אסיף מאגר המחקר החקלאי

Recent developments in organically doped sol-gel sensors: A microns-scale probe; successful trapping of purified polyclonal antibodies; solutions to the dopant-leaching problem

Year:

1994

Source of publication :

Authors :

Volume :

346

Co-Authors:

Aharonson, N., Volcani Cent, Beit Dagan, Israel
Altstein, M., Volcani Cent, Beit Dagan, Israel
Avidan, G. 
Avnir, D.
Bronshtein, A., Volcani Cent, Beit Dagan, Israel
Lewis, A.
Liberman, K.
Ottolenghi, M.
Polevaya, Y.
Rottman, C.
Samuel, J.
Shalom, S.
Strinkovski, A.
Turniansky, A.

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Abstract:

We describe recent advances made in our laboratories in the general field of organically and bio-organically doped sol-gel sensors. The developments described are: (a) The first miniaturization of a sol-gel sensor down to the microns scale, with potential applications to near-field optical microscopy, using a fluorescent pH-indicator. (b) The first successful sol-gel encapsulation of purified polyclonal antibodies, and in particular an anti-nitroaromatics immunoglobulin, with which selective sensing of nitroaromatics, an important class of environmental pollutants, was demonstrated. (c) The leaching problem, occasionally encountered in doping procedures, is solved by two methodologies: First, TMOS polymerization at high acidity and low water content was found to result in non-leachable yet reactive matrices, as demonstrated with O2 sensing by excited state pyrene and with H+ sensing by excited state pyranine; and second, doping with molecules capable of forming a covalent bond within the encapsulating cage results in the permanent anchoring of the dopant. Thus, Methyl-Red, a pH indicator, was derivatized with a silylating residue, and a polymerizing TMOS was doped with it forming a pH-shifted indicator. With both methodologies, leachability was practically zero.

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