Theranostics 2017; 7(16):4029-4040. doi:10.7150/thno.19538

Research Paper

Investigating the Effect of Chemical Structure of Semiconducting Polymer Nanoparticle on Photothermal Therapy and Photoacoustic Imaging

Dongdong Li1*, Guobing Zhang2*, Weiguo Xu3*, Junxia Wang1, Yucai Wang4✉, Longzhen Qiu2, Jianxun Ding3✉, Xianzhu Yang1✉

1. Institutes for Life Sciences, School of Medicine and National Engineering Research Center for Tissue Restoration and Reconstruction, South China University of Technology, Guangzhou, Guandong 510006, P.R. China;
2. Academy of Opto-Electronic Technology, Hefei University of Technology, Hefei, Anhui 230009, P.R. China;
3. Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130222, P. R. China;
4. School of Life Sciences and Medical Center, University of Science & Technology of China Hefei, Anhui 230027, P.R. China.
* These authors contributed equally to this work.

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) license ( See for full terms and conditions.
Li D, Zhang G, Xu W, Wang J, Wang Y, Qiu L, Ding J, Yang X. Investigating the Effect of Chemical Structure of Semiconducting Polymer Nanoparticle on Photothermal Therapy and Photoacoustic Imaging. Theranostics 2017; 7(16):4029-4040. doi:10.7150/thno.19538. Available from

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The donor-acceptor semiconducting polymers (SPs) have robust absorbance in near-infrared (NIR) region, great photostability, high photothermal conversion efficiency, and good biocompatibility. Thus, the SPs exhibit great potentials for photothermal therapy (PTT) and photoacoustic imaging (PAI). However, poor understanding of the underlying mechanisms and the correlation between the SP polymer chemical structures and their performances of PTT and PAI have significantly hindered their biomedical application. Herein, a series of acceptor-π-acceptor type (A1-π-A2) type SPs were synthesized. The diketopyrrolopyrrole (DPP) and thiophene are used as A1 electron accepting block and π-bridge, and the chemical structure of A2 unit was variable. The SPs were formulated into PEGylated nanoparticles, which ensured these SP-based nanoparticles (SP@NPs) exhibited similar size, shape, and physiological stability. Thus, the chemical structure of A2 unit was the only variable. The effects of the SP chemical structures are carefully and comprehensively evaluated through both in vitro and in vivo experiments. Our results demonstrated the chemical structure of A2 unit simultaneously impact their absorption spectra and photothermal (PT) conversion efficiency, which finally determined their PTT and PAI performances. Among these A2 acceptors, thieno[3,2-b]thiophene (TT) unit exhibited the best in vitro and in vivo anticancer efficacies and PAI performances. This study not only provides molecular insights into the design of efficient SPs for PTT and PAI but also highlights the flexibility and potential of SP@NPs for biomedical application. Thus, SP@NPs can act as a versatile nanoplatform for the development of novel light intensive imaging and therapeutic approaches.

Keywords: semiconducting polymer, donor-acceptor polymer, photothermal therapy, photostability, photoacoustic imaging.