Receptor diffusion on cell membrane is usually believed as a major factor that controls how fast a virus can enter into host cell via endocytosis.However,when receptors are densely distributed around the binding site so that receptor recruiting through diffusion is no longer energetically favorable,we thus hypothesize that another effect,the creep deformation of cytoskeleton,might turn to play the dominant role in relaxing the engulfing process.In order to deeply understand this mechanism,we propose a viscoelastic model to investigate the dynamic process of virus engulfment retarded by the creep deformation of cytoskeleton and driven by the binding of ligand-receptor bonds after overcoming resistance from elastic deformation of lipid membrane and cytoskeleton.Based on this new model,we predict the lower bound of the ligand density and the range of virus size that allows the complete engulfment,and an optimal virus size corresponding to the smallest wrapping time.Surprisingly,these predictions can be reduced to the previous predictions based on simplified membrane models by taking into account statistical thermodynamic effects.The results presented in this study may be of interest to toxicologists,nanotechnologists,and virologists.
This paper aims at developing a stochastic-elastic model of a soft elastic body adhering on a wavy surface via a patch of molecular bonds.The elastic deformation of the system is modeled by using continuum contact mechanics,while the stochastic behavior of adhesive bonds is modeled by using Bell's type of exponential bond association/dissociation rates.It is found that for sufficiently small adhesion patch size or stress concentration index,the adhesion strength is insensitive to the wavelength but decreases with the amplitude of surface undulation,and that for large adhesion patch size or stress concentration index,there exist optimal values of the surface wavelength and amplitude for maximum adhesion strength.
This study intends to investigate how the elasticity of a bacterial phage can afect the process of DNA packaging and ejection.For this purpose,we propose a unified continuum and statistical mechanics model by taking into account the efects of DNA bending deformation,electrostatic repulsion between DNA–DNA strands and elastic deformation of the phage capsid.Based on such a model,we derive the quantitative relations between packaging force,elasticity of capsid,DNA length remaining in the capsid,osmotic pressure and ejection time.The theoretically predicted results are found to agree very well with in vitro experimental observations in the literature.
