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Herein, we report a new simple and easy-to-use approach for the characterization of protein oligomerization based on fluorescence resonance energy transfer (FRET) and capillary electrophoresis with LED-induced detection. The FRET pair consisted of quantum dots (QDs) used as an emission tunable donor (emission wavelength of 450 nm) and a cyanine dye (Cy3), providing optimal optical properties as an acceptor. Nonoxidative dimerization of mammalian metallothionein (MT) was investigated using the donor and acceptor covalently conjugated to MT. The main functions of MTs within an organism include the transport and storage of essential metal ions and detoxification of toxic ions. Upon storage under aerobic conditions, MTs form dimers (as well as higher oligomers), which may play an essential role as mediators in oxidoreduction signaling pathways. Due to metal bridging by Cd2+ ions between molecules of metallothionein, the QDs and Cy3 were close enough, enabling a FRET signal. The FRET efficiency was calculated to be in the range of 11–77%. The formation of MT dimers in the presence of Cd2+ ions was confirmed by MALDI-MS analyses. Finally, the process of oligomerization resulting in FRET was monitored by CE, and oligomerization of MT was confirmed.

UV-induced fingerprint spectroscopy (UV-IFS), a new tool in a toolbox of analytical methods, is a powerful technique registering molecule-specific changes of fluorescence induced by UV irradiation. Analysis of fluorescence spectra of a sample prior and after UV irradiation enables an identification of a sample of a drug or pharmaceutics based on a comparison with signals of known standards. Moreover, UV-IFS uncovers the presence of undesired contaminations or intentional changes of the composition. Herein, we employ UV-IFS for qualitative as well as quantitative analysis of common medicines including analgesic/antipyretic (Acetaminophen), antihistamines (Loratadine and Desloratadine), and phosphodiesterase type 5 inhibitors (Tadalafil and Sildenafil citrate). UV irradiation (λ

Is there life beyond Earth? An ideal research program would first ascertain how life on Earth began and then use this as a blueprint for its existence elsewhere. But the origin of life on Earth is still not understood, what then could be the way forward? Upcoming observations of terrestrial exoplanets provide a unique opportunity for answering this fundamental question through the study of other planetary systems. If we are able to see how physical and chemical environments similar to the early Earth evolve we open a window into our own Hadean eon, despite all information from this time being long lost from our planet’s geological record. A careful investigation of the chemistry expected on young exoplanets is therefore necessary, and the preparation of reference materials for spectroscopic observations is of paramount importance. In particular, the deduction of chemical markers identifying specific processes and features in exoplanetary environments, ideally “uniquely”. For instance, prebiotic feedstock molecules, in the form of aerosols and vapours, could be observed in transmission spectra in the near future whilst their surface deposits could be observed from reflectance spectra. The same detection methods also promise to identify particular intermediates of chemical and physical processes known to be prebiotically plausible. Is Ariel truly able to open a window to the past and answer questions concerning the origin of life on our planet and the universe? In this paper, we discuss aspects of prebiotic chemistry that will help in formulating future observational and data interpretation strategies for the Ariel mission. This paper is intended to open a discussion and motivate future detailed laboratory studies of prebiotic processes on young exoplanets and their chemical signatures.

In this proof-of-concept study, we explore the detection of pesticides in food using a combined power of sensitive UV-induced fingerprint spectroscopy with selective capture by molecularly imprinted polymers (MIPs) and portable cost-effective paper-based analytical devices (PADs). The specific pesticides used herein as model compounds (both pure substances and their application products for spraying), were: strobilurins (i.e. trifloxystrobin), urea pesticides (rimsulfuron), pyrethroids (cypermethrine) and aryloxyphenoxyproponic acid herbicides (Haloxyfop-methyl). Commercially available spraying formulations containing the selected pesticides were positively identified by MIP-PADs swabs of sprayed apple and tomato. The key properties of MIP layer - imprinting factor (IF) and selectivity factor (α) were characterized using trifloxystrobin (IF-3.5, α-4.4) was demonstrated as a potential option for in-field application. The presented method may provide effective help with in-field testing of food and reveal problems such as false product labelling.

Here, we present the potential analytical applications of photochemistry in combination with fluorescence fingerprinting. Our approach analyzes the fluorescence of samples after ultraviolet light (UV) treatment. Especially in presence of metal ions and thiol-containing compounds, the fluorescence behavior changes considerably. The UV-induced reactions (changes) are unique to a given sample composition, resulting in distinct patterns or fingerprints (typically in the 230–600 nm spectral region). This method works without the need for additional chemicals or fluorescent probes, only suitable diluent must be used. The proposed method (UV fingerprinting) suggests the option of recognizing various types of pharmaceuticals, beverages (juices and wines), and other samples within only a few minutes. In some studied samples (e.g. pharmaceuticals), significant changes in fluorescence characteristics (mainly fluorescence intensity) were observed. We believe that the fingerprinting technique can provide an innovative solution for analytical detection.

Besides delivering plausible prebiotic feedstock molecules and high-energy initiators, extraterrestrial impacts could also affect the process of abiogenesis by altering the early Earth's geological environment in which primitive life was conceived. We show that iron-rich smectites formed by reprocessing of basalts due to the residual post-impact heat could catalyze the synthesis and accumulation of important prebiotic building blocks such as nucleobases, amino acids and urea.

The aim of this study was to synthesize cadmium telluride nanoparticles (CdTe NPs) modified apoferritin, and examine if apoferritin is able to accommodate CdTe NPs. Primarily, the thermostability of horse spleen apoferritin was tested and it's unfolding at 70 °C was observed. Cadmium telluride nanoparticles (CdTe NPs) were synthesized both within apoferritin protein cage and on its surface. The thermal treatment of apoferritin with CdTe NPs resulted in the aggregation of cores, which was indicated by changes in the absorption spectra and the shape of apoferritin tryptophan fluorescence. The apoferritin modified with CdTe NPs was additionally modified with gold nanoparticles and attached to magnetic particles via oligonucleotide using gold affinity to thiol group. This anchor system was used to separate the construct using external magnetic field and to analyse the molecules attached to apoferritin.

Here we report the preparation of low defect blue fluorescent graphene quantum dots (GQDs) through microwave expansion and liquid phase exfoliation (LPE) of graphite flakes with a high preparation yield of 0.63 g of GQDs per 1 g of original graphite substrate. The maximum emission in the prepared GQDs occurs at 467 nm for 370 nm excitation. The photoluminescence quantum yield of the prepared GQDs was measured as 3.4%. Prepared GQDs are composed of carbon, oxygen and nitrogen elements. They have high percentage (86%) of C-C/C=C, indicating few structural defects of the graphitic core, due to lesser number of edge- or surface-located oxygenated functional groups. This preparation technique, unlike others, does not require additional chemical components and is energetically undemanding. Furthermore, the reported method is also suitable for scalable preparation of quantum structures from other two-dimensional layered materials.

A capillary electrophoretic (CE) method using a short-sweep approach and laser-induced fluorescence (LIF) detection (ShortSweepCE-LIF) was developed for determination of Zn2+ and Cd2+ as complexes with highly selective and sensitive fluorescent probe FluoZin-3. The ShortSweepCE-LIF method, established in this work, can be used for examining competitive Zn2+ and Cd2+ binding properties of metalloproteins or peptides. The parameters including background electrolyte composition, injection pressure and time as well as separation voltage were investigated. Under the optimized conditions, 80 mM HEPES, pH 7.4, with 1.5 μM FluoZin-3 was used as an electrolyte, hydrodynamic injection was performed at 50 mbar for 5 s, and separation voltage of 25 kV. Limits of detection for Zn2+ and Cd2+ were 4 and 125 nM, respectively. The developed method was demonstrated in a study of interactions between metalothionein-2a isoform and metal ions Zn2+, Co2+ and Cd2+. It was found that FluoZin-3 was able to extract a single Zn2+ ion, while added Co2+ (in surplus) extracted only 2.4 Zn2+ ions, and Cd2+ extracted all 7 Zn2+ ions present in the metalothionein molecule.

Quantum dots (QDs) have been widely applied in the analytical field including sensitive fluorescent assays on paper-based devices. A facile in-situ synthesis of QDs after a simple reagent deposition on paper could enable a rapid low-cost fabrication of QD–modified paper with a variety of properties and purposes such as enzymatic nanoreactors. Herein, for the first time, fluorescent ZnCd QDs were prepared by in-situ synthesis in the paper matrix using thiol-containing precursors and irradiation by UV light. A successful creation of the immobilized ZnCd QDs on paper (paper@ZnCd QDs) was monitored by their intrinsic fluorescence while their peroxidase mimetic activity was evaluated by a catalytic reaction between H2O2 and a substrate (3,3′,5,5′-tetramethylbenzidine, TMB) producing a blue coloured product of charged transfer complex of TMB (oxTMB). From three thiol precursors investigated, the insulin precursor provided a greater activity than glutathione (GSH) and both considerably larger than BSA. Finally, a QDs precursor mixture deposition onto the paper matrix was evaluated by the peroxidase-mimetic activity, which was comparable with a reference method. The in-situ preparation of paper@ZnCd QDs is simple, rapid and ‘green’, with potential in biomedical applications primarily as fluorescence imaging agent and enzyme mimetic paper-based nanoreactors.

In this article, the authors report a systematic study of the self-assembly of CdTe quantum dots (QDs) stabilized by mercaptosuccinic acid (MSA) at laboratory temperature (25 °C) or after thermal treatment (90 °C). It was found that QD/MSA can be synthesized spontaneously under mild laboratory conditions (25 °C and 70 hours) without any further instrumentation or they can be treated using an increased temperature (90 °C and 8 min) to achieve the same fluorescence intensity. These QDs were used for the preparation of a fluorescent (off–on) probe based on methylene blue as a quencher for the specific determination of nucleic acid from urine. The whole process was monitored using stationary spectroscopy (absorbance and fluorescence measurement) and capillary electrophoresis (CE) with laser-induced fluorescence detection. The average size of the prepared QDs (approximately 3 nm) was determined using transmission electron microscopy and it was proven that the presented fluorescent probe combined with the CE method can be used for the sensitive determination of DNA (LOD 3 ng mL−1).

Capillary electromigration techniques have proven their capabilities in detection of variety of analytes from inorganic ions and small organic molecules through bio(macro)molecules to large analytes such as cells or nano/micro particles. Also broad range of potential applications includes food and environmental analysis, biomedical and pharmaceutical investigations or even diagnostics. In this work, it was demonstrated that capillary micellar electrokinetic chromatography is an excellent tool extremely helpful in investigations focused on prebiotic synthesis of molecules essential for formation of life on early Earth – nucleobases. In particular, rapid separation of nucleobases (

The authors report on a systematic study on the low-cost, low-temperature, and fast synthesis of water soluble quantum dots (QDs) stabilized by mercaptosuccinic acid by UV irradiation. The effects of UV irradiation (at 254 nm and 250 nm) and temperature on the precursors (Cd:Se, Cd:Te, Cd, Zn:S, Zn:Se and Zn) are described. Best results are achieved with a mixture of precursors containing cadmium, selenium and MSA where a 10-min irradiation with 254-nm light gives CdSe QDs with a quantum yield of 13.5%. The authors also describe the preparation and monitoring of the formation of QDs in sub-mg, sub-μg and sub-ng quantities, the smallest concentration being 258 pg in volume of 4 nL. The growth of the QDs can be monitored in real time by absorption, fluorescence and dynamic light scattering. The solutions of the particles also are characterized by fluorescence correlation spectroscopy and detected by LED-induced fluorescence. The preparation of such QDs by UV radiation is simple, easily controllable, and inexpensive. Conceivably, it can be integrated with lab-on-chip, micro total analysis systems or other instrumentation.

To ensure food safety and to prevent unnecessary foodborne complications this study reports fast, fully automated process for histamine determination. This method is based on magnetic separation of histamine with magnetic particles and quantification by the fluorescence intensity change of MSA modified CdSe Quantum dots. Formation of Fe2O3 particles was followed by adsorption of TiO2 on their surface. Magnetism of developed probe enabled rapid histamine isolation prior to its fluorescence detection. Quantum dots (QDs) of approx. 3 nm were prepared via facile UV irradiation. The fluorescence intensity of CdSe QDs was enhanced upon mixing with magnetically separated histamine, in concentration-dependent manner, with a detection limit of 1.6 μM. The linear calibration curve ranged between 0.07 and 4.5 mM histamine with a low LOD and LOQ of 1.6 μM and 6 μM. The detection efficiency of the method was confirmed by ion exchange chromatography. Moreover, the specificity of the sensor was evaluated and no cross-reactivity from nontarget analytes was observed. This method was successfully applied for the direct analysis of histamine in white wine providing detection limit much lower than the histamine maximum levels established by EU regulation in food samples. The recovery rate was excellent, ranging from 84 to 100% with an RSD of less than 4.0%. The main advantage of the proposed method is full automation of the analytical procedure that reduces the time and cost of the analysis, solvent consumption and sample manipulation, enabling routine analysis of large numbers of samples for histamine and highly accurate and precise results.

We present a utilization of carbon quantum dots (CQDs), passivated with polyethylene glycol as a fluorescent recognition probe for DNA damage. Synthesized CQDs were characterized in detail, using optical and electrochemical methods. Further, fluorescent behavior of CQDs was monitored in the presence of genomic DNA, isolated from Staphylococcus aureus. In laboratory conditions, after 30 min of exposure to UV irradiation (λ = 254 nm), the DNA/CQDs complex significantly increased its fluorescence. Further, stratospheric probe was suggested and crafted by using technology of 3D printing (acrylonitrile–butadiene–styrene as a material). CQDs were exploited to evaluate the DNA damage in stratospheric conditions (up to 20,000 m) by determination of fluorescence increase (λ exc = 245 nm, λ em = 400 nm), together with other parameters (temperature, humidity, altitude, pressure, UV intensity, and X-ray irradiation). The obtained data showed that the sensor utilizing the DNA/CQDs was able to identify the DNA damage, together with external conditions. It was shown the proposed concept is able to operate at temperatures lower than −70 °C. The proposed protocol may by applicable as a biosensor for long-term space missions, like international space station, missions to the Moon or Mars.

'Green nanotechnology' is a term used for the design of nanomaterials and processes that reduce or eliminate the use and/or generation of hazardous substances. In this paper, a capillary electrophoresis (CE)-driven synthesis of CdTe quantum dots (QDs) and their subsequent conjugation with a metal-binding protein metallothionein (isofom MT1) is reported. Even though the toxic materials (cadmium and potassium borohydride) were used for synthesis, the proposed method can be labeled as 'environmentally friendly' because the whole process (synthesis of QDs and MT1 conjugation) was carried out under mild conditions: ultra-low volume (nanoliter scale), relatively low temperature (50 °C), atmospheric pressure, and completed in a short time (under 90 s). Prepared QDs were also characterized by classical fluorescence spectroscopy and transmission electron microscopy. This study opens up new possibilities for the utilization of classical CE in the synthesis of nanoparticles and on-line labeling of biomolecules in the nanoliter scale in short period of time.

Nanofluidics is becoming an extensively developing technique in the field of bioanalytical chemistry. Nanoscale hole embed in an insulating membrane is employed in a vast variety of sensing platforms and applications. Although, biological nanopores have several attractive characteristics, in this paper, we focused on the solid-state nanopores due to their advantages as high stability, possibility of diameter control, and ease of surface functionalizing. A detection method, based on the translocation of analyzed molecules through nanochannels under applied voltage bias and resistive pulse sensing, is well established. Nevertheless, it seems that the new detection methods like measuring of transverse electron tunneling using nanogap electrodes or optical detection can offer significant additional advantages. The aim of this review is not to cite all related articles, but highlight the steps, which in our opinion, meant important progresses in solid-state nanopore analysis.

A novel microfluidic label-free bead-based metallothionein immunosensors was designed. To the surface of superparamagnetic agarose beads coated with protein A, polyclonal chicken IgY specifically recognizing metallothionein (MT) were immobilized via rabbit IgG. The Brdicka reaction was used for metallothionein detection in a microfluidic printed 3D chip. The assembled chip consisted of a single copper wire coated with a thin layer of amalgam as working electrode. Optimization of MT detection using designed microfluidic chip was performed in stationary system as well as in the flow arrangement at various flow rates (0-1800 μL/min). In stationary arrangement it is possible to detect MT concentrations up to 30 ng/mL level, flow arrangement allows reliable detection of even lower concentration (12.5 ng/mL). The assembled miniature flow chip was subsequently tested for the detection of MT elevated levels (at approx. level 100 μg/mL) in samples of patients with cancer. The stability of constructed device for metallothionein detection in flow arrangement was found to be several days without any maintenance needed.

The purpose of this study was to test quantum dots (QDs) separation by native and Tris–Glycine SDS-PAGE according to the protocols commonly used for protein analyses. To study the electrophoretic behaviour of quantum dots, ten samples of previously synthesized CdTe QDs stabilized with mercaptosuccinic acid (MSA) were used. Prior to electrophoresis the hydrodynamic diameters of QDs and zeta potentials were determined, as well as the fluorescence properties and stability of QDs in the running buffers. After verification of QDs stability and separation in native polyacrylamide gel, SDS-PAGE in gradient 4–20 % polyacrylamide gel was performed. Under UV irradiation a colour-dependent separation of QDs was observed, which was consistent with their hydrodynamic diameter distribution. The electrophoretic conditions were further optimized with respect to achieving the optimal colour separation, fluorescence stability and to minimize the time of analysis. Based on the results obtained, for further work 15 % polyacrylamide gels with SDS were used and the times (30–60 min) and voltage (100–150 V) used for separation were optimized. Under the optimal separation conditions (30 min, 100 V) the addition of MSA in the concentration range 0–4 mM was used to improve visualization of QDs with diameters in the range from 7 ± 2 to 4 ± 2 nm.

a b s t r a c t Arsenic compounds belong to the most controversial agents concerning human health. Arsenic (As) is considered as a top environmental element influencing human health due to its adverse effects includ- ing cancer, diabetes, cardiovascular disease, and reproductive or developmental problems. Despite the proven mutagenic, teratogenic and carcinogenic effects, the arsenic compounds are used for centuries to treat infectious diseases. In our work, we focused on studying of interactions of As(III) and/or As(V) with DNA. Interactions between arsenic ions and DNA were monitored by UV/vis spectrophotometry by measuring absorption and fluorescence spectra, atomic absorption spectrometry, electrochemical measurements (square wave voltammetry) and agarose gel electrophoresis. Using these methods, we observed a stable structure of DNA with As(III) within the concentration range 0.4-6.25 g mL −1 . Higher As(III) concentration caused degradation of DNA. However, similar effects were not observed for As(V).

A capillary electrophoretic (CE) method using a short-sweep approach and laser-induced fluorescence (LIF) detection (ShortSweepCE-LIF) was developed for determination of Zn

Sparsely tested group of platinum nanoparticles (PtNPs) may have a comparable effect as complex platinum compounds. The aim of this study was to observe the effect of PtNPs in in vitro amplification of DNA fragment of phage λ, on the bacterial cultures (Staphylococcus aureus), human foreskin fibroblasts and erythrocytes. In vitro synthesized PtNPs were characterized by dynamic light scattering (PtNPs size range 4.8-11.7 nm), zeta potential measurements (-15 mV at pH 7.4), X-ray fluorescence, UV/vis spectrophotometry and atomic absorption spectrometry. The PtNPs inhibited the DNA replication and affected the secondary structure of DNA at higher concentrations, which was confirmed by polymerase chain reaction, DNA sequencing and DNA denaturation experiments. Further, cisplatin (CisPt), as traditional chemotherapy agent, was used in all parallel experiments. Moreover, the encapsulation of PtNPs in liposomes (LipoPtNPs) caused an approximately 2.4x higher of DNA damage in comparison with CisPt, LipoCisPt and PtNPs. The encapsulation of PtNPs in liposomes also increased their antibacterial, cytostatic and cytotoxic effect, which was determined by the method of growth curves on S. aureus and HFF cells. In addition, both the bare and encapsulated PtNPs caused lower oxidative stress (determined by GSH/GSSG ratio) in the human erythrocytes compared to the bare and encapsulated CisPt. CisPt was used in all parallel experiments as traditional chemotherapy agent.

Nanomaterials in agriculture are becoming popular due to the impressive advantages of these particles. However, their bioavailability and toxicity are key features for their massive employment. Herein, we comprehensively summarize the latest findings on the phytotoxicity of nanomaterial products based on essential metals used in plant protection. The metal nanoparticles (NPs) synthesized from essential metals belong to the most commonly manufactured types of nanomaterials since they have unique physical and chemical properties and are used in agricultural and biotechnological applications, which are discussed. The paper discusses the interactions of nanomaterials and vascular plants, which are the subject of intensive research because plants closely interact with soil, water, and atmosphere; they are also part of the food chain. Regarding the accumulation of NPs in the plant body, their quantification and localization is still very unclear and further research in this area is necessary.

Doxorubicin is an effective chemotherapeutic drug, however, its toxicity is a significant limitation in therapy. Encapsulation of doxorubicin inside liposomes or ferritin cages decreases cardiotoxicity while maintaining anticancer potency. We synthesized novel apoferritin- and liposome-encapsulated forms of doxorubicin (“Apodox” and “lip-8-dox”) and compared its toxicity with doxorubicin and Myocet on prostate cell lines. Three different prostatic cell lines PNT1A, 22Rv1, and LNCaP were chosen. The toxicity of the modified doxorubicin forms was compared to conventional doxorubicin using the MTT assay, real-time cell impedance-based cell growth method (RTCA), and flow cytometry. The efficiency of doxorubicin entrapment was 56% in apoferritin cages and 42% in the liposome carrier. The accuracy of the RTCA system was verified by flow-cytometric analysis of cell viability. The doxorubicin half maximal inhibition concentrations (IC50) were determined as 170.5, 234.0, and 169.0 nM for PNT1A, 22Rv1, and LNCaP, respectively by RTCA. Lip8-dox is less toxic on the non-tumor cell line PNT1A compared to doxorubicin, while still maintaining the toxicity to tumorous cell lines similar to doxorubicin or epirubicin (IC50 = 2076.7 nM for PNT1A vs. 935.3 and 729.0 nM for 22Rv1 and LNCaP). Apodox IC50 was determined as follows: 603.1, 1344.2, and 931.2 nM for PNT1A, 22Rv1, and LNCaP.

The aim of this study was to analyze the interactions of blue and yellow fluorescent CdS quantum dots (CdS-QDs) with human papillomavirus 16 (HPV-16) oncogene E6. The interactions were investigated using chip capillary electrophoresis, spectrophotometry and square wave voltammetry (SWV). Using chip capillary electrophoresis we proved that blue fluorescent CdS-QDs (0.5 mM) caused an increase of the migration time of the E6 HPV-16 DNA–CdS-QDs complex by 42 s compared to control DNA (E6 HPV-16). The same concentration of yellow fluorescent CdS-QDs caused an increase in the migration time of the DNA–CdS-QDs complex by 108 s compared to the control DNA (E6 HPV-16). The difference in the migration times between both complexes was 66 s. Using square wave voltammetry (SWV), the reduction signal of cytosine and adenine (peak CA) was observed, after the complex with 2.5 µg mL−1 DNA was formed. A decrease of the peak CA reduction signal of the complex DNA–CdS-QDs by 90 % was caused when yellow fluorescent CdS-QDs (0.03 mM) were used. The same concentration of blue fluorescent CdS-QDs caused only a 50 % decrease of the C and A reduction signal of the DNA–CdS-QDs complex. The difference between both CdS-QDs was 40 %. Electrochemical measurements and chip electrophoresis analyses confirmed that the yellow fluorescent CdS-QDs show higher affinity to the DNA (E6 HPV-16) compared to blue ones.

Remote-controlled robotic systems are being used for analysis of various types of analytes in hostile environment including those called extraterrestrial. The aim of our study was to develop a remote-controlled robotic platform (ORPHEUS-HOPE) for bacterial detection. For the platform ORPHEUS-HOPE a 3D printed flow chip was designed and created with a culture chamber with volume 600 μL. The flow rate was optimized to 500 μL/min. The chip was tested primarily for detection of 1-naphthol by differential pulse voltammetry with detection limit (S/N = 3) as 20 nM. Further, the way how to capture bacteria was optimized. To capture bacterial cells (Staphylococcus aureus), maghemite nanoparticles (1 mg/mL) were prepared and modified with collagen, glucose, graphene, gold, hyaluronic acid, and graphene with gold or graphene with glucose (20 mg/mL). The most up to 50% of the bacteria were captured by graphene nanoparticles modified with glucose. The detection limit of the whole assay, which included capturing of bacteria and their detection under remote control operation, was estimated as 30 bacteria per μL.

In this study, we report a new three-dimensional (3D), bead-based microfluidic chip developed for rapid, sensitive and specific detection of influenza hemagglutinin. The principle of microfluidic chip is based on implementation of two-step procedure that includes isolation based on paramagnetic beads and electrochemical detection. As a platform for isolation process, streptavidin-modified MPs, which were conjugated via biotinylated glycan (through streptavidin-biotin affinity) followed by linkage of hemagglutinin to glycan, were used. Vaccine hemagglutinin (HA vaxi) was labeled with CdS quantum dots (QDs) at first. Detection of the isolation product by voltammetry was the end point of the procedure. The suggested and developed method can be used also for detection of other specific substances that are important for control, diagnosis or therapy of infectious diseases.

Taurine (2-aminoethanesulfonic acid) is an organic acid widely distributed in animal tissues. It is involved in many physiological processes. Thus, it is widely discussed especially due to its antioxidant properties. In this study, we focused on the effect of taurine supplementation on the concentration of antioxidants in blood plasma and erythrocytes of Wistar rats. Taurine was applied in feed mixture in the dosage of 0, 1, 250, 500, 750, 1000, 1500, 2000, 2500, 3000, 3500 and 4000 mg/kg. We monitored both enzymatic and non-enzymatic antioxidants – glutathione peroxidase, glutathione reductase, and superoxide dismutase and reduced/oxidized glutathione and metallothionein. Using three different methods 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), Ferric Reducing Antioxidant Power (FRAP) and free radicals, we determined antioxidant capacity. In addition, we monitored levels of uric acid and glucose. Our results revealed significant changes in both enzymatic and non-enzymatic parameters with the increasing taurine supplementation.

The electroactivity of purine and pyrimidine bases is the most important property of nucleic acids that is very useful for determining oligonucleotides using square wave voltammetry. This study was focused on the electrochemical behavior of adenine-containing oligonucleotides before and after their isolation using paramagnetic particles. Two peaks were detecte - peak A related to the reduction of adenine base and another peak B involved in the interactions between individual adenine strands and contributes to the formation of various spatial structures. The influence of the number of adenine bases in the strand in the isolation process using paramagnetic particles was investigated too. Elektroaktivita purinových a pyrimidinových bází je nejdůležitější vlastností nukleových kyselin, které jsou velmi užitečné pro stanovení oligonukleotidů pomocí obdélníkové voltametrie. Tato studie byla zaměřena na elektrochemické chování oligonukleotidů adenin obsahující před a po izolaci pomocí paramagnetických částic. Byly detekovány dva píky v souvislosti se snížením adeninu báze a dalšího vrcholu B které se podílí na interakci mezi jednotlivými prameny adenin a přispívá ke vzniku různých prostorových konstrukcí. Byl také zkoumán vliv počtu adeninů na základě v oblasti izolačního procesu pomocí paramagnetických částic.

Interactions of silver phosphate nanoparticles (SPNPs) and selenium nanoparticles (SeNPs) with Staphylococcus aureus cultures have been studied at the cellular, molecular and protein level. Significant antibacterial effects of both SPNPs and SeNPs on S. aureus were observed. At a concentration of 300 μM, SPNPs caused 37.5% inhibition of bacterial growth and SeNPs totally inhibited bacterial growth. As these effects might have been performed due to the interactions of nanoparticles with DNA and proteins, the interaction of SPNPs or SeNPs with the amplified zntR gene was studied. The presence of nanoparticles decreased the melting temperatures of the nanoparticle complexes with the zntR gene by 23% for SeNPs and by 12% for SPNPs in comparison with the control value. The concentration of bacterial metallothionein was 87% lower in bacteria after application of SPNPs (6.3 μg mg(-1) protein) but was increased by 29% after addition of SeNPs (63 μg mg(-1) protein) compared with the S. aureus control (49 μg mg(-1) protein). Significant antimicrobial effects of the nanoparticles on bacterial growth and DNA integrity provide a promising approach to reducing the risk of bacterial infections that cannot be controlled by the usual antibiotic treatments.

In this study we describe a beads-based assay for rapid, sensitive and specific isolation and detection of influenza vaccine hemagglutinin (HA). Amplification of the hemagglutinin signal resulted from binding of an electrochemical label as quantum dots (QDs). For detection of the metal and protein part of the resulting HA-CdTe complex, two differential pulse voltammetric methods were used. The procedure includes automated robotic isolation and electrochemical analysis of the isolated product. The isolation procedure was based on the binding of paramagnetic particles (MPs) with glycan (Gly), where glycan was used as the specific receptor for linkage of the QD-labeled hemagglutinin. V této studii jsme popsali test korálky založené na rychlou, citlivou a specifickou izolaci a detekci vakcíny proti chřipce hemaglutininu (HA). Amplifikace hemaglutinin signálu důsledkem vazby elektrochemického štítku podle kvantových teček (QDS). Pro detekci kovů a proteinové části výsledného HA-CdTe komplexu, byly použity dvě metody diferenciální pulsní voltametrické.Postup zahrnuje automatizované robotizované izolaci a elektrochemické analýze izolovaného produktu. Postup izolace byl založen na vázání paramagnetických částic (MPS) s glykan (Gly), kde byl použit glykanů jako specifický receptor pro propojení na QD-značeného hemaglutininu.

Microfluidic techniques have been developed intensively in recent years due to lower reagent consumption, faster analysis, and possibility of the integration of several analytical detectors into one chip. Electrochemical detectors are preferred in microfluidic systems, whereas liposomes can be used for amplification of the electrochemical signals. The aim of this study was to design a nanodevice for targeted anchoring of liposome as transport device. In this study, liposome with encapsulated Zn(II) was prepared. Further, gold nanoparticles were anchored onto the liposome surface allowing binding of thiol moiety-modified molecules (DNA). For targeted capturing of the transport device, DNA loops were used. DNA loops were represented by paramagnetic microparticles with oligo(DT)25 chain, on which a connecting DNA was bound. Capturing of transport device was subsequently done by hybridization to the loop. The individual steps were analyzed by electrochemistry and UV/Vis spectrometry. For detection of Zn(II) encapsulated in liposome, a microfluidic system was used. The study succeeded in demonstrating that liposome is suitable for the transport of Zn(II) and nucleic acids. Such transporter may be used for targeted binding using DNA anchor system.

Polymers are currently widely used to replace a variety of natural materials with respect to their favourable physical and chemical properties, and due to their economic advantage. One of the most important branches of application of polymers is the production of different products for medical use. In this case, it is necessary to face a significant disadvantage of polymer products due to possible and very common colonization of the surface by various microorganisms that can pose a potential danger to the patient. One of the possible solutions is to prepare polymer with antibacterial/antimicrobial properties that is resistant to bacterial colonization. The aim of this study was to contribute to the development of antimicrobial polymeric material ideal for covering vascular implants with subsequent use in transplant surgery. Therefore, the complexes of polymeric substances (hyaluronic acid and chitosan) with silver nitrate or silver phosphate nanoparticles were created, and their effects on gram-positive bacterial culture of Staphylococcus aureus were monitored. Stages of formation of complexes of silver nitrate and silver phosphate nanoparticles with polymeric compounds were characterized using electrochemical and spectrophotometric methods. Furthermore, the antimicrobial activity of complexes was determined using the methods of determination of growth curves and zones of inhibition. The results of this study revealed that the complex of chitosan, with silver phosphate nanoparticles, was the most suitable in order to have an antibacterial effect on bacterial culture of Staphylococcus aureus. Formation of this complex was under way at low concentrations of chitosan. The results of electrochemical determination corresponded with the results of spectrophotometric methods and verified good interaction and formation of the complex. The complex has an outstanding antibacterial effect and this effect was of several orders higher compared to other investigated complexes.

Quantum dots (QDs) belong to a new class of fluorescent agent for biochemical, medicinal or other purposes. However, QDs based on cadmium or other metals can be risky for an organism. As one of the mechanism how to detoxify cadmium-based QDs expression of metallothioneins (MT) can be considered. Due to high affinity of metallothionein to cadmium(II) ions, we attempted to develop an approach for studying of possible interaction with QDs. We prepared QDs with CdTe core and studied the interaction with MT, which we isolated from livers of Cd-administered rabbits. To study the interaction, we used the mixture of both components MT (3.6 μM): CdTe QDs (0, 0.34, 0.68, 1.02, 1.36, 1.7, 2.04 and 2.47 μM). The mixtures were studied by spectrophotometry within the range from 200 to 750 nm with detected maxima at 260 and 505 nm. Same mixtures were also analysed by differential pulse voltammetry Brdicka reaction, which supported data from spectrophotometry. Subsequently, we used fast protein liquid chromatography for purification of protein–quantum dot conjugates. We obtained the different chromatograms for (1) Apo MT, (2) CdTe QDs and (3) MT–QD complex. We also collected the fractions and subsequently analysed them on the content of Cd and MT, which confirmed the formation of CdTe QDs–MT complex.