Team:Calgary/Notebook/Electrochem

From 2012.igem.org

Week 1 (May 1-4)

This week involved planning various experiments and gathering chemicals to be tested. Unfortunately no lab work was conducted this week.

Week 2 (May 7-11)

Chlorophenol red (CPR) was oxidized in a sodium phosphate solution with zinc phthalocyanine modified carbon electrodes or just straight carbon electrodes. It was found that the modified electrodes had greater responses than their unmodified counterparts. All future work with CPR will be done with these electrodes.

Week 3 (May 14-18)

A standard curve was generated using CPR as the analyte in a sodium phosphate solution. This was made with the modified electrodes. After this it was found that the reference electrode being used, a silver/ silver chloride electrode, had stopped functioning. Switching to a reduction of hydrogen electrode (RHE) reference fixed this problem. A gold working electrode was also briefly tested to reduce the background noise caused by the capacitance of carbon. Further testing will be needed to chose a final electrode.

Week 4 (May 21-25)

This week involved testing the oxidation of CPR and para-aminophenol (PAP) in the same solution to determine if their oxidation potentials were unique. By showing that they are separate peaks it demonstrates that they can be used as two of the electrochemical components of a multiplexed biosensor. After a morning of failed tests on Thursday I finally managed to show that the peaks are unique (0.7V for PAP and 1.3V for CPR vs SHE), giving us the first step towards a final sensor.

Electrochemical detection of CPR and PAP in the same cell. PAP has the reversible wave seen at 0.75V, while CPR has the irreversible wave at 1.3V. These values were recorded in 25mL pH7 0.1M PBS with Ar bubbling on a carbon working electrode with a platinum counter electedo and an RHE as the reference electrode.

Week 5 (May 28- June 1)

This week the data collected was inconsistent across multiple runs even though the electrodes used were from the same batch. It seems that each of these electrodes is unique, presenting a challenge for analyzing results when multiple electrode setups are used.

Week 6 (June 4-8)

Sadly no work was done this week on the Electrochemistry project because help was required on different projects.

Week 7 (June 11-15)

The list of final analytes was compiled this week, giving a goal of chemicals to test with and without their sugar conjugates. The genes necessary to break these compounds apart were also noted and primers were designed so that they could be amplified. This week was mostly spent ordering in supplies for future work.