Membrane-mediated dimerization of spherocylindrical nanoparticles

We present a numerical investigation of the modes of adhesion and endocytosis of two spherocylindrical nanoparticles (SCNPs) on planar and tensionless lipid membranes, using systematic molecular dynamics simulations of an implicit-solvent model, with varying values of the SCNPs' adhesion strength and dimensions. We found that at weak values of the adhesion energy per unit of area, xi, the SCNPs are monomeric and adhere to the membrane in the parallel mode. As xi is slightly increased, the SCNPs dimerize into wedged dimers, with an obtuse angle between their major axes that decreases with increasing xi. However, as xi is further increased, we found that the final adhesion state of the two SCNPs is strongly affected by the initial distance, d(0), between their centers of mass, upon their adhesion. Namely, the SCNPs dimerize into wedged dimers, with an acute angle between their major axes, if d(0) is relatively small. However, for relatively high d(0), they adhere individually to the membrane in the monomeric normal mode. For even higher values of xi and small values of d(0), the SCNPs cluster into tubular dimers. However, they remain monomeric if d(0) is high. Finally, the SCNPs endocytose either as a tubular dimer, if d(0) is low or as monomers for large d(0), with the onset value of xi of dimeric endocytosis being lower than that of monomeric endocytosis. Dimeric endocytosis requires that the SCNPs adhere simultaneously at nearby locations.

Automated summary

This study investigates the adhesion and endocytosis modes of two spherocylindrical nanoparticles (SCNPs) on planar and tensionless lipid membranes through systematic molecular dynamics simulations. The results show that under weak adhesion energy, the SCNPs adhere to the membrane individually in a parallel mode. As the adhesion energy increases, the SCNPs form wedged dimers with an obtuse angle between their major axes. The final adhesion state and endocytosis mode of the SCNPs are strongly influenced by their initial distance and the value of adhesion energy.