The discovery of the iron oxide magnetic nanoparticle (IONP) has had profound effects in the field of nanobiotechnology. It was the first nanoparticle to be approved for human use as MRI contract agent. Recently, developments in preparation and surface modification chemistry of IONPs have led to well-controlled size and super colloidal stability of IONPs and opened a door for their widespread application in nanobiotechnology. The IONPs we develop with unique surface modification chemistry can load a large amount of organic dye molecules on their surface and produce dye labelled magnetic particles (MagDye). The brightness of a 30 nm MagDye could be 300 times higher than that of a traditional dye in comparison. MagDye also provides reaction groups such as carboxyl or amine for further conjugation with biomolecules.
Attributed to its small size and high brightness, MagDye makes it possible to measure individual virus and/or exosomes by a flow cytometer. Furthermore, since MagDye is magnetic and can be separated by a magnet, removing the unreacted biomolecules after conjugation becomes a much easier task. This may lead to the ability to magnetically separate cells or concentrate proteins for further analysis.