Polymer−DNA Hybrids as Electrochemical Probes for the Detection of DNA

Abstract

The syntheses of several norbornene block copolymers containing oligonucleotide and ferrocenyl side chains and their use in the electrochemical detection of DNA are described. Two kinds of DNA-containing block copolymers with either ferrocenyl or dibromoferrocenyl groups were prepared via ring-opening metathesis polymerization (ROMP). Based on these two distinct ferrocene derivatives, a triblock copolymer labeling strategy was developed. With this strategy, the identity of DNA target can be determined by the E1/2s of the ferrocenyl moieties and the ratio of peak currents. These polymers exhibit predictable and tailorable electrochemical properties, high DNA duplex stability, and unusually sharp melting transitions, which are highly desirable characteristics for DNA detection applications. Significantly, single-base mismatches could be easily detected using two distinct block copolymers as dual-channel detection probes in an electrochemical DNA detection format.

Electrochemical and bioelectrocatalytical properties of novel block-copolymers containing interacting ferrocenyl units

“…Poly(ferrocenyl)-based macromolecules have been demonstrated to possess useful properties for the chemical modification of electrodes and also as electrochemical sensors and electrode mediators in biosensors [15][16][17][18][19].…”

Single-step electronic detection of femtomolar DNA by target-induced strand displacement in an electrode-bound duplex

“…A wide range of electronic DNA detection schemes have been described to date (3)(4)(5), the best of which achieve limits of detection (LOD) ranging from picomolar to femtomolar. Among promising recent examples are approaches based on conductive links produced through the catalytic deposition of silver by nanoparticle-linked secondary probes (LOD 500 fM) (6), the electrocatalytic oxidation of modified bases by Os(bpy) 3 3ϩ (LOD 400 fM) (7), the electrochemistry of water-soluble, ferrocene-functionalized cationic polythiophenes (LOD 500 pM) (8) or ferrocene-linked triblock copolymer-DNA hybrids (LOD 100 pM) (9), the electron transfer of ferrocenyl-tethered poly(amido-amine)dendrimer in a sandwich-type enzyme-linked DNA sensor (LOD 100 pM) (10), charge transport from electroactive DNA intercalators (with magnetic sample concentration) (LOD 2 pM) (11), the chronopotentiometric detection of micrometer-long indium rod tracer in a DNA sandwich hybridization assay (with magnetic sample concentration) (LOD 2.6 pM) (12), and the anodic stripping voltammetry of silver nanoparticles deposited in a multistep reduction process initiated by a labeled secondary probe (LOD 0.1 fM) (13).…”

DNA Meets Synthetic Polymers — Highly Versatile Hybrid Materials

“…44, 45 The latter method might have some drawbacks because high reproducibility and efficient exposure of the phosphoramidite polymer to the solid phase is not guaranteed to the same extent as in a DNA synthesizer.…”

“…44, 45 A third variant for the preparation of DNA side chain polymers is based on polymerizable ODN-macromonomers. An acrylamide monomer was functionalized via an alkyl spacer with a phosphoramidite group that can be reacted with the 5 -end of an ODN.…”