Assessing the potential of lignin nanoparticles as drug carrier: Synthesis, cytotoxicity and genotoxicity studies.

Lignin nanoparticles synthesis is among recent developments in lignin valorization especially for biomedical applications. In this study, a new technique where complete self-assembling of lignin was ensured by simultaneous solvent displacement and flash pH change was used to optimize particle size of blank lignin nanoparticles (BLNPs) for suitability in cell uptake along with maximized yield. To establish BLNPs as drug carrier, safety studies including hemocompatibility, cytotoxicity and elaborate genotoxicity studies on Drosophila melanogaster as a model organism were done. Finally, irinotecan loaded lignin nanoparticles (DLNPs) were synthesized to establish their drug carrying potential and thorough in vitro characterization was performed. BLNPs with controllable size (⁓152 nm), low polydispersity (<0.2), maximized yield (>65%), negative surface charge (-22 to -23 mV), spherical shape and smooth surface were obtained with acceptable %hemolysis (<2%). In vitro cytotoxicity studies revealed that BLNPs were significantly toxic (74.38 ± 4.74%) in human breast adenocarcinoma (MCF-7), slightly toxic (38.8 ± 4.70%) in human alveolar epithelial adenocarcinoma (A-549) and insignificantly toxic (15.89 ± 2.84%) to human embryonic kidney (HEK-293) cells. BLNPs showed concentration dependent early neuronal defects in Drosophila, but nuclei fragmentation and gut cell damage were absent. Sustained release DLNPs with high drug loading reduced the IC50 value of irinotecan by almost 3 folds.