配体交换调控纳米金表面寡核苷酸自组装

Regulating Self-Assembly of Oligonucleotide on Gold Nanoparticles by Ligand-Exchange

以4-巯基苯甲酸(MBA)为调控分子,对照巯基己醇(MCH),基于配体交换法对纳米金(10nm)表面的寡核苷酸(DNA)自组装进行调控,并用凝胶电泳进行表征。结果表明,在纳米金表面,MCH能完全取代DNA。当MCH与纳米金的摩尔比达到2400:1后,纳米金发生凝聚,MBA不能完全取代DNA;MBA和DNA的二元组装层能使纳米金在水溶液中稳定分散。另外用DNA取代MBA的反应比用MBA取代DNA的反应更容易进行。

Agarose gel electrophoresis was used to characterize the results of ligand-exchange. The ligand- exchange strategy was used to regulate the self-assembly of oligonucleotide on 10 nm gold nanoparticles with 4-mercaptobenzoic acid （MBA） and 6-mercapto-l-hexanol （ MCH）, as the regulating molecule. The results show that the naked gold nanoparticles modified with MCH lead to irreversible aggregation but the gold nanop- articles modified with DNA and MBA are stable in solution, which impliedes that the negative charge of DNA and MBA molecules is critical in stabilizing gold nanoparticles. Both MBA and MCH can replace DNA on the surface of gold nanoparticles. The difference is that MCH can thoroughly replace the DNA on the surface of gold nanoparticles but MBA could not. At the molar ratio of MCH/gold nanoparticles = 2400/1, the aggrega- tion of gold nanoparticles is found. It is also found that the ligand-exchange reaction of using MBA as in-coming ligands and DNA as out-coming ligands is much difficult than using DNA as in-coming ligands and MBA as out-coming ligands.