title: Using AIE Luminogen for Long-term and Low-background Three-Photon Microscopic Functional Bioimaging.
abstract: Fluorescent probes are one of the most popularly used bioimaging markers to monitor metabolic processes of living cells. However, long-term light excitation always leads to photobleaching of fluorescent probes, unavoidable autofluorescence as well as photodamage of cells. To overcome these limitations, we synthesized a type of photostable luminogen named TPE-TPP with an aggregation induced emission (AIE) characteristic, and achieved its three-photon imaging with femtosecond laser excitation of 1020 nm. By using TPE-TPP as fluorescent probes, three-photon microscopy under 1020 nm excitation showed little photo-damage, as well as low autofluorescence to HeLa cells. Due to the AIE effect, the TPE-TPP nanoaggregates uptaken by cells were resistant to photobleaching under three-photon excitation for an extended period of time. Furthermore, we demonstrated that for the present TPE-TPP AIE the three-photon microscopy (with 1020 nm excitation) had a better signal to noise ratio than the two-photon microscopy (with 810 nm excitation) in tissue imaging.
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation (Zhejiang University), Centre for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies, JORCEP (Sino-Swedish Joint Research Center of Photonics), Zhejiang University, Hangzhou, 310058, China.
authors.forename: Zhenfeng
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Chemistry, The Hong Kong University of Science &Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Chris W T
authors.initials: CW
authors.lastname: Leung
authors.affiliation: Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, Hangzhou 310058, China.
authors.forename: Xinyuan
authors.initials: X
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation (Zhejiang University), Centre for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies, JORCEP (Sino-Swedish Joint Research Center of Photonics), Zhejiang University, Hangzhou, 310058, China.
authors.forename: Yalun
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Modern Optical Instrumentation (Zhejiang University), Centre for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies, JORCEP (Sino-Swedish Joint Research Center of Photonics), Zhejiang University, Hangzhou, 310058, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Qian
authors.affiliation: Department of Chemistry, The Hong Kong University of Science &Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Ben Zhong
authors.initials: BZ
authors.lastname: Tang
authors.affiliation: Bioelectromagnetics Laboratory, Zhejiang University School of Medicine, Hangzhou 310058, China.
authors.forename: Sailing
authors.initials: S
authors.lastname: He
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D007834:Lasers; D051379:Mice; D036641:Microscopy, Fluorescence, Multiphoton; D049329:Nanostructures / Q000737:chemistry; D038761:Photobleaching; D017785:Photons
chemical_list: D005456:Fluorescent Dyes