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Burden DL, Meyer JJ, Michael RD, Anderson SC, Burden HM, Peña SM, Leong-Fern KJ, Van Ye LA, Meyer EC, Keranen-Burden LM. Confirming Silent Translocation through Nanopores with Simultaneous Single-Molecule Fluorescence and Single-Channel Electrical Recordings. Anal Chem 2023; 95:18020-18028. [PMID: 37991877 PMCID: PMC10719886 DOI: 10.1021/acs.analchem.3c02329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/24/2023]
Abstract
Most of what is known concerning the luminal passage of materials through nanopores arises from electrical measurements. Whether nanopores are biological, solid-state, synthetic, hybrid, glass-capillary-based, or protein ion channels in cells and tissues, characteristic signatures embedded in the flow of ionic current are foundational to understanding functional behavior. In contrast, this work describes passage through a nanopore that occurs without producing an electrical signature. We refer to the phenomenon as "silent translocation." By definition, silent translocations are invisible to the standard tools of electrophysiology and fundamentally require a simultaneous ancillary measurement technique for positive identification. As a result, this phenomenon has been largely unexplored in the literature. Here, we report on a derivative of Cyanine 5 (sCy5a) that passes through the α-hemolysin (αHL) nanopore silently. Simultaneously acquired single-molecule fluorescence and single-channel electrical recordings from bilayers formed over a closed microcavity demonstrate that translocation does indeed take place, albeit infrequently. We report observations of silent translocation as a function of time, dye concentration, and nanopore population in the bilayer. Lastly, measurement of the translocation rate as a function of applied potential permits estimation of an effective energy barrier for transport through the pore as well as the effective charge on the dye, all in the absence of an information-containing electrical signature.
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Affiliation(s)
- Daniel L. Burden
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Joshua J. Meyer
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Richard D. Michael
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Sophie C. Anderson
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Hannah M. Burden
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Sophia M. Peña
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | | | - Lily Anne Van Ye
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Elizabeth C. Meyer
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
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Manzer ZA, Ghosh S, Roy A, Jacobs ML, Carten J, Kamat NP, Daniel S. Cell-Free Synthesis Goes Electric: Dual Optical and Electronic Biosensor via Direct Channel Integration into a Supported Membrane Electrode. ACS Synth Biol 2023; 12:502-510. [PMID: 36651574 DOI: 10.1021/acssynbio.2c00531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Assembling transmembrane proteins on organic electronic materials is one promising approach to couple biological functions to electrical readouts. A biosensing device produced in such a way would enable both the monitoring and regulation of physiological processes and the development of new analytical tools to identify drug targets and new protein functionalities. While transmembrane proteins can be interfaced with bioelectronics through supported lipid bilayers (SLBs), incorporating functional and oriented transmembrane proteins into these structures remains challenging. Here, we demonstrate that cell-free expression systems allow for the one-step integration of an ion channel into SLBs assembled on an organic conducting polymer, poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS). Using the large conductance mechanosensitive channel (MscL) as a model ion channel, we demonstrate that MscL adopts the correct orientation, remains mobile in the SLB, and is active on the polyelectrolyte surface using optical and electrical readouts. This work serves as an important illustration of a rapidly assembled bioelectronic platform with a diverse array of downstream applications, including electrochemical sensing, physiological regulation, and screening of transmembrane protein modulators.
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Affiliation(s)
- Zachary A Manzer
- R.F. School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Surajit Ghosh
- R.F. School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Arpita Roy
- R.F. School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Miranda L Jacobs
- Department of Biomedical Engineering and Interdisciplinary Biological Sciences Program, Northwestern University, Evanston, Illinois 60208, United States
| | - Juliana Carten
- R.F. School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Neha P Kamat
- Department of Biomedical Engineering, Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
| | - Susan Daniel
- R.F. School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
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