Functional thermoresponsive polymers

Takahashi, H., Matsuzaka, N., Nakayama, M., Kikuchi, A., Yamato, M., Okano, T. (2012). Terminally functionalized thermoresponsive polymer brushes for simultaneously promoting cell adhesion and cell sheet harvest Biomacromolecules, 13, 253—260. 

Miyamura et al. [170] and Kanaoka et al. [171] have succeeded in stabilizing Au clusters on polymer supports for aerobic oxidation at room temperature in the mixed solvent of water-benzotrifluoride and in water, respectively. Polymer supports could also offer new functions, such as a recycling system by using a thermoresponsive polymer-supported Au catalyst [171]. 

Gotze T, Valtink M, Nitschke M et al (2008) Cultivation of an immortalized human corneal endothelial cell population and two distinct clonal subpopulations on thermo-responsive carriers. Graefes Arch Clin Exp Ophthalmol 246 1575-1583 Gramm S, Komber H, Schmaljohann D (2005) Copolymerization kinetics of N-isopropylacryla-mide and diethylene glycol monomethylether monomethacrylate determined by online NMR spectroscopy. J Polym Sci Pol Chem 43 142-148 Hatakeyama H, Kikuchi A, Yamato M et al (2006) Bio-functionalized thermoresponsive interfaces facilitating cell adhesion and proliferation. Biomaterials 27 5069-5078... 

However, despite its widespread popularity in material science, PNIPAM has inherent disadvantages such as an irreversible phase transition and, for short polymers, a significant influence of end-groups on the thermal behavior. Moreover, strictly speaking, PNIPAM is not a bio-inert polymer. Indeed, the presence of multiple secondary amide functions in the molecular stracture of PNIPAM may lead to the formation of cooperative H-bonding interactions with other amide polymers, in particular with proteins. Thus, the design of new types of thermoresponsive polymers is a cracial topic in contemporary polymer chemistry. 

The latter class of bioorganic materials has gained momentum during the recent years, mainly because many functions have been implemented and potential applications realized [4]. The combination of nucleic acids with conjugated polymers [5] or electroactive macromolecules [6] has resulted in highly sensitive and selective probes, whilst equally important are polynucleic acids that are coimected covalently to thermoresponsive polymers such hybrids have been used successfully for the purification of plasmid DNA [7] and DNA-binding proteins [8]. 

Although chemical ligations on mammalian cell surfaces have been performed using unnatural functional groups delivered to carbohydrates [37], the number of studies of mammalian cell surface modifications with synthetic polymers remains limited [31]. In order to control biointerfacial aspects with environmental stimuli, thermoresponsive polymers were immobilized on mammalian cell surfaces. 

Thermoresponsive polymer brushes on 20 nm colloidal gold formed through ATRP of W-isopropyl acrylamide in aqueous media End-functionalized 3D self-assembled monolayers (SAMs) on GNPs by living cationic ring-opening polymerization reaction directly on GNP surfaces... 

Synthesis of various functionalized 2008 [30] iV-isopropylacrylamide- and vinylether-based polymers grafting onto various substrates detailed review of thermoresponsive polymers, block and graft copolymers synthesis of PiPAAm of various shapes ionic and neutral block copolymers self-assembly stimuli-responsive polymers new initiating systems and synthetic methodologies... 

Lian C, Wang L, Chen X, et al. Modehng swelling behavior of thermoresponsive polymer brush with lattice density functional theory, Langmuir 30(14) 4040—4048, 2014a. 

Wong and coworkers have investigated the enzymatic oligosaccharide synthesis on a thermoresponsive polymer support (Scheme 16.33). The copolymers of 7V-/-propyla-crylamide (NIPAm) and functionalized monomers are thermoresponsive and exhibit inverse temperature-dependent solubility in water they are soluble in cold water but become... 

Thermoresponsive polymers have been used in basic cell studies. For example, a PNIPAAm thiol (PNIPAAm-PEG-thiol) was synthesized and used to regulate the adhesion of cells in a microfluidic channel [66], Fibroblasts were initially cultured at 37°C to induce cell spreading and adhesion to the microfluidic surface. Then, the temperature of the microfluidic environment was reduced to 25 °C for a period of time. After 20 min, cell monolayers became detached and the morphology of individual cells was transformed to a spherical shape. Cell attachment and detachment as a function of the surface response to changing temperature is provided in Figure 6.5. 

Chemomechanical gels that function with phase transition caused by temperature changes Various pol)maers exhibit reversible phase transition in aqueous solution due to temperature variations. Representative examples include poly(vinyl methyl ether) (PVME) and poly(N-isopropylacrylamide) (PNIPAAm) [16, 17]. Common features of thermoresponsive polymers are the coexistence of hydrophilic and hydro-phobic portions in the same polymer chain. Increased hydrophobic interaction at an elevated temperature causes phase separation to take place. Gels obtained by crosslinking these polymers also show thermo-responsivity. The PNIPAAm gel shows the phase transition at 33°C in pure water. It swells at a temperature below the transition and vice versa (see Fig. 5) [18]. 

Materials that typify thermoresponsive behavior are polyethylene—poly (ethylene glycol) copolymers that are used to functionalize the surfaces of polyethylene films (smart surfaces) (20). When the copolymer is immersed in water, the poly(ethylene glycol) functionaUties at the surfaces have solvation behavior similar to poly(ethylene glycol) itself. The abiUty to design a smart surface in these cases is based on the observed behavior of inverse temperature-dependent solubiUty of poly(alkene oxide)s in water. The behavior is used to produce surface-modified polymers that reversibly change their hydrophilicity and solvation with changes in temperatures. Similar behaviors have been observed as a function of changes in pH (21—24). 

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