Challenging the Challenges of Nanoparticle Testing Using In Vitro Methods


Nashwa Osman1, Darren Sexton1 & Imran Saleem1

1Liverpool John Moores University, School of Pharmacy and Biomolecular Sciences

 Byrom Street, Liverpool, L3 3AF, UK


Introduction: In vitro testing using cell cultures are the cornerstone standard methods for the initial screen of nanoparticles (NPs) providing many valuable mechanistic evaluations for NPs interactions with the target tissues. For example, Alamar Blue (AB), Lactate Dehydrogenase assay (LDH), Reactive Oxygen Species (ROS) assays are widely used assays for evaluating NP toxicity testing. However, these methods were adopted from the conventional chemical materials toxicology testing where these materials are soluble in the testing medium. The particulate nature and the exceptional NP physicochemical characteristics influence completely their behaviour under in vitro testing that render false positive or false negative results. Our study will illustrate technical issues that can be seen in in vitro testing in commonly used assays such as AB, LDH, and ROS. Methods: Assays were performed according to standard protocols or adapted by applying procedures to minimize the NPs-interactions with the assays. Results and Discussions: Assay adaptations such as wash steps, using different procedures for the same assay, using alternative reagents, are providing better results that ensures the endpoints measured are due to genuine effects of NPs on the cells and minimise NPs-interactions with the assays. Conclusion: In vitro cell cultures-based assays require optimization to overcome major challenges with assay interference when it comes to in vitro NP toxicology testing.