Conducting Polymer-Reduced Graphene Oxide Sponge Electrode for Electrochemical Detection Based on DNA Hybridization

Abstract

In this study, polymer-supported graphene-based material was designed for electrochemical determination based on the hybridization of DNA. First, dispersions containing graphene oxide (GO) and poly­(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) polymer in different compositions were transformed into a hydrogel form through the hydrothermal treatment, then 3D and flexible PEDOT:PSS/reduced graphene oxide (RGO) composite sponge material was prepared by using a freeze-drying process. Structural and morphological characterizations showed that PEDOT:PSS polymer served as a skeleton by covering the graphene layers like a mesh and provided an increment in both mechanical strength and electrochemical performance by relatively reducing pore size in 3D material. PEDOT:PSS/RGO composite sponge has high conductivity (158 S cm–1) for utilization as an electrode and durability to lift 700 times its weight. For electrochemical determination based on the hybridization of DNA on PEDOT:PSS/RGO composite sponge material, single-stranded DNA (ssDNA) and methylene blue (MB) marked ssDNA probes were immobilized on PEDOT:PSS/RGO composite sponge material at optimum conditions. This sensor achieved a detection limit down to 17 fM with the linear range of 50 fM to 2 μM for the determination of hybridized DNA. By possessing flexible, free-standing, and durable features, PEDOT:PSS/RGO composite sponge appeared to be a promising electrode material for detection studies.

ZnS Nanoparticles‐decorated Composite Graphene Paper: A Novel Flexible Electrochemical Sensor for Detection of Dopamine

“…ZnS nanoparticles have a diameter of about 100 nm (Figure 2.a) [41]. GO was observed possessing a characteristic wrinkled sheet‐like structure in Figure 2.b [44]. TEM image of the ZnS/GO composite exhibited that ZnS nanoparticles were orderly distributed on GO without deteriorating the wrinkled sheet structure (Figure 2.c).…”

Biocompatible Graphene Oxide Nanosheets Densely Functionalized with Biologically Active Molecules for Biosensing Applications

“…After successful covalent CA coating of GO flakes, we functionalized the substrates with biocompatible, heterobifunctional NHS–PEG–COOH using the same process as for SiO 2 substrates. The ability of the CA–PEG coating on the GO substrates to allow biosensing of a specific biomolecule was tested next by preparing a DNA biosensor assay with our functionalized GO–CA–PEG substrates in comparison to GO–APTES–PEG samples. − Commonly, such biosensor assays with electrically conductive transducers like GO are performed without labels by sensing changes in conductivity upon biomolecule binding to its specific receptor. However, coating coverage and local biomolecular interactions cannot be evaluated with such approaches.…”

Three-Dimensional ZnCo-MOF Modified Graphene Sponge: Flexible Electrode Material for Symmetric Supercapacitor

“…First, the optimum amount of ZnCo-MOF was added to 15 mL of GO aqueous dispersion (5 mg mL –1 ) containing 150 mg of ascorbic acid and 2 mL of sodium dodecyl sulfate (SDS) (50% by weight) and then was stirred and foamed for 30 min (2500 rpm) to acquire a porous structure. The foamed composite dispersion was added into the reaction vessel and reacted at 75 °C for 1 h to obtain ZnCo-MOF/reduced graphene oxide sponge (ZnCo-MOF/rGOS). , ZnCo-MOF/rGOS was frozen at −18 °C for 5 h and then was allowed to reach room temperature. ZnCo-MOF/rGOS was dried at 90 °C for 5 h and was washed one to three times with distilled water to remove excess ascorbic acid.…”

“…To solve this problem, there has been a tendency to use 3D graphene materials. These materials have been reported to possess large surface areas, wide pore size distributions, high electrical conductivities, and fast redox reaction conversion performances . In order to increase the capacitance performance and lifetime of such 3D and 2D materials, many composite materials have been prepared with the use of transition metal oxides, metal sulfides, and conductive polymers, especially other carbon-based materials.…”