UCLA

Artificial lipid bilayers have many uses. They are well established for scientific studies of reconstituted ion channels, used to host engineered pore proteins for sensing, especially DNA sequencing, and can potentially be applied in nanoparticle toxicity screening. To better explore these applications, we have simplified the formation and electrical measurement of the traditional method using an apparatus that only requires fluid dispensation. We achieved simultaneous bilayer formation and measurement over a 32-element array with ~80% yield and no operator input following fluid addition. Cycling these arrays resulted in the formation and measurement of 96 out of 120 possible bilayers in 80 minutes, a sustainable rate that could significantly increase with automation and greater parallelization. We have also used this bilayer array platform to study nanoparticles. The platform was validated for this purpose through probing the interaction between amine or carboxyl modified polystyrene nanoparticles and bilayers in conditions of different ionic strength, particle concentration, bilayer charge, and pH. We discovered that NH2-NP ruptures bilayers by generating either transient or persistent pores on bilayers. Furthermore, we conducted nanoparticle toxicity screening with our bilayer array platform. For the first time we identified that CeO2, Co3O4, and In2O3 can damage lysosomal membranes, and that Fe3O4, HfO2, and TiO2 cannot. Our platform confirmed that ZnO, C60, CuO, Er2O3, Eu2O3, La2O3, and Gd2O3 disrupt lipid bilayers. The data from our bilayer array platform also indicated that the ability of nanoparticles to destruct membranes largely depends on the surface coating. In general, positive coating makes the particles more potent to membranes, and negative coating makes the particles safer. Our results about nanoparticles' ability to rupture bilayers are highly correlated with the cytotoxicity data in the literature. Therefore, our bilayer array platform has a great potential of being used for nanoparticle toxicity screening.