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Developing a real time sensing system to monitor bacteria in wound dressings.

Farrow MJ, Hunter IS, Connolly P - Biosensors (Basel) (2012)

Bottom Line: It is based on impedance sensors that could be placed at the wound-dressing interface and potentially monitor bacterial growth in real time.Impedance was measured using disposable silver-silver chloride electrodes.The main findings were that the impedance profiles obtained by silver-silver chloride sensors in bacterial suspensions could detect the presence of high cell densities.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Strathclyde, Wolfson Centre, Glasgow, G4 0NW, UK. malcolm.farrow@strath.ac.uk.

ABSTRACT
Infection control is a key aspect of wound management strategies. Infection results in chemical imbalances and inflammation in the wound and may lead to prolonged healing times and degradation of the wound surface. Frequent changing of wound dressings may result in damage to healing tissues and an increased risk of infection. This paper presents the first results from a monitoring system that is being developed to detect presence and growth of bacteria in real time. It is based on impedance sensors that could be placed at the wound-dressing interface and potentially monitor bacterial growth in real time. As wounds can produce large volumes of exudate, the initial system reported here was developed to test for the presence of bacteria in suspension. Impedance was measured using disposable silver-silver chloride electrodes. The bacteria Staphylococcus aureus were chosen for the study as a species commonly isolated from wounds. The growth of bacteria was confirmed by plate counting methods and the impedance data were analysed for discernible differences in the impedance profiles to distinguish the absence and/or presence of bacteria. The main findings were that the impedance profiles obtained by silver-silver chloride sensors in bacterial suspensions could detect the presence of high cell densities. However, the presence of the silver-silver chloride electrodes tended to inhibit the growth of bacteria. These results indicate that there is potential to create a real time infection monitor for wounds based upon impedance sensing.

No MeSH data available.


Related in: MedlinePlus

(a) The basic design of the screen-printed sensors. (b) The bacterial suspension test vial comprised a 30 mL universal vial, 5 mL of media, a specifically designed polytetrafluoroethylene (PTFE) cap and a Ag-AgCl sensor. (c) The test rig to allow parallel measurement of up to eight bacterial suspension test vials.
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biosensors-02-00171-f001: (a) The basic design of the screen-printed sensors. (b) The bacterial suspension test vial comprised a 30 mL universal vial, 5 mL of media, a specifically designed polytetrafluoroethylene (PTFE) cap and a Ag-AgCl sensor. (c) The test rig to allow parallel measurement of up to eight bacterial suspension test vials.

Mentions: The disposable silver-silver chloride (Ag-AgCl) sensors were identical to those created for a clinical trial monitoring moisture levels underneath wound dressings [15] and made available for the project by Ohmedics Ltd. (www.ohmedics.com). The sensors were manufactured by screen printing a silver chloride ink onto a flexible polyethylene substrate. Each sensor had two planar electrodes with 3 mm diameter tips, 10 cm track lengths and connection pads (Figure 1(a)). The tracks were insulated with an adhesive layer of the polyethylene. Before the experiments, the sensors were sterilised in 70% (v/v) ethanol for 10 min and rinsed three times in sterile water [24,25].


Developing a real time sensing system to monitor bacteria in wound dressings.

Farrow MJ, Hunter IS, Connolly P - Biosensors (Basel) (2012)

(a) The basic design of the screen-printed sensors. (b) The bacterial suspension test vial comprised a 30 mL universal vial, 5 mL of media, a specifically designed polytetrafluoroethylene (PTFE) cap and a Ag-AgCl sensor. (c) The test rig to allow parallel measurement of up to eight bacterial suspension test vials.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263571&req=5

biosensors-02-00171-f001: (a) The basic design of the screen-printed sensors. (b) The bacterial suspension test vial comprised a 30 mL universal vial, 5 mL of media, a specifically designed polytetrafluoroethylene (PTFE) cap and a Ag-AgCl sensor. (c) The test rig to allow parallel measurement of up to eight bacterial suspension test vials.
Mentions: The disposable silver-silver chloride (Ag-AgCl) sensors were identical to those created for a clinical trial monitoring moisture levels underneath wound dressings [15] and made available for the project by Ohmedics Ltd. (www.ohmedics.com). The sensors were manufactured by screen printing a silver chloride ink onto a flexible polyethylene substrate. Each sensor had two planar electrodes with 3 mm diameter tips, 10 cm track lengths and connection pads (Figure 1(a)). The tracks were insulated with an adhesive layer of the polyethylene. Before the experiments, the sensors were sterilised in 70% (v/v) ethanol for 10 min and rinsed three times in sterile water [24,25].

Bottom Line: It is based on impedance sensors that could be placed at the wound-dressing interface and potentially monitor bacterial growth in real time.Impedance was measured using disposable silver-silver chloride electrodes.The main findings were that the impedance profiles obtained by silver-silver chloride sensors in bacterial suspensions could detect the presence of high cell densities.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, University of Strathclyde, Wolfson Centre, Glasgow, G4 0NW, UK. malcolm.farrow@strath.ac.uk.

ABSTRACT
Infection control is a key aspect of wound management strategies. Infection results in chemical imbalances and inflammation in the wound and may lead to prolonged healing times and degradation of the wound surface. Frequent changing of wound dressings may result in damage to healing tissues and an increased risk of infection. This paper presents the first results from a monitoring system that is being developed to detect presence and growth of bacteria in real time. It is based on impedance sensors that could be placed at the wound-dressing interface and potentially monitor bacterial growth in real time. As wounds can produce large volumes of exudate, the initial system reported here was developed to test for the presence of bacteria in suspension. Impedance was measured using disposable silver-silver chloride electrodes. The bacteria Staphylococcus aureus were chosen for the study as a species commonly isolated from wounds. The growth of bacteria was confirmed by plate counting methods and the impedance data were analysed for discernible differences in the impedance profiles to distinguish the absence and/or presence of bacteria. The main findings were that the impedance profiles obtained by silver-silver chloride sensors in bacterial suspensions could detect the presence of high cell densities. However, the presence of the silver-silver chloride electrodes tended to inhibit the growth of bacteria. These results indicate that there is potential to create a real time infection monitor for wounds based upon impedance sensing.

No MeSH data available.


Related in: MedlinePlus