Ratiometric fluorescent calcium indicator dyes have been widely used for the study of the role of Ca2+ in cell physiopathology. Although these ratiometric dyes offer several advantages over others, they suffer some drawbacks which cause serious errors in measurement of intracellular Ca2+ concentration, [Ca2+]i. The present study systematically analyzes theoretical reasons and technical sources of discrepancies occurring in the measurement of the characteristics of the agonists-induced cells [Ca2+]i. In order to avoid the errors and achieve the accurate determination of [Ca2+]i, this study proposes solutions and suggests some critical measures in both theoretical and technical aspects. Therefore, this analysis can be a valuable tool in clarifying proper usages of fluorescent dyes for [Ca2+]i measurements.
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http://dx.doi.org/10.1016/j.jphotobiol.2004.11.003 | DOI Listing |
Anal Methods
January 2025
Jiangxi University of Chinese Medicine, Nan Chang, Jiangxi 330004, China.
This study reports a novel ratiometric fluorescence sensor based on a tetraphenylethylene-bipyridine covalent organic framework (TPE-Bpy-COF) for the sensitive detection of Cu, leveraging the unique coordination properties of the bipyridine moieties. The interaction between Cu and the nitrogen atoms in the bipyridine units induces fluorescence quenching at 500 nm through an efficient host-guest electron transfer mechanism, where excited-state electrons from the COF framework are transferred to the vacant orbitals of Cu. Upon excitation at 410 nm, the sensor exhibits a primary emission peak at 500 nm, which is quenched in the presence of Cu, while an overtone peak at 820 nm remains stable, serving as an internal reference for ratiometric measurements and significantly enhancing the accuracy and reliability of the sensor.
View Article and Find Full Text PDFPhotochem Photobiol Sci
January 2025
CNRS, Institut des Sciences Moléculaires d'Orsay, Université Paris-Saclay, 91405, Orsay, France.
The precise monitoring of pH is critical in various applications, particularly in biology-related areas. In this work, we report the synthesis and characterization of a novel cyanine-based fluorescent pH sensor with a pK around 6. This pH-sensitive dye features a cyanine chromophore coupled to a piperazine moiety, which modulates the protonation equilibrium and thus the optical response.
View Article and Find Full Text PDFAnal Chim Acta
February 2025
Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China. Electronic address:
Background: High-precision and broad-range pH detection is critical for health status assessment, such as signal transduction, enzyme activity, endocytosis, and cell proliferation and apoptosis. Although pH-responsive ratiometric fluorescent probes offer an effective pH monitoring strategy, their preparation often requires multi-step modification and decreases fluorescence efficiency and stability. Herein, we developed a simple method to prepare fluorescent Si dots with dual emission centers for high-precision and broad-range pH monitoring, and the detection of urease based on pH-responsive Si dots and pH monitoring in living cell was further explored.
View Article and Find Full Text PDFLuminescence
January 2025
Department of Psychiatry, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, China.
Two novel nitrogen hybrid fluorescent sensors based on the ESIPT mechanism were successfully synthesized for the detection of fluoride ions (F), and they exhibit high sensitivity and selectivity with a fast response. The detection limits even reach the parts per billion level. With the addition of F, both sensors showed a ratiometric fluorescence change with a large Stokes shift.
View Article and Find Full Text PDFMikrochim Acta
January 2025
Hebei Lansheng Bio-Tech Co, Ltd, Shijiazhuang, 052263, P. R. China.
A novel fluorescence sensing nanoplatform (CDs/AuNCs@ZIF-8) encapsulating carbon dots (CDs) and gold nanoclusters (AuNCs) within a zeolitic imidazolate framework-8 (ZIF-8) was developed for ratiometric detection of formaldehyde (FA) in the medium of hydroxylamine hydrochloride (NHOH·HCl). The nanoplatform exhibited pink fluorescence due to the aggregation-induced emission (AIE) effect of AuNCs and the internal filtration effect (IFE) between AuNCs and CDs. Upon reaction between NHOH·HCl and FA, a Schiff base formed via aldehyde-diamine condensation, releasing hydrochloric acid.
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