Cellular Signaling and Function Archives

Manipulate and Visualize Cellular Functions at Nanoscale and in Real Time

with: Optical Tweezers and Fluorescence Microscopy

You can use optical tweezers to trap and move microscopic objects in space using the attractive and repulsive forces exerted by a laser beam. For example, trap a microscopic polystyrene bead and guide it in proximity to a cell, or trap small components within a multicellular organism to study cellular functions and properties. Correlating the optical tweezers with fluorescence and label-free microscopy enables you to visualize every step of the cellular processes while at the same time measuring and manipulating them in real time. Use the optical tweezers – fluorescence and label-free microscopy, to study cell properties in different contexts:

Apply external forces to manipulate cell surfaces and follow cellular components simultaneously with multi-color confocal microscopy.
Measure forces associated with filopodia formation and track their interactions using fluorescence microscopy.
Trap and manipulate small components and organelle structures in multicellular organisms using brightfield microscopy.
Control the temperature and finetune the laser intensity to provide relevant physiological and harmless conditions.

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Optical Tweezers and Fluorescence Microscopy

Manipulate and Study Protein Droplet Dynamics and Properties in Real Time to Understand Phase Separation

with: Optical Tweezers and Fluorescence Microscopy

Mounting evidence suggests that membrane-less organelles in cells are semi-transient structures, formed to enable efficient interactions between specific biomolecules. Understanding the formation of
these structures, their physical properties, and mechano-chemical interactions have aided our understanding of several cellular processes. On top of that, the link between droplet formation and medical conditions, such as neurodegenerative amyotrophic lateral sclerosis (ALS) and cancer, has enhanced the need for appropriate assays that can assess related properties. In these cases, proteins
can aggregate to promote a successive solidification of droplets, forming gel-like or irreversible solid structures known as amyloid fibrils (plaques).

Membrane-less organelles and other subcellular structures result from liquid– liquid phase separation of proteins and RNA. These include stress granules, nucleoli, RNA-transport granules, and possibly heterochromatin formation. Studies have (since the 1930s) progressively contested the notion that the protein machinery is homogeneously distributed like a soup of soluble molecules and membranous organelles in the cytoplasm. Instead, they suggest a formation of structures through multivalent interactions associated with specific protein regions.

While we have come a long way in understanding such processes, these droplets are extremely dynamic, dissolving and forming in response to cues that we do not yet fully understand. As a result, the proponents of liquid–liquid phase separation have been unable to capture the dynamics and properties of these droplets with the current techniques. There is, in other words, a need to develop tools and systematic experiments that can unravel the fundamental processes of phase separation:

Which factors regulate liquid protein droplets and their transitions to solid aggregates?

What are the relationships between liquid protein droplets and the irreversible solid amyloid fibril structures?

What are the material properties of protein droplets during solidification?

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Optical Tweezers and Fluorescence Microscopy

Cellular Signaling and Function

Part of: Cellular Structure and Transport

Manipulate and Visualize Cellular Functions at Nanoscale and in Real Time

with: Optical Tweezers and Fluorescence Microscopy

Manipulate and Study Protein Droplet Dynamics and Properties in Real Time to Understand Phase Separation

with: Optical Tweezers and Fluorescence Microscopy

Take your research to the next level.