Abstract (eng)
Despite more than a century of research to achieve oral delivery of peptide drugs and biologics, the current clinical reality remains unchanged in terms of therapeutic administration due to the challenge of overcoming gastrointestinal barriers before reaching systemic circulation. Furthermore, the large size and complex structure of these macromolecules limit drug solubility and, therefore, bioavailability and pharmacological activity. Mesoporous silica nanoparticles have displayed unprecedented potential as drug carriers in oral delivery. However, there are still open issues related to colloidal stability, control of release rate, permeation enhancement, and mucoadhesion, which need to be addressed before achieving practical applications. To this aim, synthesis protocols were adjusted to obtain ordered mesoporous materials (i.e., MCM-48 and SBA-15) as well as dendritic nanoparticles (DMSNs). First, the functional mushroom tyrosinase Agaricus bisporus Polyphenol Oxidase 4 (AbPPO4) was chosen as a model and immobilized within SBA-15 mesopores for the structural elucidation of small humic phenols. The improved catalytic performance and enhanced stability of the adsorbed AbPPO4 showed the potential advantages of these silica-based materials as macromolecule carriers, providing appropriate enzyme confinement while retaining biological activity. Differential interactions of spherical, rod-shaped, and virus-like nanoparticles with Caco-2/HT29-MTX-E12 cells were additionally studied. Therefore, contributions of shape, aspect ratio, surface roughness, and size were evaluated considering the influence of the mucus layer and intracellular uptake pathways. Several post-grafting strategies were implemented for the functionalization of spherical DMSNs to additionally examine the impact of surface chemistry, charge, and colloidal stability on the biological performance of the nanoparticles in contact with the intestinal cells. Thus, particle penetration through the mucus, as well as paracellular permeation, intracellular distances, and chemical modulation of cell junctions, were effectively tuned. Finally, formulations for oral administration of insulin were prepared by mixing succinylated β-lactoglobulin with plain and functionalized DMSNs previously loaded with the drug. Insulin confinement avoided enzymatic drug degradation, while the incorporation of the nanocarriers in pH-sensitive protein tablets prevented premature gastric release, allowing efficient insulin transport in intestinal conditions. The ability of insulin-loaded DMSNs to be internalized by intestinal cells was tested using non-transformed human epithelial colon cells (HCEC) through live cell imaging, intracellular insulin quantification, and benchmarking the biological activity of insulin uptake with respective cell metabolic status as crucial aspects prior to in vivo testing. This thesis provides valuable insights into the design of mesoporous silica materials as carriers for bioactive macromolecules, with a focus on applications from both environmental and biomedical perspectives. Crucial aspects such as synthesis, tailored functionalization, testing of the biological activity of the confined cargoes, and optimization of the formulations for controlled release were considered. Innovative methodologies were also developed to evaluate the performance of such nanocarriers in contact with intestinal cell models towards their prominent use in oral drug delivery.