Characterization of protein adsorption onto FePt nanoparticles using dual-focus fluorescence correlation spectroscopy

• Pauline Maffre,
• Karin Nienhaus,
• Faheem Amin,
• Wolfgang J. Parak and
• G. Ulrich Nienhaus

Beilstein J. Nanotechnol. 2011, 2, 374–383, doi:10.3762/bjnano.2.43

• due to their large surface-to-volume ratio [3] and, therefore, NPs may also pose a biological hazard [4][5]. Upon incorporation into the body, NPs become exposed to biological fluids such as lung epithelial lining fluid or blood plasma, which contain a variety of dissolved molecules, especially

• overall diameter of 11 nm [11]. HSA is the major soluble constituent of human blood plasma. It serves primarily as a carrier protein for steroids, fatty acids, and thyroid hormones [18]. We found that, at concentrations typically found in blood serum, ~20 HSA molecules adsorb as a monolayer of ~3.3 nm

• thickness on these NPs, and time-resolved fluorescence quenching experiments revealed a typical protein residence time of ~100 s [11]. For transferrin [8], an important blood plasma protein involved in iron transport and delivery, we observed formation of a 7 nm thick protein corona. The FCS method is based