Fe^3＋离子修饰的金纳米粒子对DNA的高效吸附

在谷胱甘肽功能化的金纳米粒子表面螯合Fe^3＋离子后,研究了DNA分子在不同p H和盐浓度条件下在粒子表面的吸附和脱附行为。在pH〈4.0的条件下,DNA通过所含的磷酸根基团与粒子表面的Fe^3＋离子产生配位相互作用而吸附到粒子表面,此过程受盐浓度影响不大。当pH〉4.0时,由于溶液中氢氧根离子的竞争作用,使DNA的磷酸根基团不能与Fe^3＋离子配位,此时只能通过静电或氢键作用吸附,但是吸附效率很低。因此,Fe^3＋离子修饰的金纳米粒子只在低p H条件下可以实现对DNA的高效吸附。这种基于配位作用的吸附效率要高于盐桥作用,而且不会受到溶液中盐浓度的影响。

Highly Efficient Adsorption of DNA on Fe3+Modified Au Particles

Glutathione modified gold nanoparticles were charged with Fe^3＋,then the adsorption and desorption behaviors of DNA on the particle surface at different p H and different salt concentration were investigated. At p H 4. 0,DNA could be adsorbed efficiently on the particle surface driven by the coordination interactions between the Fe^3＋ions and phosphate groups of DNA,which was almost not affected by the salt concentration in the solutions. At pH 〉4. 0,the Fe^3＋ions can＇t coordinated with phosphate groups of DNA because of the competition of OH^-ions and the adsorption was driven by electrostatic interaction or hydrogen bond,which showed low eficiency. Only at lower pH,DNA could be adsorbed efficiently on the particles surface driven by the coordination interactions which provided higher efficient adsorption than driven by the salt bridges,and was almost not affected by the salt concentration in the solutions.