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We analyzed the possibility of the detection of cytochrome c (cyt c) being physically adsorbed on lipid films or covalently bounded to 11-mercapto-1-undecanoic acid (MUA) chemisorbed on the gold layer using quartz crystal microbalance... more
We analyzed the possibility of the detection of cytochrome c (cyt c) being physically adsorbed on lipid films or covalently bounded to 11-mercapto-1-undecanoic acid (MUA) chemisorbed on the gold layer using quartz crystal microbalance with dissipation monitoring (QCM-D). The negatively charged lipid film composed of a mixture of zwitterionic DMPC and negatively charged DMPG phospholipids at a molar ratio of 1:1 allowed the formation of a stable cyt c layer. Addition of DNA aptamers specific to cyt c, however, resulted in removal of cyt c from the surface. The interaction of cyt c with the lipid film and its removal by DNA aptamers were accompanied by changes in viscoelastic properties evaluated using the Kelvin–Voigt model. Cyt c covalently bound to MUA also provided a stable protein layer already at its relatively low concentrations (0.5 μM). A decrease in the resonant frequency following the addition of gold nanowires (AuNWs) modified by DNA aptamers was observed. The interaction ...
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Contamination of food by pathogens can pose a serious risk to health. Therefore, monitoring for the presence of pathogens is critical to identify and regulate microbiological contamination of food. In this work, an aptasensor based on a... more
Contamination of food by pathogens can pose a serious risk to health. Therefore, monitoring for the presence of pathogens is critical to identify and regulate microbiological contamination of food. In this work, an aptasensor based on a thickness shear mode acoustic method (TSM) with dissipation monitoring was developed to detect and quantify Staphylococcus aureus directly in whole UHT cow’s milk. The frequency variation and dissipation data demonstrated the correct immobilization of the components. The analysis of viscoelastic properties suggests that DNA aptamers bind to the surface in a non-dense manner, which favors the binding with bacteria. The aptasensor demonstrated high sensitivity and was able to detect S. aureus in milk with a 33 CFU/mL limit of detection. Analysis was successful in milk due to the sensor’s antifouling properties, which is based on 3-dithiothreitol propanoic acid (DTTCOOH) antifouling thiol linker. Compared to bare and modified (dithiothreitol (DTT), 11-m...
Research Interests: Biosensors and BioSensors
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Calmodulin (CaM) interactions with bilayer lipid membranes (BLM) were studied by measuring modulus of elasticity in direction perpendicular to the membrane plane (E perpendicular) and intramembrane potential delta psi. Upon interaction of... more
Calmodulin (CaM) interactions with bilayer lipid membranes (BLM) were studied by measuring modulus of elasticity in direction perpendicular to the membrane plane (E perpendicular) and intramembrane potential delta psi. Upon interaction of CaM with egg phosphatidylcholine and asolectin BLM the parameter E perpendicular grew slightly (not more than by 10% as compared to the respective vale for nonmodified BLM), suggesting a weak effect on the ordering of the hydrophobic moiety of the lipid bilayer. In the presence of mesocaine (Mes), a calmodulin inhibitor, CaM affected the incorporation of Mes into the membrane. It can be concluded that CaM affects the ordering of the polar (superficial) membrane region.
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The effects of fluorescent probes 9-aminoacridine (9AA) and atebrine (AT) on physical properties of liposomes and planar bilayer lipid membranes (BLM) were studied. The method of fluorescence spectroscopy and the electrostriction method... more
The effects of fluorescent probes 9-aminoacridine (9AA) and atebrine (AT) on physical properties of liposomes and planar bilayer lipid membranes (BLM) were studied. The method of fluorescence spectroscopy and the electrostriction method based on measurement of higher current harmonics were used. At low concentrations (10(-5)-5 x 10(-5) mol/l), 9AA increased fluorescence intensity, while in liposomes from soybean phosphatidylcholine fluorescence quenching occurred at higher probe concentration. Fluorescence quenching occurred over the entire concentration range tested (10(-5)-10(-4) mol/l) in liposomes made from a mixture of egg phosphatidylcholine and cardiolipin. In contrast to 9AA, AT, thanks to its hydrophobic chain, penetrates deeper into the hydrophobic membrane moiety; thus, immobilization of the molecule and an increase in fluorescence intensity was always observed. Probes adsorbed to membranes, leaving their electric capacitance effectively unchanged. Adsorption of charged d...
Research Interests: Physiology, Biophysics, Chemistry, Electrochemistry, Fluorescence, and 13 moreMedicine, Elasticity, Liposome, Medical Physiology, Membrane, Optics and Photonics, Lipid bilayers, Hydrogen-Ion Concentration, Lipid Bilayer, Electric Conductivity, Biomechanical Phenomena, fluorescent dyes, and In Vitro Techniques
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Plasmin protease plays an important role in many processes in living systems, including milk. Monitoring plasmin activity is important for control of the nutritional quality of milk and other dairy products. We designed a biosensor to... more
Plasmin protease plays an important role in many processes in living systems, including milk. Monitoring plasmin activity is important for control of the nutritional quality of milk and other dairy products. We designed a biosensor to detect the proteolytic activity of plasmin, using multiharmonic quartz crystal microbalance with dissipation (QCM-D). The β-casein immobilized on the hydrophobic surface of 1-dodecanethiol on the AT-cut quartz crystal was used to monitor plasmin activity. We demonstrated detection of plasmin in a concentration range of 0.1–20 nM, with the limit of detection about 0.13 ± 0.01 nM. The analysis of viscoelastic properties of the β-casein layer showed rapid changes of shear elasticity modulus, μ, and coefficient of viscosity, η, at plasmin sub-nanomolar concentrations, followed by modest changes at nanomolar concentrations, indicating multilayer architecture β-casein. A comparative analysis of viscoelastic properties of β-casein layers following plasmin and...
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Milk is a significant foodstuff around the world, being produced and consumed in large quantities. The safe consumption of milk requires that the liquid has an acceptably low level of microbial contamination and has not been subjected to... more
Milk is a significant foodstuff around the world, being produced and consumed in large quantities. The safe consumption of milk requires that the liquid has an acceptably low level of microbial contamination and has not been subjected to spoiling. Bacterial safety limits in milk vary by country but are typically in the thousands per mL of sample. To rapidly determine if samples contain an unsafe level of bacteria, an aptamer-based sensor specific to Escherichia coli bacteria was developed. The sensor is based on an ultra-high frequency electromagnetic piezoelectric acoustic sensor device (EMPAS), with the aptamer being covalently bound to the sensor surface by the anti-fouling linker, MEG-Cl. The sensor is capable of the selective measurement of E. coli in PBS and in cow’s milk samples down to limits of detection of 35 and 8 CFU/mL, respectively, which is well below the safe limits for commercial milk products. This sensing system shows great promise for the milk industry for the pu...
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Mycotoxins are secondary metabolites of fungi that contaminate agriculture products. Their release in the environment can cause severe damage to human health. Aptasensors are compact analytical devices that are intended for the fast and... more
Mycotoxins are secondary metabolites of fungi that contaminate agriculture products. Their release in the environment can cause severe damage to human health. Aptasensors are compact analytical devices that are intended for the fast and reliable detection of various species able to specifically interact with aptamers attached to the transducer surface. In this review, assembly of electrochemical and surface plasmon resonance (SPR) aptasensors are considered with emphasis on the mechanism of signal generation. Moreover, the properties of mycotoxins and the aptamers selected for their recognition are briefly considered. The analytical performance of biosensors developed within last three years makes it possible to determine mycotoxin residues in water and agriculture/food products on the levels below their maximal admissible concentrations. Requirements for the development of sample treatment and future trends in aptasensors are also discussed.
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A highly sensitive electrochemical DNA sensor for detection of the chemotherapeutic drug idarubicin mediated by Methylene blue (MB) has been developed. DNA from fish sperm has been immobilized at the electropolymerized layers of Azure B.... more
A highly sensitive electrochemical DNA sensor for detection of the chemotherapeutic drug idarubicin mediated by Methylene blue (MB) has been developed. DNA from fish sperm has been immobilized at the electropolymerized layers of Azure B. The incorporation of MB into the DNA layers substantially increased the sensor sensitivity. The concentration range for idarubicin determination by cyclic voltammetry was from 1 fM to 0.1 nM, with a limit of detection (LOD) of 0.3 fM. Electrochemical impedance spectroscopy (EIS) in the presence of a redox probe ([Fe(CN)6]3−/4−) allowed for the widening of a linear range of idarubicin detection from 1 fM to 100 nM, retaining LOD 0.3 fM. The DNA sensor has been tested in various real and artificial biological fluids with good recovery ranging between 90–110%. The sensor has been successfully used for impedimetric idarubicin detection in medical preparation Zavedos®. The developed DNA biosensor could be useful for the control of the level of idarubicin...
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We performed a comparative analysis of the sensitivity of aptamer-based biosensors for detection mycotoxin aflatoxin M1 (AFM1) depending on the method of immobilization of DNA aptamers and method of the detection. Label-free... more
We performed a comparative analysis of the sensitivity of aptamer-based biosensors for detection mycotoxin aflatoxin M1 (AFM1) depending on the method of immobilization of DNA aptamers and method of the detection. Label-free electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) for ferrocene labeled neutravidin layers were used for this purpose. Amino-modified DNA aptamers have been immobilized at the surface of polyamidoamine dendrimers (PAMAM) of fourth generation (G4) or biotin-modified aptamers were immobilized at the neutravidin layer chemisorbed at gold surface. In the first case the limit of detection (LOD) has been determined as 8.47 ng/L. In the second approach the LOD was similar 8.62 ng/L, which is below of allowable limits of AFM1 in milk and milk products. The aptasensors were validated in a spiked milk samples with good recovery better than 78%. Comparative analysis of the sensitivity of immuno- and aptasensors was also performed and sho...
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Using ultrasonic velocity measurements the interaction of bacteriorhodopsin (BR) with large unilamellar liposomes of dipalmitoylphosphatidylcholine (DPPC) was studied in gel (25 degrees C) and in liquid crystalline state (50 degrees C) of... more
Using ultrasonic velocity measurements the interaction of bacteriorhodopsin (BR) with large unilamellar liposomes of dipalmitoylphosphatidylcholine (DPPC) was studied in gel (25 degrees C) and in liquid crystalline state (50 degrees C) of lipid bilayer. We could show that with the increasing BR concentration the increment of ultrasonic velocity increases and a saturation occur at a BR/Liposomes of ratio approximately 0.5 mol/mol. BR incorporation into the lipid bilayer in gel state leads to an increase of the increment of the ultrasonic velocity of the lipid to 9.51 +/- 1.47 ml/mol. This could be mainly attributed to a decrease in membrane compressibility or an increase in membrane volume or both. No changes of ultrasonic velocity increment were observed with the membrane in liquid crystalline state. In this case, BR probably is not able to change the mechanical properties of a considerably disordered membrane.
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Kinetics of conductance and current-voltage characteristics (VACH) were studied on the bilayer lipid membranes from egg lecithin and cholesterol modified by gramicidin D and valinomycin. There were found significant changes of ionic... more
Kinetics of conductance and current-voltage characteristics (VACH) were studied on the bilayer lipid membranes from egg lecithin and cholesterol modified by gramicidin D and valinomycin. There were found significant changes of ionic channels conductance g, lifetime tau and non-linearity coefficient beta of VACH of modified membranes dependent on cholesterol content. In the region of high cholesterol concentrations, more than 20 mol%, there were observed abrupt changes of the ionic channels parameters: tau increased more than ten times, conductance decreased two times and beta greater than 0 in the whole region of electrolyte concentration.
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Summary. The method of electrostriction was applied to supported bilayer lipid membranes (sBLM) and Langmuir monolayers with the aim to study the peculiarities of the interaction of short oligonucleotides with lipid films and of the... more
Summary. The method of electrostriction was applied to supported bilayer lipid membranes (sBLM) and Langmuir monolayers with the aim to study the peculiarities of the interaction of short oligonucleotides with lipid films and of the duplex formation between complementary ...
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Research Interests: Chemistry, Analytical Chemistry, Biomedical Engineering, Electrochemistry, Nanotechnology, and 15 moreMedicine, Impedance Spectroscopy, DNA, Biosensor, Membrane, Impedance, Antibody, Immunoassay, Reproducibility of Results, Lipid bilayers, Affinity, Sensitivity and Specificity, Antigens, Biosensing Techniques, and Oligonucleotides
Research Interests: Chemistry, Biophysical Chemistry, Atomic Force Microscopy, Medicine, Biological Sciences, and 12 moreThrombin, Humans, Single Molecule Force Spectroscopy, Physical sciences, Streptavidin, CHEMICAL SCIENCES, Base Sequence, Protein Binding, Aptamer, Dimerization, single stranded DNA, and Rate Constant
Research Interests: Chemistry, Biophysical Chemistry, Medicine, Biological Sciences, Fibrinogen, and 14 moreThrombin, Heparin, Circular Dichroism, Differential scanning calorimetry, Physical sciences, Temperature, Potassium, CHEMICAL SCIENCES, Thermal Stability, Binding Site, Aptamer, Dimerization, single stranded DNA, and binding sites
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Structure and physical properties of biomembranes and model membranesBiomembranes belong to the most important structures of the cell and the cell organels. They play not only structural role of the barrier separating the external and... more
Structure and physical properties of biomembranes and model membranesBiomembranes belong to the most important structures of the cell and the cell organels. They play not only structural role of the barrier separating the external and internal part of the membrane but contain also various functional molecules, like receptors, ionic channels, carriers and enzymes. The cell membrane also preserves non-equillibrium state in a cell which is crucial for maintaining its excitability and other signaling functions. The growing interest to the biomembranes is also due to their unique physical properties. From physical point of view the biomembranes, that are composed of lipid bilayer into which are incorporated integral proteins and on their surface are anchored peripheral proteins and polysaccharides, represent liquid scrystal of smectic type. The biomembranes are characterized by anisotropy of structural and physical properties. The complex structure of biomembranes makes the study of thei...
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Antibiotics are often used in human and veterinary medicine for the treatment of bacterial diseases. However, extensive use of antibiotics in agriculture can result in the contamination of common food staples such as milk. Consumption of... more
Antibiotics are often used in human and veterinary medicine for the treatment of bacterial diseases. However, extensive use of antibiotics in agriculture can result in the contamination of common food staples such as milk. Consumption of contaminated products can cause serious illness and a rise in antibiotic resistance. Conventional methods of antibiotics detection such are microbiological assays chromatographic and mass spectroscopy methods are sensitive; however, they require qualified personnel, expensive instruments, and sample pretreatment. Biosensor technology can overcome these drawbacks. This review is focused on the recent achievements in the electrochemical biosensors based on nucleic acid aptamers for antibiotic detection. A brief explanation of conventional methods of antibiotic detection is also provided. The methods of the aptamer selection are explained, together with the approach used for the improvement of aptamer affinity by post-SELEX modification and computer mo...
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Modern analysis of food and feed is mostly focused on development of fast and reliable portable devices intended for field applications. In this review, electrochemical biosensors based on immunological reactions and aptamers are... more
Modern analysis of food and feed is mostly focused on development of fast and reliable portable devices intended for field applications. In this review, electrochemical biosensors based on immunological reactions and aptamers are considered in the determination of mycotoxins as one of most common contaminants able to negatively affect human health. The characteristics of biosensors are considered from the point of view of general principles of bioreceptor implementation and signal transduction providing sub-nanomolar detection limits of mycotoxins. Moreover, the modern trends of bioreceptor selection and modification are discussed as well as future trends of biosensor development for mycotoxin determination are considered.
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An impedimetric aptasensor for ochratoxin A (OTA) detection has been developed on the base of a gold electrode covered with a new modifier consisting of electropolymerized Neutral Red and a mixture of Au nanoparticles suspended in the... more
An impedimetric aptasensor for ochratoxin A (OTA) detection has been developed on the base of a gold electrode covered with a new modifier consisting of electropolymerized Neutral Red and a mixture of Au nanoparticles suspended in the dendrimeric polymer Botlorn H30®. Thiolated aptamer specific to OTA was covalently attached to Au nanoparticles via Au-S bonding. The interaction of the aptamer with OTA induced the conformational switch of the aptamer from linear to guanine quadruplex form followed by consolidation of the surface layer and an increase of the charge transfer resistance. The aptasensor makes it possible to detect from 0.1 to 100 nM of OTA (limit of detection: 0.02 nM) in the presence of at least 50 fold excess of ochratoxin B. The applicability of the aptasensor for real sample assay was confirmed by testing spiked beer samples. The recovery of 2 nM OTA was found to be 70% for light beer and 78% for dark beer.
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Guanine quadruplex (G-quadruplex) structures are one of a number of structures which are capable of adopting aptamers. G-rich DNA or RNA has an increased propensity to form quadruplex structures which have unusual biophysical and... more
Guanine quadruplex (G-quadruplex) structures are one of a number of structures which are capable of adopting aptamers. G-rich DNA or RNA has an increased propensity to form quadruplex structures which have unusual biophysical and biological properties. G-rich aptamers which form G-quadruplexes have several advantages over unstructured sequences: G-quadruplexes are non-immunogenic, thermodynamically and chemically stable and they have both higher resistance to various serum nucleases and an enhanced cellular uptake. These advantages have led to a number of synthetic oligonucleotides being studied for their potential use as therapeutic agents for cancer therapy and in the treatment of various other diseases. In addition to their suitability in the fields of medicine and biotechnology, these, highly specified, aptameric G-quadruplexes also have great potential in the further development of nano-devices; e.g. basic components in microarrays, microfluidics, sandwich assays and electroche...
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The methods of ultrasound velocity and density measurements were used to study the adiabatic compressibility of bovine serum albumin (BSA) during its oxidation by the prooxidants Cu2+ and 2,2'-azobis(2-amidinopropane) hydrochloride... more
The methods of ultrasound velocity and density measurements were used to study the adiabatic compressibility of bovine serum albumin (BSA) during its oxidation by the prooxidants Cu2+ and 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH). We did not find changes of compressibility of BSA in the presence of copper ions at rather high molar ratio Cu2+/BSA = 0.66 mol/mol. This can be explained by binding of the Cu2+ to the binding site of BSA and thus protecting the prooxidant action of the copper. However, AAPH-mediated oxidation of BSA resulted in an increase of its apparent specific compressibility (psik/beta0). These changes could be caused by the fragmentation of the protein.
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Dendrons are branched synthetic polymers suitable for preparation of nanosized drug delivery systems. Their interactions with biological systems are mainly predetermined by their chemical structure, terminal groups, surface charge, and... more
Dendrons are branched synthetic polymers suitable for preparation of nanosized drug delivery systems. Their interactions with biological systems are mainly predetermined by their chemical structure, terminal groups, surface charge, and the number of branched layers (generation). Any new compound intended to be used, alone or in combination, for medical purposes in humans must be compatible with blood. This study combined results from in vitro experiments on human blood and from laboratory experiments designed to assess the effect of amphiphilic phosphorous dendrons on blood components and model membranes, and to examine the presence and nature of interactions leading to a potential safety concern. The changes in hematological and coagulation parameters upon the addition of dendrons in the concentration range of 2–10 µM were monitored. We found that only the combination of higher concentration and higher generation of the dendron affected the selected clinically relevant parameters: ...
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Polymer nanoparticles and nano/micromotors are novel nanostructures that are of increased interest especially in the diagnosis and therapy of cancer. These structures are modified by antibodies or nucleic acid aptamers and can recognize... more
Polymer nanoparticles and nano/micromotors are novel nanostructures that are of increased interest especially in the diagnosis and therapy of cancer. These structures are modified by antibodies or nucleic acid aptamers and can recognize the cancer markers at the membrane of the cancer cells or in the intracellular side. They can serve as a cargo for targeted transport of drugs or nucleic acids in chemo- immuno- or gene therapy. The various mechanisms, such as enzyme, ultrasound, magnetic, electrical, or light, served as a driving force for nano/micromotors, allowing their transport into the cells. This review is focused on the recent achievements in the development of polymer nanoparticles and nano/micromotors modified by antibodies and nucleic acid aptamers. The methods of preparation of polymer nanoparticles, their structure and properties are provided together with those for synthesis and the application of nano/micromotors. The various mechanisms of the driving of nano/micromoto...
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A multiharmonic quartz crystal microbalance (QCM) has been applied to study the viscoelastic properties of the aptamer-based sensing layers at the surface of a QCM transducer covered by neutravidin following interaction with bacteria... more
A multiharmonic quartz crystal microbalance (QCM) has been applied to study the viscoelastic properties of the aptamer-based sensing layers at the surface of a QCM transducer covered by neutravidin following interaction with bacteria Listeria innocua. Addition of bacteria in the concentration range 5 × 103–106 CFU/mL resulted in a decrease of resonant frequency and in an increase of dissipation. The frequency decrease has been lower than one would expect considering the dimension of the bacteria. This can be caused by lower penetration depth of the acoustics wave (approximately 120 nm) in comparison with the thickness of the bacterial layer (approximately 500 nm). Addition of E. coli at the surface of neutravidin as well as aptamer layers did not result in significant changes in frequency and dissipation. Using the Kelvin–Voight model the analysis of the viscoelastic properties of the sensing layers was performed and several parameters such as penetration depth, Γ, viscosity coeffic...
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Chymotrypsin is an important proteolytic enzyme in the human digestive system that cleaves milk proteins through the hydrolysis reaction, making it an interesting subject to study the activity of milk proteases. In this work, we compared... more
Chymotrypsin is an important proteolytic enzyme in the human digestive system that cleaves milk proteins through the hydrolysis reaction, making it an interesting subject to study the activity of milk proteases. In this work, we compared detection of chymotrypsin by spectrophotometric dynamic light scattering (DLS) and quartz crystal microbalance (QCM) methods and determined the limit of chymotrypsin detection (LOD), 0.15 ± 0.01 nM for spectrophotometric, 0.67 ± 0.05 nM for DLS and 1.40 ± 0.30 nM for QCM methods, respectively. The sensors are relatively cheap and are able to detect chymotrypsin in 3035 min. While the optical detection methods are simple to implement, the QCM method is more robust for sample preparation, and allows detection of chymotrypsin in non-transparent samples. We give an overview on methods and instruments for detection of chymotrypsin and other milk proteases.
Research Interests: Biosensors and BioSensors
The determination of protease activity is very important for disease diagnosis, drug development, and quality and safety assurance for dairy products. Therefore, the development of low-cost and sensitive methods for assessing protease... more
The determination of protease activity is very important for disease diagnosis, drug development, and quality and safety assurance for dairy products. Therefore, the development of low-cost and sensitive methods for assessing protease activity is crucial. We report two approaches for monitoring protease activity: in a volume and at surface, via colorimetric and acoustic wave-based biosensors operated in the thickness-shear mode (TSM), respectively. The TSM sensor was based on a β-casein substrate immobilized on a piezoelectric quartz crystal transducer. After an enzymatic reaction with trypsin, it cleaved the surface-bound β-casein, which increased the resonant frequency of the crystal. The limit of detection (LOD) was 0.48 ± 0.08 nM. A label-free colorimetric assay for trypsin detection has also been performed using β-casein and 6-mercaptohexanol (MCH) functionalized gold nanoparticles (AuNPs/MCH-β-casein). Due to the trypsin cleavage of β-casein, the gold nanoparticles lost shelte...
Research Interests: Biosensors and BioSensors
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Early diagnostics of leukemia is crucial for successful therapy of this disease. Therefore, development of rapid, sensitive, and easy-to-use methods for detection of this disease is of increased interest. Biosensor technology is... more
Early diagnostics of leukemia is crucial for successful therapy of this disease. Therefore, development of rapid, sensitive, and easy-to-use methods for detection of this disease is of increased interest. Biosensor technology is challenged for this purpose. This review includes a brief description of the methods used in current clinical diagnostics of leukemia and provides recent achievements in sensor technology based on immuno- and DNA aptamer-based electrochemical and acoustic biosensors. The comparative analysis of immuno- and aptamer-based sensors shows a significant advantage of DNA aptasensors over immunosensors in the detection of cancer cells. The acoustic technique is of comparable sensitivity with those based on electrochemical methods; moreover, it is label-free and provides straightforward evaluation of the signal. Several examples of sensor development are provided and discussed.
Research Interests: Biosensors and BioSensors
The determination of antibiotics in food is important due to their negative effect on human health related to antimicrobial resistance problem, renal toxicity, and allergic effects. We propose an impedimetric aptasensor for the... more
The determination of antibiotics in food is important due to their negative effect on human health related to antimicrobial resistance problem, renal toxicity, and allergic effects. We propose an impedimetric aptasensor for the determination of kanamycin A (KANA), which was assembled on the glassy carbon electrode by the deposition of carbon black in a chitosan matrix followed by carbodiimide binding of aminated aptamer mixed with oligolactide derivative of thiacalix[4]arene in a cone configuration. The assembling was monitored by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. In the presence of the KANA, the charge transfer resistance of the inner interface surprisingly decreased with the analyte concentration within 0.7 and 50 nM (limit of detection 0.3 nM). This was attributed to the partial shielding of the negative charge of the aptamer and of its support, a highly porous 3D structure of the surface layer caused by a macrocyclic co...
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Neutrophil-mediated innate host defense mechanisms include pathogen elimination through bacterial phagocytosis, which activates the 5-lipoxygenase (5-LOX) product synthesis. Here, we studied the effect of synthetic... more
Neutrophil-mediated innate host defense mechanisms include pathogen elimination through bacterial phagocytosis, which activates the 5-lipoxygenase (5-LOX) product synthesis. Here, we studied the effect of synthetic oligodeoxyribonucleotides (ODNs), which mimic the receptor-recognized sites of bacterial (CpG-ODNs) and genomic (G-rich ODNs) DNAs released from the inflammatory area, on the neutrophil functions after cell stimulation with Salmonella typhimurium. A possible mechanism for ODN recognition by Toll-like receptor 9 (TLR9) and RAGE receptor has been proposed. We found for the first time that the combination of the magic peptide LRR11 from the leucine-rich repeat (LRR) of TLR9 with the CpG-ODNs modulates the uptake and signaling from ODNs, in particular, dramatically stimulates 5-LOX pathway. Using thickness shear mode acoustic method, we confirmed the specific binding of CpG-ODNs, but not G-rich ODN, to LRR11. The RAGE receptor has been shown to play an important role in promo...