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Alfken J, Neuhaus C, Major A, Taskina A, Hoffmann C, Ganzella M, Petrovic A, Zwicker D, Fernández-Busnadiego R, Jahn R, Milovanovic D, Salditt T. Vesicle condensation induced by synapsin: condensate size, geometry, and vesicle shape deformations. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2024; 47:8. [PMID: 38270681 DOI: 10.1140/epje/s10189-023-00404-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 12/28/2023] [Indexed: 01/26/2024]
Abstract
We study the formation of vesicle condensates induced by the protein synapsin, as a cell-free model system mimicking vesicle pool formation in the synapse. The system can be considered as an example of liquid-liquid phase separation (LLPS) in biomolecular fluids, where one phase is a complex fluid itself consisting of vesicles and a protein network. We address the pertinent question why the LLPS is self-limiting and stops at a certain size, i.e., why macroscopic phase separation is prevented. Using fluorescence light microscopy, we observe different morphologies of the condensates (aggregates) depending on the protein-to-lipid ratio. Cryogenic electron microscopy then allows us to resolve individual vesicle positions and shapes in a condensate and notably the size and geometry of adhesion zones between vesicles. We hypothesize that the membrane tension induced by already formed adhesion zones then in turn limits the capability of vesicles to bind additional vesicles, resulting in a finite condensate size. In a simple numerical toy model we show that this effect can be accounted for by redistribution of effective binding particles on the vesicle surface, accounting for the synapsin-induced adhesion zone.
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Affiliation(s)
- Jette Alfken
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - Charlotte Neuhaus
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - András Major
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
| | - Alyona Taskina
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany
- Theorie Biologischer Flüssigkeiten, Max-Planck-Institut für Dynamik und Selbstorganisation, Am Fassberg 11, 37077, Göttingen, Germany
| | - Christian Hoffmann
- Molekulare Neurowissenschaften, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Charitéplatz 1, 10117, Berlin, Germany
| | - Marcelo Ganzella
- Labor für Neurobiologie, Max-Planck-Institut für multidisziplinäre Naturwissenschaften, Am Fassberg 11, 37077, Göttingen, Germany
| | - Arsen Petrovic
- Institut für Neuropathologie, Universitätsmedizin Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
| | - David Zwicker
- Theorie Biologischer Flüssigkeiten, Max-Planck-Institut für Dynamik und Selbstorganisation, Am Fassberg 11, 37077, Göttingen, Germany
| | - Rubén Fernández-Busnadiego
- Institut für Neuropathologie, Universitätsmedizin Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany
| | - Reinhard Jahn
- Labor für Neurobiologie, Max-Planck-Institut für multidisziplinäre Naturwissenschaften, Am Fassberg 11, 37077, Göttingen, Germany
| | - Dragomir Milovanovic
- Molekulare Neurowissenschaften, Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Charitéplatz 1, 10117, Berlin, Germany
| | - Tim Salditt
- Institut für Röntgenphysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077, Göttingen, Germany.
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Colorimetric Assaying of Exosomal Metabolic Biomarkers. Molecules 2023; 28:molecules28041909. [PMID: 36838895 PMCID: PMC9962048 DOI: 10.3390/molecules28041909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/10/2023] [Accepted: 02/15/2023] [Indexed: 02/19/2023] Open
Abstract
Exosomes released into the extracellular matrix have been reported to contain metabolic biomarkers of various diseases. These intraluminal vesicles are typically found in blood, urine, saliva, breast milk, cerebrospinal fluid, semen, amniotic fluid, and ascites. Analysis of exosomal content with specific profiles of DNA, microRNA, proteins, and lipids can mirror their cellular origin and physiological state. Therefore, exosomal cargos may reflect the physiological processes at cellular level and can potentially be used as biomarkers. Herein, we report an optical detection method for assaying exosomal biomarkers that supersedes the state-of-the-art time consuming and laborious assays such as ELISA and NTA. The proposed assay monitors the changes in optical properties of poly(3-(4-methyl-3'-thienyloxy) propyltriethylammonium bromide) upon interacting with aptamers/peptide nucleic acids in the presence or absence of target biomarkers. As a proof of concept, this study demonstrates facile assaying of microRNA, DNA, and advanced glycation end products in exosomes isolated from human plasma with detection levels of ~1.2, 0.04, and 0.35 fM/exosome, respectively. Thus, the obtained results illustrate that the proposed methodology is applicable for rapid and facile detection of generic exosomal biomarkers for facilitating diseases diagnosis.
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Seyrig C, Poirier A, Perez J, Bizien T, Baccile N. Interpenetrated Biosurfactant-Biopolymer Orthogonal Hydrogels: The Biosurfactant's Phase Controls the Hydrogel's Mechanics. Biomacromolecules 2023; 24:33-42. [PMID: 36576429 DOI: 10.1021/acs.biomac.2c00319] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Controlling the viscoelastic properties of hydrogels is a challenge for many applications. Low molecular weight gelators (LMWGs) like bile salts and glycolipids and biopolymers like chitosan and alginate are good candidates for developing fully biobased hybrid hydrogels that combine the advantages of both components. Biopolymers lead to enhanced mechanics, while LMWGs add functionality. In this work, hybrid hydrogels are composed of biopolymers (gelatin, chitosan, and alginate) and microbial glycolipid bioamphiphiles, known as biosurfactants. Besides their biocompatibility and natural origin, bioamphiphiles can present chameleonic behavior, as pH and ions control their phase diagram in water around neutrality under strongly diluted conditions (<5 wt%). The glycolipid used in this work behaves like a surfactant (micellar phase) at high pH or like a phospholipid (vesicle phase) at low pH. Moreover, at neutral-to-alkaline pH in the presence of calcium, it behaves like a gelator (fiber phase). The impact of each of these phases on the elastic properties of biopolymers is explored by means of oscillatory rheology, while the hybrid structure is studied by small angle X-ray scattering. The micellar and vesicular phases reduce the elastic properties of the hydrogels, while the fiber phase has the opposite effect; it enhances the hydrogel's strength by forming an interpenetrated biopolymer-LMWG network.
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Affiliation(s)
- Chloé Seyrig
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire de Chimie de la Matière Condensée de Paris, LCMCP, F-75005Paris, France
| | - Alexandre Poirier
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire de Chimie de la Matière Condensée de Paris, LCMCP, F-75005Paris, France
| | - Javier Perez
- Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin, BP 48, 91192Gif-sur-Yvette Cedex, France
| | - Thomas Bizien
- Synchrotron SOLEIL, L'Orme des Merisiers Saint-Aubin, BP 48, 91192Gif-sur-Yvette Cedex, France
| | - Niki Baccile
- Sorbonne Université, Centre National de la Recherche Scientifique, Laboratoire de Chimie de la Matière Condensée de Paris, LCMCP, F-75005Paris, France
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Cao R, Kumar D, Dinsmore AD. Vesicle-Based Gel via Polyelectrolyte-Induced Adhesion: Structure, Rheology, and Response. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1714-1724. [PMID: 33513022 DOI: 10.1021/acs.langmuir.0c02921] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We describe an experimental study of soft solids composed of micron-scale lipid bilayer vesicles that adhere to one another through electrostatic attraction to an oppositely charged polymer (PDADMAC). As the polymer concentration was increased, we found a fluid phase, a solid gel phase, and a gel composed of internally reorganized vesicles. Optical microscopy images showed a nearly close-packed structure of adhered vesicles that retained their closed-cell morphology. Shear rheology measurements showed that the gel phase is a solid with a modulus at the Pa scale and with linear response up to 70% strain. We found that the modulus depends on the energy per area of membrane-membrane adhesion but does not depend on the vesicle size. We further found that the gels survived osmotic stress or dilution of the adhering polymer but could be rapidly disrupted in response to the addition of strongly binding silica nanoparticles. These results demonstrate the potential for cell-sized lipid vesicles to form a solid platform that maintains the responsive properties of the membranes. Such materials may find applications as triggerable, protective coatings of delicate surfaces.
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Affiliation(s)
- Rui Cao
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
| | - Deepak Kumar
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
- Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Anthony D Dinsmore
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, United States
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