Featured
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Research Highlights |
Single-molecule force analysis, unplugged
A nanoscopic force clamp enables high-throughput single-molecule analysis of DNA under tension without connection to a macroscopic instrument.
- Allison Doerr
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Methods in Brief |
Counting proteins by slowing diffusion
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Research Highlights |
Miniature magnetic force probes
Magnetoplasmonic nanoparticles can manipulate cell surface receptors with single-molecule precision to clarify the effects of force application and receptor clustering.
- Nina Vogt
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Research Highlights |
PCR for cellular forces
A 'mechanically induced catalytic amplification reaction' reads out receptor-mediated forces in cells.
- Allison Doerr
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Review Article |
Measuring cell-generated forces: a guide to the available tools
There is a growing appreciation that mechanical forces have important roles in many aspects of biology. This review provides a survey of methods for measuring the forces exerted by cells and discusses technical barriers to their implementation.
- William J Polacheck
- & Christopher S Chen
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Brief Communication |
Single-molecule imaging of non-equilibrium molecular ensembles on the millisecond timescale
This report describes an imaging and analysis platform enabling high-throughput single-molecule fluorescence investigations of fast, transient molecular recognition events.
- Manuel F Juette
- , Daniel S Terry
- & Scott C Blanchard
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Research Highlights |
Watching proteins fold on the ribosome
Researchers monitor cotranslational protein folding in real time.
- Rita Strack
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Method to Watch |
Protein structure through time
Advances in time-resolved crystallography make it possible to follow ever more rapid protein structural changes.
- Allison Doerr
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Brief Communication |
Noncontact three-dimensional mapping of intracellular hydromechanical properties by Brillouin microscopy
Brillouin microscopy can be used to analyze the mechanical properties of cells in a contact-free fashion. Cells in 2D and 3D environments are accessible to this technology, which provides measurements of longitudinal moduli at optical resolution.
- Giuliano Scarcelli
- , William J Polacheck
- & Seok Hyun Yun
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News & Views |
Single in the (Cell) City: a protein-folding story
An integrated single-molecule fluorescence approach enables the study of nano-to-millisecond protein conformational dynamics in living mammalian cells.
- Anne Plochowietz
- & Achillefs N Kapanidis
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Article |
Single-molecule spectroscopy of protein conformational dynamics in live eukaryotic cells
Individual protein dynamics can be studied in live eukaryotic cells from the millisecond to nanosecond level using an integrated approach to confocal single-molecule FRET spectroscopy.
- Iwo König
- , Arash Zarrine-Afsar
- & Benjamin Schuler
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Editorial |
The difficulty of a fair comparison
Comparing methods in a fair and informative manner is often not straightforward. Benchmark data sets, thoughtfully applied metrics and clear reporting can help.
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Brief Communication |
Real-time deformability cytometry: on-the-fly cell mechanical phenotyping
Real-time deformability cytometry allows the continuous mechanical characterization of cells with high throughput and is applied to distinguish cell-cycle phases, track differentiated cells and profile cell populations in whole blood.
- Oliver Otto
- , Philipp Rosendahl
- & Jochen Guck
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Technology Feature |
Biophysics: using sound to move cells
Moving and sorting cells with sound are a few of the possible applications for this no-contact technique.
- Vivien Marx
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News & Views |
Toward high-throughput biomechanical phenotyping of single molecules
Two high-throughput single-molecule force spectroscopy platforms expand the reach of this technology for biomechanical molecular phenotyping.
- David Alsteens
- , Savaş Tay
- & Daniel J Müller
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Research Highlights |
Unwinding to measure tension
Two independent groups develop tension probes based on molecular beacons to measure mechanical stimuli in live cells.
- Irene Kaganman
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Perspective |
Live-cell mass profiling: an emerging approach in quantitative biophysics
This Perspective discusses methods to measure single-cell mass and their relative strengths and weaknesses for different applications.
- Thomas A Zangle
- & Michael A Teitell
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Brief Communication |
An improved surface passivation method for single-molecule studies
Avoiding nonspecific binding is essential for performing fluorescence microscopy–based analyses of single molecules tethered to surfaces. A dichlorodimethylsilane–Tween-20–passivated surface provides a useful alternative to the standard poly(ethylene glycol) surface for single-molecule studies.
- Boyang Hua
- , Kyu Young Han
- & Taekjip Ha
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Brief Communication |
A DNA-based molecular probe for optically reporting cellular traction forces
DNA hairpins with a conjugated fluorophore-quencher pair are attached to surfaces to monitor cellular traction forces at high spatial resolution.
- Brandon L Blakely
- , Christoph E Dumelin
- & Christopher S Chen
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Research Highlights |
Imaging without labels
Researchers report an optical method to detect and image single proteins without using any labels.
- Allison Doerr
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Research Highlights |
A stir in the cytoplasm
A combination of techniques reveals that aggregate forces from all enzymes active in the cytoplasm result in randomly fluctuating forces throughout the cell.
- Irene Kaganman
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Commentary |
Single-molecule methods leap ahead
Much of our knowledge about biological systems has been obtained by examining ensembles of molecules. However, this has begun to change because of the unprecedented precision and clarity afforded by single-molecule measurements. The last decade has seen amazing advances in the resolution and complexity of these methods, making it possible to ask and answer entirely new types of biological questions.
- Taekjip Ha
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Brief Communication |
From genes to protein mechanics on a chip
A microfluidic chip is used to construct a microarray of proteins, each labeled with a dockerin tag, for high-throughput single-molecule force spectroscopy experiments using a single cohesin-modified cantilever.
- Marcus Otten
- , Wolfgang Ott
- & Hermann E Gaub
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Technology Feature |
Structural biology: 'seeing' crystals the XFEL way
X-ray free-electron lasers (XFELs) offer opportunities beyond classic X-ray crystallography, particularly for proteins that are difficult to crystallize.
- Vivien Marx
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This Month |
Richard Neutze
Proteins 'breathe' in an ultrafast way that can be captured with XFELs.
- Vivien Marx
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Brief Communication |
Visualizing a protein quake with time-resolved X-ray scattering at a free-electron laser
A 'protein quake' is directly monitored on the picosecond timescale using the method of time-resolved wide-angle X-ray scattering at an X-ray free-electron laser.
- David Arnlund
- , Linda C Johansson
- & Richard Neutze
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Brief Communication |
Nanoscale high-content analysis using compositional heterogeneities of single proteoliposomes
The compositional heterogeneity of proteoliposome reconstitution can skew the results of ensemble-average measurements of transmembrane protein structure and function. These compositional heterogeneities can be exploited, however, with a single-proteoliposome, high-content screening method.
- Signe Mathiasen
- , Sune M Christensen
- & Dimitrios Stamou
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Tools in Brief |
High-throughput optical trapping
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Tools in Brief |
Machining better cantilevers
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Research Highlights |
Background FRET
Models are presented of background fluorescence resonance energy transfer (FRET) for non-interacting membrane proteins.
- Natalie de Souza
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Methods in Brief |
Better estimates of diffusion
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Brief Communication |
Single-molecule motions enable direct visualization of biomolecular interactions in solution
Biomolecular interactions are directly detected and visualized in solution with a single-molecule method that measures time-dependent diffusion coefficient and mobility of electrokinetically trapped species.
- Quan Wang
- & W E Moerner
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Research Highlights |
Elusive vibrations
At last, a method to measure long-range vibrations in proteins may provide clues to the functional relevance of these motions.
- Allison Doerr
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Article |
Gold rotor bead tracking for high-speed measurements of DNA twist, torque and extension
Single-molecule structural transitions involving DNA twisting can be measured with substantially greater spatiotemporal resolution than previously possible with a gold rotor bead tracking (AuRBT) method. This approach uses magnetic tweezers and evanescent darkfield microscopy to track a gold nanoparticle probe attached to a DNA molecule.
- Paul Lebel
- , Aakash Basu
- & Zev Bryant
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Method to Watch |
Tiny tools to measure force
Imaging-based sensors are used to map mechanical forces exerted by cells.
- Natalie de Souza
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Research Highlights |
Unfolding to force
Applying tiny forces to single molecules at high speed reveals the mechanics behind molecule unfolding.
- Erika Pastrana
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Article |
Quantifying cell-generated mechanical forces within living embryonic tissues
Microscopic oil droplets with defined mechanical properties are used to measure forces exerted within living tissue.
- Otger Campàs
- , Tadanori Mammoto
- & Donald E Ingber
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Research Highlights |
Cells under pressure
A tiny silicon chip internalized by cells measures intracellular pressure changes.
- Allison Doerr
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Article |
STED nanoscopy combined with optical tweezers reveals protein dynamics on densely covered DNA
Single DNA-binding proteins can be tracked on densely covered DNA at high spatial and temporal resolution and in the presence of high protein concentrations by using a technique that combines optical tweezers, confocal fluorescence microscopy and stimulated emission depletion (STED) nanoscopy.
- Iddo Heller
- , Gerrit Sitters
- & Gijs J L Wuite
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Research Highlights |
The pull of a cell
Researchers leash cells to molecular tethers as an easy way to measure single-molecular binding forces.
- Tal Nawy
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Methods in Brief |
Particle imaging beyond the quantum limit
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Article |
Extracting intracellular diffusive states and transition rates from single-molecule tracking data
This paper reports an analytical method for single-particle tracking data. It identifies diffusive states of intracellular proteins and the rates of transition between them.
- Fredrik Persson
- , Martin Lindén
- & Johan Elf
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Brief Communication |
Quantitative optical trapping on single organelles in cell extract
A method is reported for optical trap calibration on lipid droplets in cell extract. It should permit quantitative studies of motor proteins in a more natural context than on beads.
- Pradeep Barak
- , Ashim Rai
- & Roop Mallik
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Tools in Brief |
Trapping a shape-shifting bacterium
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Research Highlights |
Moved by sound
Acoustic tweezers nudge cells or particles with sound waves.
- Vivien Marx
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Research Highlights |
Upgrades for the AFM
Researchers continue to improve the performance of the atomic force microscope.
- Daniel Evanko
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Correspondence |
OpenFovea: open-source AFM data processing software
- Charles Roduit
- , Bhaskar Saha
- & Sandor Kasas
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Methods in Brief |
Virtual swimmers