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Polymer domains, gelation models and sickle cell crises.
Progress in Clinical and Biological Research
|January 1, 1987
Summary
Sickle hemoglobin fibers form ordered domains. Laser photolysis reveals two polymerization phases: early asymmetric growth with increasing density, followed by symmetric domain maturation and uniform changes in light scattering and birefringence.
Area of Science:
- Biophysics
- Hematology
- Polymer Science
Background:
- Deoxygenated sickle hemoglobin polymerizes into fibers.
- These fibers form ordered spherulitic arrays known as domains.
- Understanding domain formation is crucial for sickle cell disease research.
Purpose of the Study:
- To investigate the spatial and temporal evolution of sickle hemoglobin domains.
- To characterize the distinct phases of domain formation and growth.
- To correlate changes in light scattering and birefringence during polymerization.
Main Methods:
- Laser photolysis of carboxy-sickle hemoglobin to initiate polymerization.
- Real-time monitoring of domain formation using light scattering and birefringence.
- Image analysis of a 62.5-micron square area with 2500 discrete elements.
Main Results:
- Domain formation occurs in two distinct phases.
- Early phase: asymmetric growth and increasing internal polymer density (light scattering intensity).
- Second phase: structural symmetry, spatial homogeneity, uniform scattering changes, and coupled increases in birefringence with decreasing scattering.
Conclusions:
- Sickle hemoglobin domain formation is a dynamic, multi-phase process.
- The observed phases suggest distinct mechanisms governing structural organization and polymer density.
- Birefringence and light scattering provide complementary insights into domain maturation.