Organic semiconducting polymer nanoparticles for photoacoustic labeling and tracking of stem cells in the second near-infrared window

• Main Authors: Yin, Chao, Wen, Guohua, Liu, Chao, Yang, Boguang, Lin, Sien, Huang, Jiawei, Zhao, Pengchao, Wong, Dexter Siu Hong, Zhang, Kunyu, Chen, Xiaoyu, Li, Gang, Jiang, Xiaohua, Huang, Jianping, Pu, Kanyi, Wang, Lidai, Bian, Liming
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Chemical engineering; Organic Semiconducting Polymer; Nanoparticle
• Online Access: https://hdl.handle.net/10356/137150
• Institution: Nanyang Technological University

Photoacoustic (PA) imaging and tracking of stem cells plays an important role in the real-time assessment of cell-based therapies. Nevertheless, the limitations of conventional inorganic PA contrast agents and the narrow range of the excitation wavelength in the first near-infrared (NIR-I) window hamper the applications of PA imaging in living subjects. Herein, we report the design and synthesis of a second near-infrared (NIR-II) absorptive organic semiconducting polymer (OSP)-based nanoprobe (OSPN+) for PA imaging and tracking of stem cells. Comparison studies in biological tissue show that NIR-II light excited PA imaging of the OSPN+ has significantly higher signal-to-noise ratio than NIR-I light excited PA imaging, thereby demonstrating the superiority of the OSPN+ for deep tissue imaging. With good biocompatibility, appropriate size, and optimized surface property, the OSPN+ shows enhanced cellular uptake for highly efficient PA labeling of stem cells. In vivo investigations reveal significant NIR-II PA contrast enhancement of the transplanted OSPN+-labeled human mesenchymal stem cells by 40.6- and 21.7-fold in subcutaneous and brain imaging, respectively, compared with unlabeled cases. Our work demonstrates a class of OSP-based nanomaterials for NIR-II PA stem cell imaging to facilitate a better understanding and evaluation of stem cell-based therapies.