Zhaoyong Li,1,* Yanping Lin,1,* Ting Qiu,2,* Junsheng Liang,1 Yintao Lan,3 Fan Meng,4 Chaohao Liang,4 Yiqing Zhang,4 Qingyun Wang,1 Da Shi,1 Changli Zhang,1 Yanan Shi,1 Liujun Liu,1 Yanlan Yang,1 Jian Zhang4,5 

1Department of Radiology, DongGuan Tungwah Hospital, Dongguan Key Laboratory of Radiology and Molecular Imaging, DongGuan, Guangdong, 523000, People’s Republic of China; 2Department of Radiology, Zhuhai People’s Hospital (Zhuhai Hospital Affiliated with Jinan University), Zhuhai, Guangdong, 519000, People’s Republic of China; 3Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, Guangdong, 510030, People’s Republic of China; 4School of Biomedical Engineering, Guangzhou Medical University, Guangzhou, Guangdong, 511436, People’s Republic of China; 5Department of Oncology, the Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, Guangdong, 511500, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Jian Zhang; Zhaoyong Li, Email jianzhang@gzhmu.edu.cn; lizhaoyong2003@163.com

Background: Photothermal therapy (PTT) guided by photoacoustic imaging (PAI) using nanoplatforms has emerged as a promising strategy for cancer treatment due to its efficiency and accuracy. This study aimed to develop and synthesize novel second near-infrared region (NIR-II) absorption-conjugated polymer acceptor acrylate-substituted thiadiazoloquinoxaline-diketopyrrolopyrrole polymers (PATQ-DPP) designed specifically as photothermal and imaging contrast agents for nasopharyngeal carcinoma (NPC).
Methods: The PATQ-DPP nanoparticles were synthesized and characterized for their optical properties, including low optical band gaps. Their potential as PTT agents and imaging contrast agents for NPC was evaluated both in vitro and in vivo. The accumulation of nanoparticles at tumor sites was assessed post-injection, and the efficacy of PTT under near-infrared laser irradiation was investigated in a mouse model of NPC.
Results: Experimental results indicated that the PATQ-DPP nanoparticles exhibited significant photoacoustic contrast enhancement and favorable PTT performance. Safety and non-toxicity evaluations confirmed the biocompatibility of these nanoparticles. In vivo studies showed that PATQ-DPP nanoparticles effectively accumulated at NPC tumor sites and demonstrated excellent tumor growth inhibition upon exposure to near-infrared laser irradiation. Notably, complete elimination of nasopharyngeal tumors was observed within 18 days following PTT.
Discussion: The findings suggest that PATQ-DPP nanoparticles are a promising theranostic agent for NIR-II PAI and PTT of tumors. This innovative approach utilizing PATQ-DPP nanoparticles provides a powerful tool for the early diagnosis and precise treatment of NPC, offering a new avenue in the management of this challenging malignancy.

Keywords: nasopharyngeal carcinoma, photoacoustic imaging, photothermal therapy, PATQ-DPP nanoparticles