Onset of lipid-nanoparticle cooperative association in biomembranes: role of nanoparticle charge and membrane stiffness

Nanoparticles are of great interest in Biophysics because they have been considered as next-generation tools for nanoscale targeted drug delivery. In nanoparticle-cell interactions, the first encounter occurs with the cell membrane, whose properties along with the type of nanoparticles determine the binding behaviour and changes brought upon to the cell membrane. Our recent study with multi-component phase-segregated Floating Lipid Monolayers as a model using X-ray scattering reveals that the Cationic nanoparticles have a preferential binding to one of the phases. The structural disordering and penetration depth is determined by the stiffness and charge density of the membrane¹. The recent extension of this work using Neutron Reflectivity studies reveals that the nature of the nanoparticle surface charge distributions affects their penetration and coverage over the membrane. Interestingly, it has been observed that the type of charge of the nanoparticles cause them to form lipid-nanoparticle complex by extracting lipids out of the membrane. This is mediated by particle-particle interactions and is found to occur at a critical concentration.

[1] A. Chaudhury, et. al. Soft Matter 17, 1963-1974, 2021

* This work has been supported by Department of Science and Technology, India