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Qutbuddin Y, Guinart A, Gavrilović S, Al Nahas K, Feringa BL, Schwille P. Light-Activated Synthetic Rotary Motors in Lipid Membranes Induce Shape Changes Through Membrane Expansion. Adv Mater 2024; 36:e2311176. [PMID: 38215457 DOI: 10.1002/adma.202311176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/16/2023] [Indexed: 01/14/2024]
Abstract
Membranes are the key structures to separate and spatially organize cellular systems. Their rich dynamics and transformations during the cell cycle are orchestrated by specific membrane-targeted molecular machineries, many of which operate through energy dissipation. Likewise, man-made light-activated molecular rotary motors have previously shown drastic effects on cellular systems, but their physical roles on and within lipid membranes remain largely unexplored. Here, the impact of rotary motors on well-defined biological membranes is systematically investigated. Notably, dramatic mechanical transformations are observed in these systems upon motor irradiation, indicative of motor-induced membrane expansion. The influence of several factors on this phenomenon is systematically explored, such as motor concentration and membrane composition., Membrane fluidity is found to play a crucial role in motor-induced deformations, while only minor contributions from local heating and singlet oxygen generation are observed. Most remarkably, the membrane area expansion under the influence of the motors continues as long as irradiation is maintained, and the system stays out-of-equilibrium. Overall, this research contributes to a comprehensive understanding of molecular motors interacting with biological membranes, elucidating the multifaceted factors that govern membrane responses and shape transitions in the presence of these remarkable molecular machines, thereby supporting their future applications in chemical biology.
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Affiliation(s)
- Yusuf Qutbuddin
- Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Ainoa Guinart
- Stratingh Institute for Chemistry, University of Groningen, Groningen, 9747 AG, The Netherlands
| | - Svetozar Gavrilović
- Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Kareem Al Nahas
- Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Ben L Feringa
- Stratingh Institute for Chemistry, University of Groningen, Groningen, 9747 AG, The Netherlands
| | - Petra Schwille
- Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
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2
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Qutbuddin Y, Al Nahas K, Schwille P. Controlling the mechanistic properties of lipid membranes using amphiphilic block copolymers. Biophys J 2023; 122:362a. [PMID: 36783839 DOI: 10.1016/j.bpj.2022.11.2001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Yusuf Qutbuddin
- Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Munich, Germany
| | - Kareem Al Nahas
- Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Munich, Germany
| | - Petra Schwille
- Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry, Munich, Germany
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3
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Fletcher M, Zhu J, Rubio-Sánchez R, Sandler SE, Nahas KA, Michele LD, Keyser UF, Tivony R. DNA-Based Optical Quantification of Ion Transport across Giant Vesicles. ACS Nano 2022; 16:17128-17138. [PMID: 36222833 PMCID: PMC9620405 DOI: 10.1021/acsnano.2c07496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Accurate measurements of ion permeability through cellular membranes remains challenging due to the lack of suitable ion-selective probes. Here we use giant unilamellar vesicles (GUVs) as membrane models for the direct visualization of mass translocation at the single-vesicle level. Ion transport is indicated with a fluorescently adjustable DNA-based sensor that accurately detects sub-millimolar variations in K+ concentration. In combination with microfluidics, we employed our DNA-based K+ sensor for extraction of the permeation coefficient of potassium ions. We measured K+ permeability coefficients at least 1 order of magnitude larger than previously reported values from bulk experiments and show that permeation rates across the lipid bilayer increase in the presence of octanol. In addition, an analysis of the K+ flux in different concentration gradients allows us to estimate the complementary H+ flux that dissipates the charge imbalance across the GUV membrane. Subsequently, we show that our sensor can quantify the K+ transport across prototypical cation-selective ion channels, gramicidin A and OmpF, revealing their relative H+/K+ selectivity. Our results show that gramicidin A is much more selective to protons than OmpF with a H+/K+ permeability ratio of ∼104.
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Affiliation(s)
- Marcus Fletcher
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CambridgeCB3 0HE, U.K.
| | - Jinbo Zhu
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CambridgeCB3 0HE, U.K.
| | - Roger Rubio-Sánchez
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, LondonW12 0BZ, U.K.
- fabriCELL,
Molecular Sciences Research Hub, Imperial
College London, LondonW12 0BZ, U.K.
| | - Sarah E Sandler
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CambridgeCB3 0HE, U.K.
| | - Kareem Al Nahas
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CambridgeCB3 0HE, U.K.
| | - Lorenzo Di Michele
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, LondonW12 0BZ, U.K.
- fabriCELL,
Molecular Sciences Research Hub, Imperial
College London, LondonW12 0BZ, U.K.
| | - Ulrich F Keyser
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CambridgeCB3 0HE, U.K.
| | - Ran Tivony
- Cavendish
Laboratory, University of Cambridge, J.J. Thomson Avenue, CambridgeCB3 0HE, U.K.
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Al Nahas K, Fletcher M, Hammond K, Nehls C, Cama J, Ryadnov MG, Keyser UF. Measuring Thousands of Single-Vesicle Leakage Events Reveals the Mode of Action of Antimicrobial Peptides. Anal Chem 2022; 94:9530-9539. [PMID: 35760038 PMCID: PMC9280716 DOI: 10.1021/acs.analchem.1c03564] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
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Host defense or antimicrobial
peptides hold promise for providing
new pipelines of effective antimicrobial agents. Their activity quantified
against model phospholipid membranes is fundamental to a detailed
understanding of their structure–activity relationships. However,
classical characterization assays often lack the ability to achieve
this insight. Leveraging a highly parallelized microfluidic platform
for trapping and studying thousands of giant unilamellar vesicles,
we conducted quantitative long-term microscopy studies to monitor
the membrane-disruptive activity of archetypal antimicrobial peptides
with a high spatiotemporal resolution. We described the modes of action
of these peptides via measurements of the disruption of the vesicle
population under the conditions of continuous peptide dosing using
a range of concentrations and related the observed modes to the molecular
activity mechanisms of these peptides. The study offers an effective
approach for characterizing membrane-targeting antimicrobial agents
in a standardized manner and for assigning specific modes of action
to the corresponding antimicrobial mechanisms.
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Affiliation(s)
- Kareem Al Nahas
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Marcus Fletcher
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Katharine Hammond
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, U.K.,London Centre for Nanotechnology, University College London, London WC1H 0AH, U.K
| | - Christian Nehls
- Research Center Borstel, Leibniz Lung Center, Parkallee 10, Borstel 23845, Germany
| | - Jehangir Cama
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K.,Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, U.K.,College of Engineering, Mathematics and Physical Sciences, University of Exeter, North Park Road, Exeter EX4 4QF, U.K
| | - Maxim G Ryadnov
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, U.K.,Department of Physics, King's College London, Strand Lane, London WC2R 2LS, U.K
| | - Ulrich F Keyser
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE, U.K
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Aguilar M, Al Nahas K, Barrera F, Bassereau P, Bastos M, Beales P, Bechinger B, Bonev B, Brand I, Chattopadhyay A, Clarke RJ, DeGrado W, Deplazes E, Garcia Saez AJ, Hoogenboom B, Lund R, Milán Rodríguez P, O'Shea P, Pabst G, Pal S, Roux A, Sanderson J, Semeraro EF, Sengupta D, Siegel DP, van 't Hag L, Vijayakumar A, Zoranić L. Theoretical and experimental studies of complex peptide-membrane systems: general discussion. Faraday Discuss 2021; 232:256-281. [PMID: 34909814 DOI: 10.1039/d1fd90066h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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6
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Aguilar MI, Al Nahas K, Barrera FN, Bassereau P, Bechinger B, Brand I, Chattopadhyay A, Clarke RJ, DeGrado WF, Deplazes E, Fletcher M, Fraternali F, Fuchs P, Garcia-Saez AJ, Gilbert R, Hoogenboom BW, Jarin Z, O'Shea P, Pabst G, Pal S, Sanderson JM, Seddon JM, Sengupta D, Siegel DP, Srivastava A, Tieleman DP, Tripathy M, Utterström J, Vácha R, Vanni S, Voth GA. Theoretical and experimental comparisons of simple peptide-membrane systems; towards defining the reaction space: general discussion. Faraday Discuss 2021; 232:149-171. [PMID: 34908093 DOI: 10.1039/d1fd90065j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Aguilar M, Al Nahas K, Barrera F, Bassereau P, Bastos M, Beales P, Bechinger B, Bonev B, Brand I, Chattopadhyay A, DeGrado W, Fuchs P, Garcia Saez AJ, Hoogenboom B, Kapoor S, Milán Rodríguez P, Molloy J, O'Shea P, Pabst G, Pal S, Rice A, Roux A, Sanderson J, Seddon J, Tamm LK, Vijayakumar A. Behaviour and interactions of proteins and peptides with and within membranes; from simple models to cellular membranes: general discussion. Faraday Discuss 2021; 232:375-398. [PMID: 34909817 DOI: 10.1039/d1fd90067f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Abstract
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Cell-sized vesicles
like giant unilamellar vesicles (GUVs) are
established as a promising biomimetic model for studying cellular
phenomena in isolation. However, the presence of residual components
and byproducts, generated during vesicles preparation and manipulation,
severely limits the utility of GUVs in applications like synthetic
cells. Therefore, with the rapidly growing field of synthetic biology,
there is an emergent demand for techniques that can continuously purify
cell-like vesicles from diverse residues, while GUVs are being simultaneously
synthesized and manipulated. We have developed a microfluidic platform
capable of purifying GUVs through stream bifurcation, where a vesicles
suspension is partitioned into three fractions: purified GUVs, residual
components, and a washing solution. Using our purification approach,
we show that giant vesicles can be separated from various residues—which
range in size and chemical composition—with a very high efficiency
(e = 0.99), based on size and deformability of the
filtered objects. In addition, by incorporating the purification module
with a microfluidic-based GUV-formation method, octanol-assisted liposome
assembly (OLA), we established an integrated production-purification
microfluidic unit that sequentially produces, manipulates, and purifies
GUVs. We demonstrate the applicability of the integrated device to
synthetic biology through sequentially fusing SUVs with freshly prepared
GUVs and separating the fused GUVs from extraneous SUVs and oil droplets
at the same time.
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Affiliation(s)
- Ran Tivony
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Marcus Fletcher
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Kareem Al Nahas
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Ulrich F. Keyser
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, U.K
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9
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Al Nahas K, Keyser UF. Standardizing characterization of membrane active peptides with microfluidics. Biomicrofluidics 2021; 15:041301. [PMID: 34257793 PMCID: PMC8266397 DOI: 10.1063/5.0048906] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
Antimicrobial peptides (AMPs) are emerging as important players in the fight against antibiotic resistance. In parallel, the field of microfluidics has matured and its benefits are being exploited in applications of biomimetics and standardized testing. Membrane models are essential tools extensively utilized in studying the activity and modes of action of AMPs. Here, we describe how the utilization of microfluidic platforms in characterizing membrane active peptides can develop a reliable colorful image that classical techniques have rendered black and white.
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Affiliation(s)
- Kareem Al Nahas
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB30HE, United Kingdom
| | - Ulrich F. Keyser
- Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB30HE, United Kingdom
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10
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Hammond K, Cipcigan F, Al Nahas K, Losasso V, Lewis H, Cama J, Martelli F, Simcock PW, Fletcher M, Ravi J, Stansfeld PJ, Pagliara S, Hoogenboom BW, Keyser UF, Sansom MSP, Crain J, Ryadnov MG. Switching Cytolytic Nanopores into Antimicrobial Fractal Ruptures by a Single Side Chain Mutation. ACS Nano 2021; 15:9679-9689. [PMID: 33885289 PMCID: PMC8219408 DOI: 10.1021/acsnano.1c00218] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Disruption of cell membranes is a fundamental host defense response found in virtually all forms of life. The molecular mechanisms vary but generally lead to energetically favored circular nanopores. Here, we report an elaborate fractal rupture pattern induced by a single side-chain mutation in ultrashort (8-11-mers) helical peptides, which otherwise form transmembrane pores. In contrast to known mechanisms, this mode of membrane disruption is restricted to the upper leaflet of the bilayer where it exhibits propagating fronts of peptide-lipid interfaces that are strikingly similar to viscous instabilities in fluid flow. The two distinct disruption modes, pores and fractal patterns, are both strongly antimicrobial, but only the fractal rupture is nonhemolytic. The results offer wide implications for elucidating differential membrane targeting phenomena defined at the nanoscale.
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Affiliation(s)
- Katharine Hammond
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK
- Department of Physics & Astronomy, University College London, London WC1E 6BT, UK
| | | | - Kareem Al Nahas
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | | | - Helen Lewis
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | - Jehangir Cama
- Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK
- College of Engineering, Mathematics and Phys Sciences, University of Exeter, Exeter EX4 4QF, UK
| | | | - Patrick W Simcock
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Marcus Fletcher
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Jascindra Ravi
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
| | | | - Stefano Pagliara
- Living Systems Institute, University of Exeter, Exeter EX4 4QD, UK
- College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK
- Department of Physics & Astronomy, University College London, London WC1E 6BT, UK
| | - Ulrich F Keyser
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Jason Crain
- IBM Research Europe, Hartree Centre, Daresbury WA4 4AD, UK
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Maxim G Ryadnov
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK
- Department of Physics, King’s College London, London, WC2R 2LS, UK
- Corresponding author: Prof Maxim G Ryadnov; National Physical Laboratory, Hampton Road, Teddington, TW11 0LW, UK, Tel: (+44) 20 89436078;
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11
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Ćatić N, Wells L, Al Nahas K, Smith M, Jing Q, Keyser UF, Cama J, Kar-Narayan S. Aerosol-jet printing facilitates the rapid prototyping of microfluidic devices with versatile geometries and precise channel functionalization. Appl Mater Today 2020; 19:100618. [PMID: 33521242 PMCID: PMC7821597 DOI: 10.1016/j.apmt.2020.100618] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Microfluidics has emerged as a powerful analytical tool for biology and biomedical research, with uses ranging from single-cell phenotyping to drug discovery and medical diagnostics, and only small sample volumes required for testing. The ability to rapidly prototype new designs is hugely beneficial in a research environment, but the high cost, slow turnaround, and wasteful nature of commonly used fabrication techniques, particularly for complex multi-layer geometries, severely impede the development process. In addition, microfluidic channels in most devices currently play a passive role and are typically used to direct flows. The ability to "functionalize" the channels with different materials in precise spatial locations would be a major advantage for a range of applications. This would involve incorporating functional materials directly within the channels that can partake in, guide or facilitate reactions in precisely controlled microenvironments. Here we demonstrate the use of Aerosol Jet Printing (AJP) to rapidly produce bespoke molds for microfluidic devices with a range of different geometries and precise "in-channel" functionalization. We show that such an advanced microscale additive manufacturing method can be used to rapidly design cost-efficient and customized microfluidic devices, with the ability to add functional coatings at specific locations within the microfluidic channels. We demonstrate the functionalization capabilities of our technique by specifically coating a section of a microfluidic channel with polyvinyl alcohol to render it hydrophilic. This versatile microfluidic device prototyping technique will be a powerful aid for biological and bio-medical research in both academic and industrial contexts.
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Affiliation(s)
- Nordin Ćatić
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, UK
| | - Laura Wells
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, UK
| | - Kareem Al Nahas
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK
| | - Michael Smith
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, UK
| | - Qingshen Jing
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, UK
| | - Ulrich F. Keyser
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK
| | - Jehangir Cama
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
- Corresponding author at: Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
| | - Sohini Kar-Narayan
- Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, UK
- Corresponding author at: Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, UK.
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Schaich M, Cama J, Al Nahas K, Sobota D, Sleath H, Jahnke K, Deshpande S, Dekker C, Keyser UF. An Integrated Microfluidic Platform for Quantifying Drug Permeation across Biomimetic Vesicle Membranes. Mol Pharm 2019; 16:2494-2501. [PMID: 30994358 DOI: 10.1021/acs.molpharmaceut.9b00086] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The low membrane permeability of candidate drug molecules is a major challenge in drug development, and insufficient permeability is one reason for the failure of antibiotic treatment against bacteria. Quantifying drug transport across specific pathways in living systems is challenging because one typically lacks knowledge of the exact lipidome and proteome of the individual cells under investigation. Here, we quantify drug permeability across biomimetic liposome membranes, with comprehensive control over membrane composition. We integrate the microfluidic octanol-assisted liposome assembly platform with an optofluidic transport assay to create a complete microfluidic total analysis system for quantifying drug permeability. Our system enables us to form liposomes with charged lipids mimicking the negative charge of bacterial membranes at physiological pH and salt concentrations, which proved difficult with previous liposome formation techniques. Furthermore, the microfluidic technique yields an order of magnitude more liposomes per experiment than previous assays. We demonstrate the feasibility of the assay by determining the permeability coefficient of norfloxacin and ciprofloxacin across biomimetic liposomes.
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Affiliation(s)
- Michael Schaich
- Cavendish Laboratory , University of Cambridge , JJ Thomson Avenue , Cambridge CB3 0HE , U.K
| | - Jehangir Cama
- Cavendish Laboratory , University of Cambridge , JJ Thomson Avenue , Cambridge CB3 0HE , U.K.,Living Systems Institute , University of Exeter , Stocker Road , Exeter EX4 4QD , U.K
| | - Kareem Al Nahas
- Cavendish Laboratory , University of Cambridge , JJ Thomson Avenue , Cambridge CB3 0HE , U.K
| | - Diana Sobota
- Cavendish Laboratory , University of Cambridge , JJ Thomson Avenue , Cambridge CB3 0HE , U.K
| | - Hannah Sleath
- Cavendish Laboratory , University of Cambridge , JJ Thomson Avenue , Cambridge CB3 0HE , U.K
| | - Kevin Jahnke
- Cavendish Laboratory , University of Cambridge , JJ Thomson Avenue , Cambridge CB3 0HE , U.K.,Department of Biophysical Chemistry , University of Heidelberg , Im Neuenheimer Feld 253 , D-69120 Heidelberg , Germany.,Department of Cellular Biophysics , Max Planck Institute for Medical Research , Jahnstraße 29 , D-69120 Heidelberg , Germany
| | - Siddharth Deshpande
- Department of Bionanoscience, Kavli Institute of Nanoscience , Delft University of Technology , Van der Maasweg 9 , 2629 HZ Delft , The Netherlands
| | - Cees Dekker
- Department of Bionanoscience, Kavli Institute of Nanoscience , Delft University of Technology , Van der Maasweg 9 , 2629 HZ Delft , The Netherlands
| | - Ulrich F Keyser
- Cavendish Laboratory , University of Cambridge , JJ Thomson Avenue , Cambridge CB3 0HE , U.K
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