A selective glucose sensor based on direct oxidation on a bimetal catalyst with a molecular imprinted polymer.

A selective nonenzymatic glucose sensor was developed based on the direct oxidation of glucose on hierarchical CuCo bimetal-coated with a glucose-imprinted polymer (GIP). Glucose was introduced into the GIP composed of Nafion and polyurethane along with aminophenyl boronic acid (APBA), which was formed on the bimetal electrode formed on a screen-printed electrode. The extraction of glucose from the GIP allowed for the selective permeation of glucose into the bimetal electrode surface for oxidation.

An amperometric nanobiosensor using a biocompatible conjugate for early detection of metastatic cancer cells in biological fluid.

Metastasis is the major cause of cancer-associated death in humans, and its early diagnosis will help clinicians to develop suitable therapeutic strategies which may save life of cancer patients. In this direction, we designed an amperometric biosensor using a biocompatible conjugate to diagnose cancer metastasis by detecting epithelial cell adhesion molecule expressing metastatic cancer cells (Ep-MCCs). The sensor probe is fabricated by immobilizing monoclonal capture antibody (CapAnti) on the gold nanoparticles (AuNPs)/conducting polymer composite layer.

Analysis of Phthalate Esters in Mammalian Cell Culture Using a Microfluidic Channel Coupled with an Electrochemical Sensor.

An analytical tool to monitor trace phthalate was developed using a microfluidic channel device coupled with a novel electrochemical biosensor. At first, the electrochemical sensor was constructed with biomimetic layers to reveal a large hydrogen over potential by controlling the surface charge and hydrophobicity through assembling with a lipid (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine) and a cationic molecule (toluidine blue O) bonded to a conductive polymer. The modified electrode possessing a highly negative polarization potential (approximately -1.

Ultrasensitive detection of drug resistant cancer cells in biological matrixes using an amperometric nanobiosensor.

Multidrug resistance (MDR) is a key issue in the failure of cancer chemotherapy and its detection will be helpful to develop suitable therapeutic strategies for cancer patients and overcome the death rates. In this direction, we designed a new amperometric sensor (a medical device prototype) to detect drug resistant cancer cells by sensing "Permeability glycoprotein (P-gp)". The sensor probe is fabricated by immobilizing monoclonal P-gp antibody on the gold nanoparticles (AuNPs) conducting polymer composite.

Implantable nonenzymatic glucose/O₂ micro film fuel cells assembled with hierarchical AuZn electrodes.

Hierarchical AuZn dendrites revealed electrocatalytic properties towards the glucose oxidation and the four-electron O2 reduction. The micro fuel cell using AuZn electrodes generated a power density of 2.07 and 0.

Selective nonenzymatic bilirubin detection in blood samples using a Nafion/Mn-Cu sensor.

The specific detection of biological organics without the use of an enzyme is challenging, and it is crucial for analytical and clinical chemistry. We report specific nonenzymatic bilirubin detection through the catalytic oxidation of bilirubin molecule on the Nafion/Mn-Cu surface. The catalytic ability, true surface area, morphology, crystallinity, composition, and oxidation state of the sensor surface were assessed using voltammetry, coulometry, XPS, XRD, Brunauer-Emmett-Teller (BET), SEM, EDXS, and TOF-SIMS experiments.

Cancer cell detection based on the interaction between an anticancer drug and cell membrane components.

Simple and general cancer cell detection methods are required in point-of-care diagnostics. Herein, the interaction between an anticancer drug, daunomycin, and cancer cell membrane components has been studied using an aptamer probe immobilized on a conducting polymer-gold nanoparticle composite film through electrochemical and fluorescence methods and applied to the quantitative detection of cancer cells. The developed method differentiates between cancerous and noncancerous cells effectively.

A simple separation method with a microfluidic channel based on alternating current potential modulation.

A simple separation and detection system based on an electrochemical potential modulated microchannel (EPMM) device was developed for the first time. The application of alternating current (AC) potential to the microfluidic separation channel walls, which were composed of screen printed carbon electrodes, resulted in the oscillation and fluctuation of analytes and in the formation of a perfect flat flow front. These events resulted in an increase in the effective concentration and in the fine separation of samples.

Investigation on the downregulation of dopamine by acetaminophen administration based on their simultaneous determination in urine.

A highly sensitive and selective method is developed for the simultaneous detection of dopamine (DA) and acetaminophen (AP) by reactive blue-4 (RB4) dye entrapped poly1,5-diaminonaphthalne (polyDAN) composite film layer. The polyDAN-RB4 composite is electrochemically developed at glassy carbon electrode. The polymeric film, characterized by XPS and SEM is able to catalyze the oxidation of DA and AP.

In vivo detection of glutathione disulfide and oxidative stress monitoring using a biosensor.

A highly sensitive in vivo biosensor for glutathione disulfide (GSSG) is developed using covalently immobilized-glutathione reductase (GR) and -β-nicotinamide adenine dinucleotide phosphate (NADPH) on gold nanoparticles deposited on poly[2,2':5',2″-terthiophene-3'-(p-benzoic acid)] (polyTTBA). The fabricated biosensor was characterized with SEM, TEM, XPS, and QCM. Analytical parameters affecting the biosensor performance were optimized in terms of applied potential, NADPH:GR ratio, temperature, and pH.

In vitro monitoring of i-NOS concentrations with an immunosensor: the inhibitory effect of endocrine disruptors on i-NOS release.

The amperometric immunosensor has demonstrated the toxicity of endocrine disrupters (EDs) through monitoring the in vitro i-NOS concentration change, where the antibody of inducible nitric oxide synthase (i-NOS) was immobilized on the conducting polymer-gold nanoparticles composite. The performance of the sensor and the experimental parameters affecting the immunoreaction were optimized. Neuronal cells treated by EDs decreased in the in vitro i-NOS concentration.

Separation and simultaneous detection of anticancer drugs in a microfluidic device with an amperometric biosensor.

A simple and highly sensitive method for simultaneous detection of anticancer drugs is developed by integrating the preconcentration and separation steps in a microfluidic device with an amperometric biosensor. An amperometric detection with dsDNA and cardiolipin modified screen printed electrodes are used for the detection of anticancer drugs at the end of separation channel. The preconcentration capacity is enhanced thoroughly using field amplified sample stacking and field amplified sample injection techniques.

Ag(I)-cysteamine complex based electrochemical stripping immunoassay: ultrasensitive human IgG detection.

An ultrasensitive electrochemical immunosensor for a protein using a Ag (I)-cysteamine complex (Ag-Cys) as a label was fabricated. The low detection of a protein was based on the electrochemical stripping of Ag from the adsorbed Ag-Cys complex on the gold nanoparticles (AuNPs) conjugated human immunoglobulin G (anti-IgG) antibody (AuNPs-anti-IgG). The electrochemical immunosensor was fabricated by immobilizing anti-IgG antibody on a poly-5,2':5',2''-terthiophene-3'-carboxylic acid (polyTTCA) film grown on the glassy carbon electrode through the covalent bond formation between amine groups of anti-IgG and carboxylic acid groups of polyTTCA.

Detection of daunomycin using phosphatidylserine and aptamer co-immobilized on Au nanoparticles deposited conducting polymer.

A highly sensitive and selective sensor for daunomycin was developed using phosphatidylserine (PS) and aptamer as bioreceptors. The PS and aptamer were co-immobilized onto gold nanoparticles modified/functionalized [2,2':5',2″-terthiophene-3'-(p-benzoic acid)] (polyTTBA) conducting polymer. Direct electrochemistry of daunomycin was used to fabricate a label free sensor that monitors current at -0.

A selective nitric oxide nanocomposite biosensor based on direct electron transfer of microperoxidase: removal of interferences by co-immobilized enzymes.

A highly selective nitric oxide (NO) biosensor was developed by immobilizing microperoxidase (MP) onto the MWCNT-poly-5,2':5',2″-terthiophene-3'-carboxylic acid (PTTCA) nanocomposite. Catalase (CAS) and superoxide dismutase (SOD) co-immobilized on the probe successfully protected the interferences of H(2)O(2) and O(2)(-) during NO detection. The nanocomposite layer showed the direct electron transfer processes of the immobilized CAS, SOD, and MP simultaneously at -0.

Total analysis of endocrine disruptors in a microchip with gold nanoparticles.

The development of a simple, sensitive, and direct method for the total analysis of certain endocrine disruptors was performed by integrating preconcentration steps to a separation step on a microchip through the modification of the field-amplified sample stacking and field-amplified sample injection steps. To improve the preconcentration and separation performances, the preconcentration and separation buffers were modified with citrate-stabilized gold nanoparticles (AuNPs). For the detection of the separated samples, cellulose-dsDNA/AuNPs-modified carbon paste electrodes were used at the channel end.

Triggering the redox reaction of cytochrome c on a biomimetic layer and elimination of interferences for NADH detection.

Biomimetic layers triggering the redox process of cytochrome c (cyt c) by beta-nicotinamide adenine dinucleotide (NADH) were fabricated and applied for the detection of NADH. A probe was constructed based on a conducting polymer (poly-5,2':5',2''-terthiophene-3'-carboxylic acid, poly-TTCA) formed on the Au nanoparticles, which were deposited on a screen-printed carbon electrode; the probe was modified with biomaterials including cyt c, lipids (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) and cardiolipin), and ubiquinone, which are involved in electron transfer sequence in the cell membrane. To eliminate affection of foreign biological species, we assembled a lipid bilayer using the Langmuir-Blodgett technique by controlling the density of the outward lipid layer.

Conjugated polymers and an iron complex as electrocatalytic materials for an enzyme-based biofuel cell.

Poly-5,2':5',2''-terthiophen-3'-carboxylic acid (polyTTCA) and poly-Fe(III)-[N,N'-bis[4-(5,2':5',2''-terthien-3'-yl)salicyliden]-1,2-ethanediamine] (polyFeTSED) were synthesized and electrochemically polymerized on an Au surface for use as mediators and catalysts for a biofuel cell. The atomic force microscopy (AFM) images of (a) the TTCA homopolymer (polyTTCA) and (b) the TTCA-FeTSED copolymer (poly(TTCA-FeTSED)) layers show a nanoparticle structure. The enzymes (glucose oxidase (GOx) or horseradish peroxidase (HRP)) were immobilized onto the conducting polymer layer through covalent bond formation, which allowed for direct electron transfer processes of the enzymes.

Immunosensors for detection of Annexin II and MUC5AC for early diagnosis of lung cancer.

Amperometric immunosensors were developed to diagnose lung cancer through the detection of Annexin II and MUC5AC. To fabricate the sensor probe, a conducting polymer (poly-terthiophene carboxylic acid; poly-TTCA) was electropolymerized onto a gold nanoparticle/glassy carbon electrode (AuNP/GCE) and a dendrimer (Den) was covalently bonded to the poly-TTCA through amide bond formation, where AuNPs were doped onto the dendrimer. To obtain the final sensor probe, an antibody (anti-Annexin II) and hydrazine (Hyd), which is a catalyst for the reduction of H(2)O(2) generated by glucose oxidase (GOx), were covalently attached onto the Den/AuNP-modified surface.

Direct electrochemistry of laccase immobilized on au nanoparticles encapsulated-dendrimer bonded conducting polymer: application for a catechin sensor.

The direct electrochemistry of laccase was promoted by Au nanoparticle (AuNP)-encapsulated dendrimers (Den), which was applied for the detection of catechin. To increase the electrical properties, AuNPs were captured in the interiors of the dendrimer (Den-AuNPs) as opposed to attachment at the periphery of dendrimer. To prepare Den-AuNPs, the Au(III) ions were first coordinated in the interior of dendrimer with nitrogen ligands and then reduced to form AuNPs.