Poly-A-isopropylacrylamide

J. P. Baker and R. A. Siegel, Poly(A-isopropylacrylamide) hydrogel membranes for pulsatile drug delivery, Proc. Int. Symp. Control Release Bioact. Mater, 22, 340-341 (1995). 

Kaneko, Y, Sakai, K., Kikuchi, A., Yoshida, R., Sakurai, Y, and Okano, T. Influence of freely mobile grafted chain length on dynamic properties of comb-type grafted poly(A-isopropylacrylamide) hydrogels. Macromolecules, 1995, 28, 7717-7723. 

Okano, T, Yamada, N., Sakai, H., and Sakurai, Y. A novel recovery system for cultured cells using plasma-treated polystyrene dishes graphted with poly(A-isopropylacrylamide), J. Biomed. Mater. Res., 1993, 27, 1243-1251. 

Chung, J. E., Yokoyama, M., Suzuki, K., Aoyagi, T., Sakurai, Y, and Okano, T. Reversibly thermo-responsive alkyl-terminated poly(A-isopropylacrylamide) coreshell micellar structures. Colloids Surfaces (B Biointerfaces), 1997, 9, 37-48. 

Winnik, F. M., Davidson, A. R., Hamer, G. K., and Kitano, H. Amphiphilic poly(A-isopropylacrylamide) prepared by using a lipophilc radical initiator Synthesis and solution properties in water. Macromolecules, 1992, 25, 1876-1880. 

Brazel, C. S. and Peppas, N. A. Synthesis and characterization of thermo- and chemomechanically responsive poly(A-isopropylacrylamide-co-methacryhc acid) hydrogels. Macromolecules 1995, 28, 8016-8020. 

Note 3 An example of covalent polymer gels is nei-poly(A-isopropylacrylamide) swollen in water, which shows volume phase transition during heating. 

Coexistence of Phases and the Nature of First-Order Phase Transition in Poly-A-isopropylacrylamide Gels... 

Several attempts have been made to construct stimuli-responsive polymer solution and gel systems which undergo isothermal phase transitions by external stimulation, such as photons or chemicals. Aqueous solutions of poly(A -isopropylacrylamide) having photoisomerizable chromophores or host molecules in the pendant groups showed reversible phase separations by photoirradiation or by the addition of specific metal or ammonium ions. The gels made of the polymers also underwent photostimulated or chemical-induced volume phase transitions. 

Fig. 5. Poly(A-isopropylacrylamide) gel swelling vs temperature. Circles are data points amt the solid fine is the lattice model prediction with one fitted parameter. (Reprinted with permission from [12], 1990 American Chemical Society)...

Cussler EL (1989) Isolation process using swellable poly(A-isopropylacrylamide) gels. U.S. Pat. 4,863,613... 

RODS Poly(A-isopropylacrylamide) (PIPAAm) NIH-3T3 fibroblasts Electron beam activated polymerization of 2-carboxy-iV-isopropylacrylamide through a mask on PIPAAm (or vice versa), subsequent NHS mediated binding of peptide to carboxyl functional groups 2007 [173]... 

Huo et al. [112] studied the binding of protein to a charged microgel and the influence of protein on the physical appearance and structural peculiarities of the microgel. For this purpose, pH- and temperature-sensitive poly(A-isopropylacrylamide-co-acrylic acid) [P(NIPA-co-AAc)] microgels with various... 

Xu H, Xu 1, Zhu Y, Liu H, Liu S (2006) In situ formation of silver nanoparticles with tunable spatial distribution at the poly(A-isopropylacrylamide) corona of unimolecular micelles. Macromolecules 39 8451-8455... 

Pelton RH (1988) Polystyrene and polystyrene-butadiene latexes stabilized by poly(A-isopropylacrylamide). J Polym Sci 26 9-18... 

Grabstain V, Bianco-Peled H (2003) Mechanisms controlling the temperature-dependent binding of proteins to poly(A-isopropylacrylamide) microgels. Biotechnol Prog 19 ... 

Choi, C., et al. (2006),Thermosensitive poly(A-isopropylacrylamide)-fe-poly(e-caprolac-tone) nanoparticles for efficient drag delivery system, Polymer, 47(13), 4571-4580. 

The membranes of the thermosensitive controlled-release microcapsules were constructed by a random mixing Aquacoat (Table 1) with the latex particles having poly(EA/MMA/2-hydroxyethyl methacrylate) core and poly(A-isopropylacrylamide (NIPAAm)) shell. This is an example where the membrane has the random two-phase structure as shown in Fig. 5. The microcapsules exhibited a thermosensitive release of water-soluble drug. The mechanism is explained in Fig. 6. When the temperature was changed in a stepwise manner between 30 and 50°C, the microcapsules showed an on-off pulsatile release. This on-off response was reversible. 

Ju, H.K. Kim, S.Y. Lee, Y.M. pH/temperature-respon-sive behaviour of semi-lPN and comb-type graft hydrogels composed of alginate and poly(A-isopropylacrylamide). Polymer 2001, 42, 6851-6857. 

Functional biomaterial surfaces have been created to change between being hydrophobic and hydrophilic, in response to external signals, such as differences in temperature, solvent environment, light, or electrical current. Temperature-sensitive poly(A/-isopropylacrylamide) (PNIPAm)-coated substrate is hydrophobic at a cell culture temperature of 37°C that favors cell adhesion and becomes hydrophilic at a lower temperature of 20°C, causing the detachment of cell sheets. These reversible responsive surfaces have been used to culture and harvest layers of endothelial, epithelial, lung, liver, cardiac, and kidney cells, and could eventually enable assembly of complex tissues and organs. 

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