A Versatile Method to Enhance the Operational Current of Air-Stable Organic Gas Sensor for Monitoring of Breath Ammonia in Hemodialysis Patients

Shang Yu Yu, Tin Wei Tung, Hong Yu Yang, Guan Yu Chen, Che Chi Shih, Yu Chih Lee, Chang Chiang Chen, Hsiao Wen Zan, Hsin Fei Meng, Chia Jung Lu, Chien Lung Wang, Wen Bin Jian, Olivier Soppera

Research output: Contribution to journalArticle

5 Citations (Scopus)


Point-of-care (POC) application for monitoring of breath ammonia (BA) in hemodialysis (HD) patients has emerged as a promising noninvasive health monitoring approach. In this context, many organic gas sensors have been reported for BA detection. However, one of the major challenges for its integration with affordable household POC application is to achieve stable performance for accuracy and high operational current at low voltage for low-cost read-out circuitry. Herein, we exploited the stability of the Donor-Acceptor polymer on the cylindrical nanopore structure to realize the sensors with a high sensitivity and stability. Then, we proposed a double active layer (DL) strategy that exploits an ultrathin layer of Poly(3-hexylthiophene-2,5-diyl) (P3HT) to serve as a work function buffer to enhance the operational current. The DL sensor exhibits a sustainable enhanced operational current of microampere level and a stable sensing response even with the presence of P3HT layer. This effect is carefully examined with different aspects, including vertical composition profile of DL configuration, lifetime testing on different sensing layer, morphological analysis, and the versatility of the DL strategy. Finally, we utilize the DL sensor to conduct a tracing of BA concentration in two HD patients before and after HD, and correlate it with the blood urea nitrogen (BUN) levels. A good correlation coefficient of 0.96 is achieved. Moreover, the feasibility of DL sensor integrated into a low-cost circuitry was also verified. The results demonstrate the potential of this DL strategy to be used to integrate organic sensor for affordable household POC devices.

Original languageEnglish
Pages (from-to)1023-1031
Number of pages9
JournalACS Sensors
Issue number4
Publication statusPublished - 2019 Apr 26



  • POC device
  • ammonia
  • breath
  • current enhancement
  • gas sensor
  • hemodialysis
  • stable performance

ASJC Scopus subject areas

  • Bioengineering
  • Instrumentation
  • Process Chemistry and Technology
  • Fluid Flow and Transfer Processes

Cite this

Yu, S. Y., Tung, T. W., Yang, H. Y., Chen, G. Y., Shih, C. C., Lee, Y. C., Chen, C. C., Zan, H. W., Meng, H. F., Lu, C. J., Wang, C. L., Jian, W. B., & Soppera, O. (2019). A Versatile Method to Enhance the Operational Current of Air-Stable Organic Gas Sensor for Monitoring of Breath Ammonia in Hemodialysis Patients. ACS Sensors, 4(4), 1023-1031. https://doi.org/10.1021/acssensors.9b00223