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

• Published in: ChemPhotoChem 2018-07, Vol.2 (7), p.616-621
• Main Authors: Williams, Gareth O. S., Euser, Tijmen G., Russell, Philip St. J., MacRobert, Alexander J., Jones, Anita C.
• Format: Article
• Language: English
• Subjects: lifetime; luminescence; photonic crystal fiber; photosensitization; singlet oxygen
• ISSN: 2367-0932; 2367-0932
• DOI: 10.1002/cptc.201800028

Highly sensitive, quantitative detection of singlet oxygen (1O2) 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 1O2 through 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 hollow‐core photonic crystal fibers (HC‐PCF) as a novel optofluidic modality for photosensitization and detection of 1O2. We report the use of this approach to achieve highly sensitive detection of the luminescence decay of 1O2 produced by using two common photosensitizers, Rose Bengal and Hypericin, within the 60‐μm diameter core of a 15 cm length of HC‐PCF. We demonstrate the feasibility of directly detecting sub‐picomole quantities of 1O2 by using this methodology, and identify some aspects of the HC‐PCF technology that can be improved to yield even higher detection sensitivity. Core benefits: Hollow‐core photonic crystal fiber is used as an optofluidic microreactor for generation and detection of singlet oxygen. Excitation of photosensitizer solution within the hollow core of the optical fiber enables detection of singlet oxygen with sub‐picomole sensitivity.