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Fluorescent Proteins: In Vivo Imaging


In vivo imaging is a powerful tool used to study individual plasmids or protein-protein interactions in deep-tissue organs and whole mammals. Genetically encoded fluorescent probes are suitable for stable imaging of protein interactions in living cells and live mice. Proteins for in vivo imaging have emission near or above 650 nm as signals below 650 nm are highly absorbed by hemoglobin and cause undesirable background signals.

Near-infrared fluorescent proteins for in vivo imaging are derived from bacterial phytochrome photoreceptors (BphPs). Spectrally distinct permanently fluorescent iRFP variants have been shown to have high effective brightness and allow for single or multicolor imaging. Photo-activatable iRFPs can be ‘turned on’ by non-phototoxic far-red light and are used for spatially selective imaging of tissues in living animals. Further development of the original iRFP has resulted in a split fluorescence complementation probe used for detecting protein-protein interactions in vitro and in vivo.

Learn more about in vivo imaging tools in this blog post - In Living Color: The Skinny on In Vivo Imaging Tools.

The following far red, near-infrared, and photoactivatable fluorescent empty backbone plasmids are ideal for single or multicolor in vivo imaging.

Plasmids for In Vivo Imaging

Far Red

Protein Excitation/Emission Brightness Find Plasmids
mCardinal 604/659 18 All mCardinal plasmids from article
mNeptune 600/650 13.4 pcDNA3-mNeptune-N
E2-Crimson 611/646 28.98 pEF.myc.ER-E2-Crimson


Protein Excitation/Emission Brightness Find Plasmids
iRFP670 643/670 12.7 piRFP670-N1
miRFP670 642/670 12 pmiRFP670-N1
iRFP682 663/682 10.2 piRFP682-N1
iRFP702 673/702 7.6 piRFP702-N1
miRFP703 673/703 8 pmiRFP703-N1
miRFP709 683/709 4 pmiRFP709-N1
iRFP (aka iRFP713) 690/713 6.2 piRFP
iRFP720 702/720 5.8 piRFP720-N1
iSplit 690/713 5.3 pPAS-E and pK-GAFm


Protein Excitation/Emission Brightness Find Plasmids
PAiRFP1 690/717 (after photoactivation) 3.2 pPAiRFP1-N1
PAiRFP2 692/719 (after photoactivation) 3.0 pPAiRFP2-N1

Do you have suggestions for other plasmids that should be added to this list?

Fill out our Suggest a Plasmid form or e-mail [email protected] to help us improve this resource!