title: Biocompatible Green and Red Fluorescent Organic Dots with Remarkably Large Two-Photon Action Cross Sections for Targeted Cellular Imaging and Real-Time Intravital Blood Vascular Visualization.
abstract: Fluorescent organic dots are emerging as promising bioimaging reagents because of their high brightness, good photostability, excellent biocompatibility, and facile surface functionalization. Organic dots with large two-photon absorption (TPA) cross sections are highly desired for two-photon fluorescence microscopy. In this work, we report two biocompatible and photostable organic dots fabricated by encapsulating tetraphenylethene derivatives within DSPE-PEG matrix. The two organic dots show absorption maxima at 425 and 483 nm and emit green and red fluorescence at 560 and 645 nm, with high fluorescence quantum yields of 64% and 22%, respectively. Both organic dots exhibit excellent TPA property in the range of 800-960 nm, affording upon excitation at 820 nm remarkably large TPA cross sections of 1.2×10(6) and 2.5×10(6) GM on the basis of dot concentration. The bare fluorophores and their organic dots are biocompatible and have been used to stain living cells for one- and two-photon fluorescence bioimagings. The cRGD-modified organic dots can selectively target integrin αvβ3 overexpressing breast cancer cells for targeted imaging. The organic dots are also applied for real-time two-photon fluorescence in vivo visualization of the blood vasculature of mouse ear, providing the spatiotemporal information about the whole blood vascular network. These results demonstrate that the present fluorescent organic dots are promising candidates for living cell and tissue imaging.
authors.affiliation: †College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Jiayun
authors.initials: J
authors.lastname: Xiang
authors.affiliation: §Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Cai
authors.affiliation: ∥School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Xiaoding
authors.initials: X
authors.lastname: Lou
authors.affiliation: §Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585.
authors.forename: Guangxue
authors.initials: G
authors.lastname: Feng
authors.affiliation: ∥School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Xuehong
authors.initials: X
authors.lastname: Min
authors.affiliation: ‡State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Luo
authors.affiliation: ‡State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
authors.forename: Bairong
authors.initials: B
authors.lastname: He
authors.affiliation: ⊥Singapore Immunology Network (SIgN), A*STAR (Agency for Science Technology and Research), Biopolis 138648, Singapore.
authors.forename: Chi Ching
authors.initials: CC
authors.lastname: Goh
authors.affiliation: ⊥Singapore Immunology Network (SIgN), A*STAR (Agency for Science Technology and Research), Biopolis 138648, Singapore.
authors.forename: Lai Guan
authors.initials: LG
authors.lastname: Ng
authors.affiliation: †College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.affiliation: †College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 310036, China.|‡State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
authors.forename: Zujin
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: §Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585.
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.affiliation: ‡State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China.
authors.forename: Ben Zhong
authors.initials: BZ
authors.lastname: Tang
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis; D001783:Blood Flow Velocity / Q000502:physiology*; D001808:Blood Vessels / Q000166:cytology* / Q000502:physiology*; D003116:Color; D003199:Computer Systems; D003287:Contrast Media / Q000138:chemical synthesis; D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D000069416:Intravital Microscopy / Q000379:methods*; D051379:Mice; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D010316:Particle Size; D057089:Pathology, Molecular / Q000379:methods
chemical_list: D001672:Biocompatible Materials; D003287:Contrast Media; D005456:Fluorescent Dyes
keywords: bioimaging; organic dots; tetraphenylethene; two-photon absorption; two-photon fluorescence