The Development of Indictor Cotton Swabs for the Detection of pH in Wounds

Publikation aus Materials
Sensoren und Funktionales Drucken

Cindy Schaude, Eleonore Fröhlich, Claudia Meindl, Jennifer Attard, Barbara Binder, Gerhard J. Mohr

Sensors 2017, 17, 1365; doi:10.3390/s17061365 , 6/2017


Indicator cotton swabs have been developed in order to enable faster, less expensive, and
simpler information gathering of a wound status. Swabs are normally used for cleaning the wound,
but here, they were covalently functionalized with indicator chemistry. Thus, they in principle
enable simultaneous wound cleaning and wound pH detection. Using an indicator dye with a color
change from yellow to red, combined with an inert dye of blue color, a traffic light color change
from green to red is induced when pH increases. The indicator cotton swabs (ICSs) show a color
change from green (appropriate wound pH) to red (elevated wound pH). This color change can be
interpreted by the naked eye as well as by an optical color measurement device in order to obtain
quantitative data based on the CIE L*a*b* color space. Two types of swabs have been
developed—indicator cotton swabs ICS1 with a sensitive range from pH 5 to 7 and swabs ICS2
with a sensitive range from 6.5 to 8.5. The swabs are gamma-sterilized and the effect of sterilization
on performance was found to be negligible. Furthermore, cytotoxicity testing shows cell viability
and endotoxin levels to be within the allowable range.