Rational design of near-infrared fluorescent probes for superoxide anion radical: Enhancement of self-stability and sensitivity by self-immolative linker

Strategy for Fluorescence/Photoacoustic Signal Maximization Using Dual-Wavelength-Independent Excitation

“…Because of the nucleophilic reaction between trifluoromethanesulfonate and superoxide anions, we decided to integrate QHD with trifluoromethanesulfonate as the probe QLX . As shown in Figure A, the superoxide anions may attack the SO bond of QLX causing it to gradually undergo electron transfer, which could then eventually break back into QHD for the purpose of deprotection. , Subsequently, we performed structural optimization and frontier orbitals analysis for QHD and QLX , respectively, by using DFT calculations. As shown in Figure S3, the energy gap of QLX is larger than that of QHD , which indicates that the absorption and fluorescence wavelength of QLX will be blue-shifted.…”

Harnessing Electron Spin Hyperpolarization in Chromophore–Radical Spin Probes for Subcellular Resolution in Electron Paramagnetic Resonance Imaging: Concept and Feasibility

“…However, a significant shortcoming of the EPRI technique is its poor spatial resolution (>10 μm) , for samples under ambient conditions, which seriously hampers obtaining subcellular information via EPRI. In this regard, it is worth noting that ROS, which is paramagnetic and can be detected via EPR (using suitable spin traps), is often detected by optical techniques primarily because of the latter’s ability to provide subcellular information. − However, optical techniques do not provide a fingerprint of the radical that is being trapped. Furthermore, fluorescent probes, used for their optical detection, are often nonselective, and hence such methods are prone to giving false signals. ,, Thus, given that EPR is the most direct and unambiguous probe to image paramagnetic molecules, achieving a subcellular resolution in EPRI would greatly benefit to overcome such long-standing issues.…”