Plastic deformation of erythrocyte membrane in full-term neonates and adults

Abstract

This paper presents a new micropipette technique to study tether formation (i.e. membrane fragility) of individual red blood cells (RBC). Point attached adult and full-term neonatal RBC were aspirated at different negative pressures into a large micropipette with an internal diameter of 7.8 μm. We measured the onset of tether formation at aspiration pressures of −3 and −5 mm H₂O and the length of the membrane tethers after 2, 5, 10, 15, 20, 25, and 30 s. The minimum aspiration pressure for tether formation was −3 mm H₂O for neonatal and −5 mm H₂O for adult RBC. At a pressure of −5 mm H₂O tether formation began after 10.3 ± 5.4 s in adults and 4.1 ± 2.8 s in full-term neonates. 25 s after the beginning of tether formation, the tether lengths were 14.0 ± 3.9 μm for adult RBC and 21.1 ± 4.7 μm for neonatal RBC. We conclude that plastic deformation of neonatal RBC begins at lower pressure and is faster compared with adult RBC.