Osteogenic potential of Rosuvastatin immobilized on silk fibroin nanofibers using argon plasma treatment

To begin developing a silk fibroin (SF) nanofibrous scaffolds that could promote osteogenesis, whilst enabling to deliver an active amount of Rosuvastatin (RSV) to the cells in long-time period, the present study aims to immobilize RSV onto the SF nanofibers through the argon radio frequency. Thus, the effect of plasma exposure times (0, 1, 3, and 5 min) was investigated on the morphology, loading efficiency, release profile, and osteogenesis activity. The successful loading of RSV on the SF nanofibers was proved by Fourier transformed infrared spectroscopy, Differential scanning calorimetry, and energy dispersive spectroscopy. In vitro drug release studies demonstrated that the RSV release was prolonged over a period of 21 d for plasma treated mats, while the non-plasma treated samples released the whole drug after 72 h. Moreover, the dose of RSV was controlled by the plasma exposure times, in which the highest amount of the released RSV was achieved after 3 min exposing to plasma. As suggested by MTT assay, the released amounts of RSV had no toxicity on the seeded human adipose tissue-derived stem cells and enhanced their proliferation. Moreover, using real-time reverse transcriptase-polymerase chain reaction and alizarin red staining proved that RSV-immobilized SF mats stimulate both early and late osteogenic gene differentiation in comparison with pure SF nanofibers. However, the highest differentiation was observed on the SF nanofibers treated with argon plasma for 3 min. The results support the potential of plasma treatment on sustained release of the RSV from SF nanofibers for osteogenesis enhancement.