ACS Nano http://doi.org/h6f (2012)

When nanoparticles come into contact with the physiological environment or serum-containing cell culture media, a corona of proteins immediately adsorb on the surface of the nanoparticle. These proteins, which bind weakly to the surface and are dynamically exchanging with other proteins in the environment, mask the identity of the nanoparticle and affect its biological behaviour. Kimberley Hamad-Schifferli and co-workers at Massachusetts Institute of Technology and the University of Texas at Austin have now shown that this protein corona can be used to help carry and release drugs and DNA.

The researchers loaded either DNA or an anticancer drug into the protein corona surrounding gold nanorods using two approaches. In the sequential method, the corona was first formed by mixing serum with the nanorods before adding the DNA or drug. In the simultaneous method, serum, nanorods, DNA or drug were all mixed in at the same time. The simultaneous approach led to larger hydrodynamic diameters than the sequential method, but in both cases the DNA and drug loading are 2–3 times and 7–8 times higher, respectively, than when these molecules are covalently attached on the nanorods. Laser irradiation triggered the release of the payloads, which were confirmed to still be functional after their release.

The method offers a way to carry more payload on nanoparticles compared with covalent strategies while utilizing the corona to stabilize the nanoparticles. However, due to the complex and random nature of the corona proteins, the loading of the payloads and their leakage profile are variable.