title: Direct visualization and identification of biofunctionalized nanoparticles using a magnetic atomic force microscope.
abstract: Because of its outstanding ability to image and manipulate single molecules, atomic force microscopy (AFM) established itself as a fundamental technique in nanobiotechnology. (1) We present a new modality that distinguishes single nanoparticles by the surrounding magnetic field gradient. Diamagnetic gold and superparamagnetic iron oxide nanoparticles become discernible under ambient conditions. Images of proteins, magnetolabeled with nanoparticles, demonstrate the first steps toward a magnetic analogue to fluorescence microscopy, which combines nanoscale lateral resolution of AFM with unambiguous detection of magnetic markers.
authors.affiliation: Department of Physics, Ernst-Moritz-Arndt University of Greifswald, Felix-Hausdorff-Strasse 6, D-17489 Greifswald, Germany. block@physik.uni-greifswald.de
authors.forename: Stephan
authors.initials: S
authors.lastname: Block
authors.forename: Gunnar
authors.initials: G
authors.lastname: Glöckl
authors.forename: Werner
authors.initials: W
authors.lastname: Weitschies
authors.forename: Christiane A
authors.initials: CA
authors.lastname: Helm
mesh_terms: D001709:Biotechnology / Q000379:methods*; D019921:Biotinylation; D005290:Ferric Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008280:Magnetics; D053768:Metal Nanoparticles / Q000737:chemistry; D018625:Microscopy, Atomic Force / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D011506:Proteins / Q000737:chemistry
chemical_list: D005290:Ferric Compounds; D011506:Proteins; C000499:ferric oxide; D006046:Gold