EI-FLEX Pro
Single-Molecule Fluorescence Spectroscopy

EI-FLEX Pro

See every molecule. Reveal what ensemble methods hide. Your benchtop just got Exciting.

smFRET
Freely Diffusing FRET
FCS / FCCS
Correlation Spectroscopy
384-Well
High-Throughput Ready
< 1 Hour
Sample to Insight
The Challenge

You're making decisions on averages, but your molecules aren't average.

Ensemble methods blur the detail. They average out the rare conformations, transient states and molecular subpopulations that drive your biology. You deserve to see what's really happening.

The EI-FLEX Pro is a confocal benchtop system that reveals single-molecule behaviour in free solution — no surface immobilisation, no darkroom, no PhD in optics required. Just pipette, measure and discover.

0
Research groups exploring with us
0
Countries making discoveries
0
Publications and counting
0
From unboxing to first data
Why EI-FLEX Pro

Explore more. Faster. With less faff.

01

Single-molecule clarity

Resolve hidden heterogeneity and rare conformations that ensemble averages miss. See what's really going on — one molecule at a time.

02

Your bench, your data

No darkroom. No optical table. No specialist training. Plug in, pipette, and start collecting publication-ready data before lunch.

03

We're with you

Our team of single-molecule specialists will help you design experiments, run proof-of-concept samples, and get the most from your EI-FLEX Pro.

04

Scale when you're ready

Start with coverslips. Upgrade to 96 or 384-well plates when throughput matters. One platform that grows with your research.

What Can You Do With It?

Whatever you're studying, we'll help you see it clearly

Every application below runs on a single EI-FLEX Pro. No swapping instruments, no re-training. Just different questions, same platform.

🔗

Ternary complex characterisation

PROTACs and molecular glues need stable ternary complexes to work, but ensemble methods can't tell you if one actually formed — or how long it lasts.

The EI-FLEX Pro detects ternary complex formation at single-molecule resolution in free solution, giving you binding stoichiometry, stability and kinetics in a single experiment.

smFRET · FCCS
🌀

Conformational dynamics

Your protein exists in multiple states. Ensemble averages hide them. You need to see each conformation and how they interconvert.

Freely diffusing smFRET reveals distinct conformational populations, their relative proportions, and transition rates — without surface artefacts.

smFRET-ALEX
🎯

Antibody–target engagement

You need to know if your antibody binds, how tightly, and whether it changes the target's conformation — all with minimal sample.

FCS and FCCS measure binding affinity and co-diffusion at picomolar concentrations. Add smFRET to see conformational consequences of binding.

FCS · FCCS · smFRET
🧬

Protein–nucleic acid interactions

DNA/RNA-binding proteins are central to gene regulation, but you can't study their dynamics with gels and blots.

Measure binding, unbinding and conformational rearrangements of protein–nucleic acid complexes in real time with smFRET and burst analysis.

smFRET · BURST SEARCH

Protein aggregation & oligomerisation

Aggregation is a dealbreaker for biologics — but early-stage oligomers are invisible to DLS and SEC.

FCS detects changes in diffusion time as monomers assemble into oligomers, catching aggregation events that bulk methods miss entirely.

FCS · FCCS
🔬

Structural dynamics & drug mechanism

Your drug candidate binds, but does it lock the target in the right state? You need structural context, not just a binding curve.

smFRET with ALEX excitation maps distance changes across labelling sites, revealing how drug binding reshapes the conformational landscape.

smFRET-ALEX
The Exciting Ecosystem

One stack from label design to discovery

Most instruments solve one step. We built a platform that connects all of them — so you spend less time stitching workflows together and more time doing science.

01 — DESIGN

Choose where to label

Our tools and team help you identify optimal labelling positions — maximising signal without disrupting your molecule's native behaviour.

LABEL DESIGN
02 — PREPARE

Express labelled constructs

From dye selection to conjugation strategy, we'll guide you through sample preparation that works first time — or run it for you.

SAMPLE PREP
03 — MEASURE

Capture every molecule

The EI-FLEX Pro does the heavy lifting. Confocal detection, automated acquisition, and real-time single-molecule sensitivity — all on your benchtop.

EI-FLEX PRO
04 — DISCOVER

Analyse and publish

Integrated software takes you from raw photons to publication-ready figures. FRET histograms, FCS curves, burst analysis — no third-party tools required.

INTEGRATED SOFTWARE
Software

Designed for scientists, not software engineers

Acquisition, laser control, FCS analysis and smFRET burst search — all in one place, all intuitive.

Acquisition
Lasers
FCS Analysis
smFRET ALEX
Burst Search
Example Data

What your data could look like tomorrow

Real outputs from the EI-FLEX Pro. No post-processing, no external software. Just clear, Exciting results.

smFRET Efficiency Histogram

Two distinct conformational populations, resolved beautifully at the single-molecule level using ALEX excitation.

TECHNIQUE: smFRET-ALEX

FCS Autocorrelation Curve

Diffusion times and binding kinetics extracted directly from fluorescence fluctuations. Clean curves, real insight.

TECHNIQUE: FCS

Burst Analysis Scatter

Every dot is a molecule. Individual photon bursts identified, classified and ready for your next figure.

TECHNIQUE: BURST SEARCH
Trusted by Exciting researchers at
University of Warwick Johns Hopkins University McMaster University Universität Basel University at Albany UMass Chan Medical School Lawrence Livermore National Laboratory Saint Louis University University of Iowa University of York University of Warwick Johns Hopkins University McMaster University Universität Basel University at Albany UMass Chan Medical School Lawrence Livermore National Laboratory Saint Louis University University of Iowa University of York
From Our Community

Don't take our word for it

"What sets EI-FLEX apart is its versatility — it's our go-to for probing kinetics and conformational changes that other systems can't fully resolve."

Dr. Steven Quinn
Dr. Steven Quinn
University of York

"Solution-based measurements avoid surface tethering artefacts. You label, dilute, and measure — results in minutes rather than days with TIRF systems."

Assoc. Prof. Kuang Shen
Assoc. Prof. Kuang Shen
UMass Chan Medical School

"It has opened up new avenues of research because of the combined FCS, FCCS and single-molecule FRET capabilities. A game-changer for us."

Prof. Edwin Antony
Prof. Edwin Antony
Saint Louis University
Case Study

Three weeks became one hour

When Dr. Quinn's group switched from TIRF, everything changed. Here's what happened.

RESULT
93%
less time per experiment

"We used to spend three weeks on a single TIRF-based smFRET dataset — surface prep, alignment, troubleshooting. With the EI-FLEX Pro, we go from labelled sample to a complete FRET histogram in under an hour. It's fundamentally changed how we design experiments."

Dr. Steven Quinn
Principal Investigator, University of York
3 weeks → 1 hour
Time saved
No darkroom
Setup needed
Nature (2024)
Where it ended up
How It Works

Three steps. One Exciting result.

No darkroom. No alignment nightmares. Just great science, faster.

💧
STEP 01

Pipette your sample

Add your labelled sample to a well plate or coverslip. Picomolar concentrations, microlitre volumes — so even your most precious preps go further.

~2 minutes
📡
STEP 02

Hit acquire

The software guides you through setup and runs the measurement. Single molecules, detected one at a time, as they move freely in solution. No alignment, no tweaking.

10–30 minutes
📊
STEP 03

Discover & publish

Your results are ready the moment acquisition ends — histograms, correlation curves, burst analysis, all built in and figure-ready. From sample to insight in an afternoon.

Instant
Got Questions?

We've got answers

Fast. Most researchers collect publication-quality data within their first hour. Our software walks you through everything from laser setup to analysis, and we include hands-on onboarding with our applications team as standard. You'll be an expert before your coffee goes cold.
Very little. The EI-FLEX Pro works at picomolar to nanomolar concentrations in just 20–50 µL per measurement. That means even your most precious preps are fair game — no more choosing between running the experiment and saving sample for later.
Nope. The EI-FLEX Pro is fully enclosed and sits happily on a standard lab bench. No darkroom, no optical table, no vibration isolation. Just find a spot, plug in, and start measuring. Your lab manager will thank you.
Absolutely. The EI-FLEX Pro's modular design means you can upgrade to 96-well and 384-well plate formats whenever you're ready. It's a hardware upgrade that slots in seamlessly — no retraining, no new software, no starting over.
The EI-FLEX Pro is a versatile single platform for freely-diffusing smFRET with ALEX excitation, FCS, FCCS, and burst analysis. All techniques share integrated acquisition and analysis software, so you can switch between methods without switching tools.
You get us. That means experimental design advice from genuine single-molecule experts, proof-of-concept sample runs, remote and on-site support, and ongoing software updates. We're scientists too — we want your experiments to work as much as you do.
Ready to Explore?

Your molecules are doing something Exciting. Let's find out what.

Book a live demo with our team, or send us your sample — we'll run a proof-of-concept measurement for free.

EI-FLEX Pro — see every molecule, on your benchtop
Our ecosystem Get in Touch