293 research outputs found
Improvement of electrophoresis performance by spectral analysis
This paper describes a new design of standard agarose gel electrophoresis procedure for nucleic acids analysis. The electrophoresis was improved by using the real-time spectral analysis of the samples to increase its performance. A laser beam illuminated the analysed sample at wavelength with the highest absorption of gel components. Thus, DNA band is detected well before it may exits a gel plate. A modified horizontal electrophoresis device was designed, developed and tested.Keywords: Horizontal electrophoresis, laser, spectral analysis, agarose ge
An Analytical Task: a Miniaturized and Portable ĀµConductometer as a Tool for Detection of Pesticides
Monitoring of the Surface Modification of Nanoparticlesby Electrochemical Measurements Using Scanning Electrochemical Microscope
Elektrokemijsko odreÄivanje metalotioneina kod domaÄe peradi
Metallothionein (MT) belongs to group of intracellular, low-molecular and cysteine-rich proteins with a molecular weight from 6 to 10 kDa. Owing to their high affinity to heavy metals (Zn, Cd, As, etc.) their main role is homeostatic control and detoxification of metal ions in an organism. In the present work we aimed at suggesting and utilizing electroanalytical techniques to determine content of MT in the blood serum of domestic fowls. Electrochemical measurements were performed with an AUTOLAB Analyser connected to VA-Stand 663, using a standard cell with three electrodes. Particularly, MT was detected by adsorptive transfer stripping technique in connection with differential pulse voltammetry. The detection limit of MT was estimated down to 100 fM (standards only) or down to 100 pM measured in the presence of blood serum. The average content of MT was 21.3 ĀµM. The MT level in hens was about 25 % higher than in cocks. This phenomenon can be related to higher demands on the content of this protein in hens due the requirement for ion transport to form eggshell.Metalotionein (MT) pripada grupi intracelularnih proteina male molekularne mase bogatih cisteinom, s molekularnom masom od 6 do 10 kDa. Zbog njihovog afiniteta prema teÅ”kim metalima (Zn, Cd, As, itd.) njihova glavna uloga je homeostatska kontrola i detoksifikacija iona metala u organizmu. U ovom radu predlažu se elektroanalitiÄke tehnike za odreÄivanje sadržaja MT u krvnom serumu domaÄe peradi. Elektrokemijska mjerenja izvrÅ”ena su ureÄajem AUTOLAB Analyser povezanim s VA-Stand 663, koristeÄi standardnu Äeliju s tri elektrode. Osim toga MT je odreÄivan tehnikom adsorptivnog transfera, povezanoj s voltmetrijom diferencijalnog pulsa. Granica detekcije MT je procjenjivana do 100 fM (samo standardi) ili do 100 pM, mjereno u prisutnosti krvnog seruma. ProsjeÄni sadržaj MT bio je 21.3 ĀµM. Razina MT kod kokoÅ”i bila je otprilike 25% viÅ”a nego kod pijetlova. Ta pojava može se objasniti veÄom potrebom za ovim proteinom kod kokoÅ”i zbog transporta iona prilikom stvaranja ljuske jajeta
Preparation and Properties of Various Magnetic Nanoparticles
The fabrications of iron oxides nanoparticles using co-precipitation and gadolinium nanoparticles using water in oil microemulsion method are reported in this paper. Results of detailed phase analysis by XRD and Mƶssbauer spectroscopy are discussed. XRD analysis revealed that the crystallite size (mean coherence length) of iron oxides (mainly Ī³-Fe2O3) in the Fe2O3 sample was 30 nm, while in Fe2O3/SiO2 where the Īµ-Fe2O3 phase dominated it was only 14 nm. Gd/SiO2 nanoparticles were found to be completely amorphous, according to XRD. The samples showed various shapes of hysteresis loops and different coercivities. Differences in the saturation magnetization (MS) correspond to the chemical and phase composition of the sample materials. However, we observed that MS was not reached in the case of Fe2O3/SiO2, while for Gd/SiO2 sample the MS value was extremely low. Therefore we conclude that only unmodified Fe2O3 nanoparticles are suitable for intended biosensing application in vitro (e.g. detection of viral nucleic acids) and the phase purification of this sample for this purpose is not necessary
Pharmaceutical electrochemistry: the electrochemical oxidation of paracetamol and its voltammetric sensing in biological samples based on screen printed graphene electrodes.
We present a sensitive, fast and unmodified sensor for the electrochemical detection of paracetamol. The electrochemical behaviours of paracetamol on screen printed graphene electrodes were investigated for the first time by cyclic voltammetry. The results showed that the screen printed graphene electrodes revealed exceptional electrocatalytic activity to paracetamol. The response showed by this sensor was enhanced when it was compared to the bare screen printed electrodes. When Screen Printed Graphene Electrodes were compared to bare SPE, it was shown that the response with graphene was greater than without. This is due to its unique characteristics physical and chemical, pi-pi interactions and a strong adsorptive capability. In this manuscript, the effect of supporting electrolyte, pH and scan rate were also investigated. The oxidation peak current was linearly proportional to the concentration of paracetamol in the range from 0.1 to 50 mM with a limit of detection of 20nM based on (3-s/slope), under the optimum conditions. The proposed method was successfully applied to paracetamol determination in in biological samples such as human oral fluid
Carbon composite micro- and nano-tubes-based electrodes for detection of nucleic acids
The first aim of this study was to fabricate vertically aligned multiwalled carbon nanotubes (MWCNTs). MWCNTs were successfully prepared by using plasma enhanced chemical vapour deposition. Further, three carbon composite electrodes with different content of carbon particles with various shapes and sizes were prepared and tested on measuring of nucleic acids. The dependences of adenine peak height on the concentration of nucleic acid sample were measured. Carbon composite electrode prepared from a mixture of glassy and spherical carbon powder and MWCNTs had the highest sensitivity to nucleic acids. Other interesting result is the fact that we were able to distinguish signals for all bases using this electrode
Role of Phytochelatins in Redox Caused Stress in Plants and Animals
Varied environmental compartments (such as soil and water) potentially contaminated with different metals/metalloids can impact the health of both plants and animals/humans. Trace amounts of Cu, Mn, Mo, Ni and Zn are beneficial for higher plants, whereas, Cr, Cu, Co, Mn, Mo, Se, V and Zn are known as the micronutrient metal/metalloids for animals/humans. However, elevated levels of the metals/metalloids can cause severe toxic consequences in both plants and animals/humans. Common in plants and animals/humans, phytochelatins (PCs), the principal non-protein, S-rich, thiolate peptides, protect (through different mechanisms) cellular functions and metal/metalloid homeostasis by performing their chelation and/or detoxification. With the major aim of broadening the current knowledge on the subject, this chapter (a) overviews PCsā role and modulation separately in metal/metalloid-exposed plants and animals/humans; (b) discusses major methods for determination of PCs and bioassays for enzymes involved in PC synthesis; (c) evaluates the connection of PCs with bionanoparticles; and finally (d) highlights so far unexplored aspects in the present context
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