Highly Sensitive Luminescence Detection of Photosensitized Singlet Oxygen within Photonic Crystal Fibers

Abstract

Highly sensitive, quantitative detection of singlet oxygen (1 O2) is required for the evaluation of newly developed photosensitizers and the elucidation of the mechanisms of many processes in which singlet oxygen is known, or believed, to be involved. The direct detection of 1 O2, via its intrinsic phosphorescence at 1270 nm, is challenging because of the extremely low intensity of this emission, coupled with the low quantum efficiency of currently available photodetectors at this wavelength. We introduce hollowcore photonic crystal fibre (HC-PCF) as a novel optofluidic modality for photosensitization and detection of 1 O2. We report the use of this approach to achieve highly sensitive detection of the luminescence decay of 1 O2, produced using two common photosensitizers, Rose Bengal and Hypericin, within the 60-m diameter core of a 15-cm length of HC-PCF. We demonstrate the feasibility of directly detecting sub-picomole quantities of 1 O2 using this methodology, and identify some aspects of the HC-PCF technology that can be improved to yield even higher detection sensitivity.

Visible Light-Induced Aerobic Epoxidation of α,β-Unsaturated Ketones Mediated by Amidines

“…Therefore, tetramethylguanidine, O 2 , H 2 TPP, and light are imperative. The reaction was suppressed in the presence of the singlet oxygen inhibitors 1,4-diazabicyclo­[2,2,2] octane , (DABCO) and NaN 3 (Table , entries 5 and 6). Therefore, singlet oxygen may account for the epoxidation.…”

Enhanced Optics for Time-Resolved Singlet Oxygen Luminescence Detection

“…Also, an advanced fiber-coupled optical system greatly assists in efficient singlet oxygen generation and detection. In the next design iteration, we could either miniaturize the optical setup or explore a miniaturized fiber optic probe (following the example [26]) for use in tissue and clinical studies, easy and precise placement of this fiber-coupled sensor head inside the tissue would be a huge benefit, boosting signal and spatial specificity. The SOLD system is completed by an SNSPD with improved system efficiency and reduced down to sub-Hz dark count rate.…”

In situ Detection of Cobaloxime Intermediates During Photocatalysis Using Hollow‐Core Photonic Crystal Fiber Microreactors

“…High-sensitivity UV/Vis absorption spectroscopy in HC-PCF microreactors has already found applications in a wide range of chemical sensing applications. [35][36][37] More recently, HC-PCF microreactors have been combined with fluorescence methods to detect singlet-oxygen with sub-picomole sensitivity, [38] and to perform Stern-Volmer analysis on sub-μL catalyst volumes. [39] Finally, Raman spectroscopy has been used to monitor reaction mixtures [40,41] and liquid electrolytes [42] in situ.…”