A diketopyrrolopyrrole-based small molecule with an extended conjugated skeleton and J-aggregation behavior for 808 nm laser triggered phototheranostics

• Published in: Biomaterials science Vol. 11; no. 21; pp. 7124 - 7131
• Main Authors: Liu, Jiawei, Zhang, Xinmin, Fu, Mingxuan, Wang, Xiaoyuan, Gao, Yicong, Xu, Xingpeng, Xiao, Tangxin, Wang, Qi, Fan, Quli
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 24.10.2023
• Subjects: Chemical synthesis; Conjugates; Excitation; Fluorescence; Image resolution; In vivo methods and tests; Molecular structure; Nanoparticles; Near infrared radiation; Photoluminescence; Photothermal conversion
• ISSN: 2047-4830; 2047-4849
• DOI: 10.1039/d3bm01107k

The development of phototheranostic agents, specifically those based on organic small molecules (OSMs) with long wavelength excitation/emission, is an attractive but challenging project. In this contribution, we designed and synthesized a novel conjugate small molecule with a linear structure, named DPP-OPIC. Water-soluble nanoparticle DPP-OPIC NPs were fabricated. They exhibited strong absorption in the region of 600-1000 nm, which was due to the extended conjugate length of the molecular skeleton and J-aggregation behavior. Under 808 nm laser excitation, DPP-OPIC NPs were capable of producing outstanding near-infrared-II (NIR-II, 900-1700 nm) fluorescence. The photoluminescence quantum yield was determined as 0.58%, which enabled high-resolution in vivo tumor imaging. Additionally, a notable photothermal effect with a high photothermal conversion efficiency (41.5%) was achieved by the irradiation of DPP-OPIC NPs. Hence, DPP-OPIC NPs can be used as superior phototheranostic agents, providing valuable contributions to NIR-II fluorescence imaging and photothermal therapy. A conjugated small molecule based on DPP architecture with J-aggregation behavior was designed and synthesized as a proof-of-concept example for 808 nm laser-triggered phototheranostics.