Perez-Moreno, A. M. | Search bioRxiv

bioRxiv2024

Ovalbumin-loaded mesoporous silica nanoparticles for allergen specific immunotherapy

Allergic diseases are caused by an unnecessary immune response against harmless external substances (allergens), and they pose an important economic burden for healthcare systems with a large impact on the quality of life of patients. Allergen-specific immunotherapy (AIT) is the only treatment option capable of modifying the natural history of the disease, but current AIT schemes present safety and efficacy limitations. One possible strategy to address these limitations is to encapsulate the allergen in nanoparticle carriers that can deliver it to antigen presenting cells while hiding it from effector cells responsible for the allergic reaction. In this work, we evaluate the use of allergen-loaded mesoporous silica nanoparticles (MSNs) as AIT agents. MSNs of different pore sizes were prepared and characterized, evaluating their capacity to load and release ovalbumin (OVA) as a model allergen. Extra-large pore MSNs (XL-MSNs) showed the optimal loading and release behavior, presenting also enhanced activation of the dendritic cell line DC2.4 and reduced allergenic capacity in pre-sensitized RBL-2H3 cells, both compared to free OVA. After evaluating their biodistribution following subcutaneous, sublingual or intravenous administration, their therapeutic potential in AIT was further assessed in an in vivo murine model of OVA systemic anaphylaxis. The results showed that intravenous administration of OVA-loaded XL-MSNs significantly protected the mice from anaphylaxis and induced a Th1/Treg-immune profile, while administration through other routes failed to prevent the development of an anaphylactic reaction upon provocation with OVA. These findings establish MSNs, particularly via intravenous administration, as a promising platform to develop safer and more effective AIT.

immunology↗

bioRxiv2023

Dissolving microneedle array patches containing mesoporous silica nanoparticles of different pore sizes as a tunable sustained release platform

Dissolving microneedle array patches (DMAPs) enable efficient and painless delivery of therapeutic molecules across the stratum corneum and into the upper layers of the skin. Furthermore, this delivery strategy can be combined with the sustained release of nanoparticles to enhance the therapeutic potential in a wide variety of pathological scenarios. Among the different types of nanoparticles that can be included in microneedle formulations, mesoporous silica nanoparticles (MSNs) of tuneable pore sizes constitute a promising tool as drug delivery systems for cargos of a wide range of molecular weights. However, the development of efficient methods to produce DMAP containing large amounts of MSNs of different pore sizes has not been reported. In this work, DMAP containing MSNs with varying pore sizes was prepared and characterized. After synthesizing and characterizing MSNs, the pore size of the nanoparticles (in the range of 3 to 13 nm for S-MSN and XL-MSN, respectively) was observed to influence the loading and release of both small and large molecules, using fluorescein and ovalbumin (OVA) as model cargos. Moreover, a new preparation method was developed to produce DMAP containing large amounts of these MSNs located mainly in the microneedle tips. The successful insertion of these DMAPs was confirmed in vitro (using Parafilm), ex vivo (using excised neonatal porcine skin) and in vivo (in the back of mice) models. The dissolution of the microneedles and deposition of the nanoparticles inside the skin were also confirmed both ex vivo and in vivo using fluorescent nanoparticles, with complete microneedle dissolution after 2 h of insertion in vivo. Through histological studies, the microneedle-delivered MSNs were found to end up inside antigen presenting cells in the skin tissue (either F4/80+ macrophages or CD11c+ dendritic cells). For this reason, the uptake and biological effect of the MSNs was evaluated in vitro in dendritic cells, showing that while smaller pore MSNs were taken up by cells more efficiently (with over 80 % of S-MSN uptake compared to ca. 55 % for XL-MSNs), the dendritic cells treated with OVA- loaded XL-MSNs underwent the largest degree of activation (inducing over 25 % of CD40 expression compared to less than 2 % for OVA-loaded S- MSNs). Finally, the immune response to OVA-loaded XL-MSNs in mice was evaluated after repeated administration either subcutaneously or through DMAP. The results of this experiment showed comparable levels of anti-ovalbumin immunoglobulin generation through both routes of administration (with significant production of OVA-specific IgG1 and IgG2b antibodies), highlighting the good potential of this delivery platform for vaccination or immunotherapy applications.

pharmacology and toxicology↗