- Tran-Son-Tay, R. and Needham, D. and Yeung, A. and Hochmuth, R.M., Time-dependent recovery of passive neutrophils after large deformation,
Biophys. J. (USA), vol. 60 no. 4
pp. 856 - 66 .
(last updated on 2007/04/10)
Experiments are performed in which a passive human neutrophil is deformed into an elongated `sausage' shape by aspirating it into a small glass pipette. When expelled from the pipette the neutrophil recovers its natural spherical shape in ~1 minute. This recovery process is analyzed according to a Newtonian, liquid-drop model in which a variational method is used to simultaneously solve the hydrodynamic equations for low Reynolds-number flow and the equations for membrane equilibrium with a constant membrane tension. The theoretical model gives a good fit to the experimental data for a ratio of membrane cortical tension to cytoplasmic viscosity of ~1.7×10-5 cm/s (0.17 μm/s). However, when the cell is held in the pipette for only a short time period of 5 s or less, and then expelled, the cell undergoes an initial, rapid elastic rebound suggesting that the cell behaves in this instance as a Maxwell viscoelastic liquid rather than a Newtonian liquid with constant cortical tension