Fig. 3

The loading efficiency and release kinetics of doxorubicin from plain silk spheres. a The postloading method was used for the incorporation of Dox into spheres. Dox was released from b DOXMS2 and c MS2 particles. The loaded spheres were resuspended in PBS buffer at pH 7.4, 6 or 4.5 and incubated at 37 °C for 7 days. At the indicated time points, the amount of released drug was evaluated spectrophotometrically. During the first day, the Dox release was determined after 1, 3 and 6 h of incubation. *** indicates statistical significance with p < 0.001