Lipid Head Group Charge and Fatty Acid Configuration Dictate Liposome Mobility in Neurofilament Networks

Intermediate filaments constitute a class of biopolymers whose function is still poorly understood. One example for such intermediate filaments is given by neurofilaments, large macromolecules that fill the axon of neurons. Here, reconstituted networks of purified porcine neurofilaments are studied and the diffusion behavior of different nanoparticles in the biopolymer network is evaluated. A strong dependence of particle diffusion on the charge state of the particles, and - for liposomes - also on the fatty acid configuration of lipids is observed. The results suggest that both electrostatic and hydrophobic interactions contribute to nanoparticle trapping in neurofilament networks, and that the latter is enabled by lipids with an inverted cone geometry which grant access to the hydrophobic core of the liposome shell.