Abstract
Deciphering biodistribution, biokinetics, and biological effects of nanoparticles (NPs) in entire organs with cellular resolution remains largely elusive due to the lack of effective imaging tools. Here, light sheet fluorescence microscopy in combination with optical tissue clearing was validated for concomitant three-dimensional mapping of lung morphology and NP biodistribution with cellular resolution in nondissected ex vivo murine lungs. Tissue autofluorescence allowed for label-free, quantitative morphometry of the entire bronchial tree, acinar structure, and blood vessels. Co-registration of fluorescent NPs with lung morphology revealed significant differences in pulmonary NP distribution depending on the means of application (intratracheal instillation and ventilator-assisted aerosol inhalation under anesthetized conditions). Inhalation exhibited a more homogeneous NP distribution in conducting airways and acini indicated by a central-to-peripheral (C/P) NP deposition ratio of unity (0.98 ± 0.13) as compared to a 2-fold enhanced central deposition (C/P = 1.98 ± 0.37) for instillation. After inhalation most NPs were observed in the proximal part of the acini as predicted by computational fluid dynamics simulations. At cellular resolution patchy NP deposition was visualized in bronchioles and acini, but more pronounced for instillation. Excellent linearity of the fluorescence intensity-dose response curve allowed for accurate NP dosimetry and revealed ca. 5% of the inhaled aerosol was deposited in the lungs. This single-modality imaging technique allows for quantitative co-registration of tissue architecture and NP biodistribution, which could accelerate elucidation of NP biokinetics and bioactivity within intact tissues, facilitating both nanotoxicology studies and the development of nanomedicines.
Highlights
L settings[3] resulting in the release of new guidelines by the World Health Organization (WHO) to protect workers from the potential risks of NMs.[4]
This study provides a label-free 3D visualization and morphometric analysis of the complete epithelial architecture of an entire murine lung combined with quantitative dosimetry of fluorescently
The method presented here allows for simultaneous 3D mapping of label-free lung morphology and pulmonary distribution of fluorescent NPs
Summary
L settings[3] resulting in the release of new guidelines by the World Health Organization (WHO) to protect workers from the potential risks of NMs.[4] In particular, respiratory inhalation of NMs and/or nanosized ambient particulate matter is a major public concern mainly associated with cardiovascular and pulmonary morbidity and mortality.[5,6] a number of noveldesigned nanomaterial-based drugs (nanomedicines such as liposomes and polymers) are currently being evaluated at the preclinical level or have even reached the clinical settings.[7,8,9]. Extensive scientific efforts have been focused on understanding the fate of NMs in 29 the organism and the underlying pathomechanisms of disease (or diagnostic and therapeutic effects) after respiratory delivery of NMs.[10,11]. Distribution, localization and dosimetry of NPs within whole organs and even whole organisms are of paramount importance for understanding the link between physico-chemical characteristics of NP and associated health effects.[18,19,20] Currently available in vivo imaging
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