Poly(vinyl alcohol) cryogels employed as matrices for cell immobilization. 3. Overview of recent research and developments

摘要

Poly(vinyl alcohol) cryogels, which are prepared by the freeze-thawing of concentrated aqueous solutions of the polymer, are promising gel carriers for cell immobilization. These carriers possess definite advantages when compared to other hydrogels commonly used for the same purposes. Similar benefits are as follows: (i) PVA cryogels have very high micro- and macroporosities which provide favored conditions for the nonhindered mass transfer of substrates and metabolites; (ii) the rheological characteristics of the nonbrittle matrix are excellent and allow the use of these carriers in most types of reactors; (iii) thermostability of PVA cryogels exceeds that of other commonly used thermoreversible gel carriers; (iv) the cryogels are highly resistant to biological degradation as well as being of a low sensitivity to culture media compositions; (v) PVA itself is a biologically compatible, nontoxic and readily available low-cost polymer: By cell entrapment within PVA cryogel matrices, diverse immobilized biocatalysts were prepared which were capable of performing both a simple monoenzyme biotransformation of respective substrates and a complex biosynthesis of various high- and low-molecular-weight products, decompose pollutants, and operate in biosensors. Compilation data on these biocatalysts are presented as well as the potential of this immobilization technique. (C) 1998 Elsevier Science Inc. [References: 152]