Semiconducting Polymer Nanoparticles in the Second Near-Infrared Region for Biomedical Imaging and Therapy

Semiconducting polymers are attractive optical materials in optoelectronic devices and biomedical applications because of their superior optical properties and remarkable versatility. Optical imaging in the second near-infrared window (NIR-II) has become increasingly popular owing to the merits of large penetration depth and high signal to noise ratio, leading to a great deal of interest in the exploration and development of optical probes in the NIR-II region. In this review, recent advances in the development of semiconducting polymer nanoparticles (SPNs) in the NIR-II region for biomedical imaging and therapeutics are summarized. This review focuses on the design strategies in semiconducting polymers toward enhancing their NIR-II emission for deep tissue imaging, improving their performance in photoacoustic imaging, utilizing their large absorptivity for photothermal and photodynamic therapy, and a number of comprehensive applications for multifunctional imaging and optical therapeutics. Finally, the current challenges of semiconducting polymer probes are discussed and the perspectives on the future development in the field are shared.