Spatio‐Temporally Reporting Dose‐Dependent Chemotherapy via Uniting Dual‐Modal MRI/NIR Imaging

Click Synthesis Enabled Sulfur Atom Strategy for Polymerization-Enhanced and Two-Photon Photosensitization

Facile tailoring of photosensitizers (PSs) with advanced and synergetic properties is highly expected to broaden and deepen photodynamic therapy (PDT) applications. Herein, a catalyst-free thiol-yne click reaction was employed to develop the sulfur atom-based PSs by using the in situ formed sulfur "heavy atom effect" to enhance the intersystem crossing (ISC), while such an effect can be remarkably magnified by the polymerization. The introduction of a tetraphenylpyrazine-based aggregation-induced emission (AIE) unit was also advantageous in PS design by suppressing their non-radiative decay to facilitate the ISC in the aggregated state. Besides, the resulting sulfur atom electron donor, together with a double-bond π bridge and AIE electron acceptor, created a donor-π-acceptor (D-π-A) molecular system with good two-photon excitation properties. Combined with the high singlet oxygen generation efficiency, the fabricated polymer nanoparticles exhibited an excellent in vitro two-photon-excited PDT towards cancer cells, therefore possessing a huge potential for the deep-tissue disease therapy.

Smart Nanozyme Platform with Activity-Correlated Ratiometric Molecular Imaging for Predicting Therapeutic Effects

Nanozymes with intrinsic enzyme-like characteristics have attracted enormous research interest in biological application. However, there is a lack of facile approach for evaluating the catalytic activity of nanozymes in living system. Herein, we develop a novel manganese-semiconducting polymer-based nanozyme (MSPN) with oxidase-like activity for reporting the catalytic activity of itself in acid-induced cancer therapy via ratiometric near-infrared fluorescence (NIRF)-photoacoustic (PA) molecular imaging. Notably, MSPN possess oxidase-like activity in tumor microenvironment, owing to the mixed-valent MnOx nanoparticles, which can effectively kill cancer cells. Because the semiconducting polymer (PFODBT) is conjugated with oxidase-responsive molecule (ORM), the catalytic activity of nanozyme can be correlated with the ratiometric signals of NIRF (FL₆₉₅ /FL₈₂₅ ) and PA (PA₆₈₀ /PA₇₈₀ ), which may provide new ideas for predicting anticancer efficacy of nanozymes in living system.

Singlet Oxygen Generation in Dark-Hypoxia by Catalytic Microenvironment-Tailored Nanoreactors for NIR-II Fluorescence-Monitored Chemodynamic Therapy

Singlet oxygen (¹ O₂ ) has a potent anticancer effect, but photosensitized generation of ¹ O₂ is inhibited by tumor hypoxia and limited light penetration depth. Despite the potential of chemodynamic therapy (CDT) to circumvent these issues by exploration of ¹ O₂ -producing catalysts, engineering efficient CDT agents is still a formidable challenge since most catalysts require specific pH to function and become inactivated upon chelation by glutathione (GSH). Herein, we present a catalytic microenvironment-tailored nanoreactor (CMTN), constructed by encapsulating MoO₄ ^2- catalyst and alkaline sodium carbonate within liposomes, which offers a favorable pH condition for MoO₄ ^2- -catalyzed generation of ¹ O₂ from H₂ O₂ and protects MoO₄ ^2- from GSH chelation owing to the impermeability of liposomal lipid membrane to ions and GSH. H₂ O₂ and ¹ O₂ can freely cross the liposomal membrane, allowing CMTN with a built-in NIR-II ratiometric fluorescent ¹ O₂ sensor to achieve monitored tumor CDT.