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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

Examples of the normalised magnitude profiles from the single suspension experiments: (a) Control, MHB and 0.2% glucose; (b) RN4220 in MHB and 0.2% glucose. Arrows indicate peaks of interest.
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biosensors-02-00171-f003: Examples of the normalised magnitude profiles from the single suspension experiments: (a) Control, MHB and 0.2% glucose; (b) RN4220 in MHB and 0.2% glucose. Arrows indicate peaks of interest.

Mentions: There were similar discernible differences in the normalised phase peak between the MHB with glucose and the RN4220 culture in MHB with glucose. The normalised phase peak at 17 h was between 1 and 2 Hz in all five media-only cultures, and between 10 and 32 Hz for the RN4220-glucose cultures. In addition to the differences in the normalised phase peaks the normalised magnitude peaks showed clear differences with the added glucose. In the MHB-glucose-only vials by 17 h a first peak had occurred between 1 and 3 Hz and a second one between 200 and 1.3 kHz (Figure 3(a)). In contrast, in the RN4220-glucose experiments the first and second peaks were not present at the end of the experiment, however a third peak between 2.5 k and 6.3 kHz was present, as shown in Figure 3(b). The change in the peaks shown in the RN4220 cultures occurred between 4 and 8 h after inoculation. This was repeatable over five separate culture experiments and is the first evidence that discernible differences in the normalised phase angle profiles occur due to the presence of bacteria, depending on the media contents.


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

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

Examples of the normalised magnitude profiles from the single suspension experiments: (a) Control, MHB and 0.2% glucose; (b) RN4220 in MHB and 0.2% glucose. Arrows indicate peaks of interest.
© Copyright Policy
Related In: Results  -  Collection

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

biosensors-02-00171-f003: Examples of the normalised magnitude profiles from the single suspension experiments: (a) Control, MHB and 0.2% glucose; (b) RN4220 in MHB and 0.2% glucose. Arrows indicate peaks of interest.
Mentions: There were similar discernible differences in the normalised phase peak between the MHB with glucose and the RN4220 culture in MHB with glucose. The normalised phase peak at 17 h was between 1 and 2 Hz in all five media-only cultures, and between 10 and 32 Hz for the RN4220-glucose cultures. In addition to the differences in the normalised phase peaks the normalised magnitude peaks showed clear differences with the added glucose. In the MHB-glucose-only vials by 17 h a first peak had occurred between 1 and 3 Hz and a second one between 200 and 1.3 kHz (Figure 3(a)). In contrast, in the RN4220-glucose experiments the first and second peaks were not present at the end of the experiment, however a third peak between 2.5 k and 6.3 kHz was present, as shown in Figure 3(b). The change in the peaks shown in the RN4220 cultures occurred between 4 and 8 h after inoculation. This was repeatable over five separate culture experiments and is the first evidence that discernible differences in the normalised phase angle profiles occur due to the presence of bacteria, depending on the media contents.

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