ELECTROCHEMICALDETECTION OF

BIOFILMS

Maria Irene MontenegroIsabel Alexandra Pinho

Maria João Vieira

WHAT ARE BIOFILMS?WHAT ARE BIOFILMS?

THEY ARE THE RESULT OF ADHESION AND GROWTH OF MICROORGANISMSAT INTERFACES

THEY ARE MICROENVIRONMENTS WHERE SEVERAL MICROBIALREACTIONS TAKE PLACE

BENEFICIAL BIOFILMS DETRIMENTAL BIOFILMS

DRINKING WATER PIPES

HEAT EXCHANGERS

THE NEED FOR A DETECTOR

THE NEED FOR A DETECTOR

HEALTH AREA

PRODUCTION OF SPECIFIC

PRODUCTS

WASTE WATER TREATMENT

WHAT ARE BIOFILMS?WHAT ARE BIOFILMS?

Detect biofilms:

easily

in early stages of formation

on line

MAIN LINES OF WORKMAIN LINES OF WORK

ELECTROCHEMICAL TECHNIQUESELECTROCHEMICAL 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

Potential (V vs RHE)

Cur

rent

(mA

/cm

2)

Voltammogram at a Platinum electrode in 1M sulfuric acid at 25ºC; continuous triangular potencial sweeps at 40 mV s-1. QH

c and QHa correspond, respectively, to the adsorption and

desorption of hydrogen, and QOa and QO

c to the adsorption and desorption of oxygen ( reprinted from Woods, R., 1976).

ELECTROCHEMICAL TECHNIQUESELECTROCHEMICAL TECHNIQUES

MATERIALS AND METHODSMATERIALS AND METHODS

A PLATINUM ELECTRODE

A BATCH CELL

A FLOW CELL

RE

CE

WE

SCHEMATIC VIEW OF THE BATCH CELL

MATERIALS AND METHODSMATERIALS AND METHODS

SCHEMATIC VIEW OF THE FLOW CELL

MATERIALS AND METHODSMATERIALS AND METHODS

MATERIALS AND METHODSMATERIALS AND METHODS

Pseudomonas fluorescens

CULTURE MEDIUM

PHOSPHATE BUFFER

GLUCOSE 5g/L

PEPTONE 2.5g/L

YEST EXTRACT 1.25g/L

PRELIMINARY RESULTSPRELIMINARY 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 solutionwith 5 g/L of glucose;(blue) in a buffered solution with 2.5 g/L of peptone; (light blue) in abuffered 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.

PRELIMINARY RESULTSPRELIMINARY 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.

PRELIMINARY RESULTSPRELIMINARY 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.

PRELIMINARY RESULTSPRELIMINARY 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.

PRELIMINARY RESULTSPRELIMINARY 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.

PRELIMINARY RESULTSPRELIMINARY 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.

PRELIMINARY RESULTSPRELIMINARY RESULTS

PRELIMINARY RESULTSPRELIMINARY RESULTS

PRELIMINARY RESULTSPRELIMINARY 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.

CONCLUSIONSCONCLUSIONS

THIS SEEMS TO BE A VERY PROMISSINGTECHNIQUE TO DETECT BIOFILMS

THERE IS FUTURE WORK TO BE DONE

with microelectrodes

with other cultures of microorganisms