Sequence specific nucleic acid sensing by pyrrolidinyl peptide nucleic acid and nanomaterials

Abstract

In this work, fluorescence and colorimetric nucleic acid sensing platforms based on pyrrolidinyl peptide nucleic acid (acpcPNA) probe and nanomaterials including graphene oxide (GO), reduced graphene oxide (rGO), gold nanoparticles (AuNPs), and silver nanoparticles (AgNPs) were developed. The acpcPNA probe was modified by multiple lysine residues to provide positive charges which enhanced the adsorption of the probe to various types of nanomaterials. In fluorescence detection mode, this results in higher quenching efficiency, resulting in lower background signal. Recovery of the quenched fluorescence signal was achieved upon hybridization with the complementary DNA/RNA target due to the displacement of the probe from the nanomaterials surface. When gold nanoparticles were employed as the nanomaterials, adsorption of acpcPNA probe caused a distinct red-to-purple color change in addition to the fluorescence quenching. No color and fluorescence change was observed if the PNA probe was previously hybridized with DNA/RNA targets, therefore the presence of complementary DNA or RNA targets could be visually observed. In all cases, single mismatch specificity and low detection limits in the sub-nanomolar levels were achieved. This nucleic acid detection platform therefore offers a simple, rapid, cost-effective, sensitive, and selective detection of DNA and RNA targets, and has been applied to the detection of real DNA samples.