Pyrene-Appended Boronic Acids on Graphene Foam Electrodes Provide Quantum Capacitance-Based Molecular Sensors for Lactate.

Molecular recognition and sensing can be coupled to interfacial capacitance changes on graphene foam surfaces linked to double layer effects and coupled to enhanced quantum capacitance. 3D graphene foam film electrodes (Gii-Sens; thickness approximately 40 μm; roughness factor approximately 100) immersed in aqueous buffer media exhibit an order of magnitude jump in electrochemical capacitance upon adsorption of a charged molecular receptor based on pyrene-appended boronic acids (here, 4-borono-1-(pyren-2-ylmethyl)pyridin-1-ium bromide, or abbreviated T1). This pyrene-appended pyridinium boronic acid receptor is employed here as a molecular receptor for lactate.

Non-covalent π-π functionalized Gii-sense graphene foam for interleukin 10 impedimetric detection.

Monitoring Interleukin 10 (IL-10) is essential for understanding the vast responses of T-cells in cancer, autoimmunity, and internal homeostasis after physical stress. However, current diagnostic methods are complex and more focused on medical screening rather than point-of-care monitoring. Biosensors based on graphene's conductivity and flexibility are attractive to offer simple single-use and reduced handling.

Polymer indicator displacement assay: electrochemical glucose monitoring based on boronic acid receptors and graphene foam competitively binding with poly-nordihydroguaiaretic acid.

The concept of a reversible polymer displacement sensor mechanism for electrochemical glucose monitoring is demonstrated. A pyrene-derivatised boronic acid chemo-receptor for glucose is adsorbed onto a graphene foam electrode. Spontaneous oxidative polymerisation of nordihydroguaiaretic acid (NHG) onto the graphene foam electrode leads to a redox active film (poly-NHG) covalently attached to the boronic acid receptors.

Disulfide-modified antigen for detection of celiac disease-associated anti-tissue transglutaminase autoantibodies.

A simple and rapid immunosensor for the determination of the celiac disease-related antibody, anti-tissue transglutaminase, was investigated. The antigenic protein tissue transglutaminase was chemically modified, introducing disulfide groups through different moieties of the molecule (amine, carboxylic, and hydroxyl groups), self-assembled on gold surfaces, and used for the detection of IgA and IgG autoantibodies. The modified proteins were evaluated using enzyme-linked immunosorbent assay and surface plasmon resonance, which showed that only introduction of the disulfide groups through amine moieties in the tissue transglutaminase preserved its antigenic properties.

Antibodies to wheat high-molecular-weight glutenin subunits in patients with celiac disease.

Background: Wheat gluten comprises gliadins and glutenins. The high-molecular-weight (HMW) glutenin subunits (GS)-1Dy10 are toxic for patients with celiac disease (CD). This study aimed to assess whether CD patients mount a serological response to HMW-GS-1Dy10.

Amperometric immunosensor for the determination of IgA deficiency in human serum samples.

An electrochemical immunosensor for the detection of human IgA deficiency in real human blood serum has been developed. The performance of the immunosensor presents a large but sensitive dynamic range that allows the determination of non-deficient IgA levels (>70 μg/mL) as well as of severe IgA deficiencies (0.5-5.

Electrochemical detection of celiac disease-related anti-tissue transglutaminase antibodies using thiol based surface chemistry.

Celiac disease is an autoimmune disorder that affects the gastrointestinal tract upon ingestion of gluten, which triggers the production of antibodies against gliadin and tissue transglutaminase, activating an inflammatory response and inducing tissue damage in the small intestine resulting in malabsorption. The measurement of these antibodies in an individual's blood can be used to screen for celiac disease and the criteria for definitive diagnosis is currently being revised to be based on serological analysis rather than biopsy. In the work reported here, an electrochemical immunosensor for the detection of human anti-tissue transglutaminase antibodies was developed, consisting of gold-based self-assembled monolayers of a carboxylic group terminated bipodal alkanethiol that is covalently linked to tissue transglutaminase, the antigen for the immunorecognition of circulating autoantibodies.

Screen-printed microsystems for the ultrasensitive electrochemical detection of alkaline phosphatase.

Screen printing technique has been used to manufacture a microsystem where the graphite-based electrodes hold both a functional and an architectural task. The thick film manufacturing technique has proved valid to develop a very low volume (ca. 20 microL) device where different electrochemical operations can be very efficiently performed.

Controlled electrophoretic deposition of multifunctional nanomodules for bioelectrochemical applications.

The design of an electrochemical glucose sensing device formed by the electrodeposition of multifunctional Au nanoparticles is reported here as a novel concept for an enhanced generic sensing platform. Initially gold nanoparticles (Au) were alternatively coated with a layer of positively charged redox polymer (ORP) and a negatively charged glucose oxidase (GOX) layer alternatively using layer-by-layer methodology to form multifunctional Au/ORP/GOX/ORP particles. The modification and stability of the Au nanoparticles was monitored by using UV-vis spectroscopy and zeta-potential measurements.

Towards a target label-free suboptimum oligonucleotide displacement-based detection system.

A novel method for the future development of label-free DNA sensors is proposed here. The approach is based on the displacement of a labelled suboptimum mutated oligonucleotide hybridised with the immobilised biotin-capture probe. The target fully complementary to the biotin-capture probe can displace the labelled oligonucleotide causing a subsequent decrease of the signal that verifies the presence of the target.

Electrochemical characterisation and anodic stripping voltammetry at mesoporous platinum rotating disc electrodes.

Using the technique of liquid crystal templating a rotating disc electrode (RDE) was modified with a high surface area mesoporous platinum film. The surface area of the electrode was characterised by acid voltammetry, and found to be very high (ca. 86 cm(2)).

Aptamers: molecular tools for analytical applications.

Aptamers are artificial nucleic acid ligands, specifically generated against certain targets, such as amino acids, drugs, proteins or other molecules. In nature they exist as a nucleic acid based genetic regulatory element called a riboswitch. For generation of artificial ligands, they are isolated from combinatorial libraries of synthetic nucleic acid by exponential enrichment, via an in vitro iterative process of adsorption, recovery and reamplification known as systematic evolution of ligands by exponential enrichment (SELEX).

Underpotential deposition and anodic stripping voltammetry at mesoporous microelectrodes.

Using the technique of liquid crystal templating a series of high surface area mesoporous platinum microelectrodes was fabricated. The underpotential deposition of metal ions at such electrodes was found to be similar to that at conventional platinum electrodes. The phenomena of underpotential deposition, in combination with the intrinsic properties of mesoporous microelectrodes (i.