TY - JOUR
T1 - Nucleation and growth of fibres and gel formation in sickle cell haemoglobin
AU - Samuel, Raymond E.
AU - Salmon, E. D.
AU - Briehl, Robin W.
PY - 1990
Y1 - 1990
N2 - DEOXYGENATED sickle haemoglobin polymerizes into long 210-Å diameter fibres that distort and decrease the deformability of red blood cells, and cause sickle cell disease. The fibres consist of seven intertwined double strands1-3. They can form birefringent nematic liquid crystals (tactoids)4 and spherulites5,6. Rheologiealiy, the system behaves as a gel7,8. The equilibria show a phase separation and a solubility9-14. The reaction kinetics show a delay time, are then roughly exponential and are highly dependent on concentration and temperature9,10,15-18, and accord with the double nucleation model5,19. But these conclusions are derived from macroscopic data, without direct observation of individual fibres. We have now used non-invasive video-enhanced differential interference contrast (DIC) and dark-field microscopy to observe nucleation, growth and interaction of sickle deoxyhaemoglobin fibres in real time. The fibres originate both from centres that produce many radially distributed fibres and on the surface of pre-existing fibres, from which they then branch. The resulting network is cross-linked and dynamic in that it is flexible and continues to grow and cross-link. Our results support most aspects of the double nucleation model.
AB - DEOXYGENATED sickle haemoglobin polymerizes into long 210-Å diameter fibres that distort and decrease the deformability of red blood cells, and cause sickle cell disease. The fibres consist of seven intertwined double strands1-3. They can form birefringent nematic liquid crystals (tactoids)4 and spherulites5,6. Rheologiealiy, the system behaves as a gel7,8. The equilibria show a phase separation and a solubility9-14. The reaction kinetics show a delay time, are then roughly exponential and are highly dependent on concentration and temperature9,10,15-18, and accord with the double nucleation model5,19. But these conclusions are derived from macroscopic data, without direct observation of individual fibres. We have now used non-invasive video-enhanced differential interference contrast (DIC) and dark-field microscopy to observe nucleation, growth and interaction of sickle deoxyhaemoglobin fibres in real time. The fibres originate both from centres that produce many radially distributed fibres and on the surface of pre-existing fibres, from which they then branch. The resulting network is cross-linked and dynamic in that it is flexible and continues to grow and cross-link. Our results support most aspects of the double nucleation model.
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U2 - 10.1038/345833a0
DO - 10.1038/345833a0
M3 - Article
C2 - 2359460
AN - SCOPUS:0025284406
SN - 0028-0836
VL - 345
SP - 833
EP - 835
JO - Nature
JF - Nature
IS - 6278
ER -