Building Polyvalent DNA‐Functionalized Anisotropic AuNPs using Poly‐Guanine‐Mediated <i>In‐Situ</i> Synthesis for LSPR‐Based Assays: Case Study on OncomiR‐155
Yasaman‐Sadat Borghei, Saman Hosseinkhani
Abstract
ABSTRACT DNA‐functionalized gold nanoparticles (DNA‐AuNPs) hold great promise for numerous biomedical applications, especially the building of well‐defined nanosystems. Previously reported methods for the preparation of DNA‐AuNPs all rely on the use of DNA‐bearing free thiol or disulfide groups at their 3′/5′ ends. But here we report a novel polyvalent DNA‐AuNPs conjugation approach by in‐situ fast synthesis of AuNPs at the polyguanine (G 12 ) strands. As confirmed by both TEM images and gel electrophoresis analysis, many poly G strand can form an individual anisotropic AuNP and so each AuNP functionalized with a dense layer of DNA, resulting in the formation of polyvalent (p)DNA–AuNPs. The general applicability of this novel approach was further verified in hybridization test and UV‐Vis spectroscopy results show that pDNA–AuNPs conjugation is more attractive in biomedical diagnosis and specific sequence detection like microRNA‐155 by using an extra‐strand poly G with “sticky end” that are complementary to the target sequence.