Tear of lipid membranes by nanoparticles

Membrane Binding Strength vs Pore Formation Cost─What Drives the Membrane Permeation of Nanoparticles Coated with Cell-Penetrating Peptides?

Cell-penetrating peptides (CPPs) enable the transport of nanoparticles through cell membranes. Using molecular simulations, we conduct an in-depth investigation into the thermodynamic forces governing the passive translocation of CPP-coated nanoparticles across lipid bilayers, contrasting their behavior with that of bare particles to dissect the contribution of the peptides. Our analysis unveils a distinctive two-stage translocation mechanism, where the adsorption energy of the particles overcomes the cost of forming a hydrophilic transmembrane pore. Proper evaluation of the translocation mechanisms is only possible when using two reaction coordinates, in particular, one that explicitly includes the density of the lipids on the binding site of the particle. An analysis of adsorption and activation free energies in terms of a simple kinetic model provides a clearer understanding of the CPP effect. Experimental validation using nonendocytic cells confirms the superior membrane permeation of CPP-coated particles. Our findings have implications for the rational design of more efficient cell-permeating particles.

Dissolved metal ions and mineral-liposome hybrid systems: Underlying interactions, synthesis, and characterization

Liposomes are versatile lipid-based vesicles with interesting physicochemical properties, making them excellent candidates for interdisciplinary applications in the medicinal, biological, and environmental sciences. The synthesis of mineral-liposome hybrid systems lends normally inert vesicles with the catalytic, magnetic, electrical, and optical properties of the integrated mineral species. Such applications require an understanding of the physicochemical interactions between organic molecules and inorganic crystal structures. This review provides an overview on these interactions and details on synthesis and characterization methods for these systems.