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OHSU # 2956 — Cell-permeant and water-soluble rhodamine dyes for quantitative imaging applications


Rhodamines are a class of fluorescent proteins (FP) that stand out for their higher photostability and brightness as well as easier synthesis compared to other FPs; however, classic rhodamines generally have poor water solubility and tend to aggregate in an aqueous environment. Oregon Health & Science University researchers have developed a water-soluble and cell-permeant rhodamine dye for improved quantitative imaging.

Technology Overview

Fluorescent proteins have become common optogenetic tools for investigating cell structures, functions, and underlying mechanisms of subcellular events. However, classic small molecule fluorophores often suffer from either poor water solubility or cell-impermeant issues, providing roadblocks for in vitro and in vivo optical imaging applications. OHSU researcher Dr. Summer Gibbs and colleagues have developed zwitterionic rhodamine fluorophores, which demonstrate several advantages over existing rhodamines and FPs:

  • Water permeable, thereby improving utility for applications that require aqueous environments, such as antibody conjugation and in vivo imaging.
  • Cell permeable, allowing for targeting of both intracellular and extracellular targets.
  • Lack of on-off equilibrium switching, providing improved utility for quantitative fluorescence imaging applications such as drug uptake and cellular distribution studies.

These fluorophores have significantly improved optical properties for both in vitro and in vivo studies and represent a powerful new fluorescent dye for research and diagnostic purposes.


Wang et al., OregonFluor enables quantitative intracellular paired agent imaging to assess drug target availability in live cells and tissues. Nat Chem. 2023 May;15(5):729-739. Link

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Published United States WO 2022/076586
Published United States US 2023/0287217 A1
Published European Patent Convention 4225122 A0