Laboratory for Analytical Chemistry

Citterio Laboratory


Innovation of Chemical Sensors

Keio University

Faculty of Science and Technology

Department of Applied Chemistry

Fluorescent / Luminescent Functional Dyes


Fluorescent, chemiluminescent and bioluminescent organic functional dyes are widely used molecular tools in (bio)analytical chemistry. Our research work in this field is particularly focused on the development of new intensely emitting dyes and on the extension of the available wavelength range into the near-infrared (NIR) region.


Brightly fluorescent dyes

One example are the so-called "Keio Fluorophores" (KFL-series). These dyes, derived from the borondipyrromethene (BODIPY) structure, show high extinction coefficients and high fluorescence quantum yields, making them very bright fluorophores with narrow emission spectra and high photostability. In addition, fine tuning of substituents has resulted in a family of dyes spanning a large wavelength range from the visible (550 nm) into the near-infrared (NIR) (740 nm). To demonstrate the applicability to cellular imaging, a conjugate of a KFL fluorophore and a calcium ion binding site was successfully used for the visualization of intracellular calcium in a fluorescence turn-on manner in the far-red spectral region. KFL-dyes have also been converted into molecular cassettes showing bright fluorescence emission excitable at a single wavelength.


Chemiluminescent dyes with enhanced optical properties

In order to expand the applicability of chemiluminescent dyes, a BODIPY fluorophore has been directly linked to a chemiluminescent subunit, resulting in enhanced luminescence at longer wavelength compared to the parent compound.


In Vivo Imaging Probes with Genetically Expressed Tags

Cells have been successfully labeled with fluorophores and with magnetic resonance imaging (MRI) probes by covalent linkage of specifically designed probe molecules to genetically expressed protein tags.


Other examples

Other developments of functional dyes include a variety of fluoroionophores for optical chemical sensors as well as solvatochromic fluorescent probes, among others.


For specific information, please refer to our list of publications.



Citterio Laboratory 2019

Last update: January 12, 2019