Determination of Elasticity and Stiffness of Biomolecular Condensates

Elasticity reflects the ability of a solid material to recover its original shape after deformation and compression under mechanical load. It can be quantitatively characterized by the modulus of elasticity. In biomolecular condensates, phase-separated protein droplets with specific sizes, densities and boundaries consist of liquid-like materials. However, the modulus of elasticity is not applicable to liquid materials. Therefore, the elasticity described in the field of biophase separation is apparent elasticity, which essentially reflects the stiffness of the biomolecular condensate under study. Apparent elasticity/stiffness is highly dependent on factors such as shape, size, and interfacial conditions of the biocondensate and is an important property of the object rather than a property of the material.

Customized Services

One of the hallmarks of biomolecular condensates is the ability to agglomerate and relax into different shapes in response to controlled forces. Their elasticity/stiffness is critical to their structural integrity. We have extensive experience in quantitative studies of the viscoelasticity of biomolecular condensates. Here, CD BioSciences offers a variety of techniques to measure the viscoelastic behavior of protein and nucleic acid condensates.

Passive Microrheology

We offer passive microrheology to quantitatively study the viscoelasticity of biomolecular condensates in vitro. The technique uses thermal diffusion of particles within protein/RNA concentrates to extract information about their elasticity.

✓ It is minimally invasive.

✓ Only small deformations of the sample can be detected.

✓ It is driven by thermal noise only.

✓ It is performed by tracking the position of the probe particles in condensates.

✓ Quantifies the full viscoelastic spectrum of the condensate and its viscous and elastic components as a function of deformation frequency.

Active Microrheology

Our active microrheology provides quantitative and precise information on the flow properties of biomolecular condensates. The technique uses optical tweezers to apply a force greater than the thermal force to beads embedded in the condensate, and calculates the complex and frequency-dependent spring constants of the droplets by measuring the distance of the particles and the force applied as a function of the frequency of oscillation.

✓ Suitable for systems that are too rigid to be studied by thermal fluctuations alone and where the passive tracer barely moves.

✓ Widely used to probe the response of a system to greater than thermal forces.

✓ Requires microscope setup with two independent and finely calibrated optical tweezers.

✓ Needs to produce large droplets (~10-20 μm) and spherical particles with large refractive indices that can be trapped in condensates.

✓ Can produce both surface tension and viscoelastic spectra in a single measurement.

Optical Trap Microrheology

To address the challenge of imaging particles for long periods of time, we offer optical trap microrheology to quantify the stiffness of biomolecular condensates by using optical tweezers to trap the particles and measure their thermally induced displacement.

✓ We have several post-processing, oversampling and optimization protocols for this technique.

✓ Up to 5-6 decimal viscoelastic spectra can be given from a single measurement.

CD BioSciences has cutting-edge passive and active microrheology to fully quantify the viscoelasticity of biomolecular condensates, providing you with quantitative information on the complete viscoelastic spectrum. If you have any special requirements for our services, please feel free to contact us. We are looking forward to working together with your attractive projects.