Fluorescent probes with high pKa values based on traditional, near-infrared rhodamine, and hemicyanine fluorophores for sensitive detection of lysosomal pH variations

Content Provider	Scilit
Author	Mazi, Wafa Adhikari, Rashmi Zhang, Yibin Xia, Shuai Fang, Mingxi Luck, Rudy L. Tajiri, Momoko Tiwari, Ashutosh Tanasova, Marina Liu, Haiying
Copyright Year	2019
Description	Journal: Methods Sterically hindered fluorescent probes (A-C) have been developed by introducing 2-aminophenylboronic acid pinacol ester to a traditional, A, a near-infrared rhodamine dye, B, and a near-infrared hemicyanine dye, C, forming closed spirolactam ring structures. Probe A was non-fluorescent under basic pH conditions whereas probes B and C were moderately fluorescent with fluorescence quantum yields of 9% and 5% in pH 7.4 PBS buffer containing 1% ethanol, respectively. With all probes increasing acidity leads to significant increases in fluorescence at 580 nm, 644 and 744 nm for probes A, B and C with fluorescence quantum yields of 26%, 21% and 10% in pH 4.5 PBS buffer containing 1% ethanol, respectively. Probes A, B and C were calculated to have $pK_{a}$ values of 5.81, 5.45 and 6.97. The difference in fluorescence under basic conditions is ascribed to easier opening of the closed spirolactam ring configurations due to significant steric hindrance between the 2-aminophenylboronic acid pinacol ester residue and an adjacent H atom in the xanthene derivative moiety in probe B or C. The probes show fast, reversible, selective and sensitive fluorescence responses to pH changes, and are capable of sensing lysosomal pH variations in living cells.
Related Links	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6851477/pdf
Ending Page	50
Page Count	11
Starting Page	40
ISSN	10462023
e-ISSN	10959130
DOI	10.1016/j.ymeth.2019.07.012
Journal	Methods
Volume Number	168
Language	English
Publisher	Elsevier BV
Publisher Date	2019-07-22
Access Restriction	Open
Subject Keyword	Fluorescent Probes Near-infrared Fluorescence Fluorescence Imaging
Content Type	Text
Resource Type	Article
Subject	Molecular Biology