Optimierung photodynamischer Krebstherapien auf der Grundlage physikalisch‐chemischer Faktoren

Tumor Microenvironment Responsive Single-Atom Nanozymes for Enhanced Antitumor Therapy

Single-atom nanozymes (SAzymes) with specific response to the unique tumor microenvironment (TME) feature providing 100% metal atoms utilization for high-efficient enzyme-catalyzed therapy and accurate template for the study of therapeutic mechanisms. In this review, we first introduce the various synthetic strategies of SAzymes, and the TME-responsive SAzymes activities. Next, the TME-responsive enhanced antitumor therapeutic approaches based on the enzymatic activities of SAzymes are summarized, and the corresponding therapy mechanisms are elaborated. Subsequently, a concise but concentrated summary, and the challenges and opportunities for the future design and engineering of SAzyme are outlined. As a newly-built discipline, SAzymes have vast space for development in enhanced antitumor therapy. This timely review provides guidance and constructive suggestions for the future of SAzymes.

Aggregation-Enhanced Sonodynamic Activity of Phthalocyanine-Artesunate Conjugates

The clinical prospect of sonodynamic therapy (SDT) has not been fully realized due to the scarcity of efficient sonosensitizers. Herein, we designed phthalocyanine-artesunate conjugates (e.g. ZnPcT₄ A), which could generate up to ca. 10-fold more reactive oxygen species (ROS) than the known sonosensitizer protoporphyrin IX. Meanwhile, an interesting and significant finding of aggregation-enhanced sonodynamic activity (AESA) was observed for the first time. ZnPcT₄ A showed about 60-fold higher sonodynamic ROS generation in the aggregated form than in the disaggregated form in aqueous solutions. That could be attributed to the boosted ultrasonic cavitation of nanostructures. The level of the AESA effect depended on the aggregation ability of sonosensitizer molecules and the particle size of their aggregates. Moreover, biological studies demonstrated that ZnPcT₄ A had high anticancer activities and biosafety. This study thus opens up a new avenue the development of efficient organic sonosensitizers.

Ultrasound-Enhanced Self-Exciting Photodynamic Therapy Based on Hypocrellin B

Peroxalate CL as an energy source to excite photosensitizers has attracted tremendous attention in photodynamic therapy (PDT). In this work, peroxyoxalate CPPO and hypocrellin B (HB)-based nanoparticles (CBNPs) for ultrasound (US)-enhanced self-exciting PDT were designed and prepared. CBNPs showed an excellent therapeutic effect against cancer cells with the assistance of US. This US-enhanced-chemiluminescence system avoids the dependence on external light and provides an example for inspiring more effective and precise strategies for cancer treatment.

A Near-Infrared Photo-Switched MicroRNA Amplifier for Precise Photodynamic Therapy of Early-Stage Cancers

Stimuli-responsive photodynamic therapy (PDT) is a hot topic in precise medicine, but the low abundance of responsive trigger molecules in early-stage disease limits application. Here we designed an amplifier with multiple upconversion luminances to achieve a near-infrared photo-switched cascade reaction triggered by specific microRNA and precise PDT of early-stage cancers. This amplifier was composed of photo-caged DNA nanocombs and an upconversion nanoparticle (UCNP) sensitized with IRDye 800CW. The nanocomb was prepared by assembling a photozipper-protected hairpin and two kinds of hybridizable hairpin probes on a DNA skeleton. Upon 808-nm light irradiation, the produced UV light cleaved off the photozipper to induce microRNA-responsive cascade hybridization reaction, activating the photosensitizers linked to different hairpins to generate reactive oxygen species (ROS) under the simultaneously emitted blue light for efficient PDT.