Semiconducting Polymer Nanoparticles with Intramolecular Motion‐Induced Photothermy for Tumor Phototheranostics and Tooth Root Canal Therapy

Abstract

Much effort is devoted to develop agents with superior photoacoustic/photothermal properties for improved disease diagnosis and treatment. Herein, a new fused two isoindigo (DIID)‐based semiconducting conjugated polymer (named PBDT‐DIID) is rationally designed and synthesized with a strong near‐infrared absorption band ranging from 700 to 1000 nm. Water‐dispersing nanoparticles (NPs) of PBDT‐DIID are prepared with good biocompatibility and a rather high photothermal conversion efficiency (70.6%), as the active excited‐state intramolecular twist around the central double bonds in DIID permits most of the absorbed excitation energy flow to heat deactivation pathway through internal conversion. The photoacoustic signal can be further magnified by incorporation of polylactide (PLA) in the NP core to confine the generated heat of PBDT‐DIID within NPs. The resultant doped NPs show excellent performance in photoacoustic imaging‐guided photothermal therapy in an orthotopic 4T1 breast tumor‐bearing mouse model. It is also found that the photothermal effect of the PBDT‐DIID NPs is safe and quite efficacious to highly improve the root canal treatment outcome by heating the 1% NaClO solution inside the root canal upon 808 nm laser irradiation in a human extracted tooth root canal infection model.

Biomedical applications and prospects of temperature‐orchestrated photothermal therapy

“…What's more, after killing bacteria and accelerating the repair of wounds, the CPA2 can be wholly absorbed, avoiding additional removal 194 . In the field of stomatology, some researchers also tried to use PTT in treating infected tooth root canals to improve the prognosis 195 …”

Effective design of organic luminogens for near-infrared-II fluorescence imaging and photo-mediated therapy

“…When dissolved in chloroform, the maximum absorption peak was at 847 nm and an extinction coefficient of 56.71 L cm −1 g −1 was obtained. PBDT-DIID, a novel D–A conjugated polymer, was developed and synthesized by Duan et al 59 The absorption band of the polymer PBDT-DIID ranged from 700 to1000 nm, with a peak at 776 nm. PBDT-DIID has a high molar extinction coefficient of 24.8 L g −1 cm −1 due to its improved molecular conjugation.…”

“…Because the BTII has a narrow bandgap and effective absorption in the NIR-II window, it can be used as the NIR-II absorbing photoacoustic agent. 57 Chen et al 58 59 The absorption band of the polymer PBDT-DIID ranged from 700 to1000 nm, with a peak at 776 nm. PBDT-DIID has a high molar extinction coefficient of 24.8 L g À1 cm À1 due to its improved molecular conjugation.…”

An acceptor-shielding strategy of photosensitizers for enhancing the generation efficiency of type I reactive oxygen species and the related photodynamic immunotherapy

“…Facing the increasing incidence of cancer, efficient treatment methods are urgently needed but challenging for scientists and doctors. 1–4 Among existing treatment methods, photodynamic therapy (PDT) has been focused on specific tumors due to its minimal trauma and precise selectivity. 5–7 More importantly, PDT has potential for synergistic treatment with other therapies.…”