Enhancing Both Biodegradability and Efficacy of Semiconducting Polymer Nanoparticles for Photoacoustic Imaging and Photothermal Therapy

TLDR

Theranostic nanoagents hold promise for precision medicine, yet biodegradable agents capable of photoacoustic imaging‑guided photothermal therapy remain scarce. The study reports the development of biodegradable semiconducting polymer nanoparticles with improved photoacoustic imaging and photothermal therapy efficacy for cancer treatment. The authors synthesized a biodegradable semiconducting polymer (DPPV) by exploiting enzymatically oxidizable vinylene bonds and polymer chemistry, then converted it into water‑soluble nanoparticles (SPNV). SPNV exhibited a 1.3‑fold increase in mass absorption and a 2.4‑fold boost in photothermal conversion, producing stronger PA signals and higher temperatures that enabled more sensitive tumor detection and effective photothermal ablation in mice, demonstrating a general design strategy to enhance biodegradability and therapeutic performance of optically active polymer nanoparticles.

Abstract

Theranostic nanoagents are promising for precision medicine. However, biodegradable nanoagents with the ability for photoacoustic (PA) imaging guided photothermal therapy (PTT) are rare. We herein report the development of biodegradable semiconducting polymer nanoparticles (SPNs) with enhanced PA and PTT efficacy for cancer therapy. The design capitalizes on the enzymatically oxidizable nature of vinylene bonds in conjunction with polymer chemistry to synthesize a biodegradable semiconducting polymer (DPPV) and transform it into water-soluble nanoparticles (SPNV). As compared with its counterpart SPN (SPNT), the presence of vinylene bonds within the polymer backbone also endows SPNV with a significantly enhanced mass absorption coefficient (1.3-fold) and photothermal conversion efficacy (2.4-fold). As such, SPNV provides the PA signals and the photothermal maximum temperature higher than SPNT, allowing detection and photothermal ablation of tumors in living mice in a more sensitive and effective way. Our study thus reveals a general molecular design to enhance the biodegradability of optically active polymer nanoparticles while dramatically elevating their imaging and therapeutic capabilities.