PEGylated Red-Emitting Calcium Probe with Improved Sensing Properties for Neuroscience.

Fiche publication

Date publication

novembre 2017

Journal

ACS sensors

Auteurs

Membres identifiés du Cancéropôle Est :
Dr KLYMCHENKO Andrey

Tous les auteurs :
Ponsot F, Shen W, Ashokkumar P, Audinat E, Klymchenko AS, Collot M

Lien Pubmed

https://www.ncbi.nlm.nih.gov/pubmed/29019233

Résumé

Monitoring calcium concentration in the cytosol is of main importance as this ion drives many biological cascades within the cell. To this end, molecular calcium probes are widely used. Most of them, especially the red emitting probes, suffer from nonspecific interactions with inner membranes due to the hydrophobic nature of their fluorophore. To circumvent this issue, calcium probes conjugated to dextran can be used to enhance the hydrophilicity and reduce the nonspecific interaction and compartmentalization. However, dextran conjugates also feature important drawbacks including lower affinity, lower dynamic range, and slow diffusion. Herein, we combined the advantage of molecular probes and dextran conjugate without their drawbacks by designing a new red emitting turn-on calcium probe based on PET quenching, Rhod-PEG, in which the rhodamine fluorophore bears four PEG units. This modification led to a high affinity calcium probe (K = 748 nM) with reduced nonspecific interactions, enhanced photostability, two-photon absorbance, and brightness compared to the commercially available Rhod-2. After spectral characterizations, we showed that Rhod-PEG quickly and efficiently diffused through the dendrites of pyramidal neurons with an enhanced sensitivity (ΔF/F) at shorter time after patching compared to Rhod-2.