Effects of Surface Charge for Inhaled Aerosolized Mesoporous Silica Nanoparticle

Mesoporous silica nanoparticles (MSN) have been used successfully in biomedical applications. MSN are relatively easy to make, biocompatible, and extensively researched for drug delivery. Particle size, pore diameter and surface functionalization influence MSN uptake by cells and in turn the release of drug molecules from the MSN mesopores. In this study a nose-only inhalation system was used to deliver aerosolized aqueous suspensions of individual MSN to mice to study the effects of particle surface charge on delivery and deposition in the lungs. Previous studies have shown that positively-charged MSN do not trigger acute inflammatory response in mice. This study compares the long-term inflammatory response of positively (+) and negatively (-) charged MSN in murine lungs at 0, 1, 7, and 21 days post inhalation. Surface charge was not found to have a significant effect on aerosol morphology, nor respiratory toxicity over time. MSN of both charges were rapidly uptaken (within 24 hours post-inhalation) by aleveolar macrophages and retained in macrophages at least through 21 days post-inhalation. Thus, MSN of both charges are safe nanocarriers for pulmonary drug delivery.