Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 24: Posters: Membranes and vesicles

BP 24.13: Poster

Tuesday, March 17, 2015, 14:00–16:00, Poster A

Receptor-mediated wrapping of nanoparticles — •Karandeep Singh, Sabyasachi Dasgupta, Thorsten Auth, and Gerhard Gompper — Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany

Cargo is internalized by biological cells using different internalization processes, e. g. endocytosis, phagocytosis, and pinocytosis. In all cases, the cargo is inside a carrier that interacts with the membrane. Towards the understanding of these processes, we tackle the internalization of a carrier using a minimalistic model of a spherical nanoparticle with attached ligands, a lipid bilayer membrane, and receptors that mediate the interaction between membrane and nanoparticle.

In our model, we calculate the deformation energy of the fluid membrane using the Helfrich Hamiltonian. The receptors on the membrane bind to the ligands on the nanoparticle, which we take into account using the binding energy and the entropy terms for the free energy of the receptors. For a given fraction of the particle being wrapped by the membrane, we obtain an optimum number of bound receptors at equilibrium. The number of bound receptors depends on the overall receptor density on the membrane, the binding energy gain per receptor, and the area of the membrane that is not bound to the particle. For receptor-mediated adhesion, we find that the transition between unwrapped and completely-wrapped states occurs gradually via partially-wrapped states.