Benzobisthiadiazole and Its Derivative-Based Semiconducting Polymer Nanoparticles for Second Near-Infrared Photoacoustic Imaging.

Xuelong Huang,Ning Lan,Xiuhong Liu,Haifeng He,Yanfeng Zhang,Wei Zeng

doi:10.3389/fchem.2022.842712

Abstract

Photoacoustic (PA) imaging has received more and more attention on disease diagnosis and fundamental scientific research. It is still challenging to amplify their imaging ability and reduce the toxicity of inorganic materials and exogenous contrast agents. Semiconducting polymer nanoparticles (SPNs), as a new type of contrast agent, have the advantages of low toxicity, flexible structure adjustment, good photostability, and excellent photothermal conversion efficiency. SPNs containing benzo(1,2-c;4,5-c′)bis(1,2,5)thiadiazole (BBT) units, as the most classic second near-infrared window (NIR-II, 1,000–1700 nm) PA contrast agents, can achieve light absorption in the NIR-II region, thereby effectively reducing light loss in biological tissues and improving imaging resolution. This mini review summarizes the recent advances in the design strategy of BBT and its derivative-based semiconducting polymer nanoparticles for second near-infrared photoacoustic imaging. The evolution process of BBT blocks provides a unique perspective for the design of high-performance NIR-II PA contrast agents.

Highlights

Photoacoustic (PA) imaging is a hybrid imaging technology based on light excitation and ultrasound detection, which is widely used in monitoring surgery, visualization of blood vessels, and early detection of disease biomarkers (Zhen et al, 2021)
We summarize the recent progress of Semiconducting polymer nanoparticles (SPNs) consisting of a BBT unit or its derivatives for NIR-II PA imaging
This review summarizes SPNs containing benzobisthiadiazole or its derivative segments for NIR-II PA imaging

Summary

Introduction

Photoacoustic (PA) imaging is a hybrid imaging technology based on light excitation and ultrasound detection, which is widely used in monitoring surgery, visualization of blood vessels, and early detection of disease biomarkers (Zhen et al, 2021). A safe non-ionizing laser pulse is used to irradiate the corresponding biological tissue, and the photon energy is converted into heat in a short time. The localized heat inside tissues undergoes transient thermoelastic expansion to generate ultrasonic waves. The generated ultrasonic signals are collected by a broadband ultrasonic transducer and converted into PA images. PA imaging has the advantage of the sensitive light absorption in contrast to an optical method and has the advantage of small acoustic scattering similar to an acoustic method, and exhibits better spatial resolution and imaging depth than traditional optical imaging (Yin et al, 2021)

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Conclusion