engleski

Chemical Sensors in Medical Diagnostics: Sensor for Monitoring Wound Healing

A new means of wound pH monitoring is proposed in this thesis. This approach is based around an integrated chemical sensing platform (OptiTag) composed of an optoelectronic interface and a radio frequency (RF) tag. pH was selected as our analyte after a group of potential analytes involved in the wound healing process was reviewed. The chemical interface of the sensor is a thin film immobilized pH sensitive dye, bromocresol green (BCG). Thin films were prepared by immobilization of BCG by means of sol-gel chemistry, on to a glass substrate. Sol-gel precursor/surfactant solution (cocktail) was applied to the substrates by spin coating. These films were characterised for response time, leaching and overall stability with a laboratory UV/VIS spectrophotometer. Also, pKa values and absorbance spectra of the immobilized BCG were recorded. After the films were prepared, we used them for measurements with the OptiTag. Several different experimental setups were used. Sensor response was tested for increased reflectivity, waveguiding effects and simulation of contact with an absorbent material was also performed. The absorbent material was filter paper and it was used to simulate a wound bandage. The contact simulation showed us that OptiTag can be used for contact pH measurements, within a range of 5.5 – 7.3. These values are within the range of wound fluid pH. This goes to show that OptiTag could be used for wound pH monitoring.

wound; healing; monitoring; pH sensor; sol gel; chemical sensor; wireless sensor network; optical sensor; absorbance; bromocresol green; radio-frequency identification; thin film

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