Real-time monitoring of microbial activity using hydrogel-hybridized carbon nanotube transistors

Minjun Park, Hyun Soo Kim, Taewan Kim, Junhyup Kim, Sungchul Seo, Byung Yang Lee

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


We demonstrate a unique system mainly composed of a carbon nanotube field-effect transistor (CNT-FET) integrated with malt extract agar (MEA) hydrogel for the real-time monitoring of microbial growth and activity. Consumption of nutrients and production of metabolites by microbial cells such as fungi or yeast results in the change of chemical properties of the hydrogel matrix, and this chemical change is detected by the underlying CNT-FET underneath the MEA hydrogel. In this study, we were able to distinguish the different growth phases (lag phase, log phase and stationary phase) of microbial organisms from the conductance measurement of the MEA-hybridized CNT-FET. Two fungal species (Aspergillus niger, Aspergillus versicolor), and one yeast species (Saccharomyces cerevisiae) were tested. The CNT-FET signals showed peculiar signal patterns according to the microbial species, enabling the classification of microbial species in terms of CNT-FET signal patterns. The CNT-FET signals were compared with pH change of the MEA hydrogel matrix, and the CNT-FET signal followed the microorganism activity more closely than the pH signal. We expect that this platform can serve as a suitable substitute of currently time-consuming, high-cost, and laborious microbial monitoring procedure and expedite the development of improved simultaneous monitoring of various fungal and/or bacterial organisms.

Original languageEnglish
Pages (from-to)486-492
Number of pages7
JournalSensors and Actuators, B: Chemical
Publication statusPublished - 2018 Jun 15

Bibliographical note

Funding Information:
This research was supported by the National Research Foundation of Korea (NRF) , funded by the Ministry of Science, ICT and Future Planning ( 2015R1A2A2A04002733 , 2016M3A7B4909581 ).

Publisher Copyright:
© 2018 Elsevier B.V.


  • Carbon nanotube
  • Malt extract agar
  • Microbial activity
  • Real-time monitoring
  • Transistor

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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