Electrochemistry provides a point-of-care approach for the marker indicative of Pseudomonas aeruginosa infection of cystic fibrosis patients

Abstract

It has recently been demonstrated that 2-aminoacetophenone (2-AA) is a chemical indicator in exhaled air/breath of Pseudomonas aeruginosa infection associated with progressive life threatening decline of lung function in cystic fibrosis sufferers [Scott-Thomas et al., BMC Pulm. Med., 2010, 10, 56]. Currently the detection of 2-AA involves laboratory based instrumentation such as mass spectrometry and a hand-held point-of-care type breath device would be ideal in providing real-time results within seconds to accelerate patient care decision-making processes. To this end, we demonstrate proof-of-concept that the chemical marker 2-AA, indicative of Pseudomonas aeruginosa infection, can be measured using electrochemical based sensing strategies. A range of commercially available electrode substrates are explored demonstrating for the first time that 2-AA is electrochemically active within aqueous based solutions providing an (electro)analytical signal. Glassy carbon, boron-doped diamond and platinum electrodes have been explored towards the electrochemical oxidation of 2-AA. Electrode fouling is observed requiring pre-treatment in the form of mechanical polishing between voltammetric scans and measurements. To alleviate this, screen-printed graphite electrodes are shown to be a more viable option for implementation into breath sensing devices and overcome the fouling problem since due to their low cost and disposable nature, a new electrode can be used for each measurement. The analytical utility of the platinum, screen-printed and boron-doped diamond electrodes were found to correspond to 6.85, 7.66 and 4.86 mM respectively. The challenges associated with the electrochemical sensing of 2-AA in breath that need to be overcome are discussed. This generic approach where electrochemical based technology is used to provide measurements for chemical markers in exhaled air/breath for medical diagnostics termed electrochemical breathprints (ec-breathprints), has the potential to be developed into a hand-held point-of-care breath diagnostic tool for identifying Pseudomonas aeruginosa infection in exhaled air/breath.