Singlet Oxygen Generation from Polyaminoglycerol by Spin-Flip-Based Electron Transfer

Jung Seung Nam; Youngjoo Hong; Chae Gyu Lee; Tae In Kim; Chaiheon Lee; Deok-Ho Roh; In Seong Lee; Songa Kweon; Gyunhyeok Ahn; Seung Kyu Min; Byeong-Su Kim; Tae-Hyuk Kwon

doi:10.1021/jacsau.2c00050

Singlet Oxygen Generation from Polyaminoglycerol by Spin-Flip-Based Electron Transfer

JACS Au. 2022 Mar 29;2(4):933-942. doi: 10.1021/jacsau.2c00050. eCollection 2022 Apr 25.

Authors

Jung Seung Nam^{1

2}, Youngjoo Hong³, Chae Gyu Lee^{1

2}, Tae In Kim¹, Chaiheon Lee^{1

2}, Deok-Ho Roh^{1

2}, In Seong Lee¹, Songa Kweon¹, Gyunhyeok Ahn¹, Seung Kyu Min¹, Byeong-Su Kim³, Tae-Hyuk Kwon^{1

2}

Affiliations

¹ Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
² Center for Wave Energy Materials, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.
³ Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea.

Abstract

Reactive oxygen species have drawn attention owing to their strong oxidation ability. In particular, the singlet oxygen (¹O₂) produced by energy transfer is the predominant species for controlling oxidation reactions efficiently. However, conventional ¹O₂ generators, which rely on enhanced energy transfer, frequently suffer from poor solubility, low stability, and low biocompatibility. Herein, we introduce a hyperbranched aliphatic polyaminoglycerol (hPAG) as a ¹O₂ generator, which relies on spin-flip-based electron transfer. The coexistence of a lone pair electron on the nitrogen atom and a hydrogen-bonding donor (the protonated form of nitrogen and hydroxyl group) affords proximity between hPAG and O₂. Subsequent direct electron transfer after photo-irradiation induces hPAG^•+-O₂ ^•- formation, and the following spin-flip process generates ¹O₂. The spin-flip-based electron transfer pathway is analyzed by a series of photophysical, electrochemical, and computational studies. The ¹O₂ generator, hPAG, is successfully employed in photodynamic therapy and as an antimicrobial reagent.