TY - JOUR
T1 - Organic redox-active crystalline layers for reagent-free electrochemical antibiotic susceptibility testing (ORACLE-AST)
AU - Bolotsky, Adam
AU - Muralidharan, Ritvik
AU - Butler, Derrick
AU - Root, Kayla
AU - Murray, William
AU - Liu, Zhiwen
AU - Ebrahimi, Aida
N1 - Funding Information:
The authors would like to acknowledge partial funds from the Materials-Life Science Convergence Award – supported by the Penn State's Materials Research Institute, College of Engineering, and Huck Institute of Life Sciences – and the College of Engineering Multidisciplinary Research Seed Grant. A. E. also acknowledges the Start-up Fund from Penn State University . We also thank Dr. J. Kovac for her generous donation of E. coli strains and Dr. M. Hickner for providing Nafion.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/1/15
Y1 - 2021/1/15
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85095416350&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85095416350&partnerID=8YFLogxK
U2 - 10.1016/j.bios.2020.112615
DO - 10.1016/j.bios.2020.112615
M3 - Article
C2 - 33166804
AN - SCOPUS:85095416350
SN - 0956-5663
VL - 172
JO - Biosensors and Bioelectronics
JF - Biosensors and Bioelectronics
M1 - 112615
ER -