Assembling AuNPs onto Aligned DNA Molecules

The interaction of MNPs with DNA is a well-known phenomenon [86-89], and single- or double-strand DNA is decorated by MNPs, which can easily be imaged by transmission electron microscopy (TEM) or AFM [90-92]. Various surface-functionalized AuNPs have been prepared to attach AuNPs securely to DNA molecules. In numerous studies, such AuNPs were prepared by surface modifications with cationic thiols [54, 55, 92] or intercalators [93, 94]. The ID chains of AuNPs coated with cationic trimethyl(mercaptoundecyl) ammonium monolayers were electrostatically assembled along DNA molecules in solution by the relative molar quantities of AuNPs and DNA base pairs. Since psoralen acts as a specific intercalator for A-T base pairs, the functionalized AuNPs were assembled onto the pA-pT ds-DNA [93]. Furthermore, UV irradiations induced the reaction between the psoralen units and the thymine of DNA, and then covalently fixed AuNPs to the DNA. 

Recently, we reported a one-step preparation of surface-functionalized AuNPs without ligand exchange [95]. Novel surface-functionalized AuNPs (AN-AuNPs) were prepared based on the conventional reduction of HAuCU using aniline as a reducer, so that the AN-AuNPs had a positive charge and an aromatic ring on 

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