De Santo, MarziaCatalano, StefaniaLeggio, Antonella2026-04-132024-07-19http://hdl.handle.net/10955/5769UNIVERSITY OF CALABRIA Department of Pharmacy and Health and Nutrition Science (DFSSN) PhD Course Translational Medicine Granted by Ministry for Universities and Research (MUR) Cycle XXXVIMy PhD research project focused on the design and synthesis of mesoporous silica-based nanoframworks for the targeted delivery of anticancer drugs. The use of nanomaterials for cancer treatment has revolutionized chemotherapy, improving drug efficacy and safety while reducing side effects. Mesoporous silica nanoparticles (MSNs) offer unique advantages, including tunable pore size and shape, easy surface functionalization, high loading capacity, and excellent biocompatibility, making them a promising platform for cancer therapy. Initially, my PhD research activity was concentrated on developing highly selective MSN-based nanosystems for the smart administration of bortezomib (BTZ), a first-line treatment for multiple myeloma. A novel bortezomib (BTZ) delivery system, named FOL-MSN-BTZ, was developed using NanoSiliCal Devices' proprietary MSN technology. NanoSiliCal Devices, an innovative PMI and spin-off from the University of Calabria, hosted me for an 18-month internship during my doctoral studies. The engineered FOL-MSN-BTZ nanodevices consists of MSU-type mesoporous silica nanoparticles able to selectively delivery bortezomib to folate receptor overexpressing multiple myeloma (FR+ MM) cells. The receptor-specific ligand, folic acid (FOL), grafted on the external surface of MSNs, allows tumor recognition and cell internalization, while BTZ linked to the pore internal surface by a pH-responsive bond, is released in a slightly acidic tumor microenvironment. By carefully balancing the different functionalities on the external and internal surface of MSNs we identified an optimized nanostructure that selectively induces death in FR+ tumor cells while sparing BTZ suspensions showed a significantly higher in vivo anticancer efficacy, and a better safety profile compared to conventional BTZ administration. Building on the remarkable in vitro and in vivo results of FOL-MSN-BTZ, we developed a new MSN-based nanodevice for the selective delivery of doxorubicin (DOXO). DOXO is a potent chemotherapeutic agent effective against a wide range of cancers but is associated with serious side effects, such as cardiotoxicity and myelosuppression. To mitigate these toxicities and enhance therapeutic performance through site-specific targeting and controlled release, we created the FOL-MSN-DOXO nanodevice. In this system, folic acid is again used as the targeting molecule on the external surface of the mesoporous silica nanoparticles (MSNs), while doxorubicin is conjugated to the internal pore walls through an acid-labile hydrazone bond. The FOL-MSN-DOXO nanosystem selectively targets FR-overexpressing cancer cells, while sparing the FR-low normal cells. Furthermore, FOL-MSN-DOXO uptake occurred via FR-mediated endocytosis. Additionally, a more specific DOXO-loaded prototype, HER2PEP-MSN-DOXO, featuring a peptide ligand on its external surface that can recognize the HER2 receptor, was designed and developed. This receptor is a crucial therapeutic target in treating HER2-overexpressing (HER2+) breast cancer. In this innovative design, the folic acid previously used on the MSNs' external surface was replaced with a peptide ligand specifically engineered to target the HER2 receptor. The interactions of the designed peptides with the HER2 receptor were studied and evaluated through computational analysis. After identifying the optimal amino acid sequence for interacting with HER2, we synthesized the sequence using solid-phase methodologies and anchored it to the external surface of the silica nanoparticles. The obtained nanosystem significantly inhibited the proliferation of HER2-positive cancer cells, without affecting the growth of HER2-negative healthy cells. The uptake of HER2PEP-MSN-DOX in HER2+ cancer cells occurred though HER2-mediated endocytosis. During a six-month period at the Institute Charles Gerhardt Montpellier (ICGM) in France, under the supervision of Prof. Colacino, my PhD research focused on preparing hybrid mesoporous silica-based materials using innovative, eco-friendly mechanochemical methodologies. The aim was to functionalize mesoporous silica nanoparticles (MSNs) with appropriate linkers and targeting molecules. By employing mechanochemical synthetic approaches, we selectively functionalized MSU-type starting materials on both their external and internal surfaces, creating nanodevices suitable for potential drug delivery applications. The primary goal was to optimize the traditional solvent-based process by minimizing solvent usage, waste generation, and reaction times, thereby enhancing overall process efficiency and eco-friendliness. Targeting molecules, such as small peptides, were effectively grafted onto the external surfaces of the MSNs. Additionally, the internal surfaces were successfully modified with organosilanes to develop stimuli-responsive linkers. Mechanochemical methods were also employed to improve the extraction of surfactants from within the pores of the MSNs, significantly reducing water consumption during the process. In conclusion, my PhD research on mesoporous silica-based systems for controlled release and targeted delivery of anticancer drugs has highlighted significant advancements in the field of targeted therapies and the strategic shift toward molecular multi-targeted approaches. While traditional methods like molecular recognition and pH sensitivity are still effective, the future of cancer treatment lies in molecular multi-targeted therapies, with nanotechnology playing a pivotal role in drug design. To address the complex nature of cancer and improve therapeutic outcomes in terms of both efficacy and reduced toxicity, a polypharmacology approach utilizing Molecular Multi-Targeted Nanostructured (MMTN) cancer therapeutics is proposed in perspective. The hypothesized MMTN device consists of mesoporous silica nanoparticles with an antibody-mimicking peptide on the external surface, connected via an uncleavable bond, and two small molecules inside the silica pores linked with a pH-sensitive bond that hydrolyses in the acidic tumor microenvironment. This design allows the antibody-mimicking peptide to inhibit extracellular target proteins, while the small molecules penetrate the cell to target intracellular proteins, resulting in a synergistic attack on cancer cells. This thesis encompasses published work (papers), completed studies awaiting publication, and ongoing research. Peptide sequences and part of experimental data of the synthesized systems have been omitted for confidentiality reasons, as patent applications are currently in progress.enMESOPOROUS SILICA NANOPARTICLES - DRUG DELIVERY - PEPTIDES- TARGETED THERAPHYThesis