Fluidity ONE-M enables quantification and characterisation of protein interactions in complex backgrounds or with challenging targets.


Fluidity ONE-M enables quantification and characterisation of protein interactions in complex backgrounds or with challenging targets.

Manufacturer Fluidic Analytics
Product Series Fluidity One
Measurement principle Microfluidic Diffusional Sizing (MDS)
Application Biomolecular Interactions, Nano Particle Size, Protein Conformation, Protein Interactions & Binding Affinity
Size range (hydrodynamic radius)1 - 20 nm
Molecular Weight range1.4 kDa - 14 MDa
Sample requirement3.5 µL
Sensitivity100 pM Alexa Fluor™ 488 and Alexa Fluor™ 647

Product Overview

The Fluidity ONE-M enables the quantification of protein interactions in complex backgrounds such as biological systems or serum.

Using proprietary Microfluidic Diffusional Sizing (MDS) technology, which is based on the relationship between size and diffusion rate, the Fluidity ONE-M can determine the binding affinity (KD) as well as the hydrodynamic radius or molecular size (Rh), concentration and Stoichiometry from a single experiment. 

Within one hour, binding affinity, concentration and stoichiometry measurements can occur directly in serum, eliminating time-consuming purification steps and increasing sensitivity by minimising risk of dilution effects.

This unique combination of information can help scientists determine how strongly proteins are binding, how many protein molecules are binding at a time and whether the protein is binding to its target or to something unexpected. MDS is used to determine the binding affinity between proteins and their binding partners; whether they are aptamers, lipids, DNA, small molecules or other proteins.

Contact us to discuss options for using MDS with your own samples, or select from standard assays already available. These include: Affinity and concentration determination (SARS-CoV-2 variants, SARS CoV-1, other coronaviruses); Rapid affinity-based virus neutralisation assay and Protein labelling.

  • Applications



  • Uses microfluidic diffusional sizing (MDS) technology to measure changes in molecular size(hydrodynamic radius) as binding events occur
  • Molecular size, KD, concentration and stoichiometry from a single experiment, under physiologically-relevant conditions
  • Enables development of customised protocols to study a wide range of interactions –typical run time 35 minutes for 24 data points to determine KD
  • Eliminates the risk of binding artefacts or other surface constraints – measure directly in solution –no surface immobilisation
  • Minimises consumption of precious samples 3.5 μL per data point (application dependent), 50-80 μL to determine KD


  • Characterise polyclonal antibodies
  • Track functional immune response in serum samples
  • Reveal therapeutic antibody / protein interaction mechanisms
  • Characterise disordered proteins or higher-order complexes under close to in vivo conditions
  • Explore aggregation effects and distinguish between specific and non-specific binding
  • Study interactions with antigens or other proteins, DNA or lipids

Product Enquiry


If you would like to enquire about this product, fill out this form and one of our product specialists will contact you shortly.
If you need help in the operation or repair of an instrument then please contact the Customer Help Centre directly.

Please note, product enquiries are only applicable to Australia, New Zealand, Papua New Guinea and Fiji

    Or call us instead at (02) 9541 3500