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, ξ , the SCNPs are monomeric and adhere to the membrane in the parallel mode. As ξ is slightly increased, the SCNPs dimerize into wedged dimers, with an obtuse angle between their major axes that decreases with increasing ξ . However, as ξ 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 ξ 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 ξ of dimeric endocytosis being lower than that of monomeric endocytosis. Dimeric endocytosis requires that the SCNPs adhere simultaneously at nearby locations.
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Modes of adhesion of spherocylindrical nanoparticles to tensionless lipid bilayers
The adhesion modes and endocytosis pathway of spherocylindrical nanoparticles (NPs) are investigated numerically using molecular dynamics simulations of a coarse-grained implicit-solvent model. The investigation is performed systematically with respect to the adhesion energy density ξ, NP’s diameter D, and NP’s aspect ratio α. At weak ξ, the NP adheres to the membrane through a parallel mode, i.e., its principal axis is parallel to the membrane. However, for relatively large ξ, the NP adheres through a perpendicular mode, i.e., the NP is invaginated, such as its principal axis is nearly perpendicular to the membrane. The value of ξ at the transition from the parallel to the perpendicular mode decreases with increasing the D or α, in agreement with theoretical arguments based on the Helfrich Hamiltonian. As ξ is further increased, the NP undergoes endocytosis, with the value of ξ at the endocytosis threshold that is independent of the aspect ratio but decreases with increasing D. The kinetics of endocytosis depends strongly on ξ and D. While for low values of D, the NP first rotates to a parallel orientation then to a perpendicular orientation. At high values of ξ or D, the NP is endocytosed while in the parallel orientation.
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- Award ID(s):
- 1931837
- NSF-PAR ID:
- 10391523
- Date Published:
- Journal Name:
- The Journal of Chemical Physics
- Volume:
- 156
- Issue:
- 23
- ISSN:
- 0021-9606
- Page Range / eLocation ID:
- 234901
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1063/5.0094234
