Journal article Open Access

Detection of Pseudomonas aeruginosa quorum sensing molecules at an electrified liquid|liquid micro-interface through facilitated proton transfer

Burgoyne, Edward D.; Molina-Osorio, Andrés F.; Moshrefi, Reza; Shanahan, Rachel; McGlacken, Gerard P.; Stockmann, Talia Jane; Scanlon, Micheál D.

Miniaturization of electrochemical detection methods for point-of-care-devices is ideal for their integration and use within healthcare environments. Simultaneously, the prolific pathogenic bacteria Pseudomonas aeruginosa poses a serious health risk to patients with compromised immune systems. Recognizing these two factors, a proof-of-concept electrochemical method employing a micro-interface between water and oil (w/o) held at the tip of a pulled borosilicate glass capillary is presented. This method targets small molecules produced by P. aeruginosa colonies as signalling factors that control colony growth in a pseudo-multicellular process known as quorum sensing (QS). The QS molecules of interest are 4‐hydroxy‐2‐heptylquinoline (HHQ) and 2‐heptyl‐3,4‐dihydroxyquinoline (PQS, Pseudomonas quinolone signal). Hydrophobic HHQ and PQS molecules, dissolved in the oil phase, were observed electrochemically to facilitate proton transfer across the w/o interface. This interfacial complexation can be exploited as a facile electrochemical detection method for P. aeruginosa and is advantageous as it does not depend on the redox activity of HHQ/PQS. Interestingly, the limit-of-linearity is reached as [H+]≈[ligand]. Density functional theory calculations were performed to determine the proton affinities and gas-phase basicities of HHQ/PQS, as well as elucidate the likely site of stepwise protonation within each molecule.

E.D.B. acknowledges funding received from an Irish Research Council Government of Ireland Postgraduate Scholarship Award (grant number GOIPG/2016/1217). This publication has emanated from research by M.D.S. and A.F.M.-O. supported by the European Research Council through a Starting Grant (agreement no. 716792) and in part by a research grant from Science Foundation Ireland (SFI) (grant number 13/SIRG/2137). G.M.G. and R.S. thank the Irish Research Council for funding. T.J.S is grateful to NSERC for funding with an NSERC Discovery Grant.
Files (1.2 MB)
Name Size
2020_The_Analyst_Manuscript_Open_Access.pdf
md5:15c2e86d951481a57ac6c9d219121212
778.4 kB Download
2020_The_Analyst_SI_Open_Access.pdf
md5:e4ead6b33273be8bad352f4e8d64a155
436.0 kB Download
19
75
views
downloads
Views 19
Downloads 75
Data volume 58.4 MB
Unique views 16
Unique downloads 73

Share

Cite as