Presentation of master thesis in physics. The title of the master thesis is "Effect of protein corona formation on the fusogenic properties of lipid nanoparticles interacting with reductionist models of the endosomal membrane".
Supervisor: Fredrik Höök, Department of physics at Chalmers
Examiner: Giovanni Volpe, Department of physics at Göteborgs universitet
Opponent: Julia Andersson
Efficient delivery of nucleic acids (e.g., mRNA) into cells opens up new possibilities to treat currently undruggable diseases. The use of lipid nanoparticles (LNPs) as delivery vehicles is one promising approach; however, the delivery efficiency is still considerably low. A better understanding of the processes that govern LNP-based delivery could help to increase the efficiency. The cellular organelle called endosome plays a crucial role in the cellular processing of LNPs. We tethered LNPs on a supported lipid bilayer (SLB) which mimics the lipid bilayer of an endosome. Specifically, we employed TIRF-microscopy to observe the fusion of the LNPs with the SLB upon a pH decrease. Considering those fusion events as a measure for the ability of LNPs to deliver their cargo, we assessed factors that could affect the delivery efficiency. Especially we considered the incubation of LNPs in fetal bovine serum, which leads to the formation of a so-called protein corona on the LNP surface. Comparing incubated and not incubated LNPs, we observed a trend that the time between pH decrease and fusion event is larger for incubated LNPs. This could suggest that a protein corona hinders the fusion process. Besides that, we observed that i) there seems to be a correlation between the mobility of the tethered LNPs and their ability to fuse, and ii) the ability to fuse is enhanced if the LNPs undergo a buffer exchange procedure prior to the measurement.