Polymerization of Aniline Derivative for NIR-II Phototheranostics of Tumor.

Natural biopolymers can be controllably synthesized in organisms and play important roles in biological activities. Inspired by this, the manipulation of biosynthesis of functional polymers will be an important way to obtain materials for meeting biological requirements. Herein, biosynthesis of functional conjugated polymer at the tumor site was achieved via the utilization of specific tumor microenvironment (TME) characteristics for the first time. Specially, a water-soluble aniline dimer derivative (-(3-sulfopropyl) -aminodiphenylamine, SPA) was artfully polymerized into polySPA (PSPA) nanoparticles at the tumor site, which was activated via the catalysis of hydrogen peroxide (HO) overexpressed in TME to produce hydroxyl radical (•OH) by coinjected horseradish peroxidase (HRP). Benefiting from outstanding near-infrared (NIR)-II absorption of PSPA, the polymerization process can be validly monitored by photoacoustic (PA) signal at the NIR-II region. Meanwhile, polymerization would induce the size of polymeric materials from small to large, improving the distribution and retention of PSPA at the tumor site. On the combination of NIR-II absorption of PSPA and the size variation induced by polymerization, such polymerization can be applied for tumor-specific NIR-II light mediated PA image and photothermal inhibition of tumors, enhancing the precision and efficacy of tumor phototheranostics. Therefore, the present work opens the way to manipulate TME-activated biosynthesis of functional conjugated polymer at the tumor site for overcoming formidable challenges in tumor theranostics.