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Menegon A, Pitassi S, Mazzocchi N, Redaelli L, Rizzetto R, Rolland JF, Poli C, Imberti M, Lanati A, Grohovaz F. A new electro-optical approach for conductance measurement: an assay for the study of drugs acting on ligand-gated ion channels. Sci Rep 2017; 7:44843. [PMID: 28322303 PMCID: PMC5359596 DOI: 10.1038/srep44843] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 02/14/2017] [Indexed: 01/02/2023] Open
Abstract
Ligand gated ion channels are involved in many pathophysiological processes and represent a relevant, although challenging, target for drug discovery. We propose an innovative electro-optical approach to their analysis able to derive membrane conductance values from the local membrane potential changes imposed by test current pulses and measured by fast voltage-sensitive fluorescent dyes. We exploited the potential of this proprietary method by developing a drug testing system called “ionChannel Optical High-content Microscope” (ionChannelΩ). This automated platform was validated by testing the responses of reference drugs on cells expressing different ligand-gated ion channels. Furthermore, a double-blind comparison with FLIPR and automated patch-clamp was performed on molecules designed to act as antagonists of the P2RX7 receptor. ionChannelΩ proved highly reliable in all tests, resulting faster and more cost-effective than electrophysiological techniques. Overall, ionChannelΩ is amenable to the study of ligand gated ion channels that are receiving less attention due to limitations in current assays.
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Affiliation(s)
- A Menegon
- San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.,San Raffaele University, via Olgettina 58, 20132, Milan, Italy
| | - S Pitassi
- Optotec, Via Zenale 44, 20024, Garbagnate Milanese, Milan, Italy
| | - N Mazzocchi
- San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy
| | - L Redaelli
- Axxam SpA, via Meucci 3, 20091, Bresso, Milan, Italy
| | - R Rizzetto
- Axxam SpA, via Meucci 3, 20091, Bresso, Milan, Italy
| | - J F Rolland
- Axxam SpA, via Meucci 3, 20091, Bresso, Milan, Italy
| | - C Poli
- Valore Qualità, Via Vidari 5, 27100, Pavia, Italy.,Assing, Pavia, Viale Indipendenza 11, I-27100, Pavia, Italy
| | - M Imberti
- OPEN Sistemi, via Bonomelli 24, 26100, Cremona, Italy
| | - A Lanati
- Valore Qualità, Via Vidari 5, 27100, Pavia, Italy.,Assing, Pavia, Viale Indipendenza 11, I-27100, Pavia, Italy
| | - F Grohovaz
- San Raffaele Scientific Institute, via Olgettina 60, 20132, Milan, Italy.,San Raffaele University, via Olgettina 58, 20132, Milan, Italy
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Angle MR, Cui B, Melosh NA. Nanotechnology and neurophysiology. Curr Opin Neurobiol 2015; 32:132-40. [PMID: 25889532 DOI: 10.1016/j.conb.2015.03.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 02/11/2015] [Accepted: 03/23/2015] [Indexed: 02/09/2023]
Abstract
Neuroscience would be revolutionized by a technique to measure intracellular electrical potentials that would not disrupt cellular physiology and could be massively parallelized. Though such a technology does not yet exist, the technical hurdles for fabricating minimally disruptive, solid-state electrical probes have arguably been overcome in the field of nanotechnology. Nanoscale devices can be patterned with features on the same length scale as biological components, and several groups have demonstrated that nanoscale electrical probes can measure the transmembrane potential of electrogenic cells. Developing these nascent technologies into robust intracellular recording tools will now require a better understanding of device-cell interactions, especially the membrane-inorganic interface. Here we review the state-of-the art in nanobioelectronics, emphasizing the characterization and design of stable interfaces between nanoscale devices and cells.
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Affiliation(s)
- Matthew R Angle
- Department of Materials Science and Engineering, Stanford University, CA, USA
| | - Bianxiao Cui
- Department of Chemistry, Stanford University, CA, USA
| | - Nicholas A Melosh
- Department of Materials Science and Engineering, Stanford University, CA, USA; Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
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Terpitz U, Sukhorukov VL, Zimmermann D. Prototype for automatable, dielectrophoretically-accessed intracellular membrane-potential measurements by metal electrodes. Assay Drug Dev Technol 2012; 11:9-16. [PMID: 22994967 DOI: 10.1089/adt.2012.455] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Functional access to membrane proteins, for example, ion channels, of individual cells is an important prerequisite in drug discovery studies. The highly sophisticated patch-clamp method is widely used for electrogenic membrane proteins, but is demanding for the operator, and its automation remains challenging. The dielectrophoretically-accessed, intracellular membrane-potential measurement (DAIMM) method is a new technique showing high potential for automation of electrophysiological data recording in the whole-cell configuration. A cell suspension is brought between a mm-scaled planar electrode and a μm-scaled tip electrode, placed opposite to each other. Due to the asymmetric electrode configuration, the application of alternating electric fields (1-5 MHz) provokes a dielectrophoretic force acting on the target cell. As a consequence, the cell is accelerated and pierced by the tip electrode, hence functioning as the internal (working) electrode. We used the light-gated cation channel Channelrhodopsin-2 as a reporter protein expressed in HEK293 cells to characterize the DAIMM method in comparison with the patch-clamp technique.
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Affiliation(s)
- Ulrich Terpitz
- Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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