ZIF-8, as an important photoresponsive metal-organic framework (MOF), holds great promise in the field of cancer theranostics owing to its versatile physiochemical properties. However, its photocatalytic anticancer application is still restricted because of the wide bandgap and specific response to ultraviolet light. Herein, we developed lanthanide-doped nanoparticles (LDNPs) coated with Fe/Mn bimetal-doped ZIF-8 (LDNPs@Fe/Mn-ZIF-8) for second near-infrared (NIR-II) imaging-guided synergistic photodynamic/chemodynamic therapy (PDT/CDT). The LDNPs were synthesized by encapsulating an optimal Yb3+/Ce3+-doped active shell on the NaErF4:Tm core to achieve dual-mode red upconversion (UC) and NIR-II downconversion (DC) emission upon NIR laser irradiation. At the optimal doping concentration, the UC and DC NIR-II emission intensities of LDNPs were increased 30.2- and 13.2-fold above those of core nanoparticles, which endowed LDNPs@Fe/Mn-ZIF-8 with an outstanding capability to carry out UC-mediated PDT and NIR-II optical imaging. In addition, the dual doping of Fe2+/Mn2+ markedly decreased the bandgap of the ZIF-8 photosensitizer from 5.1 to 1.7 eV, expanding the excitation threshold of ZIF-8 to the visible light region (∼650 nm), which enabled Fe/Mn-ZIF-8 to be efficiently excited by UC photons to achieve photocatalytic-driven PDT. Furthermore, Fe2+/Mn2+ ions could be responsively released in the tumor microenvironment through degradation of Fe/Mn-ZIF-8, thereby producing hydroxyl radicals (·OH) by Fenton/Fenton-like reactions to realize CDT. Meanwhile, the degradation of Fe/Mn-ZIF-8 endowed the nanosystems with tumor self-enhanced NIR-II imaging function, providing precise guidance for CDT/PDT.

Fe/Mn Bimetal-Doped ZIF-8-Coated Luminescent Nanoparticles with Up/Downconversion Dual-Mode Emission for Tumor Self-Enhanced NIR-II Imaging and Catalytic Therapy.

Owing to high antibiotic resistance and thermotolerance, bacterial biofilm infections (BBIs) are refractory to elimination. Iron is essential for bacterial growth and metabolism, and bacteria can thus accumulate iron from surrounding cells to maintain biofilm formation and survival. Consequently, iron deficiency in the biofilm microenvironment (BME) leads to the functional failure of innate immune cells. Herein, a novel antibiofilm strategy of iron‐actuated Janus ion therapy (IJIT) is proposed to regulate iron metabolism in both bacterial biofilm and immune cells. A BME‐responsive photothermal microneedle patch (FGO@MN) is synthesized by the growth of Fe3O4 nanoparticles on graphene oxide nanosheets and then encapsulated in methacrylated hyaluronic acid needle tips. The catalytic product of ·OH by FGO@MN in BME disrupts the bacterial heat‐shock proteins, coercing biofilm thermal sensitization. As synergistic mild photothermal treatment triggers iron uptake, the intracellular iron overload further induces ferroptosis‐like death. Moreover, iron‐nourished neutrophils around BME can be rejuvenated for reactivating the suppressed antibiofilm function. Thus, more than 95% BBIs elimination can be achieved by combining heat stress‐triggered iron interference with iron‐nutrient immune reactivation. Furthermore, in vivo experiments validate the scavenging of refractory BBI after 15 days, suggesting the promising perspective of IJIT in future clinical application.

Photothermal Nanozyme‐Based Microneedle Patch against Refractory Bacterial Biofilm Infection via Iron‐Actuated Janus Ion Therapy

Upregulation of heat shock proteins (HSPs) drastically compromises the treatment effect of mild photothermal therapy (PTT). Herein, we designed a polyporous Cu single atom nanozyme (Cu SAzyme) loaded with licogliflozin (LIK066) for HSP-silencing induced mild PTT. On one hand, LIK066 inhibits glucose uptake by shutting sodium-dependent glucose transporter (SGLT) "valve", effectively blocking the energy source for adenosine triphosphate (ATP) generation. Without sufficient energy, cancer cells cannot synthesize HSPs. In this work, Cu SAzyme presents extraordinary multienzyme activities to induce reactive oxygen species (ROS) storm formation, which can damage the existing HSPs in cancer cells. Through a two-pronged strategy of SGLT inhibitor and ROS storm, LIK066-loaded Cu SAzyme shows high efficiency for comprehensive removal of HSPs to realize mild PTT.

Cu Single Atom Nanozyme Based High-Efficiency Mild Photothermal Therapy through Cellular Metabolic Regulation.

Lipid peroxides accumulation induced ferroptosis is an effective cell death pathway for cancer therapy. However, the hypoxic condition of tumor microenvironment significantly suppresses the efficacy of ferroptosis. Here, we design a novel nanoplatform to overcome hypoxia-induced ferroptosis resistance. Specifically, we synthesized a novel kind of perfluorocarbon (PFOB) @ manganese oxide (MnOx) core-shell nanoparticles (PM-CS NPs). Owing to the good carrier of O2 as fuel, PM-CS NPs could induce higher level of ROS generation, lipid peroxidation and GSH depletion, as well as lower activity of GPX4, compared with MnOx NPs alone. Moreover, the supplement of O2 could relieve tumor hypoxia to break down the storage of intracellular lipid droplets and increase expression of ACSL4 (a symbol for ferroptosis sensitivity). Furthermore, upon stimulus of GSH or acidity, PM-CS NPs exhibit the "turn on" 19F-MRI signal and activatable T1/T2-MRI contrast for correlating with the release of Mn. Finally, PM-CS NPs exert high cancer inhibition rate for ferroptosis based therapy via synergetic combination of O2-mediated enhancement of key pathways of ferroptosis.

Overcoming Hypoxia-Induced Ferroptosis Resistance via 19F/1H-MRI Traceable Core-Shell Nanostructure.

Extensive research have been devoted to the exploration of multifunctional theranostic agents for cancer, but the poor tumor specificity and unsatisfactory treatment efficacy are some of the critical obstacles for their clinical translations. Herein, ferrocene‐carbon dot‐crosslinked nanoparticles (Fc‐CD NPs) were designed and fabricated for achieving highly specific and photothermal‐augmented chemodynamic therapy (CDT). The Fc‐CD NPs were found not only to inherit the immanent fluorescence, photoacoustic, and photothermal properties of carbon dots (CDs), but also be endowed with CDT that could occur selectively in tumor microenvironment (TME) due to the presence of Fc for triggering Fenton reaction. Moreover, the enlarged particle size of Fc‐CD NPs facilitated their effective accumulation at tumor sites, thus realizing great improvement for antitumor treatment outcomes. Once docking at tumor and being exposed to 660 nm laser irradiation, significantly amplified CDT effect of Fc‐CD NPs was observed due to heat‐accelerating generation of reactive oxygen species (ROS). More interestingly, since the produced ROS could in turn alleviate the thermal‐resistance of photothermal therapy (PTT), the therapeutic efficiency of integrated PTT and CDT was synergized to the maximum extent. This study on the one hand provides a facile approach to fabricate CDs‐based multifunctional theranostic nanoplatform with enhanced tumor accumulation and specificity, on the other hand emphasizes the merits of synergizing mutually beneficial therapeutic modalities for more efficient cancer therapy.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/smm2.1119

Tumor‐specific and photothermal‐augmented chemodynamic therapy by ferrocene‐carbon dot‐crosslinked nanoparticles

Combination therapy based on different mechanisms of cell death has shown promise in tumor therapy. However, when different modalities are integrated, the maximum synergy of the therapeutic effects is often lacking in the design. Herein, we report a cancer theranostic nanomedicine formula developed by considering the mechanisms of action of ferroptosis and the photothermal effect in combination therapy. The croconaine molecule was encapsulated as both a photothermal converter and an iron-chelating agent with BSA, thus leading to biocompatible and stable Cro-Fe@BSA nanoparticles (NPs). The Cro-Fe@BSA NPs in the tumor milieu showed an activated photothermal effect leading to enhanced radical formation owing to the temperature-dependent Fenton reaction kinetics, while radical formation during ferroptosis in turn prevented the heat-induced formation of heat shock proteins and thus the self-protection mechanism of cancer cells in response to heat. The activatable photoacoustic and magnetic resonance imaging performance of the Cro-Fe@BSA NPs also enabled safe and reliable cancer theranostics. 

Yanping Tan

Papers

Coordinating the Mechanisms of Action of Ferroptosis and the Photothermal Effect for Cancer Theranostics

Coordinating the Mechanisms of Action of Ferroptosis and the Photothermal Effect for Cancer Theranostics