Electrochemically monitoring the antibiotic susceptibility of Pseudomonas aeruginosa biofilms

Abstract

The condition of cells in Pseudomonas aeruginosa biofilms was monitored via the electrochemical detection of the electro-active virulence factor pyocyanin in a fabricated microfluidic growth chamber coupled with a disposable three electrode cell. Cells were exposed to 4, 16, and 100 mg L(-1) colistin sulfate after overnight growth. At the end of testing, the measured maximum peak current (and therefore pyocyanin concentration) was reduced by approximately 68% and 82% in P. aeruginosa exposed to 16 and 100 mg L(-1) colistin sulfate, respectively. Samples were removed from the microfluidic chamber, analyzed for viability using staining, and streaked onto culture plates to confirm that the P. aeruginosa cells were affected by the antibiotics. The correlation between electrical signal drop and the viability of P. aeruginosa cells after antibiotic exposure highlights the usefulness of this approach for future low cost antibiotic screening applications.

Electrochemical Detection of Pyocyanin as a Biomarker for Pseudomonas aeruginosa: A Focused Review

“…In the following years, several pyocyanin detection approaches were published using disposable screen-printed electrochemical electrodes [ 25 , 30 , 31 , 32 ]. The sensors were single-used and it was argued that the disposability of the electrodes makes them ideal for irreversible electrochemical measurements such as targeting the phenolic oxidation potential of pyocyanin.…”

“…Several sensor designs have been described in the literature, ranging from clean-room fabricated nanograss sensors, conventional rod-electrode setups to cheaper models screen-printed on paper [ 23 , 31 , 32 ]. The fabrication techniques included shadow-printing, ink-jet printing, atomic layer deposition, electrodeposition and electron-beam deposition, while the electrodes where modified with nanoparticles, carbon-nanotubes and nanoalloys in addition to biological modifications to optimize the sensitivity and detection limit [ 29 , 30 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ].…”

“…Screen-printed commercial electrodes were used to detect the pyocyanin response when PA biofilms were exposed to increasing concentrations of the antibiotic colistin sulfate. It was demonstrated that pyocyanin production was reduced by 68% and 82% when exposed to 16 and 100 mg/L of the antibiotic, respectively [ 30 ].…”

Connecting Biology to Electronics: Molecular Communication via Redox Modality

“…PYO is also a biological signaling molecule that appears to be engaged in redox‐based signaling . Thus, redox‐probing that can access information of the presence of PYO and its redox‐state should provide important insights of biological activities (e.g., of Pseudomonas infections) …”

Microfluidics for Antibiotic Susceptibility and Toxicity Testing

“…Their results showed that tetracycline can facilitate the formation of long filamentous bacteria. In addition to optical imaging and fluorescence, electrochemical sensing [ 53 ] and electrochemical impedance spectroscopy (EIS) [ 54 ] have been used to monitor the activity of biofilm under antibiotic treatment to investigate biofilm antibiotic susceptibility. Recently, Chang et al [ 55 ] demonstrated the formation of biofilm in microfluidic droplets, where biofilm was formed at the interface of double and triple emulsion droplets.…”