Patent ID: 8574549

Claim:
A method comprising: administering a diagnostic agent composition to a subject, wherein the diagnostic agent composition comprises a plurality of nanoparticles, wherein the nanoparticle comprises a core, having a core surface essentially free of silica; and a shell attached to the core surface; wherein the shell comprises at least one silane-functionalized zwitterionic moiety, wherein the silane functionalized zwitterionic moiety comprises a silane moiety and a zwitterionic moiety, and wherein the silane moiety is covalently bonded to the zwitterionic moiety via a spacer comprising less than 10 carbon atoms; and wherein the silane-functionalized zwitterionic moieties are bound to the core at the core surface without any intervening silica layer; wherein the silane functionalized zwitterionic moiety comprises a hydrolysis product of a precursor tri-alkoxy silane wherein the precursor tri-alkoxy silane is selected from a group consisting of N,N-dimethyl-3-sulfo-N-(3-(trimethoxysilyl)propyl)propan-1-aminium, 3-(methyl(3-(trimethoxysilyl)propyl)amino) propane-l-sulfonic acid, 3-(3-(trimethoxysilyl) 5 propylamino)propane-1-sulfonic acid, 2-(2-(trimethylsilyl)ethoxy(hydroxy)phosphoryloxy)-N,N,N-trimethylethanaminium, 2-(2-(trimethoxysilyl)ethyl(hydroxy)phosphoryloxy)-N,N,N-trimethylethanaminium, N,N,N-trimethyl-3-(N-3-(trimethoxysilyl)propionylsulfamoyl) propan-1-aminium, N-((2H-tetrazol-5-yl)methyl)-N,N-dimethyl-3-(trimethoxysilyl)propan-1-aminium, N-10(2-carboxyethyl)-N,N-dimethyl-3-(trimethoxysilyl)propan-1-aminium, 3-(methyl(3-(trimethoxysilyl)propyl)amino)propanoic acid, 3-(3-(trimethoxysilyl)propylamino)propanoic acid, N-(carboxymethyl)-N,N-dimethyl-3-(trimethoxysilyl)propan-1-aminium, 2-(methyl(3-(trimethoxysilyl)propyl)amino)acetic acid, 2-(3-(trimethoxysilyl)propylamino)acetic acid, 2-(4-(3-(trimethoxysilyl)propylcarbamoyl)15 piperazin-1-yl)acetic acid, 3-(4-(3-(trimethoxysilyl)propylcarbamoyl)piperazin-1-yl) propanoic acid, 2-(methyl(2-(3-(trimethoxysilyl) propylureido)ethyl)amino)acetic acid, 2-(2-(3-(trimethoxysilyl)propylureido)ethyl)amino acetic acid, and combinations thereof and imaging the subject with a diagnostic device.