Plant-derived lipid nanoparticles as a drug delivery vehicle
Prior research demonstrates the plant kingdom produces extracellular vesicles, providing sustainable and cost-efficient access to lipid nanoparticles (NPs). In this study, we isolated and characterized olive-derived NPs (ODNPs) to assess their potential as a drug delivery vehicle. ODNPs were obtained using stepwise ultracentrifugation with a sucrose gradient and their biological and physical properties were analyzed using nanoparticle tracking analysis (NTA), MTT assay, and immunofluorescence (IF) in human lung cancer cells (A549). NTA revealed variance in each of the sucrose gradient-generated fractions. Fraction 3 was the most uniform in size (~116 nm) and of high concentration (4.0 x 1012 particles/mL). This fraction was therefore selected for further testing. MTT found concentrations between 106 – 1010 ODNPs/mL did not decrease cell viability, while IF demonstrated that PKH67-stained ODNPs were present in cell cytoplasm. Six different approaches were then tested to load the anti-cancer drug doxorubicin (Dox) into ODNPs. Passive incubation of four hours was found to be the quickest and most efficient method with about 10% loading efficiency. Dox-loaded ODNPs reduced A549 cell viability by 90%, compared to only a 70% reduction from the same concentration of non-encapsulated drug. Finally, physical and biological stability assessments indicated ODNPs remain stable in concentration, size, and delivery of therapeutic effect when stored in water at 4°C. Our findings demonstrate that ODNPs are biocompatible, internalized by cells, capable of loading and delivering doxorubicin, and can be stored for a long period in minimal conditions justifying the continued investigation of plant NPs as a promising drug delivery system candidate.
