Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging are well-established techniques to acquire diverse molecular information, while their potential applications remain limited due to low sensitivity. Photochemically induced dynamic nuclear polarization (photo-CIDNP) is one of the promising methods to solve this issue, and numerous studies have been conducted to understand its physical mechanism using a particular combination of a dye and a quencher of interest. However, the research across multiple dye-quencher combinations remains largely unexplored. Here, we explore plenty of dye-quencher combinations and reveal that not only the electron transfer process but also the optimal value of the g-value difference (Δg), considerably affected by the escape process of a radical pair, plays a key role in maximizing the enhancement of the NMR signal by photo-CIDNP. The combinations of 115 quenchers with several dyes were experimentally investigated, and 36 photo-CIDNP active quenchers were revealed. Exploration of many different dye-quencher combinations with four dyes revealed that molecular diffusion significantly affects the Δg dependence of photo-CIDNP enhancement of each dye. These findings provide important insights into pioneering new dye-quencher combinations suitable for biological and medical applications.
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http://dx.doi.org/10.1063/5.0253296 | DOI Listing |
J Chem Phys
March 2025
Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku 819-0395, Fukuoka, Japan.
Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging are well-established techniques to acquire diverse molecular information, while their potential applications remain limited due to low sensitivity. Photochemically induced dynamic nuclear polarization (photo-CIDNP) is one of the promising methods to solve this issue, and numerous studies have been conducted to understand its physical mechanism using a particular combination of a dye and a quencher of interest. However, the research across multiple dye-quencher combinations remains largely unexplored.
View Article and Find Full Text PDFMethods Appl Fluoresc
July 2022
Radiation & Photochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India.
Molecular interactions are fundamental to any chemical or biological processes, and their rates define the operational sequence and control for any desirable product. Here, we deliberate on a recently developed novel fluorescence spectroscopic method, which combines fluorescence photon anti-bunching, photon bunching, time-correlated single-photon counting (TCSPC), and steady-state fluorescence spectroscopy, to study composite chemical reactions with single molecule sensitivity. The proposed method captures the full picture of the multifaceted quenching kinetics, which involves static quenching by ground state complexation and collisional quenching in the excited state under dynamic exchange of fluorophore in a heterogeneous media, and which cannot be seen by steady-state or lifetime measurements alone.
View Article and Find Full Text PDFBioconjug Chem
June 2022
Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093. United States.
Nucleic acids are well-established biomarkers of cancer with immense value in diagnostics and basic research. However, strategies to monitor these species in tissue can be challenging due to the need for amplification of imaging signal from low analyte concentrations with high specificity. Photoacoustic (PA) imaging is gaining traction for molecular imaging of proteins, small biomolecules, and nucleic acids by coupling pulsed near-infrared (NIR) excitation with broadband acoustic detection.
View Article and Find Full Text PDFMethods Mol Biol
December 2020
Skolkovo Institute of Science and Technology, Moscow, Russia.
Accurate monitoring of low levels of viral load (the number of viral particles per milliliter of plasma) in HIV-infected patients is important in terms of evaluation of the progress of antiretroviral therapy. The general approach for detection of low copy HIV RNA is reverse transcription combined with quantitative real-time PCR based on fluorescence detection. The selection of primers and the structure of fluorogenic oligonucleotide probes are crucial for sensitivity and accuracy of the assay.
View Article and Find Full Text PDFChem Sci
September 2017
Department of Chemistry , Tunghai University, Taichung 407 , Taiwan . Email:
The family of microRNAs (miRNAs) not only plays an important role in gene regulation but is also useful for the diagnosis of diseases. A reliable method with high sensitivity may allow researchers to detect slight fluctuations in ultra-trace amounts of miRNA. In this study, we propose a sensitive imaging method for the direct probing of miR-10b (miR-10b-3p, also called miR-10b*) and its target ( mRNA) in fixed cells based on the specific recognition of molecular beacons combined with highly inclined and laminated optical sheet (HILO) fluorescence microscopy.
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