Cargo-influences on the biodistribution of hollow mesoporous silica nanoparticles as studied by quantitative F-magnetic resonance imaging.

Hypothesis: Biodistribution is a key issue when it comes to medical applications of nanomaterials. Hollow mesoporous silica nanoparticles (HMSNs) loaded with fluorine compounds can be applied as positive magnetic resonance imaging (MRI) contrast agents (CAs). These CAs exhibit an unusual biodistribution which is influenced by the cargo and which could be linked to their serum protein adsorption behaviour.

Experiments: HMSNs were post-synthetically loaded with perfluoro-15-crown-5-ether (PFCE). The F signal was quantified with MRI in a murine model. Furthermore protein adsorption tests were performed in full serum.

Findings: Quantitative analysis of the F-signal revealed that the particles were exclusively accumulating in the liver 24h post-injection, and no accumulation in other reticuloendothelial system (RES) organs like spleen or lung was observed. The protein corona around non-loaded and loaded particles was therefore analysed, and more proteins adsorbed on PFCE-loaded particles as compared to the bare particles, and importantly, the amount of apolipoproteins A-1 and A-2, was clearly elevated for the PFCE-loaded particles. The results underline that the type of cargo may have major influences on the biodistribution of mesoporous silica drug vectors.