Red emissive AIE nanodots with high two-photon absorption efficiency at 1040 nm for deep-tissue in vivo imaging.
Deep-tissue penetration is highly required in in vivo optical bioimaging. We synthesized a type of red emissive fluorophore BT with aggregation-induced emission (AIE) property. BT molecules were then encapsulated with amphiphilic polymers to form nanodots, and a large two-photon absorption (2PA) cross-section of 2.9 × 10(6) GM at 1040 nm was observed from each BT nanodot, which was much larger than those at the wavelengths of 770 to 860 nm. In addition, 1040 nm light was found to have better penetration and focusing capability than 800 nm light in biological tissue, according to the Monte Carlo simulation. The toxicity and tissue distribution of BT nanodots were studied, and they were found to have good biocompatibility. BT nanodots were then utilized for in vivo imaging of mouse ear and brain, and an imaging depth of 700 μm was obtained with the femtosecond (fs) excitation of 1040 nm. The red emissive AIE nanodots with high 2PA efficiency at 1040 nm would be useful for deep-tissue functional bioimaging in the future.
State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies; JORCEP (Sino-Swedish Joint Research Center of Photonics), Zhejiang University, 310058 Hangzhou, China.
Yalun
Y
Wang
SCUT-HKUST Joint Research Laboratory, Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology (SCUT), Guangzhou 510640, China.
Rongrong
R
Hu
Department of Neurobiology, School of Medicine, Zhejiang University, Zijingang Campus, Hangzhou 310058, China.
Wang
W
Xi
State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies; JORCEP (Sino-Swedish Joint Research Center of Photonics), Zhejiang University, 310058 Hangzhou, China.
Fuhong
F
Cai
State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies; JORCEP (Sino-Swedish Joint Research Center of Photonics), Zhejiang University, 310058 Hangzhou, China.
Shaowei
S
Wang
State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies; JORCEP (Sino-Swedish Joint Research Center of Photonics), Zhejiang University, 310058 Hangzhou, China.
Zhenfeng
Z
Zhu
Bioelectromagnetics Laboratory, School of Medicine, Zhejiang University, Hangzhou 310058, China.
Rongpan
R
Bai
State Key Laboratory of Modern Optical Instrumentations, Centre for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies; JORCEP (Sino-Swedish Joint Research Center of Photonics), Zhejiang University, 310058 Hangzhou, China.
Jun
J
Qian
(160.2540) Fluorescent and luminescent materials; (160.4236) Nanomaterials; (170.3880) Medical and biological imaging; (180.2520) Fluorescence microscopy; (180.4315) Nonlinear microscopy; (190.4180) Multiphoton processes