Project of Kishore Tetala:

Title of project: Developing a flexible microreactor for isolation, sample clean-up and analysis

This Ph.D. project is part of a larger Euregio project in which the Fraunhofer Institute in Duisburg, the University of Nijmegen and Wageningen University cooperate. The common aim of the project is to develop a multi-purpose microreactor that can depending on the lay-out of the channels on the glass chip be used for sample clean-up, extraction, enrichment of specific constituents, predicting optimal reaction conditions or performing chemical synthesis.

Within the Laboratory of Organic Chemistry this project is carried out in close cooperation with the synthetic research group of Dr. Gerben Visser. One of the aims in the project is to develop a carbohydrate microreactor, which can be used for specific interactions of lectins (sugar binding proteins), screening of new lectins and in the later stage could be used as a diagnostic tool. Before developing a carbohydrate microreactor, the focus is on surface modification of the glass surface with a linker group to which different carbohydrates were covalently attached (Scheme 1). Contact angle and AFM measurements indicated a successful modification of the glass surface. Two fluorescently labelled {fluorescein-isothiocyanate (FI-TC)} legume lectins (Concanavalin A & Arachis hypogaea) were used to study specific interaction of carbohydrates with lectins. With confocal fluorescence microscopy it was possible to prove specific carbohydrate-lectin interactions (Fig. 1).

Scheme 1. Carbohydrate arrays on glass surfaces 1) Piranha solution; 2) N-(2-aminoethyl)-3-aminopropylmethyl dimethoxysilane; 3) & 5) glutaric dialdehyde; 4) 2,2^’-(ethylenedioxy)diethylamine; 6) Carbohydrate coupling and NaBH₄ for reduction.