Graphene Oxide-Assisted Nucleic Acids Assays Using Conjugated Polyelectrolytes-Based Fluorescent Signal Transduction

Abstract

In this work, we investigated the interactions between graphene oxide (GO) and conjugated polyelectrolytes (CPEs) with different backbone and side chain structures. By studying the mechanism of fluorescence quenching of CPEs by GO, we find that the charge and the molecular structure of CPEs play important roles for GO-CPEs interactions. Among them, electrostatic interaction, π-π interaction, and cation-π bonding are dominant driving forces. By using a cationic P2, we have developed a sensitive homogeneous sensor for DNA and RNA detection with a detection limit of 50 pM DNA and RNA, which increased the sensitivity by 40-fold as compared to GO-free CPE-based sensors. This GO-assisted CPE sensing strategy is also generic and shows a high potential for biosensor designs based on aptamers, proteins, peptides, and other biological probes.

Visual Detection of Multiplex MicroRNAs Using Cationic Conjugated Polymer Materials

“…4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) was obtained from Sigma. The cationic poly­[(9,9-bis­(6′- N , N , N -trimethylammonium)­hexyl) fluorenylene phenylene dibromide] used as the CCP in the FRET experiments was prepared as described in the literature . All the oligonucleotides purified by HPLC were synthesized by TaKaRa Biotechnology Co., Ltd. (Dalian, China).…”

“…T h e c a t i o n i c p o l y [ ( 9 , 9 -b i s ( 6 ′ -N , N , Ntrimethylammonium)hexyl) fluorenylene phenylene dibromide] used as the CCP in the FRET experiments was prepared as described in the literature. 38 All the oligonucleotides purified by HPLC were synthesized by TaKaRa Biotechnology Co., Ltd. (Dalian, China). The sequences of the probes and targets are listed in Table S1.…”

“…Cationic conjugated polymers (CCPs) with their powerful light-harvesting and signal amplification abilities provide a versatile detection platform for bioanalysis and biosensing. − Water-soluble CCPs as optical probes have increasingly been developed through the colorimetric and fluorometric assay for metal ions, proteins, and nucleic acids, etc. − Typically, CCPs are easy to bind with negatively charged nucleic acids via electrostatic interactions. Therefore, efficient fluorescence resonance energy transfer (FRET) can occur from CCPs to fluorophores labeled in oligonucleotide probes, which advances many homogeneous and sensitive nucleic acid detections.…”

Development of ssDNA Aptamers for Diagnosis and Inhibition of the Highly Pathogenic Avian Influenza Virus Subtype H5N1

“…Prior to characterization, the fluorescence-quenching conditions of the FAM-labeled aptamers on rGO were optimized. rGO can adsorb ssDNA through electrostatic and π−π stacking interactions [27]. Furthermore, rGO was able to adsorb the fluorescent molecules and quench the fluorescence signal, which could be applied to a sensitive detection system.…”

Fluorometric detection of mutant DNA oligonucleotide based on toehold strand displacement-driving target recycling strategy and exonuclease III-assisted suppression

“…The toehold initiated hybridization, which can enhance the rate of the SDR by a fold of 10 6 , is triggered by the overhang toehold, to which the target sequence attaches and then compels the former matched branch migrate away, forming a more thermodynamically stable duplex (Genot et al, 2011). To realize the recycling amplification, a pair of partially complementary DNA hairpins (HP 1 and HP 2 ) is admirably designed and applied (Feng et al, 2013;Zhang et al, 2013;Li et al, 2015a). Briefly, the spontaneous hybridization between the paired hairpins is kinetically blocked by the stems.…”