Square wave voltammetric detection of cholesterol with biosensor based on poly(styrene--ε-caprolactone)/MWCNTs composite.

A novel poly(styrene--ε-caprolactone)/multiwalled carbon nanotubes/cholesterol oxidase film-coated glassy carbon electrode was designed for cholesterol detection by square wave voltammetry (SWV). The biosensor responded to cholesterol with a measurement concentration range between 1 and 130 µM, a relative standard deviation of only 0.095% and accuracy of 100.42% ±2.85 with the SWV technique in the potential range from -0.6 to +0.6 V. The limit of detection was calculated to be 0.63 µM. The biosensor was preserved 91 and 84% of its initial response at the end of the 9st and 25st days, respectively. Human serum from human male AB plasma was analyzed without pretreatment except for dilution to investigate the performance of the biosensor in a complex medium.

The operation of enzymatic fuel cell fabricated with rationally designed poly(caprolactone-g-ethylene glycol) copolymers.

This study describes construction of an enzymatic fuel cell comprised of poly(caprolactone-g-ethylene glycol) coated novel glucose oxidase anode and laccase cathode. Rationally designed poly(caprolactone-g-ethylene glycol) containing various poly(ethylene glycol) percentages ranging between 2.67 and 15.04% were synthesized chemically and tested separately for operation of the fuel cell system to achieve the best energy generation. The maximum power density was found to be 80.55µWcm-2 at 0.91V (vs. Ag/AgCl) in pH5, 100mM citrate buffer (20°C) by the addition of 30mM of glucose from the electrodes coated with 11.34% poly(ethylene glycol) containing polymer with a quantity of 600µg. High poly(ethylene glycol) percentages with more numbers of long poly(ethylene glycol) brushes lead to the creation of a complexity in the polymer morphology and steric hindrance effect for electron transport. The graft copolymer was easily used for the fuel cell system owing to its biocompatible and microporous film morphology. The grafted polymer was able to facilitate enzymatic glucose oxidation and oxygen reduction while simultaneously producing high catalytic electrical currents.

Design of a mediated enzymatic fuel cell to generate power from renewable fuel sources.

The present work reported a compartment-less enzymatic fuel cell (EFC) based on newly synthesized Poly(pyrrole-2-carboxylic acid-co-3-thiophene acetic acid) film containing glucose oxidase and laccase effectively wired by p-benzoquinone incorporated into the copolymer structure. The resulting system generated a power density of 18.8 µW/cm(2) with 30 mM of glucose addition at +0.94 V at room temperature. Improvements to maximize the power output were ensured with step-by-step optimization of electrode fabrication design and operational parameters for operating the system with renewable fuel sources. We demonstrated that the improved fuel cell could easily harvest glucose produced during photosynthesis to produce electrical energy in a simple, renewable and sustainable way by generating a power density of 10 nW/cm(2) in the plant leaf within 2 min. An EFC for the first time was successfully operated in municipal wastewater which contained glycolytic substances to generate electrical energy with a power output of 3.3 µW/cm(2).

A novel poly(propylene-co-imidazole) based biofuel cell: system optimization and operation for energy generation.

This study describes the construction of an enzymatic fuel cell comprised of novel gold nanoparticles embedded poly(propylene-co-imidazole) coated anode and cathode. Working electrode fabrication steps and operational conditions for the fuel cell have been optimized to get enhanced power output. Electrical generation capacity of the optimized cell was tested by using the municipal wastewater sample. The enzymatic fuel cell system reached to maximum power density with 1 µg and 8 µg of polymer quantity and bilirubin oxidase on electrode surface, respectively. The maximum power output was calculated to be 5 µW cm(-2) at +0.56 V (vs. Ag/AgCl) in phosphate buffer (pH7.4, 100mM, 20°C) by the addition of 15 mM of glucose as a fuel source. The optimized enzymatic fuel cell generated a power density of 0.46 µW cm(-2) for the municipal wastewater sample. Poly(propylene-co-imidazole) was easily used for a fuel cell system owing to its metallic nanoparticle content. The developed fuel cell will play a significant role for energy conversion by using glucose readily found in wastewater and in vivo mediums.

Development and operation of gold and cobalt oxide nanoparticles containing polypropylene based enzymatic fuel cell for renewable fuels.

Newly synthesized gold and cobalt oxide nanoparticle embedded Polypropylene-g-Polyethylene glycol was used for a compartment-less enzymatic fuel cell. Glucose oxidase and bilirubin oxidase were selected as anodic and cathodic enzymes, respectively. Electrode fabrication and EFC operation parameters were optimized to achieve high power output. Maximum power density of 23.5 µW cm(-2) was generated at a cell voltage of +560 mV vs Ag/AgCl, in 100mM PBS pH 7.4 with the addition of 20mM of synthetic glucose solution. 20 µg of polymer amount with 185 µg of glucose oxidase and 356 µg of bilirubin oxidase was sufficient to get maximum performance. The working electrodes could harvest glucose, produced during photosynthesis reaction of Carpobrotus Acinaciformis plant, and readily found in real domestic wastewater of Zonguldak City in Turkey.

Biomonitoring of polycyclic aromatic hydrocarbons in urban and industrial environments of the Western Black Sea Region, Turkey.

This research was carried out in the cities of Zonguldak and Eregli, which have been characterized as urban and industrial environments of the Western Black Sea Region, Turkey, in order to assess the contamination of polycyclic aromatic hydrocarbons (PAHs) using mosses as biomonitors. The methodology involved the collection of moss samples (Hypnum cupressiforme), ultrasonic extraction with dichloromethane, cleanup using silica gel and analysis by liquid chromatography with ultraviolet detection. The total PAH concentrations ranged from 78.1 to 1693.5 ng g(-1) in Zonguldak and from 15.2 to 275.1 ng g(-1) in Eregli. The total PAH concentration in Eregli was about six times lower than that in Zonguldak, revealing the importance of switching from coal to natural gas in residential heating. The diagnostic ratios and the correlation analysis have indicated that coal combustion and traffic emissions were the major PAH sources at both sites. The contour maps were constructed for the determination of spatial distributions of total PAHs, and it was shown for Zonguldak as well as for Eregli that the PAH pollution was much more predominant in highly populated regions. Moving away from the city centres, a gradual decrease in PAH pollution rates was observed.