Introducing Fluidity One

In-solution sizing and quantification of native protein in 8 minutes

  • 100% in solution

    Samples are analysed in solution under near-native conditions, providing the most accurate method for characterising proteins.

  • No labels

    Measurement is performed label free on native protein, eliminating the risk that a label could affect the property or behaviour of your protein.

  • Small peptides to aggregates

    A detection range of 0.3 to 20 nm (0.1 KDa to 9 MDa) allows you to characterise any protein or protein complex.

  • Rapid results with less

    Requiring just 5 μL of sample, and with measurements in as little as 8 minutes, the Fluidity One allows you to run more experiments and collect more data

  • Eliminate contamination risk

    Disposable chips eliminate risk of contamination and mean there’s no need for time-consuming wash cycles.

  • Measure size changes directly

    Changes in size or conformation caused by misfolding, aggregation, oligomerisation or interactions can be measured directly.


A growing range of applications using Microfluidic Diffusional Sizing

In-solution protein sizing

Knowledge of a protein’s size can provide insights on how it is folded, whether it has been expressed in a full length or truncated form, if it is in an active or inactive conformation, whether it is monomeric or oligomeric or indeed whether it is in complex with additional proteins or biomolecules.

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Protein quality analysis

Poor quality protein samples can result in low quality data and wasted time in downstream applications. The speed, low sample requirement and minimal sample prep required by the Fluidity One make it the perfect tool for routine protein prep quality analysis.

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Study of protein aggregation

The study of the mechanisms of protein aggregation is of central importance to understanding fundamental biological processes such as protein assembly and turnover, as well as pathologies that are characterised by the presence of protein aggregates - such as Parkinson’s and Alzheimer’s disease. With the Fluidity One you can assess the formation of aggregates directly, without the use of labels.

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Monitoring protein-protein interactions in solution

Understanding of a protein’s function is in many cases gained through an awareness of what it interacts with, with what affinity and at what time. Monitoring protein-protein interactions (PPIs) therefore can provide deep insights into everything from basic biology to the mechanisms of disease. The Fluidity One can provide insights into PPIs in solution.

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Do you have an application in mind?

If you think our technology could advance your research we'd love to hear how.

How does the Fluidity One work?

The rate of diffusion of a particle is inversely proportional to its hydrodynamic radius – a relationship that is described by the Stokes-Einstein equation. The Fluidity One exploits this by measuring the rate of diffusion of proteins under steady state laminar flow in a microfluidic system.

To achieve steady state laminar flow, the Fluidity One uses a microfluidic system in which micro-litre volumes do not mix convectively. Consequently when a protein sample and analyte solution are run as adjacent (non-mixing) streams, the only way protein can migrate into the analyte stream is by diffusion – at a rate that is inversely proportionate to its size. This is the measurement step in the Fluidity One system, and occurs without labelling in the diffusion chamber of the chips.

Following measurement, the streams are split and a latent, fluorogenic dye is introduced to label the protein and enable detection. Fluorescence intensity in both streams is then measured, the total of which is used to determine concentration of protein, and the ratio of which can be used to determine the diffusion coefficient, and consequently the hydrodynamic radius.

Want to see it for yourself?

If you're interested to see how the Fluidity One could help your research, we're happy to talk about your work and arrange a demonstration on your site.

*sample dependent **predicted 


Size determination MDS DLS TDA

Size Measurement

Various proteins of different sizes measured by the Fluidity One, DLS and TDA (Viscosizer) with Hydrodynamic Radius reported.

The Fluidity One readings were taken in solution and required just 5 µL of sample.

See further details on the full application note here.

Accuracy at low concentrations

The size of BSA was measured by the Fluidity One along with DLS and TDA at various dilutions.

We find that the Fluidity One can provide reliable sizing down to far lower concentrations than other methods.

See the full experimental data on our application note here.

Size determination of BSA at varying concentrations MDS DLS TDA


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If you have any questions about the Fluidity One, get in touch - our friendly team are always happy to help.

Fluidic Analytics is changing how proteins are characterised

We're doing this with novel, cutting edge technology and a fantastic, committed team

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