Membrane Proteins

Membrane protein characterisation - without purification
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What does FIDA bring to Membrane Protein research?


No clogging capillary based technology

  • Sturdy and robust capillary based open platform allows for creative biophysics
  • Capillaries can run with aggregated, unpurified material without clogging
  • Aggregation is measured and quantified

Interaction studies directly in cell lysate

  • Quick screening
  • Binding based on Rh and fluorescence
  • Detect both strong and weak binding

High resolution ensures certainty and reproducibility

  • Broad range pM to ability to mM
  • Autosampler removes pipetting variability and saves time

Short assay optimisation and validation

  • Dedicated Fidabio Assay Design tool
  • First principle methods
  • Built-in QC accelerates the optimisation process
  • Absolute readouts and structural correlation facilitate efficient and reliable data validation

Save sample material

  • 40 nl of sample
  • No purification needed – high tolerance toward impurities
  • No restriction on buffer composition
  • Delivers data needed to optimised membrane protein expression conditions and increase yield
  • Possible sample recovery

Tagged or label-free

  • Tag flexibility: GFPs, HIS, Alpha tag, FLAG and similar
  • Possibility of label-free characterisation of purified membrane protein

Quality parameters in 1 run

  • Assess structural changes
  • Validation of structures as against reference models using built-in FIDA PDB Correlator
  • Absolute size measurement
  • Polydispersity Index
  • Oligomeric state
  • Aggregation behaviour of the sample – quantified
  • Ligand-binding detection and Kd quantification

Temperature controlled – retain structure and function

  • Sample stored at 5°C while operating in walk-away mode
  • Independent temperature control in sample and capillary compartment

Efficient analysis and
rapid decision-making

With the ability to utilize sample volumes as low as 4μL (typically 10μL) for the analyte and 40 nL for the indicator, as well as the flexibility to operate directly in unpurified sample matrices, FIDA users can obtain a greater number of data points in a significantly reduced timeframe.

The users place unpurified samples in the autosampler’s 96 well plates or 2x50 vials, and after a few hours they are able to make an informed choice on which membrane protein to purify for further analysis.

Fast and easy – the FIDA way.

Down to
Indicator Use

Detergent screening for solubilisation – 85% faster

Save sample material

  • 10 to 100 times less sample volume in comparison to other technologies
  • 0.12 uL per detergent (for triplicates)
  • No restrictions on buffer compositions

Work with any detergent in any concentration

  • No clogging capillaries
  • Handle cell lysate unproblematically
  • Quantify aggregation
  • 50 nM detection sensitivity level (for GFP)

Measure absolute size and fluorescence

  • High resolution of hydrodynamic radius (0.5 to 500 nm)
  • BRIC – Binding Related Intensity Change
  • Two orthogonal readouts from one set of raw data provide a full picture

Perform upfront quality control – in a single run

  • Automatic QC ahead of in-depth analysis
  • Quantitative assessment of aggregation
  • Binding site functionality
  • Polydispersity index allows users to assess uniformity in solubilisation
  • Upfront detection improves user efficiency by eliminating suboptimal detergents

How does FIDA
accelerate detergent screening
for protein solubilisation?

FIDA users are able to shorten their experiment time by 85%, saving days’ worth of time. How? Thanks to FIDA’s walk-away autosampler and the ability to identify issues with stability, oligomeric states and binding site functionality early in the workflow.

1.5 ul




Sample Volume

12 Detergents

Experimental Time

12 Detergents


Keeps the cell lysate at 5°C while operating in walk-away mode
Quantitative detection of activation and binding in complex membrane constructs
Lower sample consumption
Speed to data
In-depth quality control
Informed troubleshooting


Triple temperature control
Quantification of aggregates
Quantification of solubilised membrane protein
Polydispersity index


Accurate determination of dilute phase concentration
Relative droplet size distributions
Kinetics of droplet formation and maturation into amyloid fibrils
Determination of binding affinity between the polypeptide undergoing LLPS and LLPS-modulating compounds

Targeting common Membrane Protein Research Challenges

Expression and purification
FIDA users can determine the in-solution concentration of membrane proteins. This allows them to optimise protein crystallisation conditions and to monitor protein expression and purification processes.

With just 0.12 uL per detergent (for triplicates) in detergent screening and down to 40nl of unpurified sample needed for characterisation, FIDA uses 10 to 100 less sample volume compared to other available technologies.
Stability and conformational heterogeneity.
Triple temperature control and possibility to work in unpurified matrices allows FIDA users to increase their level of control over membrane protein stability.
Functional characterisation
Working in crude matrices allows FIDA users to increase the applicability of their results. Additionally, the polydispersity index ensures that sample heterogeneity is considered in functional characterisation.
Structural characterisation
The size measurement delivered by FIDA allows our users to monitor changes as a result of interactions with other proteins or ligands. This information is then used to analyse the structure and function of membrane proteins of interest.

FIDA is currently used in cryo-EM sample preparation processes, as well as in nanobody clone selection. Our users can apply a single technology to characterise their membrane proteins, screen detergents, produce nanobodies to immobilise their membrane proteins and run cryo-EM sample preparation.
Effective drug development
FIDA measures the change in the size of the membrane protein complex when a ligand is bound, making it an optimal tool for evaluating protein-ligand interactions. This information allows FIDA users to identify potential ligands for drug discovery.

Do you need to cryo-scan your membrane proteins?

Read about the use of FIDA in CRYO-EM

This methodology is very sensitive and useful for assessing binding in a quantitative manner using small amounts of auto-fluorescent proteins. Using this method, we can observe clear changes in apparent hydrodynamic radius (Rh) and in fluorescence signal of EYA1 as a function of increasing concentrations of peptides or of small molecules

Dana Farber Institute

''Fida  Instrument provides a ''ruler'' to measure the length of fibrils''

Stefan Rüdiger Ph.D.
Professor of Protein Chemistry of Disease; Head of Department of Chemistry

''The FIDA is very effective for screening small molecules for solubility and interactions with protein targets. A major advantage has been its ability to clearly show drug binding to difficult-to-work-with targets such as intrinsically disordered proteins and amyloids''

Dr. Alexander Taylor
Research Fellow in Biochemistry/Biophysics

I would say that this instrument is quite useful for core facilities at KI or for Swedish research community in general:

  1. it was possible to measure unlabeled membrane proteins and soluble proteins at low concentrations in small volumes very fast (~6 minutes per measurement).
  2. I also like the temperature control and the autosampler which allowed us to run a lot of samples overnight.
  3. I would say that there is a lot of potential to perform other assays as well, such as the Kd determinations etc. (For this, I use ITC which is quite time-consuming and requires a lot of protein).
  4. In addition, the software and user interface for sample runs and data analysis is quite straightforward and intuitive to use.
Postdoctoral Researcher

"What we value about FIDA is the amount of information we can get from a tiny amount of protein in a single QC run. FIDA technology enables us to understand our proteins better - particularly when they behave in unexpected ways. We chose FIDA because it gives us that vital first result quickly - we don't waste our time optimising an assay that isn't going to work."

Duncan Smith
Lead Scientist

"I am convinced. I have never before been able to detect the ternary construct formation of my construct directly in cell lysate – it took less than two hours."

Thomas Smith
Associate Director, Chemical Biology & Therapeutics

"The Fida 1’s unique capability for measuring binding Kd from weak mM level to strong pM level really enhances our bioanalytical capabilities."

Sherry Zhu
Senior Scientist

"FIDA is an in-solution technique, and thus an ideal binding assay for structurally diverse bsAbs because the analysis does not rely on potentially obstructive surface immobilization and hence it is able to perform characterizations that are unbiased by bsAb format and spatial orientation of the binding domains."

Andreas V. Madsen
PhD Student

"After thorough comparisons, it was clear that the Fida 1, amongst others, presents unique opportunities in analysis of membrane proteins, which is essential to us."

Svend Kjæer
STP Deputy

''The Fida 1 system offers a new approach to detergent screening that has significant advantages allowing essential data to be obtained faster using less material (…) this work presents a new approach to characterize membrane proteins that allows users to reducing costs and time as well as to analyze protein expressed at low levels in a short time thus overcoming any stability issues.''

Isabel Moraes
Principal Research Scientist

"I like the ease of use and the straightforward data analysis and, that experiments can be performed in any type of buffers. We get data, where no other biophysical methods worked before."

Cathrine Birck
Head of Integrated Structural Biology Platform

"The method is easy to setup in any standard laboratory and can be adopted for a high throughput (HTTP) screening, which enabled mechanistic studies of RNA nuclease interactions, as well as efficient guide RNA lead discovery (…) Fida 1 offers straightforward assay development, walk away automation, absolute measurement and ultra low sample consumption."

Denny Truong
Principal Research Associate

"FIDA provides in-depth assessment of activity combined with local and global protein structural changes by measuring the overall hydrodynamic radius of the protein with minimal sample consumption. In addition, it is possible to measure the affinity constant for the analyzed interaction."

Dr. Melanie Hug
Research Associate

"The beauty of Fida 1 is that it allows us to conduct a lot of biophysical measurements in one system using a small amount of reagent and a rapid read-out time which is important for our projects and to our customers. (…) Providing a high-quality, protein characterisation QC package is certainly extending and future proofing our capabilities in biophysical characterisation of the proteins we produce."

Mark Abbott
Managing Director

"The Fida 1 has allowed us to assess the performance of MIPs with a much higher throughput than was previously possible on other platforms. MIPs can be developed in as little as 8 weeks, which is a significant improvement on antibodies, and now they can be fully characterized at an accelerated pace too."

Alan Thomson

"Fida 1 can be used for full characterization of ternary complex formation for targeted protein degradation. The Fida 1 platform only consumes 39 nL of sample for one measurement and thus allows elaborate condition screening using very small amounts of sample material."

Roman Agafonov
Associate Director of Biochemistry, Biophysics & Structural Biology

"The Fida1 is a very user-friendly system. With the Fida software we can quickly design new methods, set up experiments, and analyze data. By far this is a great instrument and technology that has allowed us to run binding assays for LNP in solution and with flexibility to run in any complex media which we were unable to do using traditional binding methods that required ligand immobilization. The FidaBio customer service is amazing, they are very knowledgeable and responsive whenever I run into issues and need assistance. I highly recommend this instrument for LNP or any other nanoparticle characterization. The system and technology are versatile with applications beyond nanoparticles and is a must in the biophysical tool kit."

Biophysical Analytical Department
Senior Scientist, Analytical Development

"Eventually, with FIDA, we managed to characterise our LNPs. And it was done in less than 2 days. We had for a long time been struggling with SPR."

Chemical Biology and Therapeutics
Associate Director

"We had been looking for ways of quantifying our exosomes, and tested many platform, without success. In less than 2 days FIDA had developed an assay and shown trustworthy quantifications directly in fermentation broth"

Rane Harrison
Director, Analytical Development

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