Imaging of the interaction between Engineered Nano-materials and Model Liposomes
EMSL Project ID
51587
Abstract
The category of engineered nano-materials (ENM) encompasses a wide variety of materials used in everyday products, as well as, biomedical applications. Consequently, because of the prevalence of ENM, there is an increased concern for human exposure to these materials, in particular by inhalation. Some reports have stated that ENM can be bioactive and trigger an inflammatory response after being inhaled. Alveolar macrophages can come into contact with ENM, phagocytose them and subsequently release IL-1?, which is a cytokine that contributes to the inflammatory response. Preceding the release of IL-1?, a process called phagolysosomal membrane permeability (LMP) occurs. This process results in degradative enzymes being released into the cytosol, which can result in cell death or the formation of the NLRP3 inflammasome. The NLRP3 inflammasome is a protein complex responsible for the maturation of cytokines such as IL-1? and IL-18. Currently, there is a lack of understanding in how ENM contribute to LMP and what properties of the ENM dictate this process. We propose that ENM can interact with lipid membranes and this interaction will result in a change to lipid order of the membrane. In the proposed work, 100 nm liposomes composed of either POPC or DOPS are used as models for lysosomes. These liposomes are exposed to either TiO2 or ZnO for 2 hours at 37?C. Time-resolved fluorescence anisotropy measurements using the lipophilic probe, Di-4-ANEPPDHQ, provide information on changes to the lipid order of the liposomes in response to the ENM. POPC liposomes treated with TiO2 showed an increase in lipid order, while DOPS liposomes showed no significant change. On the other hand, DOPS liposomes treated with ZnO had increased lipid order, while POPC had no significant change. In order to further understand the interaction between ENM and liposome, as well as, the resulting membrane disruption, we propose to prepare samples of ENM treated liposomes for cryo-TEM imaging. An understanding of how ENM disrupt lipid membranes will aid in developing approached in minimizing ENM induced inflammation.
Project Details
Project type
Limited Scope
Start Date
2020-08-17
End Date
2020-10-17
Status
Closed
Released Data Link
Team
Principal Investigator