DOI: 10.1002/((please add manuscript number)) Article type: Communication Biomimetic electronic devices for measuring bacterial membrane disruption Charalampos Pitsalidis#, Anna-Maria Pappa#, Mintu Porel, Christine M. Artim, Gregorio C. Faria, Duc D. Duong, Christopher A. Alabi*, Susan Daniel*, Alberto Salleo* and Rόisín M. Owens* Dr. C. Pitsalidis, Dr. A.-M. Pappa, Dr. R. M. Owens Department of Chemical Engineering and Biotechnology, Philippa Fawcett Drive, CB30AS, Cambridge, UK Email: [email protected] Dr. M. Porel, Ms. C.M. Artim, Prof. C.A. Alabi, Prof. S. Daniel Department of Chemical and Biomolecular Engineering, Olin hall, Ithaca, NY 14850, USA Email: [email protected], [email protected] Dr. G.C. Faria, Dr. D.D. Duong, and Prof. A. Salleo Department of Materials Science and Engineering, Stanford University, 496 Lomita Mall, Stanford, CA 94305, USA Email: [email protected] Keywords: organic bioelectronics, antibiotic, membrane, transistor, lipid The block in the antibiotic discovery pipeline is reaching crisis levels, exacerbated by poor antibiotic stewardship.[1] Antibiotic discovery has slowed severely, in part due to failures of target-focused screening platforms[2] in identifying compounds which disrupt bacterial membranes, [3] a neglected, yet obvious target due to substantial diferences from mammalian membranes.[4,5] In vitro screening methods using lipids can elucidate interactions with the membrane at the molecular level, greatly aiding the design and rapid development of new compounds. [6,7] One 1 outstanding unresolved issue is the availability of a scalable and reliable technology to interface with robust model membranes, particularly bacterial ones. Unperturbed lipid layers are highly insulating electrically. This property is extremely sensitive to interactions with membrane disrupting species [8,9] and may be characterized by coupling with an electronic transducer, in this case the Organic Electrochemical Transistor (OECT). Here we show that lipid monolayers assembled at a liquid-liquid interface are a suitable model for characterizing compounds that disrupt the cell membrane. These monolayers block ion fow when placed between the gating electrode and the transistor channel, resulting in a substantial decrease of the gate-induced current modulation in the channel. The antibacterial compound Polymyxin B (PMB) was added to such a blocking ‘bacterial-like’ lipid monolayer, resulting in recovery of the modulation, increasing conductance. Further illustrating the potential of this device in characterizing novel anti-bacterial compounds, we show that molecular scale diferences in the recently described antibacterial amine-based oligothioetheramides (AOTs)[10] can be discerned. Indeed, the amplitude of the device response correlates well with the relative performance of the compounds in a traditional bacterial killing assay using whole cells. We anticipate that the ability to carry out a real-time, sensitive and quantitative assessment of the activity of novel membranedisrupting compounds can revolutionize the rapid characterization of antibacterial compounds, especially when combined with the potential of organic electronics for being massively scalable using semiconductor microfabrication technology[11]. 2 Current methods used for screening anti-bacterial compounds range from traditional microbiological assays based on assessing inhibition of growth in solid or liquid growth media, to more quantitative bioluminescencebased or fow cytometry-based assays. The majority of these methods rely however on culture of the targeted microorganism and optical assessment of cell death.[12–14] Electrical methods have been used in vitro to study the properties of lipid membrane, however the combination of high stability and high sensitivity is elusive. In vitro studies of membrane disruption have mainly focused on suspended lipid bilayers but inherent instabilities of such layers render this method impractical for robust high throughput approaches.[15,16] Supported or tethered lipid bilayers prepared via fusion of lipid vesicles on surfaces have been coupled with electrical transducers, however this method remains highly challenging[17,18] and has generally focussed on the study of mammalian systems for studying membrane proteins.[19] A couple of studies have been carried out using transistors as the electrical interface in an efort to amplify signal transduction, however low electr

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