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Sensors 2017, 17(6), 1245; doi:10.3390/s17061245

Smartphone-Based pH Sensor for Home Monitoring of Pulmonary Exacerbations in Cystic Fibrosis

Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA
Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
Author to whom correspondence should be addressed.
Academic Editor: Wan-Young Chung
Received: 10 April 2017 / Revised: 15 May 2017 / Accepted: 23 May 2017 / Published: 30 May 2017
(This article belongs to the Special Issue Biomedical Sensors and Systems 2017)
View Full-Text   |   Download PDF [2969 KB, uploaded 30 May 2017]   |  


Currently, Cystic Fibrosis (CF) patients lack the ability to track their lung health at home, relying instead on doctor checkups leading to delayed treatment and lung damage. By leveraging the ubiquity of the smartphone to lower costs and increase portability, a smartphone-based peripheral pH measurement device was designed to attach directly to the headphone port to harvest power and communicate with a smartphone application. This platform was tested using prepared pH buffers and sputum samples from CF patients. The system matches within ~0.03 pH of a benchtop pH meter while fully powering itself and communicating with a Samsung Galaxy S3 smartphone paired with either a glass or Iridium Oxide (IrOx) electrode. The IrOx electrodes were found to have 25% higher sensitivity than the glass probes at the expense of larger drift and matrix sensitivity that can be addressed with proper calibration. The smartphone-based platform has been demonstrated as a portable replacement for laboratory pH meters, and supports both highly robust glass probes and the sensitive and miniature IrOx electrodes with calibration. This tool can enable more frequent pH sputum tracking for CF patients to help detect the onset of pulmonary exacerbation to provide timely and appropriate treatment before serious damage occurs. View Full-Text
Keywords: biosensor; Cystic Fibrosis; pH; point-of-care; smartphone; Iridium Oxide biosensor; Cystic Fibrosis; pH; point-of-care; smartphone; Iridium Oxide

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

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Sun, A.; Phelps, T.; Yao, C.; Venkatesh, A.G.; Conrad, D.; Hall, D.A. Smartphone-Based pH Sensor for Home Monitoring of Pulmonary Exacerbations in Cystic Fibrosis. Sensors 2017, 17, 1245.

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