Study of zeolite influence on analytical characteristics of urea biosensor based on ion-selective field-effect transistors

A possibility of the creation of potentiometric biosensor by adsorption of enzyme urease on zeolite was investigated. Several variants of zeolites (nano beta, calcinated nano beta, silicalite, and nano L) were chosen for experiments. The surface of pH-sensitive field-effect transistors was modified with particles of zeolites, and then the enzyme was adsorbed. As a control, we used the method of enzyme immobilization in glutaraldehyde vapour (without zeolites). It was shown that all used zeolites can serve as adsorbents (with different effectiveness). The biosensors obtained by urease adsorption on zeolites were characterized by good analytical parameters (signal reproducibility, linear range, detection limit and the minimal drift factor of a baseline). In this work, it was shown that modification of the surface of pH-sensitive field-effect transistors with zeolites can improve some characteristics of biosensors

Biological Evaluation of Medical Devices in the Form of Suppositories for Rectal and Vaginal Use

Проблематика. Програми доклінічного вивчення безпеки продуктів у системі охорони здоров’я залежать від регуляторного статусу досліджуваних продуктів. Класифікування таких продуктів, зокрема супозиторіїв для ректального та вагінального застосування, є критичним етапом для розробки тактики їх біологічного оцінювання. Актуальними для біомедицини залишаються питання адаптації методів біологічного оцінювання медичних виробів на основі комбінації біологічно активних речовин, а також оцінки результатів такого оцінювання. Мета. Здійснити обґрунтування регуляторного статусу та біологічне оцінювання медичних виробів у формі вагінальних супозиторіїв на основі октенідину дигідрохлориду (“Продексин”) та у формі ректальних супозиторіїв на основі екстрактів рослин Saw palmetto, Levisticum officinale і Calendula officinalis (“Правенор”). Методика реалізації. Біологічне оцінювання проводили згідно з вимогами стандартів серії ISO 10993 за допомогою біологічних тест-систем in vitro та in vivo (цитотоксичність у культурі клітин та у МТТ-тесті, сенсибілізуюча та подразнювальна дія на мурчаків). Результати. Цитотоксичність (СС50) екстракту медичного виробу “Продексин” на культурі клітин Vero становила 8,35 мкг/мл у перерахунку на октенідину дигідрохлорид та 416,65 мкг/мл у перерахунку на декспантенол. Медичній виріб “Правенор” виявився нетоксичним на культурі клітин Vero. За результатами МТТ-тесту СС50 для октенідину дигідрохлориду становила 1,67 мкг/мл, декспантенолу – 83,33 мкг/мл. СС50 у перерахунку на активні інгредієнти медичного виробу “Правенор” становила 50 мг/мл для екстракту ягід карликової пальми (Saw palmetto), 16,67 мг/мл для екстракту коренів любистку лікарського (Levisticum officinale), 16,67 мг/мл для екстракту квіток нагідок лікарських (Calendula officinalis). Для медичних виробів не було виявлено сенсибілі­зуючої та шкіроподразнювальної дії на мурчаків. Висновки. Біологічне оцінювання медичних виробів у формі ректальних супозиторіїв “Правенор” і вагінальних супозиторіїв “Продексин”, проведене із використанням біологічних систем in vitro та in vivo, засвідчило прийнятний рівень безпечності цієї продукції. При визначенні цитотоксичності МТТ-тест виявився у 5 разів чутливішим порівняно з методом на основі культури клітин Vero.Background. Programs of preclinical safety studies of the health care products depend on the regulatory status of the investigated products. The classification of such products, in particular suppositories for rectal and vaginal use, is a critical step of developing tactics for their biological evaluation. Adaptation of biological evaluation methods for the medical devices based on the combination of biologically active substances, as well as evaluation of the results of such studies is urgent task of biomedicine. Objective. To substantiate the regulatory status and to carry out a biological evaluation of medical devices in the form of vaginal suppositories based on octenidine dihydrochloride ("Prodexyn") and in the form of rectal suppositories based on Saw palmetto, Levisticum officinale and Calendula officinalis extracts ("Pravenor"). Methods. Biological evaluation was conducted according to the requirements of ISO 10993 standards using in vitro and in vivo biological test systems (cytotoxicity in cell culture and the MTT test, sensitizing and irritating effect in guinea pigs). Results. The cytotoxicity (СС50) of the medical device "Prodexyn" extract in Vero cell culture was 8.35 μg/ml calculated as octenidine dihydrochloride and 416.65 μg/ml calculated as dexpanthenol. "Pravenor" medical device was found to be non-toxic in Vero cell culture. According to the results of MMT assay CC50 for octenidine dihydrochloride was 1.67 μg/ml, and 83.33 μg/ml – for dexpanthenol. CC50 indicators calculated for the different active ingredients of the medical device "Pravenor" were the following: 50 mg/ml for the dwarf palm berries extract (Saw palmetto), 16.67 mg/ml for the lovage roots extract (Levisticum officinale), and 16.67 mg/ml for the calendula flowers extract (Calendula officinalis). No sensitizing or skin irritating effects were observed in guinea pigs. Conclusions. Biological evaluation of medical devices in the form of rectal suppositories "Pravenor" and vaginal suppositories "Prodexyn" performed using in vitro and in vivo biological systems. It was demonstrated an acceptable level of safety of the products. The MTT test was 5 times more sensitive than the Vero cell culture method in determination of cytotoxicity

Cholinesterase based amperometric biosensors for assay of anticholinergic compounds

Biosensors are analytical devices being approachable for multiple analytes assay. Here, biosensors with intercepted acetylcholinesterase (AChE) or butyrylcholinesterase (BChE) are presented as tool for assay of anticholinergic compounds such as pesticides, nerve agents and some natural toxins. Principle of assay is based on evaluation of cholinesterase activity and its pertinent decrease in presence of analyte. Nerve agents, pesticides, anticholinergic drugs useable for treatment of Alzheimer′s disease as well as myasthenia gravis and aflatoxins are enlisted as compounds simply analyzable by cholinesterase biosensors

Cloud computing technologies in educational institutions

Integration into the European educational space requires the introduction into the educational process of higher education of the latest methods based on the use of ICTs. One of the main tasks of the education system is to ensure that everyone has free and open access to knowledge, taking into account their needs, abilities, and interests.To improve the learning process, it makes sense to use powerful technologies such as "cloud computing," which, while supporting traditional forms of learning, is a new stage in the development of education and a cost-effective, efficient and flexible way to meet the needs of students to obtain new knowledge. With the help of already existing technologies and tools, it is possible to create a local "computing cloud" for the educational institution to use its resources in accordance with modern educational requirements

Urease-based ISFET biosensor for arginine determination

In this work a novel biosensor for arginine determination based on the urease inhibition effect has been proposed. Ion-selective field effect transistors were used as transducers. Urease immobilized in glutaraldehyde vapor served as a biorecognition element of the biosensor. Significant part of the work was aimed at proving the urease inhibition by arginine. Optimal concentration of urea for arginine determination was chosen. Detection limit for arginine was 0.05 mM. The biosensor selectivity towards different amino acids was studied. The results of quantitative determination of L-arginine in the real sample (a drinkable solution "Arginine Veyron") were in good agreement with the producer's data (a relative error was 5.2%). The biosensor showed a good reproducibility of arginine determination

Development of novel enzyme potentiometric biosensor based on pH-sensitive field-effect transistors for aflatoxin B1 analysis in real samples

International audienceThis study aimed at the development and optimization of a potentiometric biosensor based on pH-sensitive field-effect transistors and acetylcholinesterase for aflatoxin B1 determination in real samples. Optimal conditions for bioselective elements operation were defined and analytical characteristics of the proposed biosensor were studied. The proposed biosensor characterized high operational stability and reproducibility of signal. Selectivity of acetylcholinesterase-biosensor to aflatoxins in relation to other groups of toxic substances was analyzed. The developed biosensor was applied to the determination of aflatoxin B1 in real samples (sesame, walnut and pea)

Conductometric enzyme biosensor for patulin determination

International audienc

Application of butyrylcholinesterase‐based biosensor for simultaneous determination of different toxicants using inhibition and reactivation steps

Fast and simple detection of toxic compounds in aqueous solutions is important for agriculture and pollution monitoring. Enzyme‐based electrochemical biosensors are a promising platform for this task, but they usually lack the ability to distinguish between toxicants if more than one toxicant is present in the sample. Herein, we propose a new method of detection of various toxic compounds in complex multi‐component water samples using an electrochemical biosensor and additional stages of enzyme reactivation. The biosensor is based on butyrylcholinesterase immobilized on the surface of conductometric transducers using glutaraldehyde cross‐linking. It was shown that the biosensor is sensitive to organophosphorus pesticides, heavy metals ions, glycoalkaloids, but has a limited sensitivity to mycotoxins and surfactants. We propose a procedure for the analysis of complex samples with several reactivation stages to be able to determine which category of toxicants is present. Glycoalkaloids are reversible inhibitors and biosensor's activity is restored by washing in working buffer; heavy metal ions and pesticides are irreversible inhibitors and biosensor's activity is restored by incubation in EDTA and PAM‐2 solutions, correspondingly. This biosensor can be used for the detection of separate toxicants or for analysis of their mixtures in aqueous samples. It can be also used for the evaluation of total toxicity of the samples and applied for water quality monitoring