ELECTROCHEMICAL DETECTION OF BIOFILMS

1. ELECTROCHEMICAL DETECTION OF BIOFILMS Maria Irene Montenegro Isabel Alexandra Pinho Maria João Vieira

2. WHAT ARE BIOFILMS? THEY ARE THE RESULT OF ADHESION AND GROWTH OF MICROORGANISMS AT INTERFACES THEY ARE MICROENVIRONMENTS WHERE SEVERAL MICROBIAL REACTIONS TAKE PLACE

3. WHAT ARE BIOFILMS? DETRIMENTAL BIOFILMS BENEFICIAL BIOFILMS WASTE WATER TREATMENT DRINKING WATER PIPES PRODUCTION OF SPECIFIC PRODUCTS HEAT EXCHANGERS HEALTH AREA THE NEED FOR A DETECTOR

4. MAIN LINES OF WORK Detect biofilms: easily in early stages of formation on line

5. ELECTROCHEMICAL TECHNIQUES IMPORTANT ROLE IN ANALYTICAL CHEMISTRY DETERMINATION AND QUANTIFICATION OF A LARGE NUMBER OF ORGANIC, INORGANIC AND BIOLOGICAL COMPOUNDS ALLOWING A DETECTOR TO OPERATE IN SITU

6. ELECTROCHEMICAL TECHNIQUES Voltammogram at a Platinum electrode in 1M sulfuric acid at 25ºC; continuous triangular potencial sweeps at 40 mV s-1. QHc and QHa correspond, respectively, to the adsorption and desorption of hydrogen, and QOa and QOc to the adsorption and desorption of oxygen ( reprintedfrom Woods, R., 1976).

7. MATERIALS AND METHODS A PLATINUM ELECTRODE A BATCH CELL AFLOW CELL

8. MATERIALS AND METHODS SCHEMATIC VIEW OF THE BATCH CELL

9. MATERIALS AND METHODS SCHEMATIC VIEW OF THE FLOW CELL

10. MATERIALS AND METHODS Pseudomonas fluorescens CULTURE MEDIUM PHOSPHATE BUFFER GLUCOSE 5g/L PEPTONE 2.5g/L YEST EXTRACT 1.25g/L

11. PRELIMINARY RESULTS Cyclic Voltammograms recorded on a batch cell at a scan rate of 250mV/s. Voltammograms were obtained: (white) in a buffered solution; (green) in a buffered solution with 5 g/L of glucose;(blue) in a buffered solution with 2.5 g/L of peptone; (light blue) in a buffered solution 1.25 g/L of yest extract; (red) in a buffered solution with 5 g/L of glucose, 2.5 g/L of peptone and 1.25 g/L of yest extract.

12. PRELIMINARY RESULTS Cyclic Voltammograms recorded on a batch cell at a scan rate of 250mV/s. Voltammograms were obtained: (white) in a buffered solution; (green) in a buffered solution with 5 g/L of glucose;(blue) in a buffered solution with 5 g/L of glucose and 2.5 g/L of peptone; (light blue) in a buffered solution with 5 g/L of glucose and 1.25 g/L of yest extract; (red) in a buffered solution with 5 g/L of glucose, 2.5 g/L of peptone and 1.25 g/L of yest extract.

13. PRELIMINARY RESULTS Cyclic Voltammograms recorded on a batch cell at a scan rate of 250mV/s. Voltammograms were obtained: (white) with a clean electrode in the culture medium; (green) immediatly after the electrode with biofilm is immersed on the culture medium.

14. PRELIMINARY RESULTS Cyclic Voltammograms recorded on a batch cell at a scan rate of 250mV/s. Voltammograms were obtained: (white) immediatly after the electrode is immersed in the buffered solution; (green) after 5 cycles;(blue) after 100 cycles.

15. PRELIMINARY RESULTS Cyclic Voltammograms recorded on a batch cell at a scan rate of 250mV/s. Voltammograms were obtained: (white) immediatly after the electrode is immersed in the culture medium; (green) after 5 cycles;(blue) after 100 cycles.

16. PRELIMINARY RESULTS Cyclic Voltammograms recorded on a batch cell at a scan rate of 250mV/s. Voltammograms were obtained: (white) with a clean electrode in the culture medium; (green) immediatly after the electrode with biofilm is immersed on the buffer solutions; (blue) with a clean electrode in the buffer solution.

17. PRELIMINARY RESULTS

18. PRELIMINARY RESULTS

19. PRELIMINARY RESULTS Cyclic Voltammograms recorded on a flow cell at a scan rate of 100mV/s. Voltammograms were obtained in a buffered solution : (white) without flow; (green) with a flow rate of 4 mL/s; (blue) with a flow rate of 15.8 mL/s; (red) with a flow rate of 33.3 mL/s.

20. CONCLUSIONS THIS SEEMS TO BE A VERY PROMISSING TECHNIQUE TO DETECT BIOFILMS THERE IS FUTURE WORK TO BE DONE with microelectrodes with other cultures of microorganisms