Specific binding of different vesicle populations by the hybridization of membrane-anchored DNA
Specific binding of different vesicle populations by the hybridization of membrane-anchored DNA
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DOI：
10.1021/jp075792z
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发表时间：
2007-12-13
影响因子：
2.9
通讯作者：
Vanderlick, T. Kyle
中科院分区：
文献类型：
--
作者：
Beales, Paul A.;Vanderlick, T. Kyle
我们展示了一种利用膜锚定的单链DNA进行异质囊泡结合的方法，这种方法可以在囊泡大小上使用几个数量级，如100纳米的大囊泡和直径几微米的巨囊泡。研究了DNA表面浓度和溶液离子强度范围内的聚集行为。在两个囊泡大小尺度上观察到三种类似的聚集状态。我们通过DNA结合有利性、囊泡碰撞动力学和DNA在液膜内的横向扩散来解释这三种机制的存在。DNA杂交的可逆性允许形成的结构解离，并且可以通过热或通过降低外部水环境的离子强度来实现。用热脱杂的方法完全解除大囊泡的结合是有困难的，这可能是由于DNA结合使膜间电位达到有吸引力的范德华极小值所造成的。这一障碍可以通过溶液离子强度的等温降低来克服：这减少了德拜筛选长度，耦合了DNA去杂交和膜间斥力的影响，这是由于高电荷DNA骨干之间静电斥力的增加。
We demonstrate a method of heterogeneous vesicle binding using membrane-anchored, single-stranded DNA that can be used over several orders of magnitude in vesicle size, as demonstrated for large 100 nm vesicles and giant vesicles several microns in diameter. The aggregation behavior is studied for a range of DNA surface concentrations and solution ionic strengths. Three analogous states of aggregation are observed on both vesicle size scales. We explain the existence of these three regimes by a combination of DNA binding favorability, vesicle collision kinetics, and lateral diffusion of the DNA within the fluid membrane. The reversibility of the DNA hybridization allows dissociation of the structures formed and can be achieved either thermally or by a reduction in the ionic strength of the external aqueous environment. Difficulty is found in fully unbinding giant vesicles by thermal dehybridization, possibly frustrated by the attractive van der Waals minimum in the intermembrane potential when brought into close contact by DNA binding. This obstacle can be overcome by the isothermal reduction of the ionic strength of the solution: this reduces the Debye screening length, coupling the effects of DNA dehybridization and inter-membrane repulsion due to the increased electrostatic repulsion between the highly charged DNA backbones.