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Here, a three-dimensional (3D) carbohydrate microarray-based plasmon resonance light scattering (RLS) assay has been established for studying carbohydrate–lectin binding with high selectivity. The 3D carbohydrate microarray is fabricated by immobilizing amino-modified carbohydrates on the home-made fourth-generation (G4) NH2-terminated poly(amidoamine) dendrimers (PAMAM)-modified substrate. After marking the carbohydrate–lectin binding events by 13 nm peptide-stabilized gold nanoparticles through the biotin–avidin reaction, the 3D microarray can be directly detected by the RLS scanner without the conventional silver enhancement step. The well defined recognition systems: three monosaccharides (Man-α, Glc-α and Gal-β) with two lectins (Con A and RCA 120), have been chosen here to establish the RLS assay, respectively. Quantitative determination of the surface dissociation constants (KD,surf) for surface carbohydrates and lectins has been achieved. In addition, inhibition values (i.e.the inhibition constants (Ki) and the concentrations of inhibitors required to produce 50% inhibition (IC50)) for inhibitors in solution are also demonstrated by the saccharide competing assays. [ABSTRACT FROM AUTHOR]

To develop a novel high-throughput tool for monitoring specific affinity of microbes with lectins, a kind of lectin microarray has been fabricated by immobilizing lectins on epoxide-derivatized glass slides and used to capture microbes. The capturing events are marked by attachment of lectin-conjugated gold nanoparticles followed by silver deposition to enhance the resonance light scattering (RLS) of the particles. The interactions of 16 lectins with four bacteria and one fungus were proffled by this approach. We demonstrated that the gold-nanoparticle-labeled array was suitable for identifying the binding affinity of lectin with bacterium, as well as determining the bacterium with high sensitivity. More importantly, we found that the growth of microbial strains in different culture media resulted in significant changes in their binding affinities with lectins, which might be important to the pathogenesis of the organisms. [ABSTRACT FROM AUTHOR]