High Contrast Detection of Carotid Neothrombus with Strong Near-Infrared Absorption Selenium Nanosphere Enhanced Photoacoustic Imaging

Fengbing He,1,* Wenzhong Hou,1,* Yintao Lan,1,2 Weijian Gao,1 Mengyu Zhou,1 Jinghang Li,1 Shutong Liu,1 Bin Yang,1 Jian Zhang1 1Qingyuan People’s Hospital, The Sixth Affiliated Hospital of Guangzhou Medical University, School of Biomedical Engineering, Guangzhou Medical University, Guangdong, People’s Republic of China; 2Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangdong, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jian Zhang, Email jianzhang@gzhmu.edu.cnBackground: Carotid artery thrombosis is the leading cause of stroke. Since there are no apparent symptoms in the early stages of carotid atherosclerosis onset, it causes a more significant clinical diagnosis. Photoacoustic (PA) imaging provides high contrast and good depth information, which has been used for the early detection and diagnosis of many diseases.Methods: We investigated thrombus formation by using 20% ferric chloride (FeCl3) in the carotid arteries of KM mice for the thrombosis model. The near-infrared selenium/polypyrrole (Se@PPy) nanomaterials are easy to synthesize and have excellent optical absorption in vivo, which can be used as PA contrast agents to obtain thrombosis information.Results: In vitro experiments showed that Se@PPy nanocomposites have fulfilling PA ability in the 700 nm to 900 nm wavelength range. In the carotid atherosclerosis model, maximum PA signal enhancement up to 3.44, 4.04, and 5.07 times was observed by injection of Se@PPy nanomaterials, which helped to diagnose the severity of carotid atherosclerosis.Conclusion: The superior PA signal of Se@PPy nanomaterials can identify the extent of atherosclerotic carotid lesions, demonstrating the feasibility of PA imaging technology in diagnosing carotid thrombosis lesion formation. This study demonstrates nanocomposites and PA techniques for imaging and diagnosing carotid thrombosis in vivo.Keywords: photoacoustic contrast agent, molecular imaging, Se@PPy nanocomposites, carotid artery thrombus