Sol-gel synthesis and structure of silica hybrid biomaterials

The present paper deals with the influence of the main silica precursors and the type and quantity of organic components (HEMA, PEO and chitin) on the structure of hybrid materials and their applicability for microbial cell immobilization. The sol-gel synthesis and structure formation of gels have been investigated by means of XRD, FT-IR, BET, SEM and AFM techniques. The type of precursors is of paramount importance for the formation of strong chemical bonds between inorganic and organic components of synthesized materials. AFM demonstrated the existence of hybrid nanostructure with well-defined nanounits and their aggregates. Whole thermophilic bacterial cells producing nitrilase and characterized by cyanocompound degradation activity, have been immobilized by: entrapment within the sol-gel network, adsorption and chemical binding on the surface. The synthesized hybrid nanobiomaterials could be successfully used as matrices for immobilization of living prokaryotic cells and find application in biodegradation processes of toxic environmental pollutants. (C) 2007 Elsevier B.V. All rights reserved.