title: Nanoparticle-mediated monitoring of carbohydrate-lectin interactions using Transient Magnetic Birefringence.
abstract: The development of sensitive and easy-to-use biosensors that allow an adequate characterization of specific weak biological interactions like carbohydrate-lectin interactions still remains challenging today. Nanoparticles functionalized with carbohydrates are one of the most powerful systems for studying carbohydrate-lectin interactions, because they mimic the multivalent presentation of carbohydrates encountered in nature, for example when viruses and bacteria bind to cells. On the basis of the model system glucose-Concanavalin A (ConA), we explore the application of Transient Magnetic Birefringence (TMB) to study these weak interactions, using glucose-functionalized colloidal magnetite nanoparticles (NPs) as probes. We demonstrate that the binding dynamics can be monitored and derive a model to obtain the apparent cooperativity. For our studies, we use nanoparticles of 6 and 8 nm in diameter. The ConA-generated response shows apparent cooperativity, due to the cross-linking of nanoparticles by the ConA tetramer which has four binding sites. Cooperativity is higher for 6 nm NPs, possibly due to a better accessibility of all four ConA binding sites on smaller NPs, enhancing cross-linking. For this system, we find a detection limit of 3-23 nM.
authors.affiliation: IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid, Spain.
authors.forename: Mariana
authors.initials: M
authors.lastname: Köber
authors.forename: Maria
authors.initials: M
authors.lastname: Moros
authors.forename: Laura
authors.initials: L
authors.lastname: Franco Fraguas
authors.forename: Valeria
authors.initials: V
authors.lastname: Grazú
authors.forename: Jesus M
authors.initials: JM
authors.lastname: de la Fuente
authors.forename: Mónica
authors.initials: M
authors.lastname: Luna
authors.forename: Fernando
authors.initials: F
authors.lastname: Briones
mesh_terms: D003208:Concanavalin A / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry*; D008280:Magnetics; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles
chemical_list: D003208:Concanavalin A; D005947:Glucose