http://www.cd-bioparticles.com/p/Absolute-Mag™-Carboxylic-Acid-Iron-Oxide-Nanoparticles-lyophilized-25-nm_20_193_211_4961.htmlAbsolute Mag™ Carboxylic Acid Iron Oxide Nanoparticles, which are coated with amphiphilic polymer in lyophilized powder form, are water-soluble iron oxide nanocrystals. The functional group on surface is carboxylic acid. Their zeta potential is from -30 mV to -50 mV. Their organic layers contain a monolayer of oleic acid and a monolayer of amphiphilic polymer, whose thickness is about 4 nm.The hydrodynamic size of the nanocrystals is about 8-10 nm larger than their inorganic core size measured by TEM. Absolute Mag™ Carboxylic Acid Iron Oxide Nanoparticles can be reconstituted in DI water, DMSO, or DMF to any desired concentration less than 10 mg Fe/mL to meet do any conjugation, such as protein, peptide and other amine containing molecules, in the solvent system.