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3578885 
Journal Article 
Synthesis of monodisperse biotinylated p(NIPAAm)-coated iron oxide magnetic nanoparticles and their bioconjugation to streptavidin 
Narain, R; Gonzales, M; Hoffman, AS; Stayton, PS; Krishnan, KM 
2007 
1 
Langmuir
ISSN: 0743-7463
EISSN: 1520-5827 
23 
11 
6299-6304 
English 
17451262 
WOS:000246456700065 
We describe here the synthesis of 10 nm, monodisperse, iron oxide nanoparticles that we have coated with temperature-sensitive, biotinylated p(NIPAAm) (b-PNIPAAm). The PNIPAAm was prepared by the reversible addition fragmentation chain transfer polymerization (RAFT), and one end was biotinylated with a PEO maleimide-activated biotin to form a stable thioether linkage. The original synthesized iron oxide particles were stabilized with oleic acid. They were dispersed in dioxane, and the oleic acid molecules were then reversibly exchanged with a mixture of PNIPAAm and b-PNIPAAm at 60 degrees C. The b-PNIPAAm-coated magnetic nanoparticles were found to have an average diameter of approximately 15 nm by dynamic light scattering and transmission electron microscopy. The ability of the biotin terminal groups on the b-PNIPAAm-coated nanoparticles to interact with streptavidin was confirmed by fluorescence and surface plasmon resonance. It was found that the b-PNIPAAm-coated iron oxide nanoparticles can still bind with high affinity to streptavidin in solution or when the streptavidin is immobilized on a surface. We have also demonstrated that the binding of the biotin ligands on the surface of the temperature-responsive magnetic nanoparticles to streptavidin can be turned on and off as a function of temperature. 
Acrylamides; Coated Materials, Biocompatible; Ferric Compounds; Fluorescent Dyes; Polymers; ferric oxide; 1K09F3G675; 6SO6U10H04; Streptavidin; 9013-20-1; Index Medicus; Surface Plasmon Resonance; Coated Materials, Biocompatible -- chemistry; Temperature; Protein Binding; Microscopy, Electron; Biotin -- chemistry; Streptavidin -- chemistry; Metal Nanoparticles -- chemistry; Acrylamides -- chemistry; Ferric Compounds -- chemistry; Metal Nanoparticles -- ultrastructure; Polymers -- chemistry