Antonio Martín-Rodríguez

Glioblastoma multiforme (GBM) is the most common and aggressive malignant brain tumor characterized by poor prognosis and limited treatment options. Despite current therapies combining surgery, radiotherapy, and chemotherapy, GBM remains highly resistant to treatment, largely due to the challenges of drug delivery across the blood-brain barrier (BBB). Nanoparticles (NPs) have shown promise as drug carriers, but their clinical translation is hindered by limited brain accumulation and rapid clearance by the immune system. In this study, we explored the potential of GBM cell membrane (CM)-coated NPs (G-NPs) as a strategy to improve GBM targeting and, therefore, efficient treatments. We optimized the CM isolation protocol using U87-MG human GBM cells and identified the Heidolph homogenizer as the most effective technique for producing pure, enriched CM fractions, proposing it as a standard method due to its high scalability. G-NPs were extensively characterized, demonstrating excellent colloidal stability under biological conditions. Flow cytometry revealed the enhanced uptake of G-NPs by U87-MG cells compared to non-coated NPs. Notably, the specific homotargeting capability of G-NPs toward human glioblastoma cells was ultimately confirmed by demonstrating a marked specificity of the glioblastoma CM coating when compared to human fibroblast CM-coated NPs, highlighting selective tumor cell-type targeting. Additionally, the coating of NPs with GBM CMs not only did not impede the physiological passage of NPs across the human in vitro BBB, but interestingly, increased the BBB permeability to G-NPs. These findings highlight that biomimetic coating of NPs with GBM cells is a potential strategy to create platforms for the targeted chemotherapy of GBM.

> N-oleoylethanolamine (OEA) is a lipid mediator that acts as a satiety factor. The main limiting factor for its administration is its poor water solubility. We designed and characterized new nanoemulsions as delivery system for hydrophobic compounds such as OEA. The nanoemulsion components and preparation methods were selected in order to achieve the desired final properties. Then, we evaluated the in vivo properties of the nanoemulsions as drug-delivery systems testing the anorectic effects of OEA in rats after both intragastric and intraperitoneal administration. The in vivo toxicity of the nanoemulsions was evaluated after a 3-week treatment. Nanoemulsions proved to be stable, nontoxic and had no effect on feeding behavior when administered without OEA. The effects of OEA were observable after its oral and parenteral administration with the nanoemulsions to 24-h fasted rats, finding a better efficacy compared with a vehicle containing Tween(®) 20 (Sigma-Aldrich, MO, USA) after oral administration. These results support the efficacy of these nanoemulsions to deliver highly hydrophobic bioactive drugs.