Facile syntheses of conjugated polymers for photothermal tumour therapy

Zhen Zheng,Peiyao Chen,Chengfan Wu,Yinchu Ma,Yucai Wang,Gaolin Liang

doi:10.1038/s41467-019-09226-6

Abstract

Development of photothermal materials which are able to harness sunlight and convert it to thermal energy seems attractive. Besides carbon-based nanomaterials, conjugated polymers are emerging promising photothermal materials but their facile syntheses remain challenging. In this work, by modification of a CBT-Cys click condensation reaction and rational design of the starting materials, we facilely synthesize conjugated polymers poly-2-phenyl-benzobisthiazole (PPBBT) and its dihexyl derivative with good photothermal properties. Under the irradiation of either sunlight-mimicking Xe light or near-infrared laser, we verify that PPBBT has comparable photothermal heating-up speed to that of star material single-wall carbon nanotube. Moreover, PPBBT is used to fabricate water-soluble NPPPBBT nanoparticles which maintain excellent photothermal properties in vitro and photothermal therapy effect on the tumours exposed to laser irradiation. We envision that our synthetic method provides a facile approach to fabricate conjugated polymers for more promising applications in biomedicine or photovoltaics in the near future.

Highlights

Development of photothermal materials which are able to harness sunlight and convert it to thermal energy seems attractive
Element composition analysis of the X-ray photoelectron spectroscopy (XPS) spectrum suggested that the atom number ratio between N and S (N/S, 1.02) was near to 1:1 (Supplementary Figure 3 and Supplementary Table 1), indicating a very high polymerization degree of the PPBBT product
The gel permeation chromatography (GPC) trace of PPBBT showed that the number-average molecular weight of the polymer was about 23,176 with a polydispersity (PDI) of 1.34 (Supplementary Figure 4 and Supplementary Table 2)

Summary

Introduction

Development of photothermal materials which are able to harness sunlight and convert it to thermal energy seems attractive. By modification of a CBT-Cys click condensation reaction and rational design of the starting materials, we facilely synthesize conjugated polymers poly-2phenyl-benzobisthiazole (PPBBT) and its dihexyl derivative with good photothermal properties. Current monomer species for the syntheses of conjugated polymers are quite limited and available conjugated polymers with excellent photothermal properties are quite few[17] This calls for new molecular structures and efficient reactions to fabricate conjugated polymers for the applications of energy exploitation. Inspired by the abovementioned pioneering studies, in this work, we modify abovementioned CBT-Cys click condensation reaction and rationally design the starting materials for the facile fabrication of conjugated polymers. In vivo experiments show that the NPPPBBT nanoparticles are effectively accumulated in the tumour site due to their enhanced permeability and retention (EPR) effect and have excellent PTT efficiency against tumour

Methods

Results

Conclusion