Noncovalent Assembly of Carbon Nanotubes and Single-Stranded DNA: An Effective Sensing Platform for Probing Biomolecular Interactions

TLDR

The study develops a new class of fluorescent biosensors based on single‑walled carbon nanotubes and single‑stranded DNA to probe biomolecular interactions in a homogeneous format. The sensing platform relies on SWNTs interacting with dye‑labeled DNA oligonucleotides that quench fluorescence until a target displaces the DNA, restoring signal, allowing detection by fluorescence spectroscopy and quantified by anisotropy and intensity measurements for DNA hybridization and aptamer‑protein interactions.

Abstract

In this paper, we report the assembly of single-walled carbon nanotubes (SWNTs) and single-stranded DNA to develop a new class of fluorescent biosensors which are able to probe and recognize biomolecular interactions in a homogeneous format. This novel sensing platform consists of a structure formed by the interaction of SWNTs and dye-labeled DNA oligonucleotides such that the proximity of the nanotube to the dye effectively quenches the fluorescence in the absence of a target. Conversely, and very importantly, the competitive binding of a target DNA or protein with SWNTs for the oligonucleotide results in the restoration of fluorescence signal in increments relative to the fluorescence without a target. This signaling mechanism makes it possible to detect the target by fluorescence spectroscopy. In the present study, the schemes for such fluorescence changes were examined by fluorescence anisotropy and fluorescence intensity measurements for DNA hybridization and aptamer−protein interaction studies.