Delivery of [Ru(η6-p-cymene)Cl2{Ph2P(CH2)3SPh-1κP}] using unfunctionalized and mercapto functionalized SBA-15 mesoporous silica: Preparation, characterization and in vitro study

SBA-15 (Santa Barbara Amorphous 15) mesoporous silica and its functionalized form (with 3-mercaptopropyl-triethoxysilane) SBA-15 similar to SH were used as carriers for [Ru(eta(6)-p-cymene)Cl-2(Ph2P(CH2)(3)SPh-kappa P)] complex, denoted as [Ru]. Prepared mesoporous silica nanomaterials were characterized by traditional methods. Materials without [Ru] complex did not show any cytotoxic activity against melanoma B16 and B16-F10 cell lines. On the contrary, materials containing [Ru] such as SBA-151[Ru] and SBA-15 similar to SH1[Ru], exhibited very high activity against tested tumor cell lines, moreover with similar inhibitory potential. According to the loaded amount of the [Ru] in SBA-151[Ru] and SBA-15 similar to SH1[Ru] the IC50 values are 1-2 mu M depending on the test used, thus in comparison to [Ru] alone the activity of nanomaterials containing [Ru] are elevated 3-6 times in vitro. However, the mechanism of apoptosis induction differs for these two mesoporous silica. Unlike reference [Ru] compound and SBA-15 similar to SH1[Ru], SBA-151[Ru] induces high caspase activation. Discrepancy in mechanism of drugs action at intracellular level points towards an influence of functionalization as well as availability of the drug. Moreover, both SBA-151[Ru] and SBA-15 similar to SH1[Ru] similarly to [Ru] are declining autophagy in B16 cell line.