POLY(VINYLALCOHOL) CRYOGELS EMPLOYED AS MATRICES FOR CELL IMMOBILIZATION - 3 - OVERVIEW OF RECENT RESEARCH AND DEVELOPMENTS

Poly(vinyl alcohol) cryogels, which are prepared by the freeze-thawing of concentrated aqueous solutions of the polymer, are promising gel c arriers for cell immobilization. These carriers possess definite advan tages when compared to other hydrogels commonly used for the same purp oses. Similar benefits are as follows: (i) PVA cryogels have very high micro- and macroporosities which provide favored conditions for the n onhindered mass transfer of substrates and metabolites; (ii) the rheol ogical characteristics of the nonbrittle matrix are excellent and allo w the use of these carriers in most types of reactors; (iii) thermosta bility of PVA cryogels exceeds that of other commonly used thermorever sible gel carriers; (iv) the cryogels are highly resistant to biologic al degradation as well as being of a low sensitivity to culture media compositions; (v) PVA itself is a biologically compatible, nontoxic an d readily available low-cost polymer: By cell entrapment within PVA cr yogel matrices, diverse immobilized biocatalysts were prepared which w ere capable of performing both a simple monoenzyme biotransformation o f respective substrates and a complex biosynthesis of various high- an d low-molecular-weight products, decompose pollutants, and operate in biosensors. Compilation data on these biocatalysts are presented as we ll as the potential of this immobilization technique. (C) 1998 Elsevie r Science Inc.