title: Quantitative detection of protein arrays.
abstract: We introduce a quantitative method that utilizes scanning electron microscopy for the analysis of protein chips (SEMPC). SEMPC is based upon counting target-coated gold particles interacting specifically with ligands or proteins arrayed on a derivative microscope glass slide by utilizing backscattering electron detection. As model systems, we quantified the interactions of biotin and streptavidin and of an antibody with its cognate hapten. Our method gives quantitative molecule-counting capabilities with an excellent signal-to-noise ratio and demonstrates a broad dynamic range while retaining easy sample preparation and realistic automation capability. Increased sensitivity and dynamic range are achieved in comparison to currently used array detection methods such as fluorescence, with no signal bleaching, affording high reproducibility and compatibility with miniaturization. Thus, our approach facilitates the determination of the absolute number of molecules bound to the chip rather than their relative amounts, as well as the use of smaller samples.
authors.affiliation: Physics of Complex Systems Department, Weizmann Institute of Science, POB 26, Rehovot 76100, Israel. nava.levit-binnun@weizmann.ac.il
authors.forename: Nava
authors.initials: N
authors.lastname: Levit-Binnun
authors.forename: Ariel B
authors.initials: AB
authors.lastname: Lindner
authors.forename: Ory
authors.initials: O
authors.lastname: Zik
authors.forename: Zelig
authors.initials: Z
authors.lastname: Eshhar
authors.forename: Elisha
authors.initials: E
authors.lastname: Moses
mesh_terms: D000906:Antibodies; D001710:Biotin; D006046:Gold; D006241:Haptens; D008855:Microscopy, Electron, Scanning; D040081:Protein Array Analysis / Q000379:methods*; D011506:Proteins / Q000032:analysis*; D015203:Reproducibility of Results; D019809:Streptavidin
chemical_list: D000906:Antibodies; D006241:Haptens; D011506:Proteins; D001710:Biotin; D006046:Gold; D019809:Streptavidin