Influence of Pore Size in Protein G'-Grafted Mesoporous Silica Nanoparticles as a Serum Pretreatment System for In Vitro Allergy Diagnosis

Immunomodulatory potential of rapamycin-loaded mesoporous silica nanoparticles: pore size-dependent drug loading, release, and in vitro cellular responses

Rapamycin is a potent immunosuppressive drug that has been recently proposed for a wide range of applications beyond its current clinical use. For some of these proposed applications, encapsulation in nanoparticles is key to ensure therapeutic efficacy and safety. In this work, we evaluate the effect of pore size on mesoporous silica nanoparticles (MSN) as rapamycin nanocarriers. The successful preparation of MSN with 4 different pore sizes was confirmed by dynamic light scattering, zeta potential, transmission electron microscopy and N2 adsorption. In these materials, rapamycin loading was pore size-dependent, with smaller pore MSN exhibiting greater loading capacity. Release studies showed sustained drug release from all MSN types, with larger pore MSN presenting faster release kinetics. In vitro experiments using the murine dendritic cell (DC) line model DC2.4 showed that pore size influenced the biological performance of MSN. MSN with smaller pore sizes presented larger nanoparticle uptake by DC2.4 cells, but were also associated with slightly larger cytotoxicity. Further evaluation of DC2.4 cells incubated with rapamycin-loaded MSN also demonstrated a significant effect of MSN pore size on their immunological response. Notably, the combination of rapamycin-loaded MSN with an inflammatory stimulus (lipopolysaccharide, LPS) led to changes in the expression of DC activation markers (CD40 and CD83) and in the production of the proinflammatory cytokine TNF-α compared to LPS-treated DC without nanoparticles. Smaller-pored MSN induced more substantial reductions in CD40 expression while eliciting increased CD83 expression, indicating potential immunomodulatory effects. These findings highlight the critical role of MSN pore size in modulating rapamycin loading, release kinetics, cellular uptake, and subsequent immunomodulatory responses.

Spatially Confined Nanoreactors Designed for Biological Applications

The applications of nanoreactors in biology are becoming increasingly significant and prominent. Specifically, nanoreactors with spatially confined, due to their exquisite design that effectively limits the spatial range of biomolecules, attracted widespread attention. The main advantage of this structure is designed to improve reaction selectivity and efficiency by accumulating reactants and catalysts within the chambers, thus increasing the frequency of collisions between reactants. Herein, the recent progress in the synthesis of spatially confined nanoreactors and their biological applications is summarized, covering various kinds of nanoreactors, including porous inorganic materials, porous crystalline materials with organic components and self-assembled polymers to construct nanoreactors. These design principles underscore how precise reaction control could be achieved by adjusting the structure and composition of the nanoreactors to create spatial confined. Furthermore, various applications of spatially confined nanoreactors are demonstrated in the biological fields, such as biocatalysis, molecular detection, drug delivery, and cancer therapy. These applications showcase the potential prospects of spatially confined nanoreactors, offering robust guidance for future research and innovation.