International Journal of Nanomedicine (Mar 2020)
A Correlative Imaging Study of in vivo and ex vivo Biodistribution of Solid Lipid Nanoparticles
Abstract
Silvia Mannucci,1 Federico Boschi,2,* Barbara Cisterna,1,* Elisabetta Esposito,3 Rita Cortesi,3 Claudio Nastruzzi,3 Enrica Cappellozza,1 Paolo Bernardi,1 Andrea Sbarbati,1 Manuela Malatesta,1 Laura Calderan1 1Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona I-37134, Italy; 2Department of Computer Science, University of Verona, Verona I-37134, Italy; 3Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Ferrara I-44121, Italy*These authors contributed equally to this workCorrespondence: Manuela MalatestaDepartment of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona I-37134, ItalyTel +39 045 8027569Email [email protected]: Solid lipid nanoparticles are largely used in biomedical research and are characterized by high stability and biocompatibility and are also able to improve the stability of various loaded molecules. In vitro studies demonstrated that these nanoparticles are low cytotoxic, while in vivo studies proved their efficiency as nanocarriers for molecules characterized by a low bioavailability. However, to our knowledge, no data on the systemic biodistribution and organ accumulation of solid lipid nanoparticles in itself are presently available.Methods: In this view, we investigated the solid lipid nanoparticles biodistribution by a multimodal imaging approach correlating in vivo and ex vivo analyses. We loaded solid lipid nanoparticles with two different fluorophores (cardiogreen and rhodamine) to observe them with an optical imager in the whole organism and in the excised organs, and with fluorescence microscopy in tissue sections. Light and transmission electron microscopy analyses were also performed to evaluate possible structural modification or damage due to nanoparticle administration.Results: Solid lipid nanoparticles loaded with the two fluorochromes showed good optic characteristics and stable polydispersity. After in vivo administration, they were clearly detectable in the organism. Four hours after the injection, the fluorescent signal occurred in anatomical districts corresponding to the liver and this was confirmed by the ex vivo acquisitions of excised organs. Brightfield, fluorescence and transmission electron microscopy confirmed solid lipid nanoparticles accumulation in hepatocytes without structural damage.Conclusion: Our results support the systemic biocompatibility of solid lipid nanoparticles and demonstrate their detailed biodistribution from the whole organism to organs until the cells.Keywords: lipid-based nanoparticles, systemic biodistribution, optical imaging, light microscopy, transmission electron microscopy, tissue accumulation
