Exploiting the protein corona around gold nanorods for loading and triggered release.

We form coronas of serum proteins on gold nanorods (NRs) coated with cetyltrimethylammonium bromide (CTAB). These coronas can be exploited for their ability to hold small molecular therapeutics at a capacity much higher (~5-10×) than what covalent conjugation strategies can achieve. Coronas are loaded with DNA oligonucleotides and Doxorubicin, showing that they can hold species of either negative or positive charge. Payload capacity varies with assembly strategy, ionic strength, and loading concentration. Payload release can be achieved by increasing the temperature or by ultrafast laser excitation of the NRs at their longitudinal surface plasmon resonance. DNA leakage from the corona is minimal within the first 3 days of preparation, although Dox leakage was more significant. The coronas also stabilize the NRs in buffer and biological media. This study demonstrates the biological utility of the protein corona around nanomaterials, contrasting the common view of the corona as an undesirable biological response.