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1. Light-triggered electrochemical biosensor using singlet oxygen for self-powered operation and glucose detection

   https://doi.org/10.1016/j.talanta.2025.129048  

   Gupta, Akhilesh Kumar; Buller, Robert; Krasnoslobodtsev, Alexey V (October 2025, Talanta)

   This study introduces a light-activated sensing strategy that integrates photosensitization with electrochemical detection. The sensor employs Eosin Y, a photosensitizer that generates singlet oxygen (1O2) via type II photosensitization. Immobilized within a thin polymer matrix on a carbon working electrode, Eosin Y produces 1O2, under green light (520 nm) illumination, initiating a redox process that yields a measurable current. To incorporate biosensing capabilities and enable self-powered operation, this 1O2 – mediated process was coupled with glucose oxidase (GOx) to construct a fully operational glucose biosensor. The addition of glucose reverses the current flow by causing GOx to compete for electrons, with the resulting current magnitude correlating with glucose concentration providing a sensitive measure of glucose. The biosensor, as proof-of-principle, demonstrated excellent performance over a range of glucose concentrations (0–73 mM), achieving a detection limit (LOD) of 2.8 mM for steady state photocurrent under oxygen-saturated conditions. This platform leverages light and 1O2 as stimuli for tunable, on-demand signal control, offering a novel approach for adaptive, real-time biosensing technologies. 

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2. Self-catalyzing photoredox polymerization for recyclable polymer catalysts

   https://doi.org/10.1039/d1py00208b  

   Lessard, Jacob J.; Scheutz, Georg M.; Korpusik, Angie B.; Olson, Rebecca A.; Figg, C. Adrian; Sumerlin, Brent S. (April 2021, Polymer Chemistry)

   null (Ed.)

   We describe a self-catalyzing photoredox polymerization system for the modular generation of macromolecular photocatalysts. Specifically, we designed a photoactive eosin Y-derived monomer that can induce photoelectron/energy transfer, while simultaneously partaking in reversible addition–fragmentation chain transfer polymerization as a monomer, affording polymer catalysts with tunable eosin Y incorporations. 

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3. UV-light crosslinked photocatalytic polymer gels for batch and continuous flow reactions

   https://doi.org/10.1039/D4PY00313F  

   Freeburne, Sarah; Pester, Christian W (July 2024, Polymer Chemistry)

   This article describes the synthesis and characterization of a UV-crosslinked Eosin Y-photocatalytic gel and studies its performance in the oxidation of thioanisole in batch and flow reactors. 

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4. Open-air green-light-driven ATRP enabled by dual photoredox/copper catalysis

   https://doi.org/10.1039/D2SC04210J  

   Szczepaniak, Grzegorz; Jeong, Jaepil; Kapil, Kriti; Dadashi-Silab, Sajjad; Yerneni, Saigopalakrishna S.; Ratajczyk, Paulina; Lathwal, Sushil; Schild, Dirk J.; Das, Subha R.; Matyjaszewski, Krzysztof (October 2022, Chemical Science)

   Photoinduced atom transfer radical polymerization (photo-ATRP) has risen to the forefront of modern polymer chemistry as a powerful tool giving access to well-defined materials with complex architecture. However, most photo-ATRP systems can only generate radicals under biocidal UV light and are oxygen-sensitive, hindering their practical use in the synthesis of polymer biohybrids. Herein, inspired by the photoinduced electron transfer-reversible addition–fragmentation chain transfer (PET-RAFT) polymerization, we demonstrate a dual photoredox/copper catalysis that allows open-air ATRP under green light irradiation. Eosin Y was used as an organic photoredox catalyst (PC) in combination with a copper complex (X–Cu II /L). The role of PC was to trigger and drive the polymerization, while X–Cu II /L acted as a deactivator, providing a well-controlled polymerization. The excited PC was oxidatively quenched by X–Cu II /L, generating Cu I /L activator and PC˙ + . The ATRP ligand (L) used in excess then reduced the PC˙ + , closing the photocatalytic cycle. The continuous reduction of X–Cu II /L back to Cu I /L by excited PC provided high oxygen tolerance. As a result, a well-controlled and rapid ATRP could proceed even in an open vessel despite continuous oxygen diffusion. This method allowed the synthesis of polymers with narrow molecular weight distributions and controlled molecular weights using Cu catalyst and PC at ppm levels in both aqueous and organic media. A detailed comparison of photo-ATRP with PET-RAFT polymerization revealed the superiority of dual photoredox/copper catalysis under biologically relevant conditions. The kinetic studies and fluorescence measurements indicated that in the absence of the X–Cu II /L complex, green light irradiation caused faster photobleaching of eosin Y, leading to inhibition of PET-RAFT polymerization. Importantly, PET-RAFT polymerizations showed significantly higher dispersity values (1.14 ≤ Đ ≤ 4.01) in contrast to photo-ATRP (1.15 ≤ Đ ≤ 1.22) under identical conditions. 

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5. Synthetic Applications and Computational Perspectives on Eosin Y Induced Direct HAT Process

   https://doi.org/10.1055/a-1385-9398  

   Inoa, Joan; Dominici, Grecia; Eldabagh, Reem; Foley, Jonathan J.; Xing, Yalan (June 2021, Synthesis)

   null (Ed.)

   Abstract In recent years, advancements in photocatalysis have allowed for a plethora of chemical transformations under milder conditions. Many of these photochemical reactions utilize hydrogen atom transfer processes to obtain desired products. Hydrogen atom transfer processes can follow one of two unique pathways: the first, a direct path and the second, an indirect path. In this paper, we highlight the ability of eosin Y to act as a direct hydrogen atom transfer catalyst from both synthetic and computational chemistry perspectives. 

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