1,721,000 research outputs found
Observation of E-cadherin adherens junction dynamics with metal-induced energy transfer imaging and spectroscopy
Full text linkEpithelial cadherin (E-cad) mediated cell-cell junctions play a crucial role in the establishment and maintenance of tissues and organs. In this study, we employed metal-induced energy transfer imaging and spectroscopy to investigate variations in intermembrane distance during adhesion between two model membranes adorned with E-cad. By correlating the measured intermembrane distances with the distinct E-cad junction states, we probed the dynamic behavior and diversity of E-cad junctions across different binding pathways. Our observations led to the identification of a transient intermediate state referred to as the X-dimeric state and enabled a detailed analysis of its kinetics. We discovered that the formation of the X-dimer leads to significant membrane displacement, subsequently impacting the formation of other X-dimers. These direct experimental insights into the subtle dynamics of E-cad-modified membranes and the resultant changes in intermembrane distance provide perspectives on the assembly of E-cad junctions between cells. This knowledge enhances our comprehension of tissue and organ development and may serve as a foundation for the development of innovative therapeutic strategies for diseases linked to cell-cell adhesion abnormalities
Measuring sub-nanometer fluctuations at microsecond temporal resolution with metal-and graphene-induced energy transfer spectroscopy
No full textObservation of E-cadherin Adherens Junction Dynamics with Metal-Induced Energy Transfer Imaging and Spectroscopy
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Leaflet‐specific Structure and Dynamics of Solid and Polymer Supported Lipid Bilayers
Full text linkPolymer‐supported or tethered lipid bilayers serve as versatile platforms for mimicking plasma membrane structure and dynamics, yet the impact of polymer supports on lipid bilayers remains largely unresolved. In this study, we introduce a novel methodology that combines graphene‐induced energy transfer (GIET) with line‐scan fluorescence lifetime correlation spectroscopy (lsFLCS) to examine the structural and dynamic properties of lipid bilayers. Our findings reveal that polymer supports markedly influence both the structural parameters, such as the membrane height from the substrate, its thickness, as well as dynamic properties, including leaflet‐specific diffusion coefficients and interleaflet coupling. These findings highlight the complex interplay between a polymer support and the lipid bilayers. By resolving leaflet‐specific diffusion and heights of the two leaflets from the substrate, this study emphasizes the potential of GIET‐lsFLCS for probing membrane dynamics and structure. These insights significantly advance the understanding and application of polymer‐supported membranes across diverse research contexts
Graphene- and metal-induced energy transfer for single-molecule imaging and live-cell nanoscopy with (sub)-nanometer axial resolution
No full textMonolagen‐Spezifische Struktur und Dynamik von Oberflächen‐ und Polymer‐Gestützten Lipiddoppelschichten
Full text linkKurzzusammenfassung: Polymergestützte oder polymergekoppelte (polymer tethered) Lipid‐Doppelschichten dienen als vielseitige Modellsysteme für die Struktur und Dynamik von Plasmamembranen, doch der Einfluss der Polymerkopplung auf die Eigenschaften der Lipid‐Doppelschichten blieb bisher weitgehend unberücksichtigt. In dieser Studie stellen wir eine neuartige Methodik vor, nämlich eine Kombination aus Graphen‐induziertem Energietransfer (GIET) mit Line‐Scan‐Fluoreszenz‐Lebensdauer‐Korrelationsspektroskopie (lsFLCS), um die strukturellen und dynamischen Eigenschaften von Lipid‐Doppelschichten zu untersuchen. Unsere Ergebnisse zeigen, dass die Polymerkopplung sowohl die strukturellen Parameter, wie die Membranhöhe über dem Substrat und die Membrandicke, als auch die dynamischen Eigenschaften, einschließlich monolagen‐spezifischer Diffusionskoeffizienten und der Kopplung zwischen den Monolagen, erheblich beeinflussen. Diese Erkenntnisse verdeutlichen das komplexe Zusammenspiel zwischen Polymerunterlage und Lipid‐Doppelschicht. Mit der Messung der monolagen‐spezifischen Diffusion und des Abstandes der beiden Monolagen vom Substrat demonstriert diese Studie das Potenzial von GIET‐lsFLCS für die Untersuchung von Membrandynamik und ‐struktur. Diese Erkenntnisse sind wichtig für ein besseres Verständnis und die Anwendung polymergekoppelter Membrane in verschiedenen Forschungsbereichen
Measuring sub-nanometer undulations at microsecond temporal resolution with metal- and graphene-induced energy transfer spectroscopy
Full text linkAbstract Out-of-plane fluctuations, also known as stochastic displacements, of biological membranes play a crucial role in regulating many essential life processes within cells and organelles. Despite the availability of various methods for quantifying membrane dynamics, accurately quantifying complex membrane systems with rapid and tiny fluctuations, such as mitochondria, remains a challenge. In this work, we present a methodology that combines metal/graphene-induced energy transfer (MIET/GIET) with fluorescence correlation spectroscopy (FCS) to quantify out-of-plane fluctuations of membranes with simultaneous spatiotemporal resolution of approximately one nanometer and one microsecond. To validate the technique and spatiotemporal resolution, we measure bending undulations of model membranes. Furthermore, we demonstrate the versatility and applicability of MIET/GIET-FCS for studying diverse membrane systems, including the widely studied fluctuating membrane system of human red blood cells, as well as two unexplored membrane systems with tiny fluctuations, a pore-spanning membrane, and mitochondrial inner/outer membranes
Measuring Photophysical Transition Rates with Fluorescence Correlation Spectroscopy and Antibunching
No full textWe present a new method that combines fluorescence correlation spectroscopy (FCS) on the microsecond time scale with fluorescence antibunching measurements on the nanosecond time scale for measuring photophysical rate constants of fluorescent molecules. The antibunching measurements allow us to quantify the average excitation rate of fluorescent molecules within the confocal detection volume of the FCS measurement setup. Knowledge of this value allows us then to quantify, in an absolute manner, the intersystem crossing rate and triplet state lifetime from the microsecond temporal decay of the FCS curves. We present a theoretical analysis of the method and estimate the maximum bias caused by the averaging of all quantities (excitation rate, photophysical rates) over the confocal detection volume, and we show that this bias is smaller than 5\% in most cases. We apply the method for measuring the photophysical rate constants of the widely used dyes Rhodamine~110 and ATTO~655
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