Role of Electrostatic Interactions in Two Dimensional Self Assembly of Tobacco Mosaic Viruses on Cationic Lipid Mololayers
We explore two-dimensional self-assembly of tobacco mosaic viruses (TMVs) on a substrate-supported, fluid lipid monolayer by manipulating the electrostatic interactions, with specific focus on the effects of the cationic lipid concentration in the monolayer and the presence of Ca{sup 2+} ions in the surrounding bulk solution. The TMV assemblies were characterized by grazing-incidence X-ray scattering and atomic force microscopy, and the inter-particle interaction quantified through X-ray scattering data analysis. In the absence of Ca{sup 2+} ions, we found that higher charge densities on the lipid monolayer led to poorer in-plane order, which may be attributed to faster adsorption kinetics, due to the surface potential that increases with charge density. At the same time, higher lipid-charge densities also resulted in weaker repulsion between TMVs, due to partial screening of Coulomb repulsion by mobile cationic lipids in the monolayer. The lipid-charge dependence was diminished with increasing concentration of Ca{sup 2+} ions, which also led to tighter packing of TMVs. The results indicate that Ca{sup 2+} ions strengthen the screening of Coulomb repulsion between TMVs and consequently enhance the role of attractive forces. Control experiments involving Na{sup +} ions suggest that the attractive inter-TMV interaction has contributions from both the van der Waals force and the counter-ion-induced attraction that depends on ion valence.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- DOE - OFFICE OF SCIENCE
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1019506
- Report Number(s):
- BNL-95156-2011-JA; R&D Project: LS001; KC0401030; TRN: US201115%%179
- Journal Information:
- Journal of Collid and Interface Science, Vol. 358, Issue 2; ISSN 0021-9797
- Country of Publication:
- United States
- Language:
- English
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