G-rich oligonucleotide-functionalized gold nanoparticle aggregation.
Guanine-rich DNA sequences commonly form helical quadruplex structures via Hoogsteen hydrogen bonds. The aggregation behavior of the nanoparticles, which are functionalized with four-guanine-terminated 27-base sequences at a nanoparticle-to-DNA ratio of 1:60, is investigated. To some extent, the guanine-quadruplex structures between the gold nanoparticles (GNPs) promote nanoparticle aggregation. However, the coordination site of the metal ion on the nanoparticle surface is partially passivated: the stability of guanine-rich DNA-GNPs is slightly lower than that of the usual DNA-GNPs, and the metal-ion specificity of nanoparticle assembly is substantially decreased. Thus, a mechanism for the aggregation of guanine-rich sequence-modified GNPs is proposed. It is possible to obtain a stable guanine-rich sequence-functionalized nanoparticle solution at high ionic strength by regulating guanine-rich DNA sequences. The controllability of guanine-rich sequence-modified nanoparticles makes the secondary structure of DNA a potentially useful candidate for DNA analysis and disease diagnostics. Figure Proposed mechanism for the aggregation of G-rich sequence-functionalized GNP.
Wu
Zai-Sheng
ZS
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Guo
Meng-Meng
MM
Shen
Guo-Li
GL
Yu
Ru-Qin
RQ
D001483:Base Sequence; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles; D009841:Oligonucleotides / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
D009841:Oligonucleotides; D006046:Gold