Controlled Solubility Smart Polymers

Enzymes are normally used as water-soluble homogeneous catalysts or immobilized onto water-insoluble solid supports. The many advantages of immobilized systems have been outlined in this chapter. Yet insoluble immobilized enzyme preparations can also have serious drawbacks. First, efficiency with macromolecular or insoluble 

Buchholz, J. Klein, Methods Enzymol 1987, 135, 3-30. W. Hartmeier, Immobili-sierte Biokatalysatoren, Springer Verlag, Berlin, 1986, 14—16. 

Seelbach, C. Wandrey, Industrial Biotransformations, Wiley-VCH, Wein-heim, 2000. 

4 Methods in Enzymology, Vol. 44, K. Mos-bach, Editor, Academic Press, 1976. Immobilised Enzymes, I. Chibata (ed), Wiley, New York, 1978. J. F. Kennedy and J. M. S. Cabral, Solid Phase Biochemistry, W. H. Scou-ten (ed), Wiley Interscience, New York, 

Methods in Enzymology, Vol. 135, 136 and 137, K. Mosbach (ed), Academic Press, 1987. Protein Immobilization, Fundamentals and Applications, R. F. Taylor (ed), Marcel Dekker, Inc., New York, 1991. Industrial Application of Immobilized Biocatalysts, A. Tanaka, T. Tosa, T. Kobayashi (eds), Marcel Dekker, New York, 1993. Methods in Bio- 

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Due to difficulties in directly designing LCST polymers, water-soluble LCST type thermosensitive polymers have been used to create smart polymer systems controlled by guest molecules by incorporating molecular recognition sites. ... 

Poly(A alkyl acrylamide)s and poly(7V-isopropylacrylamide) in particular are the other type of LCST polymers our group has studied. Poly(iV-isopropylacrylamide) is soluble below 31 C in water but insoluble above that temperature. Our group has used this temperature induced phase change has been used as a way to isolate, recover and reuse water-soluble polymer-bound catalysts. It is also a way to make a smart catalysts, catalysts that can turn off an exothermic reaction without external temperature control. Such on/off behavior is seen for both catalysts and substrates. 

Smart biomaterials will likely be resorbable polymers tailored at the molecular level and able to respond to changes in the miCToenvironment and interactions with tissue cells. A great challenge for the future development of biomaterials is the controlled differentiation of target cells in the presence of biomaterials. Typically, differentiation is controlled by soluble growth factors and cytokines. 

Expensive slow- or controlled-release fertilizers—including such low-solubility compounds as urea formaldehyde or products coated with sulfur or polymers—have been used almost exclusively on lawns and gardens and account for only a fraction of 1 % of total nitrogen applications. This should change with the wider introduction of less expensively produced nitrification inhibitors see Thomaschewski, D. 1998. Coming soon smart fertilizers. Fertilizer International 366 76. 

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