Large Pore Mesoporous Silica and Organosilica Nanoparticles for Pepstatin A Delivery in Breast Cancer Cells

(1) Background: Nanomedicinehas recently emerged as a new area of research, particularly to fight cancer. In this field, we were interested in the vectorization of pepstatinA, a peptide which does not cross cell membranes, but which is a potent inhibitor of cathepsin D, an aspartic proteaseparticularly overexpressed in breast cancer. (2) Methods: We studied two kinds of nanoparticles. For pepstatinA delivery, mesoporous silica nanoparticleswith large pores (LPMSNs) and hollow organosilica nanoparticles(HOSNPs) obtained through the sol–gel procedure were used. The nanoparticleswere loaded with pepstatinA, and then the nanoparticleswere incubated with cancer cells. (3) Results: LPMSNs were monodisperse with 100 nm diameter. HOSNPs were more polydisperse with diameters below 100 nm. Good loading capacities were obtained for both types of nanoparticles. The nanoparticleswere endocytosed in cancer cells, and HOSNPs led to the best results for cancer cell killing. (4) Conclusions: Mesoporous silica-based nanoparticleswith large pores or cavities are promising for nanomedicineapplications with peptides.