Ligand-Receptor Interactions in Chains of Colloids: When Reactions Are Limited by Rotational Diffusion
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- 作者：Nam-Kyung Lee ; Albert Johner ; Fabrice Thalmann ; Laetitia Cohen-Tannoudji ; Emanuel Bertrand ; Jean Baudry ; Jé ; rô ; me Bibette ; Carlos M. Marques
- 刊名：Langmuir
- 出版年：2008
- 出版时间：February 19, 2008
- 年：2008
- 卷：24
- 期：4
- 页码：1296 - 1307
- 全文大小：491K
- 年卷期：v.24,no.4(February 19, 2008)
- ISSN：1520-5827
文摘
We discuss the theory of ligand receptor reactions between two freely rotating colloids in close proximity to oneother. Such reactions, limited by rotational diffusion, arise in magnetic bead suspensions where the beads are driveninto close contact by an applied magnetic field as they align in chainlike structures. By a combination of reaction-diffusion theory, numerical simulations, and heuristic arguments, we compute the time required for a reaction to occurin a number of experimentally relevant situations. We find in all cases that the time required for a reaction to occuris larger than the characteristic rotation time of the diffusion motion 
rot. When the colloids carry one ligand only anda number n of receptors, we find that the reaction time is, in units of rot, a function simply of n and of the relativesurface 
occupied by one reaction patch = 
rC2/(4r2), where rC is the ligand receptor capture radius and r is theradius of the colloid.
rot. When the colloids carry one ligand only anda number n of receptors, we find that the reaction time is, in units of rot, a function simply of n and of the relativesurface occupied by one reaction patch = rC2/(4r2), where rC is the ligand receptor capture radius and r is theradius of the colloid.