Simple surface functionalization strategy for immunosensing detection of aflatoxin B1

This paper describes the strategy of functionalization of gold electrodes surfaces in aim to obtain a new impedimetric immunosensor for the detection of aflatoxin B1, a common toxic food contaminant. The immunosensor elaboration is based on immobilization of anti-aflatoxin antibody on gold electrodes modified with a cross-linked film of bovine serum albumin, by a four-step protocol. The immunosensor is based on a simple design and requires small volumes of toxic aflatoxin solution. All the steps of the immunosensor elaboration and the immunochemical reaction between aflatoxin and antibody were followed using atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The resistance to charge transfer (Rct) was the most sensitive parameter to changes induced to the interfacial properties of the immunosensor by the incubation with aflatoxin and varied linearly with aflatoxin concentration in the range 1-20 ng/mL. The immunosensor was applied for the detection of aflatoxin in spiked plant extracts with good recovery factors

Ochratoxin A Detection on Antibody- Immobilized on BSA-Functionalized Gold Electrodes

Ochratoxin A (OTA)-a toxin produced by Aspergillus carbonarius, Aspergillus ochraceus, and Penicillium verrucosum-is one of the most-abundant food-contaminating mycotoxins. To avoid the risk of OTA consumption for humans and animals, the rapid detection and quantitation of OTA level in different commodities are of great importance. In this work, an impedimetric immunosensor for ochratoxin A (OTA) detection, a common toxic botanical contaminant, was developed via the immobilization of anti-OTA antibody on bovine serum albumin modified gold electrodes. A four-step reaction protocol was tested to modify the gold electrode and obtain the sensing substrate. All the steps of the immunosensor elaboration and also the immunochemical reaction between surface-bound antibody and ochratoxin A were analyzed using cyclic voltammetry and electrochemical impedance spectroscopy. Modification of the impedance due to the specific antigen-antibody reaction at immunosensor surface, was used in order to detect ochratoxin A. Linear proportionality of the charge transfer resistance to the concentration of OTA allows ochratoxin A detection in the range of 2.5-100 ng/mL

Optimization of electrochemical detection of L-Ascorbic acid from Plant Food Supplements using screen printed transducers

The importance of Ascorbic acid (vitamin C) in several biological processes, and during the last years as active compounds used in several pesticides (L-Ascorbic acid is used as a fungicide on glasshouse tomato, potato, and field and glasshouse flower bulbs) is a challenge for groups of researchers to develop new, rapid and sensitive method for its detection. Methods for the detection of Ascorbic acid (AA) were developed and optimised using differential pulse voltammetry (DPV) analysis with modified carbon-printed electrodes with cobalt phthalocyanine. There was studied detection of Ascorbic acid in hydrochloric acid 2% as supporting media. Results showed that the method developed for Ascorbic acid analyses can be used to assay different samples as teas and plant food supplements containing different botanicals

Synthesis and characterization of bioglass thin films

We report the successful pulsed laser deposition on medical grade Ti substrates of thin films made of two bioactive glasses in the SiO2 - Na2O- K2O - CaO - MgO - P2O5 system. The films were topographically and chemically characterized by confocal scanning laser microscopy and Fourier transform infrared spectrophotometry. Our studies proved that chemical composition was similar in the base material and deposited films. The latter were rather uniform and rough enough to favor enhanced biocompatibility

New Electrochemical Detection Strategies for Iodinated Compounds

Iodine is a micronutrient of high importance for the health and good development ofindividuals. It is contained in many foods, but it is also part of the chemical component of oceans and soil. Its deficiency is still a problem of humanity, which has a serious repercussion on our health. It is therefore important to have specific, fast and cost effective methods of iodine detection from different samples. This work aims to identify optimal parameters for potassium iodide (KI) detection from different media, to be further applied to real samples: plant extracts, water, biological fluids. Results showed a significant difference in electrochemical results, depending on the pH values of the mixture and also on the time which influences the compounds stability. Differential pulse voltammetry and cyclic voltammetry using carbon printed sensors, as well as microsensors for redox status or direct iodide detection are important analytical tools which have a wide range of applications in the food, medicine, toxicology and other domains

Nanostructured bioglass thin films synthesized by pulsed laser deposition: CSLM, FTIR investigations and in vitro biotests

We report the synthesis by pulsed laser deposition of thin structures of two bioactive glasses belonging to the SiO2-Na2O-K2O-CaO-MgO-P2O5 system, on medical grade Ti substrates. We evaluated their biocompatibility after immersion in simulated body fluids and by performing cells adhesion tests. The Films were characterized by confocal scanning laser microscopy and Fourier transform infrared spectrometry, before and after 30 and 46 days immersion in fluids. Our studies demonstrated that deposited coatings were degraded in simulated fluids. A new apatite layer was synthesized by ions changing with the fluid during the decomposition of bioglasses. We investigated after immersion in fluids cells adhesion and the cytoskelet organization of synthesized structures, by fluorescence microscopy. A good adhesion to bioglass coatings was evidenced

Antimicrobial thin films based on ayurvedic plants extracts embedded in a bioactive glass matrix

Ayurvedic medicine is one of the oldest medical systems. It is an example of a coherent traditional system which has a time-tested and precise algorithm for medicinal plant selection, based on several ethnopharmacophore descriptors which knowledge endows the user to adequately choose the optimal plant for the treatment of certain pathology. This work aims for linking traditional knowledge with biomedical science by using traditional ayurvedic plants extracts with antimicrobial effect in form of thin films for implant protection. We report on the transfer of novel composites from bioactive glass mixed with antimicrobial plants extracts and polymer by matrix-assisted pulsed laser evaporation into uniform thin layers onto stainless steel implant-like surfaces. The comprehensive characterization of the deposited films was performed by complementary analyses: Fourier transformed infrared spectroscopy, glow discharge optical emission spectroscopy, scanning electron microscopy, atomic force microscopy, electrochemical impedance spectroscopy, UV-VIS absorption spectroscopy and antimicrobial tests. The results emphasize upon the multifunctionality of these coatings which allow to halt the leakage of metal and metal oxides into the biological fluids and eventually to inner organs (by polymer use), to speed up the osseointegration (due to the bioactive glass use), to exert antimicrobial effects (by ayurvedic plants extracts use) and to decrease the implant price (by cheaper stainless steel use)

New approaches for electrochemical detection of ascorbic acid

Ascorbic acid, well known as vitamin C, acts as antioxidant, helping the prevention of cell damage caused by free radicals. The paper presents fast methods for detecting ascorbic acid, using differential pulse voltammetry in different designed experiments. There were studied the possibilities of detection using buffer systems with pH 5.8, 7.0, 7.4 and original transducers. Each compound was analysed specifically at the potential indicated by the maximum signal appeared during the electrochemical study. The method could be successfully applied for single compound detection in food and drug samples