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Modeling the relative dynamics of DNA-coated colloids.
James P Lee-Thorp1, Miranda Holmes-Cerfon1
1Courant Institute of Mathematical Sciences, New York University, 251 Mercer St., New York, NY 10012, USA. holmes@cims.nyu.edu.
Soft Matter
|September 28, 2018
Summary
We developed a theoretical model for microscale colloidal particles on DNA surfaces. DNA-induced friction can be significantly higher than hydrodynamic friction, impacting particle dynamics and assembly.
Area of Science:
- Theoretical physics
- Materials science
- Biophysics
Background:
- Colloidal particles interacting with DNA surfaces are crucial in nanotechnology and biophysics.
- Understanding the friction dynamics is essential for controlling particle behavior.
Purpose of the Study:
- To develop a theoretical model for microscale colloidal particle dynamics on DNA-coated surfaces.
- To quantify DNA-induced friction and compare it with hydrodynamic friction.
- To investigate the influence of DNA properties and relative motion on friction.
Main Methods:
- Constructed a theoretical model for a microscale colloidal particle (interval) on a DNA-coated surface (line with springs).
- Averaged over fast DNA dynamics to derive an evolution equation including friction and diffusion.
- Used a mean-field extension to higher dimensions to estimate the friction tensor for a rotating and translating disc.
- Analyzed friction coefficients for different DNA properties (stiffness, length) and motion types (rolling vs. sliding).
Main Results:
- The derived evolution equation includes both friction and diffusion.
- DNA-induced friction coefficient is approximately 100 times larger than hydrodynamic friction for typical parameters.
- Friction for a disc rolling on short, stiff DNA approaches zero, while sliding friction remains high.
- Friction depends non-trivially on the type of relative motion.
Conclusions:
- DNA-induced friction can dominate over hydrodynamic friction in colloidal systems.
- This friction must be incorporated into simulations of DNA-coated colloids and ligand-receptor systems.
- The type of relative motion significantly affects friction, potentially guiding particle assembly into metastable states.
- Results suggest new possibilities for controlling colloidal self-assembly through friction pathways.
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