19/09/2017 1:29 PM
    
1st Satellite Workshop “High Sophisticated Biosensor Systems and their Application”

  


Microdialysis and Continuous Automated Real-Time Online Monitoring using Biosensors                                                                                                                  

MARK T. O´CONNELL       

Probe_BRNO2011.pdf

Fast detection of antioxidants

      
H. KOUTKOVÁ - VRÁNOVÁ, J. KREJČÍ, I. GAJDOŠÍK


Antioxidants have a positive effect on human health because they restrict the activity of oxygen radicals. The presence of antioxidants can reduce emergence of heart-vascular diseases and some types of cancer. The best known antioxidants are Vitamin A, C, E, coenzyme Q10, bioflavonoids, polyphenols etc. Green tea, coffee and wine contain polyphenols and flavonoids therefore those drinks should show antioxidants positive effect. Antioxidant activity was measured and compared for four commercial bagged tea, two instant coffee, two black coffee and two types of wine. Celaskon tablets 100 mg (Acidum ascorbicum) were measured too at different concentrations. 

Cyclic voltammetry as an easy and cheap method for qualitative determination of antioxidant activity was used. Redox characteristics of solution were evaluated by cyclic voltammetry. Two parameters from cyclic voltamogram can characterize antioxidant. First parameter is potential of anodic oxidation peak. The lower the value of anodic oxidation peak the better antioxidant. Second parameter, anodic current, is corresponding to concentration of antioxidant. Screen printed electrochemical sensors (BVT Technologies) with glassy carbon working electrode and potenciostat EA 161 (eDAQ) with e-coder ED210 (eDAQ) were used for the fast detection of antioxidants.                                                                                                                                    

BVT Technologies - Antioxidants.pdf

mini RDE

R. ŠEJNOHOVÁ, V. HANÁK

A rotating disc electrode (RDE) is one of the best methods to obtain efficient mass transport in a highly reproducible manner. The main advantage of RDE consists of possibility to control the mass transport by rotation speed. Classical RDE involve a platinum wire within glass tubing sealed in the plastic body of the RDE. The shape of the insulating mantle has an important role for the RDE function. BVT Technologies, a.s. developed mini RDE as disposable insert where the active surface is made by screen-printing.

 mini RDE.pdf

Application of Soret phenomenon to electrochemical sensor response improvement,

J. KREJČÍ, T. MARVÁNEK, H. KOUTKOVÁ, J. KREJČÍ jr., Z. GROSMANOVÁ

The gradient of concentration in Nernst layer is the driving force which assures the mass transport to the electrode. The diffusion is generally slow. It is desired to improve the electrode response and sensitivity which means to make the mass transport more intensive. There are two possibilities:
1. Decrease of the effective Nernst layer thickness due to hydrodynamic forces which increases the gradient of concentration as a driving force responsible for the mass transport through Nernst layer.
2. Add another driving force to induce the additional mass flow through Nernst layer to the electrode surface.
The poster presents the use of temperature gradient as a driving force for thermodiffusion to make the mass transport to the electrode more intensive. The sensors with electrodes system - working electrode, reference electrode and auxiliary electrode and heating system consisting of two resistors and temperature sensing element were integrated on the ceramic base. The advantage of ceramics lies in the fact that the thermal conductivity is very high and in case of BeO ceramics comparable with metals. It enables precise control of working electrode temperature and applying the temperature gradient exclusively to the Nernst layer.

 BVT Technologies - Soret.pdf

Development of integrated microfluidic platforms for cell analysis

G. PASIRAYI, J. KREJČÍ, V. HANÁK, V. AUGER

The purpose of this work is to: develop an integrated microfluidic device for biological cell analysis. The device was fabricated from polymer material using computer numerical milling methods and 3D Thin Film Technology (TFT). 3D TFT was used to construct a microreactor for microorganism testing by incorporating very small transparent PET (polyethylene terephthalate) microfilters which enables the trapping of cells. The 3D TFT technological work was based on the BVT patent (CZ297082 for Czech patent and US2005-0204939 for USA). The functionality of the system will be tested by using Scenedesmus quadricauda as model algae cells due to their robustness and ease of use.

 Development of integrated microfluidic platforms for cell analysis.pdf
   

The influence of hydrogen peroxide and pyocyanin in the life cycle of Scenedesmus quadricauda

G. PASIRAYI, L. UHLIŘOVÁ, V. AUGER, J. KREJČÍ

The main objective of this research is to study the life process of algae and their interaction with toxic chemical compounds and to observe their growth pattern. This work seeks to investigate the effect of oxidative stress and the protective mechanisms that are employed by algae cells to shield themselves from such effects. The effects of hydrogen peroxide and pyocyanin (a secondary metabolite derived from Pseudomonas aeruginosa) to induce oxidative stress on the algae Scenedesmus quadricauda was investigated. The effect of oxidative stress on the cells was determined by measuring oxygen production in real time using a state of the art oxygen electrode sensor (BVT), followed by cell viability measurements and morphological studies. The electrode sensor enabled better recording of life-time process of algae in a short time period of <10 hours. Preliminary findings show that hydrogen peroxide and pyocyanin induce some form of stress on the algae cells leading to cell death as shown by microscopic examination of the specimens.

 The influence of hydrogen peroxide and pyocyanin in the life cycle of.pdf

Optimalisation of analytical methods for Benzo(a)pyrene (BaP) determination in smoked meat products

E. LEDESMA, J. S. MONTE, J. MONTE, M. RENDUELES, M. DÍAZ

Benzo(a)pyrene (BaP) is a chemical compound whose major carcinogenic effect has been recognized by the international scientific community. Organizations like the International Agency for Research on Cancer (IARC), the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) warn about the danger of this compound. It belongs to the polycyclic aromatic hydrocarbons (PAH) group. These compounds are mainly generated by the incomplete combustion of organic matter (wood combustion, for example). PAH are carcinogenic and bioaccumulable, so they are highly dangerous due to the fact that they are able to be absorbed through the skin, inhalation and ingestion and to be accumulated in the body. The EC Regulation Nº 1881/2006 of December 19, 2006 has set maximum allowed amounts of BaP in foods. In smoked meats and smoked meat products the limit allowed is 5 μg/kg.

 OPTIMISATION OF ANALYTICAL METHODS FOR BENZO(a)PYRENE (BaP) DETERMINATION IN SMOKED MEAT PRODUCTS.pdf