Stimuli-sensitive thin films prepared by a layer-by-layer deposition of 2-iminobiotin-labeled poly(ethyleneimine) and avidin
Stimuli-sensitive thin films prepared by a layer-by-layer deposition of 2-iminobiotin-labeled poly(ethyleneimine) and avidin
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DOI：
10.1021/la0508341
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发表时间：
2005-08-30
期刊：
影响因子：
3.9
通讯作者：
Anzai, J
中科院分区：
文献类型：
--
作者：
Inoue, H;Anzai, J
通过在固体表面逐层沉积亲和素和2-亚胺生物素标记的聚乙烯亚胺(ib-PEI)，制备了由亲和素和2-亚胺-生物素标记的聚乙烯亚胺(ib-PEI)组成的层状薄膜，并研究了改变环境pH值和在溶液中加入生物素对其崩解的影响。亲和素/ib-PEI层状膜只能在pH为10-12的溶液中沉积。由于ib-PEI中的质子化2-亚胺生物素残基与亲和素的亲和力较低，因此在pH为9或更高的酸性介质中不能形成膜。亲和素/ib-PEI层状膜在pH为8-12的溶液中是稳定的，而在pH为5-7的介质中，膜由于质子化为ib-PEI中的2-亚胺-生物素残基而自发分解。在溶液中加入生物素或类似物时，由于生物素或类似物优先结合到亲和素的结合部位，亲和素/ib-PEI膜也会解体。通过改变刺激剂的类型(生物素或类似物)及其浓度来任意控制分解速度。加入10(-5)M的生物素或去硫生物素可使亲和素/ib-PEI膜迅速崩解，而加入相同浓度的硫辛酸或2-(4‘-羟基苯偶氮)苯甲酸则崩解速度较慢。在10(-3)M硫辛酸或2-(4‘-羟基苯偶氮)苯甲酸溶液中，膜在1min内完全分解。因此，分解速度高度依赖于刺激剂的浓度。结果表明，由于质子化的2-亚胺生物素对亲和素的亲和力较低，因此在pH为12的条件下，膜在刺激下的分解较慢，而在pH为8的介质中，膜的分解速度较快。本系统可用于构建能够释放药物或其他功能分子的刺激敏感设备。
Layered thin films composed of avidin and 2-iminobiotin-labeled poly(ethyleneimine) (ib-PEI) were prepared by a layer-by-layer deposition of avidin and ib-PEI on a solid surface, and the disintegration induced by changing environmental pH and adding biotin in the solution was studied. The avidin/ib-PEI layered film could be deposited only from the solutions of pH 10-12. The film did not form in pH 9 or more acidic media because of a low affinity of protonated 2-iminobiotin residues in ib-PEI to avidin. The avidin/ ib-PEI layered films were stable in pH 8-12 solutions, while in pH 5-7 media the film decomposed spontaneously as a result of the protonation to 2-iminobiotin residues in ib-PEI. The avidin/ib-PEI films were disintegrated also upon addition of biotin and analogues in the solution owing to the preferential binding of biotin or analogues to the binding site of avidin. The decomposition rate was arbitrarily controlled by changing the type of stimulant (biotin or analogues) and its concentration. The avidin/ib-PEI films were disintegrated rapidly by addition of 10(-5) M of biotin or desthiobiotin, while the rate was slower upon adding the same concentration of lipoic acid or 2-(4'-hydroxyphenylazo)benzoic acid. On the other hand, the film was fully decomposed within 1 min in the 10(-3) M lipoic acid or 2-(4'-hydroxyphenylazo)benzoic acid solution. Thus, the decomposition rate is highly dependent on the concentration of the stimulants. It was observed that the stimuli-induced decomposition of the films is slow at pH 12, in contrast to a rapid decomposition in pH 8 medium due to a low affinity of the protonated 2-iminobiotin to avidin. The present system may be useful for constructing stimuli-sensitive devices that can release drug or other functional molecules.