Sol gel silicates

X. Yang, L. Huaa, H. Gonga, and S.N. Tan, Covalent immobilization of an enzyme (glucose oxidase) onto a carbon sol-gel silicate composite surface as a biosensing platform. Anal. Chim. Acta 478, 67-75 (2003). 

F. Akbarian, B.S. Dunn and J.I. Zink, Porous sol-gel silicates containing gold particles as matrices for surface-enhanced Raman spectroscopy, J. Raman Spectrosc., 27 (1996) 775. 

Figure 5 Templating of sol-gel silicate materials using surfactants.

Martin RA, Yue S, Hanna JV, Lee PD, Newport RJ, Smith ME, Jones JR (2012) Characterizing the hierarchical structures of bioactive sol-gel silicate glass and hybrid scaffolds for bone regeneration. Philos Trans Ser A Mathemat Phys Eng Sci 370(1963) 1422-1443... 

Table 5.4 Sol-Gel Silicate Compositions for Bulk Gels, Fibers, Films, and Powders...

The structure of the sol-gel silicate depends on the relative rates of the hydrolysis and condensation reactions, as well as on the reverse reactions [Eqs. (5.25)-(5.27)]. The influence of the reaction conditions on the mechanism and kinetics of the reactions forms a key issue in understanding the structural evolution. 

Incorporation of a second polymeric phase and subsequently burning or leaching it out vacates large voids in the sol-gel silicate [5,6,231] and other films and monoliths (e.g., titania, [232] and tungsten oxide, [233]). This concept was first used for sol-gel thin-layer chromatographic plates [234] and monolithic columns [235]. 

However, the encapsulation of proteins in thin silicate films is less straightforward as compared to the encapsulation in monoliths. Very few reports on snccess-ful immobilization of proteins in thin (noncomposite) sol-gel silicate films exist to date (e.g., [63,257-260]). The successfnl encapsulation protocols in thin films can, in most cases, be attribnted to the incorporation of the enzyme in-between layers [219] or in a sandwich construction between the silicate layer and the condnctive matrix... 

A comprehensive and readable review of molecular imprinting, which, however, preceded most of the sol-gel developments discussed here, was written by Haupt and Mosbach [290]. Additional relevant reviews are given by references 291-294. Three general modes of molecular imprinting in sol-gel silicates are currently used to retain the memory of the imprinted molecule within the inorganic hosts. 

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