Biophysical Society Thematic Meeting | Ascona, Switzerland

Liposomes, Exosomes, and Virosomes: From Modeling Complex Membrane Processes to Medical Diagnostics and Drug Delivery

Poster Abstracts

22-POS Board 11 Polystyrene Nanoparticles Alter the Structure and Stability of Model Cell Membranes David R. Van Doren, Luke Cuculis. Shelli L. Frey , Gettysburg College, Gettysburg, PA, USA. Unique material properties of nanoparticles (NPs) contribute to a diversity of applications that range from increasing transparency and protection of sunscreen to transporting drugs across cell membranes without damaging the cell itself. Because the interactions of NPs with biological membranes have not been fully characterized to correlate surface physical and chemical characteristics with mode of action, model cell membranes exposed to NPs were monitored with fluorescence microscopy. Giant unilamellar vesicles (GUVs) composed of 1:1:1 dipalmitoylphosphatidylcholine (DPPC)/1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/cholesterol were prepared with 0.8% mol fluorescent TR-DHPE, exposed to NPs either during the vesicle electroformation process or afterwards, and then imaged. The effects of varying concentrations of 40, 60, or 100 nm functionalized polystyrene NPs were measured through morphology changes and vesicle size distributions. Aminated polystyrene particles reduced the size of stable GUVs with the magnitude of the effect scaling with NP concentration. Additionally, the distribution of aminated nanoparticles within the membrane resulted in lipid tubule formation that extended from the vesicle structure; the membrane bending may be attributed to a NP crowding mechanism. Carboxylated particles produced less dramatic effects compared to the control system. In both cases, high NP concentration completely prevented GUV formation, indicating a saturation concentration effect. Understanding the features impacting NP-membrane interactions may help elucidate health and environmental implications of these associations and direct the design of better NP-based technology.

59