Thiadiazoloquinoxaline-Based Semiconducting Polymer Nanoparticles for NIR-II Fluorescence Imaging-Guided Photothermal Therapy.

Xuxuan Gu,Keyue Liao,Xiaomei Lu,Quli Fan,Wei Huang

doi:10.3389/fbioe.2021.780993

Abstract

Phototheranostics have gained more and more attention in the field of cancer diagnosis and therapy. Among a variety of fluorophores for phototheranostics, semiconducting polymer nanoparticles (SPNs), which are usually constructed by encapsulating hydrophobic semiconducting polymers (SPs) with amphiphilic copolymers, have shown great promise. As second near-infrared (NIR-II) fluorescence imaging has both higher imaging resolution and deeper tissue penetration compared with first near-infrared (NIR-I) fluorescence imaging, NIR-II fluorescent SPNs have been widely designed and prepared. Among numerous structural units for semiconducting polymers (SPs) synthesis, thiadiazoloquinoxaline (TQ) has been proved as an efficient electron acceptor unit for constructing NIR-II fluorescent SPs by reacting with proper electron donor units. Herein, we summarize recent advances in TQ-based SPNs for NIR-II fluorescence imaging-guided cancer photothermal therapy. The preparation of TQ-based SPNs is first described. NIR-II fluorescence imaging-based and multimodal imaging-based phototheranostics are sequentially discussed. At last, the conclusion and future perspectives of this field are presented.

Highlights

Among numerous cancer therapeutic approaches, phototherapy is one of the most promising approaches because of its good therapeutic efficacy and low side effects (Li and Pu, 2019; Yang and Chen, 2019)
A variety of materials have been developed for phototheranostics, such as small molecule dyes (Zhen et al, 2018; Wang et al, 2019a; Wang et al, 2020), inorganic nanoparticles, (Liu et al, 2020), (Vankayala and Hwang, 2018) metal organic frameworks (MOFs), and covalent organic frameworks (COFs) (Guan et al, 2019; Feng et al, 2020; Zhu et al, 2020; Wang et al, 2021; Xia et al, 2021; Yao et al, 2021)
By choosing proper electron donor units to polymerize with TQ, semiconducting polymers (SPs) with NIR-II emission can be synthesized

Summary

INTRODUCTION

Among numerous cancer therapeutic approaches, phototherapy is one of the most promising approaches because of its good therapeutic efficacy and low side effects (Li and Pu, 2019; Yang and Chen, 2019). Photothermal therapy (PTT) and photodynamic therapy (PDT), which both use light to trigger the therapeutic process, have been widely studied and applied for cancer therapy (Zhen and Pu, 2018; Jiang et al, 2020; Xie et al, 2020a; Xu and Pu, 2021; Zhen et al, 2021). Light can be used as an excitation source for optical imaging such as fluorescence and photoacoustic (PA) imaging (Cui et al, 2017; Sheng et al, 2018; Yin et al, 2018; Cheng and Pu, 2020). By choosing proper materials, phototheranostics which combine imaging and therapy

Emission wavelength

Quantum yield

Findings

DISCUSSION