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Reevaluating Protein Photoluminescence: Remarkable Visible Luminescence upon Concentration and Insight into the Emission Mechanism
Author(s) -
Wang Qian,
Dou Xueyu,
Chen Xiaohong,
Zhao Zihao,
Wang Shuang,
Wang Yunzhong,
Sui Kunyan,
Tan Yeqiang,
Gong Yongyang,
Zhang Yongming,
Yuan Wang Zhang
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201906226
Subject(s) - phosphorescence , photoluminescence , luminescence , tryptophan , amino acid , chemistry , photochemistry , fluorescence , phenylalanine , bovine serum albumin , aromatic amino acids , tyrosine , aggregation induced emission , amorphous solid , organic chemistry , materials science , biochemistry , optoelectronics , optics , physics
It is a textbook knowledge that protein photoluminescence stems from the three aromatic amino acid residues of tryptophan(Trp), tyrosine (Tyr), and phenylalanine (Phe), with predominant contributions from Trp. Recently, inspired by the intrinsic emission of nonaromatic amino acids and poly(amino acids) in concentrated solutions and solids, we revisited protein light emission using bovine serum albumin (BSA) as a model. BSA is virtually nonemissive in dilute solutions (≤0.1 mg mL −1 ), but highly luminescent upon concentration or aggregation, showing unique concentration‐enhanced emission and aggregation‐induced emission (AIE) characteristics. Notably, apart from well‐documented UV luminescence, bright blue emission is clearly observed. Furthermore, persistent room‐temperature phosphorescence ( p ‐RTP) is achieved even in the amorphous solids under ambient conditions. This visible emission can be rationalized by the clustering‐triggered emission (CTE) mechanism. These findings not only provide an in‐depth understanding of the emissive properties of proteins, but also hold strong implications for further elucidating the basis of tissue autofluorescence.