Application of electroanalytical techniques for assessment of human cells

Rapid development of cell technologies stipulates the need for informative and express methods for the analysis of viability and physiological activity of human cells. We studied analytical possibilities of novel tools for comprehensive characterization of bioelectrochemical properties of living cells, e.g. surface charge of cellular membrane and redox activity of metabolites. Using Malvern Zetasizer dynamic light scattering analyzer we proposed an approach to assessment of zeta potential of human cells and detection of phosphatidylserine on their surface as an early apoptotic marker. On the basis of modified electrodes we designed sensors exhibiting high sensitivity towards electroactive cellular metabolites including antioxidants and macroergic molecules. The sensors were applied for assessment of metabolic activity/energetic status of human cells (blood cells and cell cultures). Electrochemical signal of adenine nucleotides of cells on sensor surface correlated with intracellular level of ATP according to luciferase assay and was found to be more sensitive to alteration in cell viability than conventional MTS test. On the basis of disposable screenprinted electrodes we fabricated a prototype of portable analyzer for rapid analysis of cell health (e.g. for donor cells) in less than 5 ?l volume of cell sample. Proposed tools and methods are of interest in cell transplantology, basic research and cell-based medical diagnostics

Electrochemical sensor for blood deoxyribonucleases: Design and application to the diagnosis of autoimmune thyroiditis

We designed an electrochemical sensor based on a carbon nanotube modified electrode (ME) to analyze DNA-cleaving activity. The cleavage of high molecular weight DNA resulted in an increase in the oxidation current from DNA guanine nucleotides due to a change in DNA adsorptive behavior on the surface of the ME. DNA digestion with DNAse I was accompanied by a linear increase in the DNA signal in proportion to the enzyme activity. We then proposed an assay based on the sensor for the direct assessment of the total deoxyribonuclease activity of blood serum as well as the separate detection of DNAse I and DNA abzymes. The assay was applied to analyze deoxyribonucleases in sera from 21 healthy donors and 17 patients with autoimmune thyroiditis. Our results show that the response of the sensor to DNA cleavage by blood deoxyribonucleases is a promising diagnostic criterion for autoimmune thyroiditis. This sensor can be implemented in a disposable screen-printed electrode format for application in clinical laboratories. © 2011 Springer-Verlag

Binding and purification of plasmid DNA using multi-layered carbon nanotubes

We propose a new method for the separation of nucleic acids using multi-layered carbon nanotubes (CNTs) as an adsorbent. According to agarose gel electrophoresis, oxidized water-stable CNTs adsorb certain forms of nucleic acids, such as high molecular weight RNA, chromosomal DNA, linear and denatured forms of plasmid DNA. However, CNTs do not adsorb supercoiled form of plasmid DNA. Nucleic acids bound to CNTs can be readily removed by centrifugation whereas supercoiled plasmid DNA remains in solution. Upon the addition of divalent metal ions supercoiled plasmid DNA forms relatively stable complexes with CNTs due to chelation. Thus, new details about association of nucleic acids with CNTs were revealed and stoichiometry of the complexes was estimated. Our results can be used for fine purification of supercoiled plasmid DNA for gene therapy applications as well as manipulation of nucleic acids for biosensor design. © 2011 Elsevier B.V

Decreased serum cell-free DNA levels in rheumatoid arthritis

Purpose: Recent studies have demonstrated that serum/plasma DNA and RNA molecules in addition to proteins can serve as biomarkers. Elevated levels of these nucleic acids have been found not only in acute, but also in chronic conditions, including autoimmune diseases. The aim of this study was to assess cell-free DNA (cfDNA) levels in sera of rheumatoid arthritis (RA) patients compared to controls. Methods: cfDNA was extracted from sera of patients with early and established RA, relapsing-remitting multiple sclerosis patients (RRMS) and healthy subjects, and its concentration was determined by quantitative PCR using two amplicons, Alu115 and β-actin205, corresponding to Alu repetitive elements and the β-actin single-copy gene, respectively. Serum DNase activity was measured by a single radial enzyme diffusion method. Results: Reduced levels of cfDNA were observed in patients with establi

Профилактика постишемического неврологического дефицита путем модуляции экспрессии АДФ-рибозилциклазы в клетках головного мозга (экспериментальное исследование)

Objective: to study the mechanism that is responsible for impaired neuronal cell electroexcitability and viability, which is associated with modification of ADP-ribosyl cyclase in cerebral ischemic lesion, as well as the possibilities of pathogenet-ically correcting these disorders.Materials and methods. Acute cerebral ischemia was simulated in vivo on noninbred albino male rats, by ligating the right common carotid artery under general anesthesia. y-Interferon was intraperitoneally administered to the mammal in a dose of 5000 IU/kg body weight once daily for 3 days until unilateral extravasal occlusion of the common carotid artery occurred. The activity of ADP-ribosyl cyclase was evaluated by the fluorometric technique. CD38 expression in the brain cells was immunohistohemically detected. The severity of neurological symptoms was evaluated using the international NSS scale for laboratory animals. Cognitive dysfunction was recorded employing the standard test — the Morris water maze. The validity of differences was assessed by Student’s t-test and T-test, by applying STATISTICA version 6.0 (StatSoft-Russia, 1999) and BIOSTATISTICA programs.Results. Progressive neurological and cognitive deficit-induced changes occurred in the activity and expression of ADP-ribosyl cyclase/CD38 in the neuronal and glial cells in the course of brain ischemia. Neuroprotection and prevention of postischemic cognitive dysfunction were achieved by the use of y-interferon as a modifier of the brain cell expression of CD38/ADP-ribosyl cyclase. Цель исследования . Изучение механизма нарушения электровозбудимости и жизнеспособности клеток нейрональ-ной природы, ассоциированного с изменением активности АДФ-рибозилциклазы, при ишемическом повреждении головного мозга, а также возможности патогенетической коррекции этих нарушений.Материалы и методы. Моделирование острой ишемии головного мозга in vivo осуществлялось перевязкой под общей анестезией правой общей сонной артерии на белых беспородных крысах-самцах. В течение 3 дней до унилатеральной экстравазальной окклюзии общей сонной артерии млекопитающему вводили внутрибрюшинно препарат гамма-интерферона в дозе 5000 МЕ/кг массы, 1 раз в сутки. Активность АДФ-рибозилциклазы оценивалась флуориметрическим методом. Детекция CD38 в клетках головного мозга осуществлялась иммуногистохимически. Оценка степени выраженности неврологической симптоматики осуществлялась с использованием международной шкалы NSS для лабораторных животных. Регистрация когнитивной дисфункции у лабораторных животных осуществлялась с использованием стандартного теста — водного лабиринта Морриса. Оценку достоверности различий осуществляли с использованием t-критерия Стьюдента и Т-теста, с помощью программ STATISTICA v. 6.0 [StatSoft-Russia, 1999] и BIOSTATISTICA.Результаты. В динамике ишемии головного мозга происходили изменения активности и экспрессии АДФ-рибозилцикла-зы/CD38 в клетках нейрональной и глиальной природы, ассоциированные с нарастанием неврологического и когнитивного дефицита. Нейропротективный эффект и профилактика постишемической когнитивной дисфункции достигались использованием гамма-интерферона как модулятора экспрессии CD38/АДФ-рибозилциклазы в клетках мозга.

Assessment of metabolic activity of human cells in solution and in polymer matrix with the use of metabolite-sensitive sensors

We developed metabolite-sensitive electrochemical sensors on the basis of electrodes modified with a thick film of carbon nanotubes. Modified electrodes provide efficient pre-adsorption of cellular metabolites and their sensitive detection using anodic square-wave voltammetry. On the electrode surface both adhered and non-adhered human cells produce three oxidation peaks at the potentials of + 0.82, + 1.05, and + 1.17 V attributed to three groups of cellular metabolites: amino acid-derived antioxidants including glutathione, guanine nucleotides, and also adenine nucleotides including ATP. The electrochemical response was well correlated with cell viability, intracellular ATP level and induction of apoptosis, as determined by independent assays. Developed sensors allow for robust and cost-effective assessment of ATP in cells in contrast to enzyme-based electrodes and conventional bioluminescent assay. Results can be used for rapid analysis of human cells for the purpose of medical diagnostics, transplantology, and toxicological screening. Additionally, we combined modified electrodes with human cells entrapped in agarose matrix. The resulting biosensor allowed for electrochemical monitoring of metabolic activity and death of cells within polymeric matrix that is of interest for tissue engineering applications. © 2012 Elsevier B.V. All rights reserved

La Patrie : journal quotidien, politique, commercial et littéraire

19 mai 19161916/05/19 (A75)

Application of electroanalytical techniques for assessment of human cells

Rapid development of cell technologies stipulates the need for informative and express methods for the analysis of viability and physiological activity of human cells. We studied analytical possibilities of novel tools for comprehensive characterization of bioelectrochemical properties of living cells, e.g. surface charge of cellular membrane and redox activity of metabolites. Using Malvern Zetasizer dynamic light scattering analyzer we proposed an approach to assessment of zeta potential of human cells and detection of phosphatidylserine on their surface as an early apoptotic marker. On the basis of modified electrodes we designed sensors exhibiting high sensitivity towards electroactive cellular metabolites including antioxidants and macroergic molecules. The sensors were applied for assessment of metabolic activity/energetic status of human cells (blood cells and cell cultures). Electrochemical signal of adenine nucleotides of cells on sensor surface correlated with intracellular level of ATP according to luciferase assay and was found to be more sensitive to alteration in cell viability than conventional MTS test. On the basis of disposable screenprinted electrodes we fabricated a prototype of portable analyzer for rapid analysis of cell health (e.g. for donor cells) in less than 5 ?l volume of cell sample. Proposed tools and methods are of interest in cell transplantology, basic research and cell-based medical diagnostics

Assessment of metabolic activity of human cells in solution and in polymer matrix with the use of metabolite-sensitive sensors

We developed metabolite-sensitive electrochemical sensors on the basis of electrodes modified with a thick film of carbon nanotubes. Modified electrodes provide efficient pre-adsorption of cellular metabolites and their sensitive detection using anodic square-wave voltammetry. On the electrode surface both adhered and non-adhered human cells produce three oxidation peaks at the potentials of + 0.82, + 1.05, and + 1.17 V attributed to three groups of cellular metabolites: amino acid-derived antioxidants including glutathione, guanine nucleotides, and also adenine nucleotides including ATP. The electrochemical response was well correlated with cell viability, intracellular ATP level and induction of apoptosis, as determined by independent assays. Developed sensors allow for robust and cost-effective assessment of ATP in cells in contrast to enzyme-based electrodes and conventional bioluminescent assay. Results can be used for rapid analysis of human cells for the purpose of medical diagnostics, transplantology, and toxicological screening. Additionally, we combined modified electrodes with human cells entrapped in agarose matrix. The resulting biosensor allowed for electrochemical monitoring of metabolic activity and death of cells within polymeric matrix that is of interest for tissue engineering applications. © 2012 Elsevier B.V. All rights reserved

Application of electroanalytical techniques for assessment of human cells

Rapid development of cell technologies stipulates the need for informative and express methods for the analysis of viability and physiological activity of human cells. We studied analytical possibilities of novel tools for comprehensive characterization of bioelectrochemical properties of living cells, e.g. surface charge of cellular membrane and redox activity of metabolites. Using Malvern Zetasizer dynamic light scattering analyzer we proposed an approach to assessment of zeta potential of human cells and detection of phosphatidylserine on their surface as an early apoptotic marker. On the basis of modified electrodes we designed sensors exhibiting high sensitivity towards electroactive cellular metabolites including antioxidants and macroergic molecules. The sensors were applied for assessment of metabolic activity/energetic status of human cells (blood cells and cell cultures). Electrochemical signal of adenine nucleotides of cells on sensor surface correlated with intracellular level of ATP according to luciferase assay and was found to be more sensitive to alteration in cell viability than conventional MTS test. On the basis of disposable screenprinted electrodes we fabricated a prototype of portable analyzer for rapid analysis of cell health (e.g. for donor cells) in less than 5 ?l volume of cell sample. Proposed tools and methods are of interest in cell transplantology, basic research and cell-based medical diagnostics