Sol-gel polymers

Gill, I. and Ballesteros, A. (1998) Encapsulation of biologicals within silicate, siloxane, and hybrid sol-gel polymers An efficient and generic approach. Journal of the American Chemical Society, 120, 8587-8598. 

A number of promising C02 sensors have been described13,33. The phase-fluorometric system employing dual luminophore referencing, which is rather complex (two dyes, internal buffer system, sol-gel polymer matrix), has demonstrated satisfactory working characteristics33. But it still has to prove its safety and cost-effectiveness, and requires extensive validation with real food samples. 

So far, the prevalent method to immobilize protein is sol-gel/polymer embedment of protein. It usually embeds and immobilizes protein in a three-dimensional netlike structure of macromolecule polymer. This technology has some characteristics such as mild conditions, multifarious sol-gels, and controllable membrane aperture and figure. It can also retain the bioactivity of protein well when applied to a high concentration of protein. However, the aggregation process is difficult to control. 

The concept of thin films of a molecularly imprinted sol-gel polymer with specific binding sites for a target analyte is general and can be applied also to electrochemical sensors. For example, a sensor to detect parathion in aqueous solutions is based on films cast on glass substrates and on glassy carbon electrodes (Figure 6.14).12... 

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In order to increase the selectivity and efficiency of extraction, novel stationary phases have been developed, particularly in trace analysis. Cyclodextrins, graphi-tized carbon blacks, and conductive polymers such as polypyrrole and poly aniline have been investigated [73]. Sol-gel polymers also seem to be interesting. A particularly important feature is the high thermal stability of these polymers [74]. Recent applications for analysis of biological samples have been described in several articles [75-81]. Review articles present recent developments in methodology, the SPME technique [82-84], and novel coatings [85, 86]. 

Cummins, W., Duggan, P., McLoughlin, P. A comparative study of the potential of acrylic and sol-gel polymers for molecular imprinting Anal. Chim. Acta, 2005, 542, 52-60... 

I. Gill and A. Ballesteros, Encapsulation of biologicals within silicate, siloxmie, mid hybrid sol-gel polymers an efficient and generic approach. J. Am. Chem. Soc. 120, 8587-8589 (1998). 

Figure 2.12 Proposed polymeric structure for entrapping 2,5-dihydroxyl benzoic acid into the sol-gel polymer [691. Reproduced with permission from Lin, Y.-S., Chen, Y.-C. (2002) Laser Desorption/ionization Time-of-Flight Mass Spectrometry on Sol-Cel-Derived 2,5-Dihy-droxybenzoic Acid Film. Anal. Chem. 74 5793-5798. Copyright (2002) American Chemical Society...

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