Characterizing Cytotoxicity and Cellular Fate of Lipid Nanoparticles (LNPs) for Drug Delivery Applications

Abstract

Lipid nanoparticles (LNPs) have emerged as promising vectors for the delivery of
therapeutic agents, particularly in the fields of gene therapy and targeted drug delivery.
Despite their growing use, the detailed interactions between LNPs and human cells
remain not fully understood. This thesis investigates the cellular uptake, localization,
viability and morphological responses of two human cancer cell lines, A-549 (lung
carcinoma) and Hep-G2 (liver carcinoma), upon exposure to LNPs.
To study these interactions, LNPs, produced by RNAnalytics, labelled with a fluorescent
dye (AcoDye600) as well as unlabeled, were applied to cultured cells. The cellular uptake
and localization were then monitored in on slides cultivated cells through fluorescence
microscopy at multiple time points. Morphological changes were observed by light
microscopy to detect cellular responses indicative of stress or adaptation. Cell viability
and proliferation following LNP exposure were assessed using CCK-8 assays to
determine any cytotoxic effects. The retention of LNPs in cells and cell supernatant after
different exposure times was determined through fluorescence-measurements.
The results showed that LNPs are rapidly internalized by both cell lines, with uptake
occurring within minutes of exposure. Fluorescence microscopy demonstrated that LNPs
predominantly accumulate in the cytoplasm surrounding the cell nuclei without
penetrating it. Over time, these intracellular particles tended to cluster into aggregates,
possibly reflecting cellular mechanisms for processing or export of the nanoparticles.
Morphological evaluations identified early cellular responses: A-549 cells developed
spindle-shaped protrusions while Hep-G2 cells exhibited enlarged intracellular vacuoles,
potentially related to increased endocytic or lysosomal activity. Importantly, viability
assays, conducted with different LNP concentrations, showed no significant cytotoxic
effects. This indicates that LNP exposure at the tested concentrations is well tolerated
by both cell lines.
Together, these findings demonstrate efficient and stable uptake of LNPs by human
cancer cells without inducing acute toxicity, while highlighting early morphological
changes that may indicate stress reactions. This work provides valuable insights into
LNP-cell interactions, contributing to the optimization and safer design of LNP-based
drug delivery systems in biomedical applications.

Datum der Bewilligung	2025
Originalsprache	Englisch
Betreuer/-in	Agnes Grünfelder (Betreuer)