A novel protein-based anticancer drug encapsulating nanosphere: apoferritin-doxorubicin complex.

Developing a drug delivery system, which is uniform, biocompatible, stable and non-toxic, is a challenging issue in anticancer drug delivery strategies. Ferritin is a nano-size spherical protein with an internal cavity where drug molecules can be encapsulated. The apoferritin-doxorubicin complex has been formed by 'opening' and 'closing' the apoferritin sphere in the presence of doxorubicin. The doxorubicin encapsulation was carried out using direct and step-wise change of pH of the solution from 2.5 to 7.4. Non-denaturing polyacrylamide gels showed that the protein cage of the complex successfully self-assembles into its nanosphere form. It was found that up to 28 molecules of doxorubicin can be capsulated per apoferritin protein and no significant drug leakage occurs during the first two days. The apoferritin-doxorubicin complex is a promising nanocarrier for the delivery of anticancer drugs.