Magnetically assisted DNA assays: high selectivity using conjugated polymers for amplified fluorescent transduction

Abstract

We report a strategy for conjugated polymer (CP)-based optical DNA detection with improved selectivity. The high sensitivity of CP-based biosensors arises from light harvesting by the CP and the related amplified fluorescent signal transduction. We demonstrate that the use of magnetic microparticles significantly improves the selectivity of this class of DNA sensors. Compared with previously reported DNA sensors with CP amplification, this novel sensing strategy displays excellent discrimination against non-cognate DNA in the presence of a protein mixture or even human serum. We also demonstrate that the magnetically assisted DNA sensor can conveniently identify even a single-nucleotide mismatch in the target sequence.

Comparative Analysis of Fluorescence Reporter Signals Based on Intensity, Anisotropy, Time-Resolution, and Wavelength-Ratiometry

“…Since this distance is comparable with the dimensions of many biological macromolecules and of their complexes, many possibilities can be realized for coupling the response with the changes in sensor geometry. The most popular approaches use conformational change in double labeled sensor [29], enzymatic splitting of covalent bond between two labeled units [30] and competitive substitution of labeled competitor in a complex with labeled sensor [31].…”

Labeling-free fluorescent detection of DNA hybridization through FRET from pyrene excimer to DNA intercalator SYBR green I

“…Homogeneous DNA hybridization assays based on fluorescence resonance energy transfer (FRET) between energy-transfer chromophore pairs are attractive because of their simplicity of operation and use of standard optical equipment . Recently, the FRET strategy employing water-soluble cationic conjugated polymers (CCP) with a large number of chromophoric repeat units, which enable the transfer of excitation energy along the whole backbone of the CCP to the reported chromophore via FRET, has been paid more attention for DNA detection with high sensitivity and selectivity (Feng et al, 2011;Jiang et al, 2009;Liu et al, 2014;Xu et al, 2005Xu et al, , 2010. Bazan and co-workers designed a three-color DNA detection assay with CCP and a fluorophorelabeled peptide nucleic acid strand through efficient FRET from CCP to the fluorophore (Liu and Bazan, 2004).…”

Homogeneous and one-step fluorescent allele-specific PCR for SNP genotyping assays using conjugated polyelectrolytes

“…Therefore, CPs can be used as the optical platforms in highly sensitive chemical and biological sensors (Ho et al, 2005(Ho et al, , 2008Yang et al, 2005;Gaylord et al, 2002;Xu et al, 2005;Feng et al, 2007;He et al, 2005;Lee et al, 2007;Li et al, 2005;Nilsson and Inganäs, 2003). More recently, we have been developed a two-step SNP genotyping method based on cationic CPs and allele-specific primer extension (Duan et al, , 2008.…”