A transfection-free solution to image the full endoplasmic reticulum within minutes



BrightER is a selective, cell-permeable endoplasmic reticulum probe conjugated to a bright photostable rhodamine dye. Just dilute and drip 10µL per mL of cell culture medium and you immediately visualize the endoplasmic reticulum (ER) structure up to the nucleus in live cell experiments. So far, all experiments ended up with full ER structure images.

A technology designed by Raphaël Gaudin and Yonis Bare




Stain your most recalcitrant cells and preserve your cell physiology


Image as long as you want, keep growing your cells, and repeat. No need to wash out!

ER specific 

Staining of the entire ER in continuity with the nuclear membrane  


No need for complicated resuspension. Simply add BrightER to your culture medium and image within minutes 


Compatible with both human and non-human cell types 


Get a bright and homogeneous signal, suitable for low laser intensity imaging 


Seed & grow 

your cells

Add BrightER

directly to your full culture medium


Technical information

Read the Safety Datasheet.

Detection method
: Fluorescent 
Wavelength range
: Ex:557/Em:576. 
Dye type:
For use with:
Confocal microscopes
SubCellular localization:
Endoplasmic reticulum

up to 4 months at -20°C

Absorption (dotted line) and emission (solid line) spectrum of BrightER
Image obtained on Fluorescence SpectraViewer (Thermo Fisher Scientific)

live imaging of ER morphological features and dynamic processes such as membrane contact sites, intracellular trafficking, secretory pathways, viral infections, translation, protein folding and unfolded protein response (UPR), nuclear envelop formation upon mitosis, cellular calcium regulation and many others.

Tested and validated on (cell types): HeLa, U-2 OS (human osteosarcoma), SVG-A (human astrocytes), SUM159 (human breast cancer cells), Vero E6 (monkey kidney epithelial cells).

Suggestions for use: The BrightER dye may be added directly in full media. In most cases, a final 50µM concentration is sufficient for immediate and bright ER staining; however, optimization may be needed for some cell types, conditions, and applications. BrightER is detected through standard TRITC and DsRed filters.

1 kit includes: 
- One vial of 100µL BrightER 5mM in DMSO+PEG solution.

One BrightER kit is sufficient to prepare 10 mL of final imaging medium when used at the recommended 50 µM concentration.

Green probe

We do understand that each assay goes with specific imaging requirements, and we are willing to suit your experimental preferences as much as possible. Therefore, our team is currently working on expanding the panel of colors available by developing a green BrightER version. 



Raphaël Gaudin and Yonis Bare

Our team has a long-standing interest in studying the spatiotemporal dynamics of viral infections. To this end, we develop tools to characterize how viruses penetrate into cells and reach their replication site, and engineer antiviral strategies to inhibit those steps. One day, we serendipitously noticed that one of the fluorescent molecules we had synthesized was unable to impact viral infection, but specifically localized on the endoplasmic reticulum. We decided to explore this further. Experiments indicated that this molecule was indeed a very good ER marker. It did not show apparent side effect on the cells: good cell viability, “normal” ER shape, no impact on secretory function.

When we met Aurelien Pasturel from Idylle, we realized that we could share it with the community of biologists interested in ER morphologies and functions. We were really tempted by this new adventure, and here we are!"

"The first time I went to Montpellier to talk to an audience of innovative researchers about our technology transfer solution, Raphaël took the opportunity to arrange a meeting. He came to see me the day following the presentation with a whole bunch of projects under his belt. Our exchanges led us to his surprising discovery of an excellent fluorescent probe specific of the endoplasmic reticulum while working on a marked anti-viral. A beautiful story of serendipity that marked the beginning of our collaboration.".

Aurelien Pasturel
New projects, Idylle

Combining BrightER

You may also like to combine BrightER with these R&D products


Combine them together to make live imaging of ER dynamics in response to compression


Use them both to make live imaging of ER localization/remodeling in cell migration

Contact us about your ER-tracking needs!