TY - JOUR
T1 - Detection of bacterial metabolism in lag-phase using impedance spectroscopy of agar-integrated 3D microelectrodes
AU - Butler, Derrick
AU - Goel, Nishit
AU - Goodnight, Lindsey
AU - Tadigadapa, Srinivas
AU - Ebrahimi, Aida
N1 - Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2019/3/15
Y1 - 2019/3/15
N2 - Traditional methods for detection of metabolically-active bacterial cells, while effective, require several days to complete. Development of sensitive electrical biosensors is highly desirable for rapid detection and counting of pathogens in food, water, or clinical samples. Herein, we develop a highly-sensitive non-Faradaic impedance sensor which detects metabolic activity of E. coli cells in a mere 1 μl of sample volume and without any sample filtration/purification. The three dimensional (3D) interdigitated electrodes (IDEs) along with self-assembled gold-nickel (Au-Ni) nanostructures significantly amplify the sensitivity by increasing the sensing area almost three-fold. The developed microsystem is integrated with an agar-based growth medium and monitors the metabolism of bacterial cells, enabling bacterial detection in approximately one hour after inoculation, i.e. in the lag-phase. Incorporation of a secondary agar layer as a biocompatible passivation layer protects the IDEs from potential Faradaic reactions and enhances sensitivity to modulation of the non-Faradaic impedance due to cellular metabolism. The resultant label-free sensor is capable of selective identification of metabolizing cells (vs. dead cells) across a wide linear range (10–1000 cells/μl). These results help pave the way for rapid antibacterial susceptibility testing at the point-of-need, which is currently a major challenge in healthcare.
AB - Traditional methods for detection of metabolically-active bacterial cells, while effective, require several days to complete. Development of sensitive electrical biosensors is highly desirable for rapid detection and counting of pathogens in food, water, or clinical samples. Herein, we develop a highly-sensitive non-Faradaic impedance sensor which detects metabolic activity of E. coli cells in a mere 1 μl of sample volume and without any sample filtration/purification. The three dimensional (3D) interdigitated electrodes (IDEs) along with self-assembled gold-nickel (Au-Ni) nanostructures significantly amplify the sensitivity by increasing the sensing area almost three-fold. The developed microsystem is integrated with an agar-based growth medium and monitors the metabolism of bacterial cells, enabling bacterial detection in approximately one hour after inoculation, i.e. in the lag-phase. Incorporation of a secondary agar layer as a biocompatible passivation layer protects the IDEs from potential Faradaic reactions and enhances sensitivity to modulation of the non-Faradaic impedance due to cellular metabolism. The resultant label-free sensor is capable of selective identification of metabolizing cells (vs. dead cells) across a wide linear range (10–1000 cells/μl). These results help pave the way for rapid antibacterial susceptibility testing at the point-of-need, which is currently a major challenge in healthcare.
UR - http://www.scopus.com/inward/record.url?scp=85054471062&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85054471062&partnerID=8YFLogxK
U2 - 10.1016/j.bios.2018.09.057
DO - 10.1016/j.bios.2018.09.057
M3 - Article
C2 - 30297173
AN - SCOPUS:85054471062
SN - 0956-5663
VL - 129
SP - 269
EP - 276
JO - Biosensors and Bioelectronics
JF - Biosensors and Bioelectronics
ER -