Arunas Ramanavicius | Vilnius University (original) (raw)
Papers by Arunas Ramanavicius
Electrochimica Acta, Jun 1, 2014
Electrochimica Acta, Sep 1, 2023
Springer proceedings in physics, 2020
Analysis of pharmaceuticals and biologically active materials recently can be performed by biosen... more Analysis of pharmaceuticals and biologically active materials recently can be performed by biosensors, which can be based on conducting polymers. Therefore, in this Mini Review some achievements in the synthesis and application of conducting polymer—polypyrrole (Ppy), which is often used in the design of sensors and biosensors, are overviewed. Some perspective methods of conducting polymer synthesis are outlined. Significant attention has been paid to electrochemical, chemical and biochemical synthesis of conducting polymers (CPs) , which were developed by authors. The applicability of polypyrrole based functional layers in the design of electrochemical biosensors is overviewed. The adaptability of enzyme—glucose oxidase (GOx), which can be applied as (i) biological recognition element—in the design of glucose biosensors, (ii) a biocatalyst—in the synthesis of some above mentioned conducting polymers, is discussed. Part of biocompatibility related aspects of some conducting polymers are also discussed and some insights in the application of polypyrrole-based coatings for implantable sensors are outlined.
Journal of Pharmaceutical and Biomedical Analysis, May 1, 2023
Mikrochimica Acta, Apr 8, 2014
International Journal of Molecular Sciences, Mar 18, 2023
Biosensors
The development of microbial fuel cells based on electro-catalytic processes is among the novel t... more The development of microbial fuel cells based on electro-catalytic processes is among the novel topics, which are recently emerging in the sustainable development of energetic systems. Microbial fuel cells have emerged as unique biocatalytic systems, which transform the chemical energy accumulated in renewable organic fuels and at the same time reduce pollution from hazardous organic compounds. However, not all microorganisms involved in metabolic/catalytic processes generate sufficient redox potential. In this research, we have assessed the applicability of the microorganism Rhizobium anhuiense as a catalyst suitable for the design of microbial fuel cells. To improve the charge transfer, several redox mediators were tested, namely menadione, riboflavin, and 9,10-phenanthrenequinone (PQ). The best performance was determined for a Rhizobium anhuiense-based bio-anode mediated by menadione with a 0.385 mV open circuit potential and 5.5 μW/cm2 maximal power density at 0.35 mV, which gen...
Biosensors
In this study, graphite rod (GR) electrodes were electrochemically modified by dendritic gold nan... more In this study, graphite rod (GR) electrodes were electrochemically modified by dendritic gold nanostructures (DGNs) followed by immobilization of glucose oxidase (GOx) in the presence of mediator phenazine methosulfate (PMS). Modified with polyaniline (PANI) or polypyrrole (Ppy), GOx/DGNs/GR electrodes were used in glucose biosensor design. Different electrochemical methods were applied for the registration of glucose concentration, and constant potential amperometry (CPA) was chosen as the best one. PANI and Ppy layers synthesized enzymatically on the GOx/DGNs/GR electrodes extended the linear glucose determination range, the width of which depended on the duration of PANI- and Ppy-layers formation. Enzymatically formed polypyrrole was determined as the most suitable polymer for the modification and formation of the glucose biosensor instead of polyaniline, because it was 1.35 times more sensitive and had a 2.57 times lower limit of detection (LOD). The developed glucose biosensor ...
International Journal of Molecular Sciences
The serologic diagnosis of coronavirus disease 2019 (COVID-19) and the evaluation of vaccination ... more The serologic diagnosis of coronavirus disease 2019 (COVID-19) and the evaluation of vaccination effectiveness are identified by the presence of antibodies specific to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this paper, we present the electrochemical-based biosensing technique for the detection of antibodies specific to the SARS-CoV-2 proteins. Recombinant SARS-CoV-2 spike proteins (rSpike) were immobilised on the surface of a gold electrode modified by a self-assembled monolayer (SAM). This modified electrode was used as a sensitive element for the detection of polyclonal mouse antibodies against the rSpike (anti-rSpike). Electrochemical impedance spectroscopy (EIS) was used to observe the formation of immunocomplexes while cyclic voltammetry (CV) was used for additional analysis of the surface modifications. It was revealed that the impedimetric method and the elaborate experimental conditions are appropriate for the further development of electrochemical ...
Biosensors
In recent years, many efforts have been made to develop rapid, sensitive and user-friendly glucos... more In recent years, many efforts have been made to develop rapid, sensitive and user-friendly glucose biosensors for monitoring blood glucose concentration in patients. In this study, the electrochemical glucose biosensors based on graphite rod (GR) electrode electrochemically modified with dendritic gold nanostructures (DGNs) and glucose oxidase (GOx) were developed. Phenazine methosulfate was used as a soluble redox mediator. Three GOx immobilization methods: adsorption on DGNs and cross-linking with glutaraldehyde (GA) vapour (GA-GOx/DGNs/GR), covalent immobilization on DGNs modified with 11-mercaptoundecanoic acid self-assembled monolayer (SAM) (GOx-SAM/DGNs/GR) and covalent immobilization on SAM with additional cross-linking with GA vapour (GA-GOx-SAM/DGNs/GR), were used. It was determined that GA significantly improved the stability of the enzyme layer. The difference of maximal current generated during the enzymatic reaction (ΔImax) equal to 272.06 ± 8.69 µA was obtained using a...
Journal of Nanobiotechnology
Early detection of viral pathogens by DNA-sensors in clinical samples, contaminated foods, soil o... more Early detection of viral pathogens by DNA-sensors in clinical samples, contaminated foods, soil or water can dramatically improve clinical outcomes and reduce the socioeconomic impact of diseases such as COVID-19. Clustered regularly interspaced short palindromic repeat (CRISPR) and its associated protein Cas12a (previously known as CRISPR-Cpf1) technology is an innovative new-generation genomic engineering tool, also known as ‘genetic scissors’, that has demonstrated the accuracy and has recently been effectively applied as appropriate (E-CRISPR) DNA-sensor to detect the nucleic acid of interest. The CRISPR-Cas12a fromPrevotella and Francisella 1are guided by a short CRISPR RNA (gRNA). The unique simultaneouscis-andtrans-DNA cleavage after target sequence recognition at the PAM site, sticky-end (5–7 bp) employment, and ssDNA/dsDNA hybrid cleavage strategies to manipulate the attractive nature of CRISPR–Cas12a are reviewed. DNA-sensors based on the CRISPR-Cas12a technology for rapid...
Sensors, 2022
This review is dedicated to the development of molecularly imprinted polymers (MIPs) and the appl... more This review is dedicated to the development of molecularly imprinted polymers (MIPs) and the application of MIPs in sensor design. MIP-based biological recognition parts can replace receptors or antibodies, which are rather expensive. Conducting polymers show unique properties that are applicable in sensor design. Therefore, MIP-based conducting polymers, including polypyrrole, polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline and ortho-phenylenediamine are frequently applied in sensor design. Some other materials that can be molecularly imprinted are also overviewed in this review. Among many imprintable materials conducting polymer, polypyrrole is one of the most suitable for molecular imprinting of various targets ranging from small organics up to rather large proteins. Some attention in this review is dedicated to overview methods applied to design MIP-based sensing structures. Some attention is dedicated to the physicochemical methods applied for the transduction of ...
Sensors, 2022
Electrically conductive polymers are promising materials for charge transfer from living cells to... more Electrically conductive polymers are promising materials for charge transfer from living cells to the anodes of electrochemical biosensors and biofuel cells. The modification of living cells by polypyrrole (PPy) causes shortened cell lifespan, burdens the replication process, and diminishes renewability in the long term. In this paper, the viability and morphology non-modified, inactivated, and PPy-modified yeasts were evaluated. The results displayed a reduction in cell size, an incremental increase in roughness parameters, and the formation of small structural clusters of polymers on the yeast cells with the increase in the pyrrole concentration used for modification. Yeast modified with the lowest pyrrole concentration showed minimal change; thus, a microbial fuel cell (MFC) was designed using yeast modified by a solution containing 0.05 M pyrrole and compared with the characteristics of an MFC based on non-modified yeast. The maximal generated power of the modified system was 47...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2021
Abstract In this research, scanning electrochemical microscopy (SECM) and electrochemical impedan... more Abstract In this research, scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS) were applied for the evaluation of surface characteristics of electrochemical (amperometric) biosensor based on two composite structures consisting of perforated polycarbonate membrane modified by carbon-nanomaterials and glucose oxidase. The first structure consisted of the polycarbonate filter membrane, punctured by 400 nm holes (PCM) consequently modified with single walled carbon nanotubes (SWCNT) and graphene oxide (GO) layer (PCM/SWCNT/GO); and the other structure consisted of the same PCM, consequently modified with SWCNT and reduced graphene oxide (rGO) layer (PCM/SWCNT/rGO). These two composite structures were developed and applied in biosensor design. In order to form a biosensing surfaces the PCM/SWCNT/GO and PCM/SWCNT/rGO composite structures were modified by immobilized glucose oxidase (GOx). The surface of GOx modified PCM/SWCNT/GO composite structure (PCM/SWCNT/GO/GOx) was evaluated by SECM redox-competition mode at different glucose concentrations. It was determined that PCM/SWCNT/GO/GOx composite structure is suitable for the design of amperometric glucose biosensors, because SWCNT/GO layer facilitates electron transfer from GOx via the oxidation of formed catalyzed reaction product H2O2. Therefore, the PCM/SWCNT/GO/GOx structure is a promising material for the design of amperometric glucose biosensors and biofuel cells, which are useful for a wide variety of environmental purposes and green energy production using food-industry waste.
Living cells mechanical properties establishment from Atomic force microscopy (AFM) force-separat... more Living cells mechanical properties establishment from Atomic force microscopy (AFM) force-separation curves is a challenge because the calculated Young’s modulus depends on the applied mathematical model. The more reliable results can be obtained using finite element models. In this work, yeast cells with different mechanical properties were measured by AFM. To change cells mechanical properties, yeasts were immersed in 9, 10-phenanthrenequinone, which changed cells’ membranes elasticity. 3D finite element model of the whole cell was created to calculate reacting force when AFM tip indents the cell in the same way as in the real experiment. It was found that our model is capable to draw the information about cells mechanical properties and visco-elastic behavior of cells membranes.
Scientific Reports, 2021
In this study, we reported the development of Prussian blue (PB), poly(pyrrole-2-carboxylic acid)... more In this study, we reported the development of Prussian blue (PB), poly(pyrrole-2-carboxylic acid) (PPCA), and glucose oxidase (GOx) biocomposite modified graphite rod (GR) electrode as a potential biocathode for single enzyme biofuel cell fuelled by glucose. In order to design the biocathode, the GR electrode was coated with a composite of PB particles embedded in the PPCA shell and an additional layer of PPCA by cyclic voltammetry. Meanwhile, GOx molecules were covalently attached to the carboxyl groups of PPCA by an amide bond. The optimal conditions for the biocathode preparation were elaborated experimentally. After optimization, the developed biocathode showed excellent electrocatalytic activity toward the reduction of H2O2 formed during GOx catalyzed glucose oxidation at a low potential of 0.1 V vs Ag/AgCl, as well as good electrochemical performance. An electrocatalytic current density of 31.68 ± 2.70 μA/cm2 and open-circuit potential (OCP) of 293.34 ± 15.70 mV in O2-saturate...
Coatings, 2020
An electrochemically synthesised porous anodic aluminium oxide (pAAO) layer has been analysed by ... more An electrochemically synthesised porous anodic aluminium oxide (pAAO) layer has been analysed by means of spectroscopic ellipsometry. The determined thickness of the formed pAAO layer obtained from spectroscopic ellipsometry measurements and modelling was 322.75 ± 0.12 nm. The radius of the nanopores estimated from SEM images was 39 ± 5 nm and the distance between nanopores was 107 ± 6 nm. The investigation of human serum albumin (HSA) adsorption on the pAAO coating showed that: (i) the protein concentration inside nanopores, depending on exposure time, approximately was from 200 up to 600 times higher than that determined in buffer solution; (ii) the initial phase of the adsorption process is slow (3.23 mg·cm−3·min−1) in comparison with the protein desorption rate (21.2 mg·cm−3·min−1) by means of pAAO layer washing; (iii) conventional washing with PBS solution and deionised water does not completely remove HSA molecules from pAAO pores and, therefore, the HSA concentration inside n...
The Journal of Physical Chemistry C, 2018
Journal of The Electrochemical Society, 2019
In this research, conducting polymer – polypyrrole (Ppy), was electrochemically polymerized on th... more In this research, conducting polymer – polypyrrole (Ppy), was electrochemically polymerized on the indium tin oxide coated glass (glass/ITO) electrode. The adhesion of Ppy on the surface of ITO was improved by modification with triethoxymethylsilane (TEMS). Potential cycling was applied for electrochemical deposition of Ppy layer and cyclic voltammograms were recorded during the deposition to monitor polymerization process. Cyclic voltammetry and the potential pulse sequence (PPS)-based chronoamperometry methods complemented the registration of absorbance spectra of glass/ITO(TEMS)/Ppy at various pH and different concentrations of CO2. The applicability of glass/ITO(TEMS)/Ppy electrode in the design of electrochromic sensor sensitive toward CO2 has been evaluated. Cyclic voltammetry based experiments at different potential sweep rates in presence and absence of CO2 were performed in order to evaluate charge transfer phenomenon in glass/ITO(TEMS)/Ppy structure
Sensors and Actuators B: Chemical, 2019
Electrochimica Acta, Jun 1, 2014
Electrochimica Acta, Sep 1, 2023
Springer proceedings in physics, 2020
Analysis of pharmaceuticals and biologically active materials recently can be performed by biosen... more Analysis of pharmaceuticals and biologically active materials recently can be performed by biosensors, which can be based on conducting polymers. Therefore, in this Mini Review some achievements in the synthesis and application of conducting polymer—polypyrrole (Ppy), which is often used in the design of sensors and biosensors, are overviewed. Some perspective methods of conducting polymer synthesis are outlined. Significant attention has been paid to electrochemical, chemical and biochemical synthesis of conducting polymers (CPs) , which were developed by authors. The applicability of polypyrrole based functional layers in the design of electrochemical biosensors is overviewed. The adaptability of enzyme—glucose oxidase (GOx), which can be applied as (i) biological recognition element—in the design of glucose biosensors, (ii) a biocatalyst—in the synthesis of some above mentioned conducting polymers, is discussed. Part of biocompatibility related aspects of some conducting polymers are also discussed and some insights in the application of polypyrrole-based coatings for implantable sensors are outlined.
Journal of Pharmaceutical and Biomedical Analysis, May 1, 2023
Mikrochimica Acta, Apr 8, 2014
International Journal of Molecular Sciences, Mar 18, 2023
Biosensors
The development of microbial fuel cells based on electro-catalytic processes is among the novel t... more The development of microbial fuel cells based on electro-catalytic processes is among the novel topics, which are recently emerging in the sustainable development of energetic systems. Microbial fuel cells have emerged as unique biocatalytic systems, which transform the chemical energy accumulated in renewable organic fuels and at the same time reduce pollution from hazardous organic compounds. However, not all microorganisms involved in metabolic/catalytic processes generate sufficient redox potential. In this research, we have assessed the applicability of the microorganism Rhizobium anhuiense as a catalyst suitable for the design of microbial fuel cells. To improve the charge transfer, several redox mediators were tested, namely menadione, riboflavin, and 9,10-phenanthrenequinone (PQ). The best performance was determined for a Rhizobium anhuiense-based bio-anode mediated by menadione with a 0.385 mV open circuit potential and 5.5 μW/cm2 maximal power density at 0.35 mV, which gen...
Biosensors
In this study, graphite rod (GR) electrodes were electrochemically modified by dendritic gold nan... more In this study, graphite rod (GR) electrodes were electrochemically modified by dendritic gold nanostructures (DGNs) followed by immobilization of glucose oxidase (GOx) in the presence of mediator phenazine methosulfate (PMS). Modified with polyaniline (PANI) or polypyrrole (Ppy), GOx/DGNs/GR electrodes were used in glucose biosensor design. Different electrochemical methods were applied for the registration of glucose concentration, and constant potential amperometry (CPA) was chosen as the best one. PANI and Ppy layers synthesized enzymatically on the GOx/DGNs/GR electrodes extended the linear glucose determination range, the width of which depended on the duration of PANI- and Ppy-layers formation. Enzymatically formed polypyrrole was determined as the most suitable polymer for the modification and formation of the glucose biosensor instead of polyaniline, because it was 1.35 times more sensitive and had a 2.57 times lower limit of detection (LOD). The developed glucose biosensor ...
International Journal of Molecular Sciences
The serologic diagnosis of coronavirus disease 2019 (COVID-19) and the evaluation of vaccination ... more The serologic diagnosis of coronavirus disease 2019 (COVID-19) and the evaluation of vaccination effectiveness are identified by the presence of antibodies specific to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this paper, we present the electrochemical-based biosensing technique for the detection of antibodies specific to the SARS-CoV-2 proteins. Recombinant SARS-CoV-2 spike proteins (rSpike) were immobilised on the surface of a gold electrode modified by a self-assembled monolayer (SAM). This modified electrode was used as a sensitive element for the detection of polyclonal mouse antibodies against the rSpike (anti-rSpike). Electrochemical impedance spectroscopy (EIS) was used to observe the formation of immunocomplexes while cyclic voltammetry (CV) was used for additional analysis of the surface modifications. It was revealed that the impedimetric method and the elaborate experimental conditions are appropriate for the further development of electrochemical ...
Biosensors
In recent years, many efforts have been made to develop rapid, sensitive and user-friendly glucos... more In recent years, many efforts have been made to develop rapid, sensitive and user-friendly glucose biosensors for monitoring blood glucose concentration in patients. In this study, the electrochemical glucose biosensors based on graphite rod (GR) electrode electrochemically modified with dendritic gold nanostructures (DGNs) and glucose oxidase (GOx) were developed. Phenazine methosulfate was used as a soluble redox mediator. Three GOx immobilization methods: adsorption on DGNs and cross-linking with glutaraldehyde (GA) vapour (GA-GOx/DGNs/GR), covalent immobilization on DGNs modified with 11-mercaptoundecanoic acid self-assembled monolayer (SAM) (GOx-SAM/DGNs/GR) and covalent immobilization on SAM with additional cross-linking with GA vapour (GA-GOx-SAM/DGNs/GR), were used. It was determined that GA significantly improved the stability of the enzyme layer. The difference of maximal current generated during the enzymatic reaction (ΔImax) equal to 272.06 ± 8.69 µA was obtained using a...
Journal of Nanobiotechnology
Early detection of viral pathogens by DNA-sensors in clinical samples, contaminated foods, soil o... more Early detection of viral pathogens by DNA-sensors in clinical samples, contaminated foods, soil or water can dramatically improve clinical outcomes and reduce the socioeconomic impact of diseases such as COVID-19. Clustered regularly interspaced short palindromic repeat (CRISPR) and its associated protein Cas12a (previously known as CRISPR-Cpf1) technology is an innovative new-generation genomic engineering tool, also known as ‘genetic scissors’, that has demonstrated the accuracy and has recently been effectively applied as appropriate (E-CRISPR) DNA-sensor to detect the nucleic acid of interest. The CRISPR-Cas12a fromPrevotella and Francisella 1are guided by a short CRISPR RNA (gRNA). The unique simultaneouscis-andtrans-DNA cleavage after target sequence recognition at the PAM site, sticky-end (5–7 bp) employment, and ssDNA/dsDNA hybrid cleavage strategies to manipulate the attractive nature of CRISPR–Cas12a are reviewed. DNA-sensors based on the CRISPR-Cas12a technology for rapid...
Sensors, 2022
This review is dedicated to the development of molecularly imprinted polymers (MIPs) and the appl... more This review is dedicated to the development of molecularly imprinted polymers (MIPs) and the application of MIPs in sensor design. MIP-based biological recognition parts can replace receptors or antibodies, which are rather expensive. Conducting polymers show unique properties that are applicable in sensor design. Therefore, MIP-based conducting polymers, including polypyrrole, polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline and ortho-phenylenediamine are frequently applied in sensor design. Some other materials that can be molecularly imprinted are also overviewed in this review. Among many imprintable materials conducting polymer, polypyrrole is one of the most suitable for molecular imprinting of various targets ranging from small organics up to rather large proteins. Some attention in this review is dedicated to overview methods applied to design MIP-based sensing structures. Some attention is dedicated to the physicochemical methods applied for the transduction of ...
Sensors, 2022
Electrically conductive polymers are promising materials for charge transfer from living cells to... more Electrically conductive polymers are promising materials for charge transfer from living cells to the anodes of electrochemical biosensors and biofuel cells. The modification of living cells by polypyrrole (PPy) causes shortened cell lifespan, burdens the replication process, and diminishes renewability in the long term. In this paper, the viability and morphology non-modified, inactivated, and PPy-modified yeasts were evaluated. The results displayed a reduction in cell size, an incremental increase in roughness parameters, and the formation of small structural clusters of polymers on the yeast cells with the increase in the pyrrole concentration used for modification. Yeast modified with the lowest pyrrole concentration showed minimal change; thus, a microbial fuel cell (MFC) was designed using yeast modified by a solution containing 0.05 M pyrrole and compared with the characteristics of an MFC based on non-modified yeast. The maximal generated power of the modified system was 47...
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2021
Abstract In this research, scanning electrochemical microscopy (SECM) and electrochemical impedan... more Abstract In this research, scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS) were applied for the evaluation of surface characteristics of electrochemical (amperometric) biosensor based on two composite structures consisting of perforated polycarbonate membrane modified by carbon-nanomaterials and glucose oxidase. The first structure consisted of the polycarbonate filter membrane, punctured by 400 nm holes (PCM) consequently modified with single walled carbon nanotubes (SWCNT) and graphene oxide (GO) layer (PCM/SWCNT/GO); and the other structure consisted of the same PCM, consequently modified with SWCNT and reduced graphene oxide (rGO) layer (PCM/SWCNT/rGO). These two composite structures were developed and applied in biosensor design. In order to form a biosensing surfaces the PCM/SWCNT/GO and PCM/SWCNT/rGO composite structures were modified by immobilized glucose oxidase (GOx). The surface of GOx modified PCM/SWCNT/GO composite structure (PCM/SWCNT/GO/GOx) was evaluated by SECM redox-competition mode at different glucose concentrations. It was determined that PCM/SWCNT/GO/GOx composite structure is suitable for the design of amperometric glucose biosensors, because SWCNT/GO layer facilitates electron transfer from GOx via the oxidation of formed catalyzed reaction product H2O2. Therefore, the PCM/SWCNT/GO/GOx structure is a promising material for the design of amperometric glucose biosensors and biofuel cells, which are useful for a wide variety of environmental purposes and green energy production using food-industry waste.
Living cells mechanical properties establishment from Atomic force microscopy (AFM) force-separat... more Living cells mechanical properties establishment from Atomic force microscopy (AFM) force-separation curves is a challenge because the calculated Young’s modulus depends on the applied mathematical model. The more reliable results can be obtained using finite element models. In this work, yeast cells with different mechanical properties were measured by AFM. To change cells mechanical properties, yeasts were immersed in 9, 10-phenanthrenequinone, which changed cells’ membranes elasticity. 3D finite element model of the whole cell was created to calculate reacting force when AFM tip indents the cell in the same way as in the real experiment. It was found that our model is capable to draw the information about cells mechanical properties and visco-elastic behavior of cells membranes.
Scientific Reports, 2021
In this study, we reported the development of Prussian blue (PB), poly(pyrrole-2-carboxylic acid)... more In this study, we reported the development of Prussian blue (PB), poly(pyrrole-2-carboxylic acid) (PPCA), and glucose oxidase (GOx) biocomposite modified graphite rod (GR) electrode as a potential biocathode for single enzyme biofuel cell fuelled by glucose. In order to design the biocathode, the GR electrode was coated with a composite of PB particles embedded in the PPCA shell and an additional layer of PPCA by cyclic voltammetry. Meanwhile, GOx molecules were covalently attached to the carboxyl groups of PPCA by an amide bond. The optimal conditions for the biocathode preparation were elaborated experimentally. After optimization, the developed biocathode showed excellent electrocatalytic activity toward the reduction of H2O2 formed during GOx catalyzed glucose oxidation at a low potential of 0.1 V vs Ag/AgCl, as well as good electrochemical performance. An electrocatalytic current density of 31.68 ± 2.70 μA/cm2 and open-circuit potential (OCP) of 293.34 ± 15.70 mV in O2-saturate...
Coatings, 2020
An electrochemically synthesised porous anodic aluminium oxide (pAAO) layer has been analysed by ... more An electrochemically synthesised porous anodic aluminium oxide (pAAO) layer has been analysed by means of spectroscopic ellipsometry. The determined thickness of the formed pAAO layer obtained from spectroscopic ellipsometry measurements and modelling was 322.75 ± 0.12 nm. The radius of the nanopores estimated from SEM images was 39 ± 5 nm and the distance between nanopores was 107 ± 6 nm. The investigation of human serum albumin (HSA) adsorption on the pAAO coating showed that: (i) the protein concentration inside nanopores, depending on exposure time, approximately was from 200 up to 600 times higher than that determined in buffer solution; (ii) the initial phase of the adsorption process is slow (3.23 mg·cm−3·min−1) in comparison with the protein desorption rate (21.2 mg·cm−3·min−1) by means of pAAO layer washing; (iii) conventional washing with PBS solution and deionised water does not completely remove HSA molecules from pAAO pores and, therefore, the HSA concentration inside n...
The Journal of Physical Chemistry C, 2018
Journal of The Electrochemical Society, 2019
In this research, conducting polymer – polypyrrole (Ppy), was electrochemically polymerized on th... more In this research, conducting polymer – polypyrrole (Ppy), was electrochemically polymerized on the indium tin oxide coated glass (glass/ITO) electrode. The adhesion of Ppy on the surface of ITO was improved by modification with triethoxymethylsilane (TEMS). Potential cycling was applied for electrochemical deposition of Ppy layer and cyclic voltammograms were recorded during the deposition to monitor polymerization process. Cyclic voltammetry and the potential pulse sequence (PPS)-based chronoamperometry methods complemented the registration of absorbance spectra of glass/ITO(TEMS)/Ppy at various pH and different concentrations of CO2. The applicability of glass/ITO(TEMS)/Ppy electrode in the design of electrochromic sensor sensitive toward CO2 has been evaluated. Cyclic voltammetry based experiments at different potential sweep rates in presence and absence of CO2 were performed in order to evaluate charge transfer phenomenon in glass/ITO(TEMS)/Ppy structure
Sensors and Actuators B: Chemical, 2019