Synergetic Approach for Simple and Rapid Conjugation of Gold Nanoparticles with Oligonucleotides

Abstract

Attaching thiolated DNA on gold nanoparticles (AuNPs) has been extremely important in nanobiotechnology because DNA-AuNPs combine the programmability and molecular recognition properties of the biopolymers with the optical, thermal, and catalytic properties of the inorganic nanomaterials. However, current standard protocols to attach thiolated DNA on AuNPs involve time-consuming, tedious steps and do not perform well for large AuNPs, thereby greatly restricting applications of DNA-AuNPs. Here we demonstrate a rapid and facile strategy to attach thiolated DNA on AuNPs based on the excellent stabilization effect of mPEG-SH on AuNPs. AuNPs are first protected by mPEG-SH in the presence of Tween 20, which results in excellent stability of AuNPs in high ionic strength environments and extreme pHs. A high concentration of NaCl can be applied to the mixture of DNA and AuNP directly, allowing highly efficient DNA attachment to the AuNP surface by minimizing electrostatic repulsion. The entire DNA loading process can be completed in 1.5 h with only a few simple steps. DNA-loaded AuNPs are stable for more than 2 weeks at room temperature, and they can precisely hybridize with the complementary sequence, which was applied to prepare core-satellite nanostructures. Moreover, cytotoxicity assay confirmed that the DNA-AuNPs synthesized by this method exhibit lower cytotoxicity than those prepared by current standard methods. The proposed method provides a new way to stabilize AuNPs for rapid and facile loading thiolated DNA on AuNPs and will find wide applications in many areas requiring DNA-AuNPs, including diagnosis, therapy, and imaging.

Selective single molecule nanopore sensing of proteins using DNA aptamer-functionalised gold nanoparticles

“…48–50 The sequence of the lysozyme-binding aptamer (LBA) 51,52 (shown in Fig. 1C) included a spacer of 10 thymine bases (underlined) to minimize the steric hindrance from AuNPs when LBA bound with lysozyme.…”

“…To improve stability and enable better control of the surface aptamer concentration, the AuNPs were modified with PEG-thiol (MW 1000). 50 The concentration of both PEG-thiol and the lysozyme binding aptamer (LBA) were optimized to yield a final AuNP to aptamer ratio of 2 : 1 and quantified using a fluorescence based assay (Fig. S2†).…”

In Situ Growth of Plasmonic Gold Nanoparticles for the Direct and Sensitive Colorimetric Assay of Glucose

“…Compared with the spectrum of formed Au NPs in the sensing condition containing Tween‐20, absorbance behavior of the Au NPs without Tween‐20 centered at 640 nm with a broader shape. The red‐shift and broader absorbance spectrum illustrated that the corresponding generated Au NPs ascribed by glucose would aggregate without Tween‐20 . Obviously, Tween‐20 plays an important role in stabilizing the Au NPs for colorimetric sensing.…”

RNA interference for glioblastoma therapy: Innovation ladder from the bench to clinical trials

“…AuNPs have shown to possess feasible characteristics for diagnostic, imaging, and therapy. The surface of AuNPs can enable multiple coupling with drugs, CNS-specific ligands and oligonucleotides [175,176]. In fact, thiolated nucleic acids can be covalently attached to the AuNPs and therefore facilitate their delivery to brain tumors.…”