Predicting Nanoparticle Uptake by Biological Membranes: Theory and Simulation

Abstract

We describe a new approach which predicts the level of internalisation or complete wrapping of nanoparticles by liposomes in solution. It is based on a generalisation of elastic theory to nanoscale particles with physical property data obtained from atomistic and coarse-grained simulations. We apply this approach to determine the maximum number of nanoparticles of a given type that can be internalised by a given liposome and give examples of how our approach might be used to identify and/or design nanoparticles with different uptakes: New data that could be correlated with nanoparticle toxicity experiments . We briefly discuss the possibility of designing nanoscale separations process.

Size dependency of gold nanoparticles interacting with model membranes

“…As noted above, accordingly to the extended elastic theory 33 , all AuNPs will adhere to liposomes and enter in the liposome lumen by endocytosis, until the increase in tension (surface and bending) shuts out further complete wetting at a maximum tension. For a 179 nm liposome only spherical NPs with diameters <15 nm can enter before lockdown is complete.…”

“…Refinement of the elastic theory to include the finite thickness of the membrane (~4 nm) and the variation of W with NP diameter 33 leads to a new contact energy w s SLB (where supported lipid bilayer (SLB) recognises that the energy may be different to a free bilayer) and more accurate critical diameters. We defined a new contact energy:…”

“…So that the theory predicts AuNPs always adhere while the critical diameters for other common nanoparticles such as uncharged silica are: quartz 41 nm, cristobalite 25 nm and amorphous silica 7.5 nm. The effect of negative surface charges either raises or lowers the critical diameter depending on the surface considered 33 and NP geometry also plays a significant role with cylindrical NPs have a critical diameter < spheres which may make it favourable for spheres to aggregate into rod-like structures 33 .…”