Prof. Shengliang Li published a novel bioimaging tool in ACS Nano

The brain is the main organ responsible for the administration and management of complex life and also is the nuclear problem of science. A better understanding of how the brain structure and functions will improve the human's ability to explore the origin of life and the occurrence and progression of disease. To achieve the above goal, scientists have been committed to explore new tool and technology for brain imaging, such as positron emission tomography (PET), magnetic resonance imaging (MRI), and ultrasonograhy. Although the above-noted methods can receive lossless in vivo imaging of brain and imaging information, there are still defects in image accuracy and spatial resolution. In particular, the reported methods do not provide an adequate information in subcellular structure and functions. For several hundred years, optical imaging is considered as a imaging pattern with high resolution and sensitivity. However, the background fluorescence and light scattering of biological tissue severely limited their application in deep-tissue imaging. Thus, exploring new technology and probe for deep-tissue imaging with high resolution and sensitivity remains a big challenge.

Recently, Prof. Shengliang Li's group at the College of Pharmaceutical Sciences, Soochow University, published a research paper entitled Bright Near-Infrared π-Conjugated Oligomer Nanoparticles for Deep-Brain Three-Photon Microscopy Excited at the 1700-nm WindowIn VivoinACS Nano.The team reports a designed and synthesized fluorescent molecule (OFET) forin vivomouse brain imaging with three-photon microscopy at a record imaging depth. Upon the long excitation in the second NIR window of 1720 nm, brain vasculatures of a mouse located at a depth of 1696 μm can be clearly resolvedin vivowithout observable cytotoxicity even in a high concentration. This work offers a feasible horizon for deep-tissue 3PM imaging using π-conjugated materials.Corresponding authors included Prof. Shengliang Li, Prof. Ke Wang from Shenzhen University, and Prof. Chun-Sing Lee from the City University of Hong Kong.

Figure 1.Deep-Brain Three-Photon Microscopy Excited at the 1700 nm Windowin Vivowith Near-Infrared Nanoparticles.

In this work, a conjugated oligomer OFET molecule was developed to receive a relatively high fluorescence brightness and a near-infrared (NIR) maximum emission at 820 nm after integrating as water-dispersible nanoparticles (OEFT NPs). Under 1720 nm excitation, OFET NPs show a large three-photon action cross-section, which is more than twice that of the commonly used sulforhodamine 101 (SR101) dye. Benefiting from the high tissue penetration depths for both the long excitation in the second NIR window of 1720 nm and the emission wavelength in the first NIR window of 820 nm, a high brightness, and a large action cross-section of three-photon, OFET NPs have good deep-brain imaging performance. Brain vasculatures of a mouse located at a depth of 1696 μm can be clearly resolved in vivo. With no observable cytotoxicity even in a high concentration, the present OFET NPs suggest that fluorescent π-conjugated oligomers are of great potential in high-resolution 3PM imaging of in vivo deep tissue. This work provides a new strategy for the design and synthesis of innovative NIR-II-excited organic fluorescent probes for high-resolution bioimaging.

Reference:Shengliang Li,* Xiangquan Deng, Hui Cheng, Xiaozhen Li, Yingpeng Wan, Chen Cao, Jie Yu, Ying Liu, Yi Yuan, Ke Wang,* and Chun-Sing Lee*,Bright Near-Infrared π-Conjugated Oligomer Nanoparticles for Deep-Brain Three-Photon Microscopy Excited at the 1700-nm WindowIn Vivo.ACS Nano2022,16, 1280-12487.

Linker：https://pubs.acs.org/doi/10.1021/acsnano.2c03813

Prof. Shengliang Li is a distinguished professor at the College of Pharmaceutical Sciences at Soochow University and is a principal investigator in the laboratory of Advanced Bio-Photon and Nanomedicine. He has co-authored 90 papers with over 3800 times of citations (H-Index 35) and 4 ESI Highly Cited Paper (ESI 1%). Prof. Shengliang Li holds 4 PCT patent applications and received 4 Chinese patents. He is a Young Editorial Board Member for Chinese Chemical Letters. His research focuses on molecular design, nanotechnology engineering, and mechanistic studies of photoactive drugs and probes for enabling disease theranostics, chemical biology, and environmental health applications.