**3. Conclusions**

The design, synthesis, and characterization of MMNPs systems, with optimal characteristics to be stable, water-soluble, biocompatible, with good size control and distribution is a promising field for the design of innovative nanoplatforms for cancer therapy. NPs with sizes lower than 100 nm, and optimal size distribution, are more easily dispersed in physiological aqueous suspensions, allowing the nanoparticles to be bioavailable and facilitating cell internalization through endocytosis or pinocytosis. Loading of the MMNPs systems with poorly soluble anticancer drugs into the mesoporous structure, and not on the surface of the nanoparticles, may be useful to improve the transport and bioavailability of these therapeutic agents, increasing their performance and lowering their side effects. Preliminary studies in our group showed that silica-based MMNPs are biocompatible, as no impact on cell viability was observed even at high concentrations of the mesoporous material. When the chemotherapeutic agent was loaded into the MMNPs, testing showed that cell viability was affected even at when low concentrations were loaded into the nanocarrier. Comparison with cell cultures exposed to the free anticancer drug showed lower antiproliferation activity with respect to that of the drug-loaded WMS nanoparticles, indicating an enhancement of bioavailability for the chemotherapeutic agent under the conditions of this study. These preliminary results are stimulating and suggest that MMNPs could become an effective alternative for the treatment of certain types of cancer.
