Impedimetric detection of Pseudomonas aeruginosa attachment on flexible ITO-coated polyethylene terephthalate substrates

Lakshmi Deepika Bharatula; Enrico Marsili; James J. Kwan

doi:10.1016/j.electacta.2019.135390

Impedimetric detection of Pseudomonas aeruginosa attachment on flexible ITO-coated polyethylene terephthalate substrates

Lakshmi Deepika Bharatula, Enrico Marsili, James J. Kwan

Research output: Journal Publication › Article › peer-review

18 Citations (Scopus)

Abstract

Biofilm monitoring in environmental and biomedical applications remains a challenge. Currently, conventional biochemical methods do not provide a quick quantitative measure of attached biomass. Thus, there is a need for rapid in situ detection tools for routine biofilm characterization. Electrochemical impedance spectroscopy (EIS) characterizes the electroactivity of bacteria within a biofilm and has been extensively used to monitor strong electroactive biofilms. Yet, studies on weak electricigens such as Pseudomonas aeruginosa remain underrepresented. Here, conductive indium tin oxide coated polyethylene terephthalate (ITO:PET) sheets were used as flexible growth substrates instead of more conventional carbonaceous or gold materials. EIS was compared with standard optical methods for the detection of P. aeruginosa biofilms formed on ITO:PET under static growth conditions. Relaxation time analysis showed a dominant time constant at approximately 1 s and confirmed the validity of a two time constant equivalent circuit model for the biofilm impedance. The interfacial resistance calculated from the equivalent circuit analysis showed a rapid drop after bacterial attachment whereas capacitance of the biofilm was masked by the capacitance of ITO:PET. The trends for interfacial resistance and capacitance were independent to the geometry of the ITO:PET working electrode. Moreover, most robust behaviour was observed for rectangular electrodes. EIS across a broad range of potentials with and without inhibitors showed a marked difference between the interfacial resistance of viable and energy inhibited biofilms. Moreover, EIS of exopolysaccharide Δpsl mutant showed a substantial drop in current. Overall, our results indicated that EIS enabled the detection of biofilm formation across large surface areas as early as 24 h after inoculation for the weak electroactive species P. aeruginosa using a flexible polymeric substrate.

Original language	English
Article number	135390
Journal	Electrochimica Acta
Volume	332
DOIs	https://doi.org/10.1016/j.electacta.2019.135390
Publication status	Published - 1 Feb 2020
Externally published	Yes

Keywords

Biofilm
Electrochemical impedance spectroscopy
ITO:PET
Pseudomonas aeruginosa

ASJC Scopus subject areas

General Chemical Engineering
Electrochemistry

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10.1016/j.electacta.2019.135390

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title = "Impedimetric detection of Pseudomonas aeruginosa attachment on flexible ITO-coated polyethylene terephthalate substrates",

abstract = "Biofilm monitoring in environmental and biomedical applications remains a challenge. Currently, conventional biochemical methods do not provide a quick quantitative measure of attached biomass. Thus, there is a need for rapid in situ detection tools for routine biofilm characterization. Electrochemical impedance spectroscopy (EIS) characterizes the electroactivity of bacteria within a biofilm and has been extensively used to monitor strong electroactive biofilms. Yet, studies on weak electricigens such as Pseudomonas aeruginosa remain underrepresented. Here, conductive indium tin oxide coated polyethylene terephthalate (ITO:PET) sheets were used as flexible growth substrates instead of more conventional carbonaceous or gold materials. EIS was compared with standard optical methods for the detection of P. aeruginosa biofilms formed on ITO:PET under static growth conditions. Relaxation time analysis showed a dominant time constant at approximately 1 s and confirmed the validity of a two time constant equivalent circuit model for the biofilm impedance. The interfacial resistance calculated from the equivalent circuit analysis showed a rapid drop after bacterial attachment whereas capacitance of the biofilm was masked by the capacitance of ITO:PET. The trends for interfacial resistance and capacitance were independent to the geometry of the ITO:PET working electrode. Moreover, most robust behaviour was observed for rectangular electrodes. EIS across a broad range of potentials with and without inhibitors showed a marked difference between the interfacial resistance of viable and energy inhibited biofilms. Moreover, EIS of exopolysaccharide Δpsl mutant showed a substantial drop in current. Overall, our results indicated that EIS enabled the detection of biofilm formation across large surface areas as early as 24 h after inoculation for the weak electroactive species P. aeruginosa using a flexible polymeric substrate.",

keywords = "Biofilm, Electrochemical impedance spectroscopy, ITO:PET, Pseudomonas aeruginosa",

author = "Bharatula, {Lakshmi Deepika} and Enrico Marsili and Kwan, {James J.}",

note = "Funding Information: The authors thank Assoc. Professor Scott Rice (Singapore Centre for Environmental Life Sciences Engineering, NTU) for his critical insights during the research. The authors also thank Mr. Yu Hao Foo, Mr. Noel Sng (School of Chemical and Biomedical engineering, NTU) and Ms. Janice Low (Singapore Polytechnic) for their help. This work was financially supported by Nanyang Technological University Start-Up Grant (M4081814) and Singapore Centre for Environmental Life Sciences Engineering (SCELSE), whose research is supported by the National Research Foundation Singapore, Ministry of Education, Nanyang Technological University and National University of Singapore, under its Research Centre of Excellence Programme. This research is also supported by the Singapore Ministry of Health's National Medical Research Council under its NMRC/OFYIRG/0034/2017. Funding Information: The authors thank Assoc. Professor Scott Rice (Singapore Centre for Environmental Life Sciences Engineering, NTU) for his critical insights during the research. The authors also thank Mr. Yu Hao Foo, Mr. Noel Sng (School of Chemical and Biomedical engineering, NTU) and Ms. Janice Low (Singapore Polytechnic) for their help. This work was financially supported by Nanyang Technological University Start-Up Grant ( M4081814 ) and Singapore Centre for Environmental Life Sciences Engineering (SCELSE), whose research is supported by the National Research Foundation Singapore , Ministry of Education , Nanyang Technological University and National University of Singapore , under its Research Centre of Excellence Programme. This research is also supported by the Singapore Ministry of Health{\textquoteright}s National Medical Research Council under its NMRC/OFYIRG/0034/2017 . Publisher Copyright: {\textcopyright} 2019 Elsevier Ltd",

year = "2020",

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doi = "10.1016/j.electacta.2019.135390",

language = "English",

volume = "332",

journal = "Electrochimica Acta",

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T1 - Impedimetric detection of Pseudomonas aeruginosa attachment on flexible ITO-coated polyethylene terephthalate substrates

AU - Bharatula, Lakshmi Deepika

AU - Marsili, Enrico

AU - Kwan, James J.

N1 - Funding Information: The authors thank Assoc. Professor Scott Rice (Singapore Centre for Environmental Life Sciences Engineering, NTU) for his critical insights during the research. The authors also thank Mr. Yu Hao Foo, Mr. Noel Sng (School of Chemical and Biomedical engineering, NTU) and Ms. Janice Low (Singapore Polytechnic) for their help. This work was financially supported by Nanyang Technological University Start-Up Grant (M4081814) and Singapore Centre for Environmental Life Sciences Engineering (SCELSE), whose research is supported by the National Research Foundation Singapore, Ministry of Education, Nanyang Technological University and National University of Singapore, under its Research Centre of Excellence Programme. This research is also supported by the Singapore Ministry of Health's National Medical Research Council under its NMRC/OFYIRG/0034/2017. Funding Information: The authors thank Assoc. Professor Scott Rice (Singapore Centre for Environmental Life Sciences Engineering, NTU) for his critical insights during the research. The authors also thank Mr. Yu Hao Foo, Mr. Noel Sng (School of Chemical and Biomedical engineering, NTU) and Ms. Janice Low (Singapore Polytechnic) for their help. This work was financially supported by Nanyang Technological University Start-Up Grant ( M4081814 ) and Singapore Centre for Environmental Life Sciences Engineering (SCELSE), whose research is supported by the National Research Foundation Singapore , Ministry of Education , Nanyang Technological University and National University of Singapore , under its Research Centre of Excellence Programme. This research is also supported by the Singapore Ministry of Health’s National Medical Research Council under its NMRC/OFYIRG/0034/2017 . Publisher Copyright: © 2019 Elsevier Ltd

PY - 2020/2/1

Y1 - 2020/2/1

N2 - Biofilm monitoring in environmental and biomedical applications remains a challenge. Currently, conventional biochemical methods do not provide a quick quantitative measure of attached biomass. Thus, there is a need for rapid in situ detection tools for routine biofilm characterization. Electrochemical impedance spectroscopy (EIS) characterizes the electroactivity of bacteria within a biofilm and has been extensively used to monitor strong electroactive biofilms. Yet, studies on weak electricigens such as Pseudomonas aeruginosa remain underrepresented. Here, conductive indium tin oxide coated polyethylene terephthalate (ITO:PET) sheets were used as flexible growth substrates instead of more conventional carbonaceous or gold materials. EIS was compared with standard optical methods for the detection of P. aeruginosa biofilms formed on ITO:PET under static growth conditions. Relaxation time analysis showed a dominant time constant at approximately 1 s and confirmed the validity of a two time constant equivalent circuit model for the biofilm impedance. The interfacial resistance calculated from the equivalent circuit analysis showed a rapid drop after bacterial attachment whereas capacitance of the biofilm was masked by the capacitance of ITO:PET. The trends for interfacial resistance and capacitance were independent to the geometry of the ITO:PET working electrode. Moreover, most robust behaviour was observed for rectangular electrodes. EIS across a broad range of potentials with and without inhibitors showed a marked difference between the interfacial resistance of viable and energy inhibited biofilms. Moreover, EIS of exopolysaccharide Δpsl mutant showed a substantial drop in current. Overall, our results indicated that EIS enabled the detection of biofilm formation across large surface areas as early as 24 h after inoculation for the weak electroactive species P. aeruginosa using a flexible polymeric substrate.

AB - Biofilm monitoring in environmental and biomedical applications remains a challenge. Currently, conventional biochemical methods do not provide a quick quantitative measure of attached biomass. Thus, there is a need for rapid in situ detection tools for routine biofilm characterization. Electrochemical impedance spectroscopy (EIS) characterizes the electroactivity of bacteria within a biofilm and has been extensively used to monitor strong electroactive biofilms. Yet, studies on weak electricigens such as Pseudomonas aeruginosa remain underrepresented. Here, conductive indium tin oxide coated polyethylene terephthalate (ITO:PET) sheets were used as flexible growth substrates instead of more conventional carbonaceous or gold materials. EIS was compared with standard optical methods for the detection of P. aeruginosa biofilms formed on ITO:PET under static growth conditions. Relaxation time analysis showed a dominant time constant at approximately 1 s and confirmed the validity of a two time constant equivalent circuit model for the biofilm impedance. The interfacial resistance calculated from the equivalent circuit analysis showed a rapid drop after bacterial attachment whereas capacitance of the biofilm was masked by the capacitance of ITO:PET. The trends for interfacial resistance and capacitance were independent to the geometry of the ITO:PET working electrode. Moreover, most robust behaviour was observed for rectangular electrodes. EIS across a broad range of potentials with and without inhibitors showed a marked difference between the interfacial resistance of viable and energy inhibited biofilms. Moreover, EIS of exopolysaccharide Δpsl mutant showed a substantial drop in current. Overall, our results indicated that EIS enabled the detection of biofilm formation across large surface areas as early as 24 h after inoculation for the weak electroactive species P. aeruginosa using a flexible polymeric substrate.

KW - Biofilm

KW - Electrochemical impedance spectroscopy

KW - ITO:PET

KW - Pseudomonas aeruginosa

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DO - 10.1016/j.electacta.2019.135390

M3 - Article

AN - SCOPUS:85076362606

SN - 0013-4686

VL - 332

JO - Electrochimica Acta

JF - Electrochimica Acta

M1 - 135390

ER -

Impedimetric detection of Pseudomonas aeruginosa attachment on flexible ITO-coated polyethylene terephthalate substrates

Abstract

Keywords

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