Cecilia Cristea | University of Medicine and Pharmacy "Iuliu Hatieganu" Cluj-Napoca (original) (raw)

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Papers by Cecilia Cristea

Molecules, 2021

Food safety and quality control pose serious issues to food industry and public health domains, i... more Food safety and quality control pose serious issues to food industry and public health domains, in general, with direct effects on consumers. Any physical, chemical, or biological unexpected or unidentified food constituent may exhibit harmful effects on people and animals from mild to severe reactions. According to the World Health Organization (WHO), unsafe foodstuffs are especially dangerous for infants, young children, elderly, and chronic patients. It is imperative to continuously develop new technologies to detect foodborne pathogens and contaminants in order to aid the strengthening of healthcare and economic systems. In recent years, peptide-based sensors gained much attention in the field of food research as an alternative to immuno-, apta-, or DNA-based sensors. This review presents an overview of the electrochemical biosensors using peptides as molecular bio-recognition elements published mainly in the last decade, highlighting their possible application for rapid, non-de...

Talanta, 2017

In this work, we report the design, the development and the characterization of the analytical pe... more In this work, we report the design, the development and the characterization of the analytical performances of a colorimetric smartphone-based immunosensor for the detection of cancer antigen 125 (CA125). The immunosensor was based on a sandwich strategy in which the primary antibody was immobilized by spotting onto the 3D nitrocellulose membrane. The immunospots were subsequently incubated with CA125 solutions, followed by the affinity reaction with a secondary antibody labeled with gold nanoparticles (AuNPs). The antibody-AuNPs captured onto immunospots induced the silver deposition from a silver enhancer solution leading to the formation of gold-silver nanoparticles of different grey color spots depending on CA125 concentration. The 8 megapixels smartphone camera was integrated in a home-made dark box and used as transducer of color image acquisition and data handling. The pixel intensity of the captured images was determined by an image processing algorithm. The experimental par...

IRBM, 2008

This paper deals with the development of a disposable electrochemical sensor for the detection of... more This paper deals with the development of a disposable electrochemical sensor for the detection of hydrogen peroxide, using screen-printed carbon-based electrodes (SPCEs) modified with multi-wall carbon nanotubes (MWCNs) dispersed in a polyethylenimine (PEI) mixture. The modified sensors showed an excellent electrocatalytic activity towards the analyte, respect to the high overvoltage characterising unmodified screen-printed sensors. The composition of the PEI/MWCNT dispersion was optimised in order to improve the sensitivity and reproducibility. The optimised sensor showed good reproducibility (10% RSD calculated on three experiments repeated on the same electrode), whereas a reproducibility of 15% as RSD was calculated on electrodes from different preparations. Preliminary experiments carried out using glucose oxidase (GOD) as biorecognition element gave rise to promising results indicating that these new devices may represent interesting components for biosensor construction.

Studia Universitatis Babes Bolyai Chemia, 2012

The hydroxylamines constitute an interesting class of organic intermediates. In this paper we pre... more The hydroxylamines constitute an interesting class of organic intermediates. In this paper we present the electrosynthesis of different hydroxylamines in different electrolytes having as major goal synthesys of new class of compounds from the nitroderivatives, such starting materials [1]. In this purpose we made the detailed study of the electrochemical behaviour for the nitro derivatives and hydroxyl amines [2-4]: having the main structure of 2 amino-p-nitro phenyl 1,3 propane some simple molecule, named "model" molecules (nitrobenzene, p-toluene or nitrobenzylic alcohol). phenothiazine nitroderivatives Using two different type of cell (Hg batch cell and the "redox" cell, equipped with porous graphite felt electrodes) the hydroxylamines have been generated and captured in reaction with different reagents.

Biosensors - Micro and Nanoscale Applications, 2015

International journal of electrochemical science

Farmacia

An ultrasensitive and specific label-free irrununosensor for the detection of acetaminophen is pr... more An ultrasensitive and specific label-free irrununosensor for the detection of acetaminophen is presented. Protein G-magnetic microparticles retained by the external magnetic field at the surface of carbon based screen printed electrodes were used as immobilization platform. The modified beads were then used to capture the anti-acetaminophen antibody immediately followed by the immunological reaction between the antibody and its antigen, acetaminophen. After optimizing all the steps involved in the immunosensor development, a limit of detection of 1.76 mu M was obtained on differential pulse voltammetry measurements.

Journal of environmental protection and ecology

The electrochemical behavior of 2,7-bis-(pyrazole-3(5)-ylazo)-1,8-dihidroxynaphtalene-3,6-disulph... more The electrochemical behavior of 2,7-bis-(pyrazole-3(5)-ylazo)-1,8-dihidroxynaphtalene-3,6-disulphonic acid (bis-PACA) and its complexes with Cu(II), Cd(II), Ni(II), Pb(II) and Hg(II) was investigated using voltammetry. Experiments were performed in the concentration range from 5×10-5 to 7×10-4 M of bis- pyrazole-azo-chromotropic acid (bis-PACA). Linear dependence of current intensity versus bis-PACA concentration was obtained in the investigated concentration range. According to the obtained results, the process is controlled by diffusion. The elaboration of a Cu(II) selective electrode by using bis-PACA as modifier was also investigated.

Electrochimica Acta, 2015

ABSTRACT

Electrochemistry Communications, 2015

ABSTRACT A sensitive electrochemical molecularly imprinted sensor was developed for the detection... more ABSTRACT A sensitive electrochemical molecularly imprinted sensor was developed for the detection of estradiol, by electropolymerization of p-aminothiophenol functionalized gold nanoparticles in the presence of estradiol as template molecule. The extraction of the template leads to the formation of cavities that are able to recognize and bind estradiol with high affinity. The performance of the developed sensor for the detection of estradiol was investigated by linear sweep voltammetry using a hexacyanoferrate/hexacyanoferrite solution as redox probe. The molecularly imprinted sensor exhibits a broad linear range, between 3.6 fM and 3.6 nM and a limit of quantification of 1.09 fM. Compared to the non-imprinted sensor, the imprinted sensor exhibits high affinity for the binding of estradiol. Moreover, selectivity studies, performed towards binding of testosterone, a hormone with similar chemical structure, proved high sensor selectivity. Furthermore, the molecularly imprinted sensor was applied for the analysis of spiked river samples with good recoveries.

IFMBE Proceedings, 2009

Printed electrodes, named SPE, are miniaturized devises that are manufactured by printing multipl... more Printed electrodes, named SPE, are miniaturized devises that are manufactured by printing multiple successive layers of different inks on a plastic or ceramic solid support, after a well established design, in accordance to the performances and the analysis in which they will be used [1]. The printed electrochemical cell is represented by a graphite working electrode with a diameter of 3-4mm, a graphite contra-electrode and a silver pseudo-reference [2]. The low production cost, the easy of mass production, the flexibility in design, the possibility of using small volumes make these devises very attractive for practical use [3]. The one time use devices seem to be an attractive alternative, but they should ensure a high reproducibility from sensor to sensor, a low cost-efficacy ratio, simplicity of mass production, long term stability during storage, portability and simplicity in use [4].

Analytica Chimica Acta, 2015

This study describes the advancements made over the last five years in the development of electro... more This study describes the advancements made over the last five years in the development of electrochemical sensors and biosensors for acetaminophen detection. This study reviews the different configurations based on unmodified and chemically modified carbon nanotubes and graphene. The influence of various modifiers on the two types of materials is presented along with their role on the enhancement of the selectivity and sensitivity of (bio)sensors. The review is focused on a comparative description of the applications of carbon-based nanomaterials towards acetaminophen detection and presents the results in a critical manner.

International journal of electrochemical science

Molecules, 2021

Food safety and quality control pose serious issues to food industry and public health domains, i... more Food safety and quality control pose serious issues to food industry and public health domains, in general, with direct effects on consumers. Any physical, chemical, or biological unexpected or unidentified food constituent may exhibit harmful effects on people and animals from mild to severe reactions. According to the World Health Organization (WHO), unsafe foodstuffs are especially dangerous for infants, young children, elderly, and chronic patients. It is imperative to continuously develop new technologies to detect foodborne pathogens and contaminants in order to aid the strengthening of healthcare and economic systems. In recent years, peptide-based sensors gained much attention in the field of food research as an alternative to immuno-, apta-, or DNA-based sensors. This review presents an overview of the electrochemical biosensors using peptides as molecular bio-recognition elements published mainly in the last decade, highlighting their possible application for rapid, non-de...

Talanta, 2017

In this work, we report the design, the development and the characterization of the analytical pe... more In this work, we report the design, the development and the characterization of the analytical performances of a colorimetric smartphone-based immunosensor for the detection of cancer antigen 125 (CA125). The immunosensor was based on a sandwich strategy in which the primary antibody was immobilized by spotting onto the 3D nitrocellulose membrane. The immunospots were subsequently incubated with CA125 solutions, followed by the affinity reaction with a secondary antibody labeled with gold nanoparticles (AuNPs). The antibody-AuNPs captured onto immunospots induced the silver deposition from a silver enhancer solution leading to the formation of gold-silver nanoparticles of different grey color spots depending on CA125 concentration. The 8 megapixels smartphone camera was integrated in a home-made dark box and used as transducer of color image acquisition and data handling. The pixel intensity of the captured images was determined by an image processing algorithm. The experimental par...

IRBM, 2008

This paper deals with the development of a disposable electrochemical sensor for the detection of... more This paper deals with the development of a disposable electrochemical sensor for the detection of hydrogen peroxide, using screen-printed carbon-based electrodes (SPCEs) modified with multi-wall carbon nanotubes (MWCNs) dispersed in a polyethylenimine (PEI) mixture. The modified sensors showed an excellent electrocatalytic activity towards the analyte, respect to the high overvoltage characterising unmodified screen-printed sensors. The composition of the PEI/MWCNT dispersion was optimised in order to improve the sensitivity and reproducibility. The optimised sensor showed good reproducibility (10% RSD calculated on three experiments repeated on the same electrode), whereas a reproducibility of 15% as RSD was calculated on electrodes from different preparations. Preliminary experiments carried out using glucose oxidase (GOD) as biorecognition element gave rise to promising results indicating that these new devices may represent interesting components for biosensor construction.

Studia Universitatis Babes Bolyai Chemia, 2012

The hydroxylamines constitute an interesting class of organic intermediates. In this paper we pre... more The hydroxylamines constitute an interesting class of organic intermediates. In this paper we present the electrosynthesis of different hydroxylamines in different electrolytes having as major goal synthesys of new class of compounds from the nitroderivatives, such starting materials [1]. In this purpose we made the detailed study of the electrochemical behaviour for the nitro derivatives and hydroxyl amines [2-4]: having the main structure of 2 amino-p-nitro phenyl 1,3 propane some simple molecule, named "model" molecules (nitrobenzene, p-toluene or nitrobenzylic alcohol). phenothiazine nitroderivatives Using two different type of cell (Hg batch cell and the "redox" cell, equipped with porous graphite felt electrodes) the hydroxylamines have been generated and captured in reaction with different reagents.

Biosensors - Micro and Nanoscale Applications, 2015

International journal of electrochemical science

Farmacia

An ultrasensitive and specific label-free irrununosensor for the detection of acetaminophen is pr... more An ultrasensitive and specific label-free irrununosensor for the detection of acetaminophen is presented. Protein G-magnetic microparticles retained by the external magnetic field at the surface of carbon based screen printed electrodes were used as immobilization platform. The modified beads were then used to capture the anti-acetaminophen antibody immediately followed by the immunological reaction between the antibody and its antigen, acetaminophen. After optimizing all the steps involved in the immunosensor development, a limit of detection of 1.76 mu M was obtained on differential pulse voltammetry measurements.

Journal of environmental protection and ecology

The electrochemical behavior of 2,7-bis-(pyrazole-3(5)-ylazo)-1,8-dihidroxynaphtalene-3,6-disulph... more The electrochemical behavior of 2,7-bis-(pyrazole-3(5)-ylazo)-1,8-dihidroxynaphtalene-3,6-disulphonic acid (bis-PACA) and its complexes with Cu(II), Cd(II), Ni(II), Pb(II) and Hg(II) was investigated using voltammetry. Experiments were performed in the concentration range from 5×10-5 to 7×10-4 M of bis- pyrazole-azo-chromotropic acid (bis-PACA). Linear dependence of current intensity versus bis-PACA concentration was obtained in the investigated concentration range. According to the obtained results, the process is controlled by diffusion. The elaboration of a Cu(II) selective electrode by using bis-PACA as modifier was also investigated.

Electrochimica Acta, 2015

ABSTRACT

Electrochemistry Communications, 2015

ABSTRACT A sensitive electrochemical molecularly imprinted sensor was developed for the detection... more ABSTRACT A sensitive electrochemical molecularly imprinted sensor was developed for the detection of estradiol, by electropolymerization of p-aminothiophenol functionalized gold nanoparticles in the presence of estradiol as template molecule. The extraction of the template leads to the formation of cavities that are able to recognize and bind estradiol with high affinity. The performance of the developed sensor for the detection of estradiol was investigated by linear sweep voltammetry using a hexacyanoferrate/hexacyanoferrite solution as redox probe. The molecularly imprinted sensor exhibits a broad linear range, between 3.6 fM and 3.6 nM and a limit of quantification of 1.09 fM. Compared to the non-imprinted sensor, the imprinted sensor exhibits high affinity for the binding of estradiol. Moreover, selectivity studies, performed towards binding of testosterone, a hormone with similar chemical structure, proved high sensor selectivity. Furthermore, the molecularly imprinted sensor was applied for the analysis of spiked river samples with good recoveries.

IFMBE Proceedings, 2009

Printed electrodes, named SPE, are miniaturized devises that are manufactured by printing multipl... more Printed electrodes, named SPE, are miniaturized devises that are manufactured by printing multiple successive layers of different inks on a plastic or ceramic solid support, after a well established design, in accordance to the performances and the analysis in which they will be used [1]. The printed electrochemical cell is represented by a graphite working electrode with a diameter of 3-4mm, a graphite contra-electrode and a silver pseudo-reference [2]. The low production cost, the easy of mass production, the flexibility in design, the possibility of using small volumes make these devises very attractive for practical use [3]. The one time use devices seem to be an attractive alternative, but they should ensure a high reproducibility from sensor to sensor, a low cost-efficacy ratio, simplicity of mass production, long term stability during storage, portability and simplicity in use [4].

Analytica Chimica Acta, 2015

This study describes the advancements made over the last five years in the development of electro... more This study describes the advancements made over the last five years in the development of electrochemical sensors and biosensors for acetaminophen detection. This study reviews the different configurations based on unmodified and chemically modified carbon nanotubes and graphene. The influence of various modifiers on the two types of materials is presented along with their role on the enhancement of the selectivity and sensitivity of (bio)sensors. The review is focused on a comparative description of the applications of carbon-based nanomaterials towards acetaminophen detection and presents the results in a critical manner.

International journal of electrochemical science