The treatment of chronic wounds, particularly those associated with diabetic complications, is a perennial problem for modern healthcare services, affecting an ever-increasing portion of society.This is particularly worrisome given that the diabetic population and associated costs are set to at least double in size in the next 25 years. In the US alone, approximately 6.5 million people suffer from slow healing wounds, with healthcare costs in the region of $25 billion annually. A critical factor that needs to be considered when dealing with chronic wounds is infection. This can have a huge impact on healing time and could inevitably lead to further discomfort of the patient and complications that could ultimately be life threatening. Most chronic wounds (>74%) are treated within the community and as such there can be a delay in the patient seeking medical attention resulting in a deterioration of the wound condition. It is estimated that 12% of individuals with a chronic foot ulcer, will require amputation due to infection.

A new approach to the design of disposable pH sensors that can be directly integrated within conventional wound dressings and which can communicate to an app on a smart phone (Figure 1) is described. The system is based on an aminoacid / peptide functionalized electrode interface through which the pH can be rapidly determine through either potentiometric or voltammetric means. It has been shown that wound pH can be a versatile marker of wound condition and can be used to track the stage of healing. Importantly, sustained changes in pH from a given regime could provide an early warning signal for the early onset of infection.  A range of bioactive groups have been assessed in terms of their ability to facilitate the long term/periodic monitoring of pH with a matrix which can express significant amounts of exudate that would otherwise irreversibly contaminate conventional electrode substrates.

This presentation details characterization of the fabrication processes, the electrode response and the clinical utility of the measurement. The integration of the sensing substrate within the dressing and its communication with the smart phone/tablet via an Arduino system is described and critically assessed. Ultimately, the aim would be for the development of a prototype that would be able to alert the patient to the onset of infection.