Organic redox-active crystalline layers for reagent-free electrochemical antibiotic susceptibility testing (ORACLE-AST)

Rapid antibiotic susceptibility testing (AST) is critical in determining bacterial resistance or susceptibility to a particular antibiotic. Simple-to-use phenotype-based AST platforms can assist care-givers in timely prescription of the right antibiotic. Monitoring the change of bacterial viability by measuring electrochemical Faradaic current is a promising approach for rapid AST. However, the existing works require mixing redox-active reagents in the solution which can interfere with the antibiotics. In this paper, we developed a facile electrodeposition process for creating a redox-active crystalline layer (denoted as RZx) on pyrolytic graphite sheets (PGS), which was then utilized as the sensing layer for reagent-free electrochemical AST. To demonstrate the proof-of-principle, we tested the sensors with Escherichia coli (E. coli) K-12 treated with two antibiotics, ampicillin and kanamycin. While the sensors enable detection of bacterial metabolism mainly due to pH-sensitivity of RZx (∼ 53 mV/pH), secreted redox-active metabolites/compounds from whole cells are likely contributing to the signal as well. By monitoring the differential voltammetric signals, the sensors enable accurate prediction of the minimum inhibitory concentration (MIC) in 60 min (p < 0.03). The sensors are stable after 60 days storage in ambient conditions and enable analysis of microbial viability in complex solutions, as demonstrated in spiked milk and human whole blood.



Work Title Organic redox-active crystalline layers for reagent-free electrochemical antibiotic susceptibility testing (ORACLE-AST)
Open Access
  1. Adam Bolotsky
  2. Ritvik Muralidharan
  3. Derrick Butler
  4. Kayla Root
  5. William Murray
  6. Zhiwen Liu
  7. Aida Ebrahimi
  1. Redox-active
  2. Organic crystal
  3. Electrochemical sensor
  4. Rapid antibiotic susceptibility testing
  5. Metabolic activity
  6. Reagent-free
License CC BY-NC-ND 4.0 (Attribution-NonCommercial-NoDerivatives)
Work Type Article
  1. Biosensors and Bioelectronics
Publication Date November 6, 2020
Publisher Identifier (DOI)
Deposited November 19, 2021




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Work History

Version 1

  • Created
  • Added Creator Adam Bolotsky
  • Added Creator Ritvik Muralidharan
  • Added Creator Derrick Butler
  • Added Creator Kayla N Root
  • Added Creator William Thomas Murray
  • Added Creator Zhiwen Liu
  • Added Creator Seyedehaida Ebrahimi
  • Added 1-s2.0-S0956566320306059-main.pdf
  • Updated License Show Changes
  • Published
  • Updated
  • Updated Keyword, Publisher, Publisher Identifier (DOI), and 1 more Show Changes
    • Redox-active, Organic crystal, Electrochemical sensor, Rapid antibiotic susceptibility testing, Metabolic activity, Reagent-free
    • Elsevier
    • Biosensors and Bioelectronics
    Publisher Identifier (DOI)
    • 10.1016/j.bios.2020.112615
    Publication Date
    • 2021-01-15
    • 2020-11-06
  • Renamed Creator Kayla Root Show Changes
    • Kayla N Root
    • Kayla Root
  • Renamed Creator William Murray Show Changes
    • William Thomas Murray
    • William Murray
  • Renamed Creator Aida Ebrahimi Show Changes
    • Seyedehaida Ebrahimi
    • Aida Ebrahimi
  • Updated