A highly sensitive DNA aptamer-based fluorescence assay for sarcosine detection down to picomolar levels.

Sarcosine is an amino acid derivative, which is considered as a key metabolite in various metabolic processes. Therefore, simple and sensitive detection methods are needed for further understanding its metabolic role and diagnostic value. In this study, we developed a novel method that meets the need for practical and sensitive detection in a complex medium mimicking urine conditions.

A novel non-competitive amperometric immunosensor by using thiourea-glutaraldehyde-modified gold electrode for immunoglobulin M detection.

A novel non-competitive amperometric immunosensor based on a self-assembled monolayer (SAM) of thiourea modified by a polymeric Schiff's base of glutaraldehyde on gold electrode has been developed for determination of IgM. Alkaline phosphatase (ALP)-conjugated monoclonal anti-mouse immunoglobulin M (IgM) antibody was selectively bound to IgM molecules onto the surface of the electrode. Electrochemical response arising from the catalytic reaction of alkaline phosphatase enzyme.

Immobilization of anti-aflatoxin B1 antibody by UV polymerization of aniline and aflatoxin B1 detection via electrochemical impedance spectroscopy.

In the study, we investigated the practicality of the UV polymerization of aniline for anti-aflatoxin B1 antibody immobilization, and utilization of the resulting biosensor in the impedimetric determination of aflatoxin B1. The anti-aflatoxin B 1 antibody was physically immobilized on gold electrodes by UV polymerization of aniline at a fixed wavelength. The biosensor was based on specific interaction anti-aflatoxin B1 - aflatoxin B1 recognition and investigation of this recognition event by electrochemical impedance spectroscopy.

α-Amylase monitoring by a novel amperometric biosensor based on Au electrode: its optimization, characterization, and application.

A low-cost and sensitive amperometric biosensor was developed for the determination of α-amylase activity. The biosensor was constructed by immobilizing glucose oxidase-gelatin via glutaraldehyde on the Au electrode surface. Measurements were carried out chronoamperometrically at -0.

Sulfite determination by an inhibitor biosensor-based mushroom (Agaricus bisporus) tissue homogenate.

The aim of the study presented here is to develop a biosensor based on mushroom (Agaricus bisporus) tissue homogenate for sensitive and economical determination of sulfite in foods. The working principle of the biosensor is based on an inhibition effect of sulfite on polyphenol oxidases in mushroom. Mushroom tissue homogenate was immobilized by gelatin and glutaraldehyde on a Clark-type oxygen electrode.

A novel biosensor based on glucose oxidase for activity determination of α - amylase.

A glucose oxidase-based biosensor was developed for the determination of α-amylase activity. The determination method is based on monitoring the decrease in dissolved oxygen concentration related to the starch concentration, for which starch gives a reaction with α-amylase. Optimization parameters, including glucose oxidase amount, gelatin amount, and glutaraldehyde percentage for cross-linking, were investigated.

Development of an impedimetric aflatoxin M1 biosensor based on a DNA probe and gold nanoparticles.

The present work describes the construction and application of a new DNA biosensor for detection of aflatoxin M1. In order to immobilize a thiol-modified single stranded DNA (ss-HSDNA) probe that specifically bound aflatoxin M1, a self-assembled monolayer of cysteamine and gold nanoparticles on the SAM were prepared on gold electrodes, layer-by-layer. The assembly processes of cysteamine, gold nanoparticles, and ss-HSDNA were monitored with the help of electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques.

A biosensor for the determination of β-galactosidase activity: a different viewpoint on biosensors.

β-galactosidase splits lactose into glucose and galactose. Because of its biotechnological interest, we presented a biosensor system in order to monitor β-galactosidase activity. Immobilization steps of the biosensor were identified by cyclic voltammograms and electrochemical impedance spectroscopy.

β-galactosidase determination by an electrochemical biosensor mediated with ferrocene.

Abstract: In this paper, a new viewpoint on the activity determination of β-galactosidase is reported. Glucose oxidase was directly immobilized on a glassy carbon electrode and mediated by ferrocene. The biosensor's performance was based on mediated electron transfer by ferrocene, which reduced via glucose oxidase reaction.

Electrochemical cysteine determination in serum samples by Hg thin film sensor.

Cysteine is a nonessential aminoacid, meaning that cysteine can be made in the human body. It is one of the few amino acids that contain sulfur. This allows cysteine to bond in a special way and maintain the structures of proteins in the body.

A biosensor based on zucchini (Cucurbita pepo L.) homogenate as a biorecognition layer for ascorbic acid determination.

An amperometric biosensor based on zucchini (Cucurbita pepo) tissue homogenate is presented. The zucchini tissue homogenate was crosslinked with gelatine using glutaraldehyde and fixed on a pretreated teflon membrane. The zucchini tissue contained the enzyme ascorbate oxidase and this enzyme catalyzed the oxidation of ascorbic acid in the presence of dissolved oxygen.

Construction and comparison of Trametes versicolor laccase biosensors capable of detecting xenobiotics.

Amperometric biosensors using laccase from Trametes versicolor as a bioelement were developed for 2,4-dichloro phenoxy acetic acid (2,4-D). Laccase enzyme was immobilized by gelatin and glutaraldehyde onto a Clark oxygen probe and screen printed electrodes (SPEs). Amperometric and chronoamperometric measurements were carried out with the biosensors.

A biosensor utilizing quince (Cydonia vulgaris) tissue homogenate for dopamine determination in pharmaceutical preparations.

Dopamine is a hormone and neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. Chemically, it is a phenethylamine. Dopamine can be supplied as a medication that acts on the sympathetic nervous system, producing effects such as increased heart rate and blood pressure.

Sensitive nitrate determination in water and meat samples by amperometric biosensor.

This study describes a novel biosensor method for specific determination of nitrate in food and water samples by using nitrate reductase (NR) (EC 1.9.6.

Sulfite determination by a biosensor based on bay leaf tissue homogenate: very simple and economical method.

Of all the food additives for which the FDA has received adverse reaction reports, the ones that most closely resemble true allergens are sulfur-based preservatives. Sulfites are used primarily as antioxidants to prevent or reduce discoloration of light-colored fruits and vegetables, such as dried apples and potatoes, and to inhibit the growth of microorganisms in fermented foods such as wine. This work aims to prepare an electrochemical biosensor based on bay leaf tissue homogenate that contains polyphenol oxidase enzyme abundantly for sulfite detection in foods.

Pseudomonas putida based amperometric biosensors for 2,4-D detection.

Amperometric biosensors using Pseudomonas putida cells as a bioelement were developed for 2,4-dichloro phenoxy acetic acid (2,4-D). After the adaptation process of Pseudomonas putida to 2,4-D, cells were immobilized onto the screen printed graphite electrodes (SPG) as well as Clark oxygen probe by gelatin and glutaraldehyde. Optimum pH, temperature, and stability of the biosensor were investigated.

H2O2 determination by a biosensor based on hemoglobin.

The detection of hydrogen peroxide, H2O2, plays an important role in many fields including industry, environmental protection, and clinical control. Hydrogen peroxide can be toxic if ingested, inhaled, or by contact with the skin or eyes. Hemoglobin is a molecule with four electroactive iron hemes which can be used as an ideal model molecule for the study of electron transfer reactions of heme proteins and also for biosensing and electrocatalysis.

Direct determination of sulfite in food samples by a biosensor based on plant tissue homogenate.

In the work described here, a biosensor was developed for the determination of sulfite in food. Malva vulgaris tissue homogenate containing sulfite oxidase enzyme was used as the biological material. M.

Development of a catalase based biosensor for alcohol determination in beer samples.

An amperometric biosensor based on catalase enzyme for alcohol determination was developed. To construct the biosensor catalase was immobilized by using gelatin and glutaraldehyde on a Clark type dissolved oxygen (DO) probe covered with a teflon membrane which is sensitive for oxygen. The working principle of the biosensor depends on two reactions, which one is related to another, catalyzed by catalase enzyme.

A biosensor based on urate oxidase-peroxidase coupled enzyme system for uric acid determination in urine.

A new amperometric biosensor based on urate oxidase-peroxidase coupled enzyme system for the specific and selective determination of uric acid in urine was developed. Commercially available urate oxidase and peroxidase were immobilized with gelatin by using glutaraldehyde and fixed on a pretreated teflon membrane. The method is based on generation of H(2)O(2) from urine uric acid by urate oxidase and its consuming by peroxidase and then measurement of the decreasing of dissolved oxygen concentration by the biosensor.

A novel amperometric biosensor based on spinach (Spinacia oleracea) tissue homogenate for urinary oxalate determination.

In this study, a novel spinach (Spinacia oleracea) tissue homogenate-based biosensor for determination of oxalate in urine was developed. The biosensor was constructed by immobilizing tissue homogenate of spinach (S. oleracea) onto a high-sensitive teflon membrane of a dissolved oxygen (DO) probe.

A mushroom (Agaricus bisporus) tissue homogenate based alcohol oxidase electrode for alcohol determination in serum.

To construct homogenized tissue based biosensors by using plant tissue materials is a relatively new development in the biosensor technology. In this study, a homogenized mushroom (Agaricus bisporus) tissue based electrode in which alcohol oxidase activity was developed by immobilizing with gelatin and cross-linking agent glutaraldehyde at dissolved oxygen probe for determination of ethyl alcohol. The electrode response depends linearly on ethyl alcohol concentration between 0.

A new enzyme electrode based on ascorbate oxidase immobilized in gelatin for specific determination of l-ascorbic acid.

A biosensor for the specific determination of l-ascorbic acid in fruit juices and vitamin C tablets was developed using ascorbate oxidase (EC 1.10.3.

A novel biosensor for specific determination of hydrogen peroxide: catalase enzyme electrode based on dissolved oxygen probe.

A biosensor for the specific determination of hydrogen peroxide was developed using catalase (EC 1.11.1.

A biosensor based on Bay leaf (Laurus nobilis L.) tissue homogenate: improvement of the stability characteristics by a simple bio-imprinted technique.

Although enzymes are effective biocatalysts that are widely used in biosensors, a major drawback that hampers many of these biotechnological applications of enzymes is their limited stability. Applications that use very pure, high value proteins need to employ effective stabilization technology, primarily due to cost considerations and availability of the proteins used. For this purpose, interest in bio-imprinting techniques increases because it allows stability characteristics of enzymes to be improved.