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Label-Free Detection of Lectins on Carbohydrate-Modified Boron-Doped Diamond Surfaces

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journal contribution
posted on 01.10.2010, 00:00 by Sabine Szunerits, Joanna Niedziǒłka-Jönsson, Rabah Boukherroub, Patrice Woisel, Jean-Sébastien Baumann, Aloysius Siriwardena
This paper describes the label-free detection of carbohydrate−lectin interactions. The sensor consists of a boron-doped diamond (BDD) electrode terminated with alkynyl surface groups, which have been functionalized via the CuACC (copper(I)-catalyzed azide−alkyne cycloaddition) “click” reaction with carbohydrate analogues bearing an azido-terminating arm. In this work, electrochemical impedance spectroscopy (EIS) was used as an effective technique to probe the specific interactions of the surface-bound carbohydrates with their complementary lectin partners, and the response was found to be dependent on the relative density of sugar units immobilized on the BDD surface. A BDD interface with 60% surface-bound mannose showed a detection limit of ∼5 ± 0.5 nM for Lens culinaris lectin, with an affinity constant of KA = (2.63 ± 0.5) × 106 M−1.