–alter–Val) peptides were successfully synthesized for the systematic evaluation of the micellization behavior of alternating peptides. Three-component polymerization employing an aldehyde, a primary ammonium chloride, and potassium isocyanoacetate afforded four alternating peptides in excellent yields. We investigated the dependence of the hydrophilic–lipophilic balance of alternating peptides on the micellization behavior. All the aqueous solutions of alternating peptides exhibited upper critical solution temperature (UCST) behaviors, strongly indicating that the alternating binary pattern would mainly contribute to the UCST behaviors. The cloud points of alternating peptides shifted to higher temperatures as the side chains became more hydrophilic, which is opposite to the trend of typical surfactants. Such unusual micellization behaviors appeared to be dependent on the quasi-stable structure of single polymer chains formed in water.

Upper-critical solution temperature (UCST) polymer functionalized graphene oxide as thermally responsive ion permeable membrane for energy storage devices

2014 ◽  
Vol 2 (43) ◽  
pp. 18204-18207 ◽  
Author(s):  
Jingmei Shen ◽  
Kai Han ◽  
Elizabeth J. Martin ◽  
Yi Y. Wu ◽  
Mayfair C. Kung ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Solution Temperature ◽  
Functionalized Graphene ◽  
Energy Storage Devices ◽  
Permeable Membrane ◽  
Functionalized Graphene Oxide ◽  
Critical Solution Temperature ◽  
Storage Devices ◽  
Thermally Responsive ◽  
Upper Critical Solution Temperature

A UCST polymer functionalized graphene oxide as a thermally responsive ion permeable membrane.

Synthesis and Lcst Behavior of Thermally Responsive Poly(N-Isopropylacrylamide)/Layered Silicate Nanocomposites

1996 ◽  
Vol 457 ◽  
Author(s):  
Phillip B. Messersmith ◽  
F. Znidarsich
Keyword(s):  
Aqueous Suspension ◽  
Layered Silicate ◽  
Polymer Nanocomposite ◽  
Solution Temperature ◽  
Stimuli Responsive ◽  
Thermally Responsive ◽  
Isopropyl Acrylamide ◽  
Lcst Behavior ◽  
Hydrogel Composites

ABSTRACTStimuli responsive polymeric hydrogel composites were synthesized by room temperature copolymerization of N-isopropyl acrylamide and methylene bisacrylamide (crosslinking monomer) in an aqueous suspension of Na-montmorillonite. Hydrogels containing 3.5 weight % of montmorillonite exhibited a lower critical solution temperature (LCST) similar to unmodified PNIPAM hydrogel (approximately 32°C), and underwent a reversible 60–70% volume shrinkage when heated from ambient temperature to above the LCST. However, hydrogels containing 10 weight% montmorillonite did not exhibit a measurable LCST, and underwent considerably less shrinkage when heated. A solvent exchange reaction was used to replace the water with an acrylic monomer, which was polymerized in-situ to create a delaminated montmorillonite/polymer nanocomposite.

scholarly journals Constrained thermoresponsive polymers – new insights into fundamentals and applications

2021 ◽  
Vol 17 ◽  
pp. 2123-2163
Author(s):  
Patricia Flemming ◽  
Alexander S Münch ◽  
Andreas Fery ◽  
Petra Uhlmann
Keyword(s):  
Phase Transition ◽  
Current Knowledge ◽  
Polymer Chains ◽  
Switching Behavior ◽  
Solution Temperature ◽  
Miscibility Gap ◽  
Underlying Structure ◽  
Thermoresponsive Polymers ◽  
Critical Solution Temperature ◽  
Stimuli Responsive Polymers

In the last decades, numerous stimuli-responsive polymers have been developed and investigated regarding their switching properties. In particular, thermoresponsive polymers, which form a miscibility gap with the ambient solvent with a lower or upper critical demixing point depending on the temperature, have been intensively studied in solution. For the application of such polymers in novel sensors, drug delivery systems or as multifunctional coatings, they typically have to be transferred into specific arrangements, such as micelles, polymer films or grafted nanoparticles. However, it turns out that the thermodynamic concept for the phase transition of free polymer chains fails, when thermoresponsive polymers are assembled into such sterically confined architectures. Whereas many published studies focus on synthetic aspects as well as individual applications of thermoresponsive polymers, the underlying structure–property relationships governing the thermoresponse of sterically constrained assemblies, are still poorly understood. Furthermore, the clear majority of publications deals with polymers that exhibit a lower critical solution temperature (LCST) behavior, with PNIPAAM as their main representative. In contrast, for polymer arrangements with an upper critical solution temperature (UCST), there is only limited knowledge about preparation, application and precise physical understanding of the phase transition. This review article provides an overview about the current knowledge of thermoresponsive polymers with limited mobility focusing on UCST behavior and the possibilities for influencing their thermoresponsive switching characteristics. It comprises star polymers, micelles as well as polymer chains grafted to flat substrates and particulate inorganic surfaces. The elaboration of the physicochemical interplay between the architecture of the polymer assembly and the resulting thermoresponsive switching behavior will be in the foreground of this consideration.

Pyrene-labeled amphiphilic poly-(N-isopropylacrylamides) prepared by using a lipophilic radical initiator: synthesis, solution properties in water, and interactions with liposomes

1995 ◽  
Vol 73 (11) ◽  
pp. 2030-2040 ◽  
Author(s):  
Françoise M. Winnik ◽  
Alexander Adronov ◽  
Hiromi Kitano
Keyword(s):  
Polymeric Micelles ◽  
Polymer Concentration ◽  
Polymer Chains ◽  
Solution Temperature ◽  
Solution Properties ◽  
Excimer Emission ◽  
Elastic Light Scattering ◽  
Critical Solution Temperature ◽  
Liposome Suspension ◽  
Hydrophobic Tail

Fluorescently labeled amphiphilic poly-(N-isopropylacrylamides) (PNIPAM) substituted with a N-[4-(1-pyrenyl)butyl]-N-n-octadecyl group at the chain end were prepared by free-radical polymerization in dioxane of N-isopropylacrylamide (NIPAM) using 4,4′-azobis{4-cyano-N,N-[4-(1-pyrenyl)butyl]-n-octadecyl}pentanamide as the initiator. The solution properties of the polymers in water were studied as a function of polymer concentration and temperature. Quasi-elastic light-scattering measurements and fluorescence experiments monitoring the pyrene excimer and pyrene monomer emissions revealed the presence of multimolecular polymeric micelles below the lower critical solution temperature (LCST) of PNIPAM. These underwent partial, reversible reorganization as they were heated above the LCST. The interactions of the pyrene-labeled amphiphilic PNIPAM with dimyristoylphosphatidylcholine (DMPC) liposomes have been examined in water at 25 °C. From fluorescence experiments it was established that the polymeric micelles are disrupted irreversibly upon contact with the liposomes. The anchoring of the polymer chains occurs by insertion of their hydrophobic tail within the phospholipidic bilayer, as evidenced from a large decrease of the pyrene excimer emission relative to pyrene monomer emission. The copolymers remained anchored within the bilayer as the temperature of the copolymer–liposome suspension was raised above the LCST of PNIPAM. Keywords: liposome, poly-(N-isopropylacrylamide), fluorescence, micelles.

Superabsorbent Nanohydrogels of Poly (N-Isopropyl Acrylamide-Co-Itaconic Acid) Grafted on Starch — Synthesis and Swelling Study

Nano LIFE ◽  
2016 ◽  
Vol 06 (02) ◽  
pp. 1650005 ◽  
Author(s):  
Karim Pourjamal ◽  
Marziyeh Fathi ◽  
Ali Akbar Entezami ◽  
Mohammad Hasanzadeh ◽  
Nasrin Shadjou
Keyword(s):  
Itaconic Acid ◽  
Starch Synthesis ◽  
Ammonium Persulfate ◽  
Solution Temperature ◽  
Scanning Calorimetry ◽  
Critical Solution Temperature ◽  
Dsc Studies ◽  
Isopropyl Acrylamide ◽  
Effects Of Ph

Biopolymer-based superabsorbent nanohydrogel consisting of N-isopropylacrylamide and itaconic acid (IA) was grafted on to starch backbone in an aqueous solution in the absence of the cross-linker agents. The copolymerization reaction occurred in the presence of ammonium persulfate (APS) as an initiator. The effect of N-isopropylacrylamide-to-IA ratio and different concentrations of initiator were investigated. The nanohydrogel composition was characterized by Fourier transform infrared spectroscopy (FTIR). The thermal stability was analyzed by Thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) studies were employed for determination of lower critical solution temperature in hydrogels. Dynamic light scattering analysis showed a narrow size distribution around 70–200[Formula: see text]nm for the synthesized nanohydrogels. The effects of pH on swelling behavior of the hydrogel were investigated. The obtained nanohydrogels, due to their pH and thermo dual sensitive properties, have the potential to be used in the drug delivery systems.

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