title: Quantifying particle coatings using high-precision mass measurements.
abstract: We present a general method to quantify coatings on microparticle surfaces based on the additional mass. Particle buoyant mass is determined in a solution with a density that is nearly equivalent to that of the core particle, reducing the magnitude and uncertainty of the measurement. Under these conditions, added material with a different density than that of the core is a larger fraction of the total buoyant mass of the coated particle. This method can resolve a buoyant mass difference between uncoated and coated particles of ~1 fg. For the protein layer on the 3 μm polystyrene spheres measured herein, this is equivalent to 1/10th of a full layer.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Knudsen
authors.forename: Marcio G
authors.initials: MG
authors.lastname: von Muhlen
authors.forename: Scott R
authors.initials: SR
authors.lastname: Manalis
mesh_terms: D000818:Animals; D055910:Antibodies, Immobilized / Q000276:immunology; D001710:Biotin / Q000737:chemistry / Q000378:metabolism; D006041:Goats; D007074:Immunoglobulin G / Q000737:chemistry* / Q000276:immunology; D008863:Microspheres; D008970:Molecular Weight; D011137:Polystyrenes / Q000737:chemistry; D019809:Streptavidin / Q000737:chemistry / Q000378:metabolism; D020349:Surface Plasmon Resonance
chemical_list: D055910:Antibodies, Immobilized; D007074:Immunoglobulin G; D011137:Polystyrenes; D001710:Biotin; D019809:Streptavidin