ortho-Chlorination of phenoxy 1,2-dioxetane yields superior chemiluminescent probes for in vitro and in vivo imaging

• Published in: Organic & biomolecular chemistry Vol. 16; no. 10; pp. 1708 - 1712
• Main Authors: Eilon-Shaffer, Tal, Roth-Konforti, Michal, Eldar-Boock, Anat, Satchi-Fainaro, Ronit, Shabat, Doron
• Format: Journal Article
• Language: English
• Published: CAMBRIDGE Royal Soc Chemistry 2018; Royal Society of Chemistry
• Subjects: Animals; beta-Galactosidase - analysis; Cancer; Cell Line, Tumor; Chemiluminescence; Chemistry; Chemistry, Organic; Emission; Galactosidase; Halogenation; Heterocyclic Compounds - chemical synthesis; Heterocyclic Compounds - chemistry; Humans; Imaging techniques; In vivo methods and tests; Luminescence; Luminescent Agents - chemical synthesis; Luminescent Agents - chemistry; Luminescent Measurements - methods; Mice; Mice, Inbred BALB C; Neoplasms - enzymology; Optical Imaging - methods; Physical Sciences; Probes; Science & Technology; β-Galactosidase; CATALYZED CHEMILUMINESCENCE; SUBSTITUTED DIOXETANE; ALKALINE-PHOSPHATASE; CHEMISTRY; MYELOPEROXIDASE ACTIVITY; BIOLUMINESCENCE; PEPTIDE
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/c8ob00087e

A recent methodology, developed by our group, has enabled a dramatic improvement in the emissive nature of the excited species, formed during the chemiexcitation of dioxetanes under physiological conditions. This approach has resulted in the discovery of distinct phenoxy-dioxetane luminophores that produce a chemiluminescence signal via a direct-mode of emission. Here, we show a significant pK(a) effect of our new phenoxy-dioxetanes on their chemiexcitation and on their ability to serve as chemiluminescent turn-ON probes for biological applications. Using an appropriate phenoxy-dioxetane probe with a direct-mode of emission, we were able to image beta-galactosidase activity, in cancer cells and in tumor-bearing mice. To the best of our knowledge, this is the first example to demonstrate in vitro and in vivo endogenous enzymatic chemiluminescence images obtained by a single-component phenoxy-dioxetane probe. We anticipate that our strategy, for the design and synthesis of such distinct luminophores, will assist in providing new effective turn-ON probes for non-invasive intravital chemiluminescence imaging techniques.