An ultrasensitive sandwich type electrochemiluminescence immunosensor for triiodothyronine detection using silver nanoparticle-decorated graphene oxide as a nanocarrier

A Novel Strategy for Selective Thyroid Hormone Determination Based on an Electrochemical Biosensor with Graphene Nanocomposite

This article presents a novel and selective electrochemical bioassay with antibody and laccase for the determination of free thyroid hormone (free triiodothyronine, fT3). The biosensor was based on a glassy carbon electrode modified with a Fe₃O₄@graphene nanocomposite with semiconducting properties, an antibody (anti-PDIA3) with high affinity for fT3, and laccase, which was responsible for catalyzing the redox reaction of fT3. The electrode modification procedure was investigated using a cyclic voltammetry technique, based on the response of the peak current after modifications. All characteristic working parameters of the developed biosensor were analyzed using differential pulse voltammetry. Obtained experimental results showed that the biosensor revealed a sensitive response to fT3 in a concentration range of 10-200 µM, a detection limit equal to 27 nM, and a limit of quantification equal to 45.9 nM. Additionally, the constructed biosensor was selective towards fT3, even in the presence of interference substances: ascorbic acid, tyrosine, and levothyroxine, and was applied for the analysis of fT3 in synthetic serum samples with excellent recovery results. The designed biosensor also exhibited good stability and can find application in future medical diagnostics.

An enzyme-free electrochemiluminescence sensing probe based on ternary nanocomposite for ultrasensitive determination of chlorpyrifos

Herein, an innovative enzyme free electrochemiluminescence chlorpyrifos sensor was reported based on the incorporation of ternary nanocomposite (ruthenium nanobeads/silver nanoparticles/graphene oxide) on the surface of glassy carbon electrode. The silver nanoparticles as a robust signal enhancing agent were well deposited on the modified graphene oxide/glassy carbon electrode and exhibited supreme electrocatalytic proficiency. Then, Ru(bipy)₃²⁺ species in bead-like nanoparticles were uniformly anchored on the surface of the modified electrode with the help of chitosan, as a good crosslinking agent. Boron nitride quantum dots as a new coreactant species showed the excellent proficiency for signal enhancement of the fabricated electrode. The fabricated electrode was successfully used as an ultra-sensitive sensor for trace analysis of chlorpyrifos by ECL technique. The wide linear range and the low detection limit were obtained from 5.0 × 10^-15 to 4.2 × 10^-9 M and 6.5 × 10^-16 M, respectively.

A review of electrogenerated chemiluminescent biosensors for assays in biological matrices

Electrogenerated chemiluminescence (ECL) is the production of light via electron transfer reactions between electrochemically produced reagents. ECL-based biosensors use specific biological interactions to recognize an analyte and produce a luminescent signal. Biosensors fabricated with novel biorecognition species have increased the number of analytes detected. Some of these analytes include peptides, cells, enzymes and nucleic acids. ECL biosensors are selective, simple, sensitive and have low detection limits. Traditional methods use ruthenium complexes or luminol to generate ECL. Nanomaterials can be incorporated into ECL biosensors to improve efficiency, but also represent a new class of ECL emitters. This article reviews the application of ruthenium complex, luminol and nanomaterial-based ECL biosensors to making measurements in biological matrices over the past 4 years.

Preparation of graphene oxide-wrapped carbon sphere@silver spheres for high performance chlorinated phenols sensor

A template-activated strategy was developed to construct core/shell structured carbon sphere@silver composite based on one-pot hydrothermal treatment. The CS@Ag possessed a uniform three-dimensional interconnected microstructure with an enlarged surface area and catalytic activity, which was further mechanically protected by graphene oxide (GO) nanolayers to fabricate intriguing configuration, which was beneficial for efficiently preventing the aggregation and oxidation of AgNPs and improving the electrical conductivity through intimate contact. By immobilizing this special material on electrode surface, the CS@Ag@GO was further used for sensitive determination of chlorinated phenols including 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol. The tailored structure, fast electron transfer ability and facile preparation of CS@Ag@GO made it a promising electrode material for practical applications in phenols sensing.

Tough and thermally resistant cyanate ester resin with significantly reduced curing temperature and low dielectric loss based on developing an efficient graphene oxide/Mn ion metal–organic framework hybrid

High performance cyanate ester resins based on a graphene oxide/Mn ion metal–organic framework hybrid with efficient catalysis and toughening effects.

Recent advance in fabricating monolithic 3D porous graphene and their applications in biosensing and biofuel cells

Graphene shows great potential in biosensing and bioelectronics. To facilitate graphene's applications and enhance its performance, recently, three-dimensional (3D) graphene-based materials especially free-standing porous graphene with tunable pore size and void space, have attracted increasing attention for bio-related applications owing to their special features. 3D graphene usually shows the following merits such as an interconnected porous network, a high electronic conductivity, a large active surface area, good chemical/thermal stability and can be more easily handled compared with dispersed graphene sheets. With modified surface properties, graphene can also be bio-friendly. These properties make 3D graphene a perfect candidate as high-performance electrode materials in bioelectronics devices. In this review, we discuss recent advance in fabricating monolithic 3D graphene and their applications in biosensing and biofuel cells.