Ionic, Structural, and Temperature Effects on DNA Nanoparticles Formed by Natural and Synthetic Polyamines
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- 作者：Veena Vijayanathan ; Jasleen Lyall ; Thresia Thomas ; Akira Shirahata ; and T. J. Thomas
- 刊名：Biomacromolecules
- 出版年：2005
- 出版时间：March 2005
- 年：2005
- 卷：6
- 期：2
- 页码：1097 - 1103
- 全文大小：176K
- 年卷期：v.6,no.2(March 2005)
- ISSN：1526-4602
文摘
We synthesized analogues of spermine and studied the effects of chemical structure, ionic strength, andtemperature on 
-DNA nanoparticle formation. Effective concentration of polyamines for DNA condensation(EC50) was lowest for hexamines (0.2 
M) and highest for spermine (tetramine, 4.2 M). The EC50 valueincreased with [Na+]. Dynamic light scattering showed nanoparticles with hydrodynamic radii (Rh) of 40-50 nm. Effect of temperature on Rh was measured between 20 and 70 
C. For spermine, Rh remained relativelystable until 50 C and increased significantly at >60 C. In contrast, the hexa- and penta-valent analoguesexhibited a gradual increase in Rh between 20 and 70 C. The nanoparticles were mainly toroidal, as revealedby electron microscopy (EM). EM studies showed changes in morphology and size of condensed structureswith an increase in temperature. A possible mechanism for the differential effects of temperature on DNAnanoparticles might involve different modes of DNA-polyamine interactions.
-DNA nanoparticle formation. Effective concentration of polyamines for DNA condensation(EC50) was lowest for hexamines (0.2 M) and highest for spermine (tetramine, 4.2 M). The EC50 valueincreased with [Na+]. Dynamic light scattering showed nanoparticles with hydrodynamic radii (Rh) of 40-50 nm. Effect of temperature on Rh was measured between 20 and 70 C. For spermine, Rh remained relativelystable until 50 C and increased significantly at >60 C. In contrast, the hexa- and penta-valent analoguesexhibited a gradual increase in Rh between 20 and 70 C. The nanoparticles were mainly toroidal, as revealedby electron microscopy (EM). EM studies showed changes in morphology and size of condensed structureswith an increase in temperature. A possible mechanism for the differential effects of temperature on DNAnanoparticles might involve different modes of DNA-polyamine interactions.