A Facile Ion-Doping Strategy To Regulate Tumor Microenvironments for Enhanced Multimodal Tumor Theranostics

Nanozymes-Engineered Metal-Organic Frameworks for Catalytic Cascades-Enhanced Synergistic Cancer Therapy

The efficiency of chemical intercommunication between enzymes in natural networks can be significantly enhanced by the organized catalytic cascades. Nevertheless, the exploration of two-or-more-enzymes-engineered nanoreactors for catalytic cascades remains a great challenge in cancer therapy because of the inherent drawbacks of natural enzymes. Here, encouraged by the catalytic activity of the individual nanozyme for benefiting the treatment of solid tumors, we propose an organized in situ catalytic cascades-enhanced synergistic therapeutic strategy driven by dual-nanozymes-engineered porphyrin metal-organic frameworks (PCN). Precisely, catalase-mimicking platinum nanoparticles (Pt NPs) were sandwiched by PCN, followed by embedding glucose oxidase-mimicking ultrasmall gold nanoparticles (Au NPs) within the outer shell, and further coordination with folic acid (P@Pt@P-Au-FA). The Pt NPs effectively enabled tumor hypoxia relief by catalyzing the intratumoral H₂O₂ to O₂ for (1) enhancing the O₂-dependent photodynamic therapy and (2) subsequently accelerating the depletion of β-d-glucose by Au NPs for synergistic starving-like therapy with the self-produced H₂O₂ as the substrate for Pt NPs. Consequently, a remarkably strengthened antitumor efficiency with prevention of tumor recurrence and metastasis was achieved. This work highlights a rationally designed tumor microenvironment-specific nanoreactor for opening improved research in nanozymes and provides a means to design a catalytic cascade model for practical applications.

MnFe2O4-decorated large-pore mesoporous silica-coated upconversion nanoparticles for near-infrared light-induced and O2 self-sufficient photodynamic therapy

The limited light penetration depth and tumor hypoxia are two natural shortcomings of photodynamic therapy (PDT). Overcoming these two issues within a single system is still a great challenge. Herein, photosensitizer (PS)-loaded and PEG-modified MnFe2O4-decorated large-pore mesoporous silica-coated β-NaYF4:20%Yb,2%Er@β-NaYF4 upconversion nanoparticles (UCMnFe-PS-PEG) as excellent PDT agents are successfully prepared for NIR light-mediated and O2 self-sufficient PDT. The large mesoporous structure observably increases PS loading efficiency (11.33 wt%) and the green luminescence from upconversion nanoparticles activated by NIR is able to activate PSs to generate ROS effectively. In addition, sub-10 nm MnFe2O4 nanoparticles work as a Fenton catalyst to generate O2in situ. In vivo experiments further prove that UCMnFe-PS-PEG not only provides magnetic guidance to the tumor, but also overcomes tumor hypoxia and dramatically enhances PDT efficiency. Furthermore, in vivo MR and UCL imaging are performed for accurate cancer therapy. We believe that the successful construction of the multifunctional UCMnFe-PS-PEG provides more revelations for developing advanced nano-drug systems for cancer therapy.

Coordinatively Unsaturated Fe3+ Based Activatable Probes for Enhanced MRI and Therapy of Tumors

Exogenous Fe^III can be used for cancer magnetic resonance (MR) imaging and potentially for cancer treatment by a ferroptosis pathway or photothermal ablation. To achieve this, effective and accurate delivery of Fe^III to cancerous sites is critical, requiring a balance of release kinetics of Fe³⁺ in tumorous and normal tissues. A nanoprobe is described consisting of upconversion luminescence (UCL) nanoparticles as a core and a coordinatively unsaturated Fe^III -containing Fe³⁺ /gallic acid complex as a shell. Owing to the introduction of an unsaturated coordination structure, Fe^III in the nanoprobe can be released only in the tumor microenvironment in response to the lightly acidic pH. The multiple UCLs are used for quantitatively visualizing the release of Fe³⁺ in vivo, whilst the release resultant serves as a photothermal agent. This nanoprobe exhibited ligand-free tumor targeting ability, activatable MR imaging performance, and efficacious therapeutic effects against tumors in vivo.

Reasonably retard O2 consumption through a photoactivity conversion nanocomposite for oxygenated photodynamic therapy

Photodynamic therapy (PDT) brings excellent treatment outcome while also causing poor tumor microenvironment and prognosis due to the uncontrolled oxygen consumption. To solve this issue, a novel PDT strategy, oxygenated PDT (maintain the tumor oxygenation before and after PDT) was carried out by a tumor and apoptosis responsive photoactivity conversion nanocomposite (MPPa-DP). Under physiological conditions, this nanocomposite has a low photoactivity. While at H₂O₂-rich tumor microenvironment, the nanocomposite could react with overexpressed H₂O₂ to produce O₂ and release high photoactivity chimeric peptide PPa-DP for oxygenated tumor and PDT. Importantly, when the PDT mediates cell apoptosis, the photoactivity of PPa-DP be effectively quenched and the O₂ consumption appeared retard, which avoided further consumption of residual O₂ on apoptotic cells. In vitro and vivo studies revealed that this nanocomposite could efficiently change photoactivity, reasonable control O₂ consumption and increase residual O₂ content of tumor after PDT.

A Mn(III)-Sealed Metal-Organic Framework Nanosystem for Redox-Unlocked Tumor Theranostics

Here, a Mn(III)-sealed metal-organic framework (MOF) nanosystem based on coordination between Mn(III) and porphyrin (TCPP) via a one-pot method was designed and constructed. Mn(III), as a sealer, not only quenched TCPP-based fluorescence but also inhibited reactive oxygen species (ROS) generation, which made MOFs an "inert" theranostic nanoparticle. Interestingly, upon endocytosis by tumor cells, MOFs were disintegrated into Mn(II) and free TCPP by intracellular glutathione (GSH) in tumor cells, owing to redox reaction between Mn(III) and GSH. This disintegration would lead to consumption of antioxidant GSH and activated Mn(II)-based magnetic resonance imaging (MRI) as well as TCPP-based fluorescent imaging. More importantly, such a GSH-regulated TCPP release could implement controllable ROS generation under irradiation, which avoided side effects (inflammation and damage of normal tissues). As a consequence, after unlocking by GSH, Mn(III)-sealed MOFs could significantly improve the therapeutic efficiency of photodynamic therapy by combining controlled ROS generation and GSH depletion after precise dual tumor homing.

Catalase-like metal-organic framework nanoparticles to enhance radiotherapy in hypoxic cancer and prevent cancer recurrence

Tumor hypoxia typically occurs inside a solid tumor with an inadequate oxygen supply, sharply reducing the therapeutic efficiency of radiotherapy and significantly increasing the risk of local tumor recurrence. Herein, we designed folic acid modified enzyme-like hafnium-based manganoporphyrin metal-organic framework nanoparticles (MnTCPP-Hf-FA MOF NPs) to overcome hypoxia-induced radioresistance and prevent postoperative recurrence. Hf, a high-Z element, can effectively absorb X-ray energy and convert O2 and H2O into reactive oxygen species to induce cell apoptosis. The MnTCPP ligand has an enzyme-like ability to catalytically decompose endogenous H2O2 into O2 for enhancing RT in hypoxic tumors. In vivo experiments revealed that the MOF NPs could effectively inhibit melanoma growth and prevent tumor postoperative recurrence with only one X-ray irradiation after intravenous injection. We expect that the current study provides a versatile approach for solving the critical radioresistance issue of hypoxic tumors.

Specific Generation of Singlet Oxygen through the Russell Mechanism in Hypoxic Tumors and GSH Depletion by Cu-TCPP Nanosheets for Cancer Therapy

The generation of singlet oxygen (¹ O₂ ) during photodynamic therapy is limited by the precise cooperation of light, photosensitizer, and oxygen, and the therapeutic efficiency is restricted by the elevated glutathione (GSH) levels in cancer cells. Herein, we report that an ultrathin two-dimensional metal-organic framework of Cu-TCPP nanosheets (TCPP=tetrakis(4-carboxyphenyl)porphyrin) can selectively generate ¹ O₂ in a tumor microenvironment. This process is based on the peroxidation of the TCPP ligand by acidic H₂ O₂ followed by reduction to peroxyl radicals under the action of the peroxidase-like nanosheets and Cu²⁺ , and their spontaneous recombination reaction by the Russell mechanism. In addition, the nanosheets can also deplete GSH. Consequently, the Cu-TCPP nanosheets can selectively destroy tumor cells with high efficiency, constituting an attractive way to overcome current limitations of photodynamic therapy.

Nitroreductase-Activatable Theranostic Molecules with High PDT Efficiency under Mild Hypoxia Based on a TADF Fluorescein Derivative

High specificity detection and site-specific therapy are still the main challenges for theranostic anticancer prodrugs. In this work, we reported two smart activatable theranostic molecules based on a thermally activated delayed fluorescence fluorescein derivative. Nitroreductase induced by a mild hypoxia microenvironment of a solid tumor was used to activate the fluorescence and photodynamic therapy (PDT) efficiency by employing the intramolecular photoinduced electron transfer mechanism. A high PDT efficiency under 10% oxygen concentration was achieved, which is better than that of porphyrin (PpIX), a traditional photosensitizer. Such an excellent PDT efficiency can be attributed to lysosome disruption because the theranostic molecule can specifically enter the lysosomes of cells. Importantly, the strategy of targeting the mild hypoxic cells in the edge of tumor tissue could heal the "Achilles' heel" of traditional PDT. We believe that this theranostic molecule has a high potential to be applied in clinical investigation as a theranostic anticancer prodrug.

Photocatalysis Enhancement for Programmable Killing of Hepatocellular Carcinoma through Self-Compensation Mechanisms Based on Black Phosphorus Quantum-Dot-Hybridized Nanocatalysts

Recently reported black phosphorus quantum dots (BPQDs) possess unique photocatalysis activities. However, the environmental instability accompanied by a hypoxic tumor microenvironment (TME) seriously hindered the bioapplications of BPQDs, especially in oxygen-dependent photodynamic therapy (PDT). Here, we construct a hepatocellular carcinoma (HCC)-specific targeting aptamer "TLS11a"-decorated BPQDs-hybridized nanocatalyst, which can specifically target HCC tumor cells and self-compensate oxygen (O₂) into hypoxic TME for enhancing PDT efficiency. The BPQD-hybridized mesoporous silica framework (BMSF) with in situ synthesized Pt nanoparticles (PtNPs) in the BMSF is simply prepared. After being decorated by TLS11a aptamer/Mal-PEG-NHS, the resultant nanosystem (refer as Apt-BMSF@Pt) exhibits excellent environmental stability, active targeting ability to HCC cells, and self-compensation ability of oxygen. Compared with the PEG-BMSF@Pt without H₂O₂ incubation, the PEG-BMSF@Pt nanocatalyst exhibits 4.2-folds O₂ and 1.6-folds ¹O₂ generation ability in a mimetic closed-system in the presence of both H₂O₂ and near-infrared laser. In a mouse model, the Apt-BMSF@Pt can effectively accumulate into tumor sites, and the core of BMSF subsequently can act as a photosensitizer to generate reactive oxygen species, while the PtNPs can serve as a catalyst to convert H₂O₂ into O₂ for enhancing PDT through self-compensation mechanisms in hypoxic TME. By comparison of the tumor volume/weight, H&E, and immunohistochemical analysis, the excellent antitumor effects with minimized side effects of our Apt-BMSF@Pt could be demonstrated in vivo. Taken together, the current study suggests that our Apt-BMSF@Pt could act as an active targeting nanocatalyst for programmable killing of cancer cells in hypoxic TME.

Plasmonic MoO3-x nanoparticles incorporated in Prussian blue frameworks exhibit highly efficient dual photothermal/photodynamic therapy

Development of near infrared (NIR) light-responsive nanomaterials for high performance multimodal phototherapy within a single nanoplatform is still challenging in technology and biomedicine. Herein, a new phototherapeutic nanoagent based on FDA-approved Prussian blue (PB) functionalized oxygen-deficient molybdenum oxide nanoparticles (MoO_3-x NPs) is strategically designed and synthesized by a facile one-pot size/morphology-controlled process. The as-prepared PB-MoO_3-x nanocomposites (NCs) with a uniform particle size of ∼90 nm and high water dispersibility exhibited strong optical absorption in the first biological window, which is induced by plasmon resonance in an oxygen-deficient MoO_3-x semiconductor. More importantly, PB-MoO_3-x NCs not only exhibited a high photothermal conversion efficiency of ∼63.7% and photostability but also offered a further approach for the generation of reactive oxygen species (ROS) upon singular NIR light irradiation which significantly improved the therapeutic efficiency of the PB agent. Furthermore, PB-MoO_3-x NCs showed a negligible cytotoxic effect in the dark, but an excellent therapeutic effect toward two triple-negative breast cancer (TNBC) cell lines at a low concentration (20 μg mL^-1) of NCs and a moderate NIR laser power density. Additionally, efficient tumor ablation and metastasis inhibition in a 4T1 TNBC mouse tumor model can also be realized by synergistic photothermal/photodynamic therapy (PTT/PDT) under a single continuous NIR wave laser. Taken together, this study paved the way for the use of a single nanosystem for multifunctional therapy.

Smart Metal-Organic Framework-Based Nanoplatforms for Imaging-Guided Precise Chemotherapy

Good biocompatibility, active tumor targeting, and stimulus-responsive release offer great opportunity for precise imaging-guided tumor treatment. However, the current strategies for the fabrication of smart theranostic platforms suffer from tedious synthesis processes. Here, we propose a universal and facile strategy for the fabrication of smart nanoscale metal-organic framework (NMOF)-based nanoplatforms for imaging-guided precise chemotherapy. As a proof of concept, 5-boronobenzene-1,3-dicarboxylic acid (BBDC), as a versatile ligand, was employed for the first time with Gd³⁺ as metal nodes to prepare a smart magnetic resonance (MR) imaging-guided drug-delivery system. Specific reversible diol-borate condensation enables effortless coating of glucose on the NMOFs to improve their biocompatibility. The specific interaction between glucose and glucose-transported protein ensures active tumor-targeting ability. Moreover, the glucose layer, as a pH-responsive diol-borate gatekeeper, prevents the premature leakage of drugs. The proposed smart theranostic nanoplatform was well used in MR imaging-guided tumor-targeted precise chemotherapy. This strategy is simply extended to the design of other MOF-glucose composites for diverse applications, such as X-ray computed tomography imaging of gastrointestinal tract with Yb-MOFs-Glu. BBDC, as a functional ligand, provides a simple and universal way to fabricate smart NMOF theranostic platforms with multifunction as "three birds with one stone". The facile and universal strategy lays down a new way to develop multifunctional nanoagents for precision medicine.

GE11-PDA-Pt@USPIOs nano-formulation for relief of tumor hypoxia and MRI/PAI-guided tumor radio-chemotherapy

GE11-PDA-Pt@USPIOs can relieve tumor hypoxic conditions efficiently and are highly effective for radio-chemotherapy of EGFR-positive tumors.

H2O2-activated oxidative stress amplifier capable of GSH scavenging for enhancing tumor photodynamic therapy

An oxidative stress amplifier (OSA) capable of GSH scavenging and accelerated release by positive feedback was fabricated for enhancing the efficacy of tumor photodynamic therapy (PDT).

De Novo Design of Polymeric Carrier to Photothermally Release Singlet Oxygen for Hypoxic Tumor Treatment

Intratumoral hypoxia extremely limits the clinic applications of photodynamic therapy (PDT). Endoperoxides allow thermally releasing singlet oxygen (¹O₂) in a defined quantity and offer promising opportunities for oxygen-independent PDT treatment of hypoxic tumors. However, previous composite systems by combining endoperoxides with photothermal reagents may result in unpredicted side effects and potential harmful impacts during therapy in vivo. Herein, we de novo design an all-in-one polymer carrier, which can photothermally release ¹O₂. The strategy has been demonstrated to effectively enhance the production of ¹O₂ and realize the photodamage in vitro, especially in hypoxic environment. Additionally, the polymer carrier accumulates into tumor after intravenous injection via the enhanced permeation and retention effects and accelerates the oxygen-independent generation of ¹O₂ in tumors. The oxidative damage results in good inhibitory effect on tumor growth. Realization of the strategy in vivo paves a new way to construct photothermal-triggered oxygen-independent therapeutic platform for clinical applications.

Sulfosalicylic acid/Fe3+ based nanoscale coordination polymers for effective cancer therapy by the Fenton reaction: an inspiration for understanding the role of aspirin in the prevention of cancer

A new type of pH-responsive nanoscale coordination polymer for ROS-enhanced cancer therapy.

A glucose/O2 fuel cell-based self-powered biosensor for probing a drug delivery model with self-diagnosis and self-evaluation

Extending the application of self-powered biosensors (SPB) into the drug delivery field is highly desirable. Herein, a robust glucose/O2 fuel cell-based biosensor is successfully integrated with a targeted drug delivery system to create a self-sustained and highly compact drug delivery model with self-diagnosis and self-evaluation (DDM-SDSE). The glucose/O2 fuel cell-based biosensor firstly performs its diagnostic function by detecting the biomarkers of cancer. The drug delivery system attached on the anode of the glucose/O2 fuel cell can be released during the diagnostic operation to guarantee the occurrence of a therapy process. Accompanied by the therapy process, the glucose/O2 fuel cell-based biosensor can also act as an evaluation component to dynamically monitor the therapy efficacy by analyzing drug-induced apoptotic cells. In addition, the use of an abiotic catalyst largely improves the stability of the glucose/O2 fuel cell without sacrificing the output performance, further ensuring long-time dynamic evaluation as well as highly sensitive diagnosis and evaluation in this DDM-SDSE. Therefore, the present study not only expands the application of SPBs but also offers a promising in vitro "diagnosis-therapy-evaluation" platform to acquire valuable information for clinical cancer therapy.

A high therapeutic efficacy of polymeric prodrug nano-assembly for a combination of photodynamic therapy and chemotherapy

Combination of photodynamic therapy and chemotherapy has been emerging as a new strategy for cancer treatment. Conventional photosensitizer tends to aggregate in aqueous media, which causes fluorescence quenching, reduces reactive oxygen species (ROS) production, and limits its clinical application to photodynamic therapy. Traditional nanoparticle drug delivery system for chemotherapy also has its disadvantages, such as low drug loading content, drug leakage, and off-target toxicity for normal tissues. Here, we developed a reduction-sensitive co-delivery micelles TB@PMP for combinational therapy, which composed of entrapping a red aggregation-induced emission fluorogen (AIEgen) for photodynamic therapy and PMP that contains a reduction-sensitive paclitaxel polymeric prodrug for chemotherapy. AIEgen photosensitizer illustrates a much improved photostability and ROS production efficiency in aggregate state and PMP loads a high dose of paclitaxel and carries a smart stimuli-triggered drug release property. This co-delivery system provides a better option that replaces AIEgen photosensitizer for cancer diagnosis and therapy.

Xiaoqing Yi et al. report a co-drug delivery micelle system that demonstrates a high therapeutic efficacy for cancer. This system shows a much improved drug load, photostability, and production of reactive oxygen species, compared to traditional photosensitizer-loaded nanoparticles.

Mn-Fe layered double hydroxide nanosheets: a new photothermal nanocarrier for O2-evolving phototherapy

Iron-manganese layered double hydroxide nanosheets were developed as an effective photothermal nanocarrier for loading a photosensitizer. The catalase-like activity enables the nanosheets to decompose H₂O₂ into O₂, overcoming tumor hypoxia and enhancing O₂-dependent photodynamic therapy (PDT). The combination of PDT and photothermal therapy (PTT) can almost completely eliminate tumor tissues.

Delivery of Phosphorescent Anticancer Iridium(III) Complexes by Polydopamine Nanoparticles for Targeted Combined Photothermal-Chemotherapy and Thermal/Photoacoustic/Lifetime Imaging

Recently, phosphorescent iridium complexes have demonstrated great potential as anticancer and imaging agents. Dopamine is a melanin-like mimic of mussel adhesive protein that can self-polymerize to form polydopamine (PDA) nanoparticles that demonstrate favorable biocompatibility, near-infrared absorption, and photothermal effects. Herein, PDA nanoparticles are functionalized with β-cyclodextrin (CD) substitutions, which are further assembled with adamantane-modified arginine-glycine-aspartic acid (Ad-RGD) tripeptides to target integrin-rich tumor cells. The thus formed PDA-CD-RGD nanoparticles can deliver a phosphorescent iridium(III) complexes LysoIr ([Ir(ppy)2(l)]PF6, ppy = 2-phenylpyridine, L = (1-(2-quinolinyl)-β-carboline) to form a theranostic platform LysoIr@PDA-CD-RGD. It is demonstrated that LysoIr@PDA-CD-RGD can be applied for targeted combined cancer photothermal-chemotherapy and thermal/photoacoustic/two-photon phosphorescence lifetime imaging under both in vitro and in vivo conditions. This work provides a useful strategy to construct multifunctional nanocomposites for the optimization of metal-based anticancer agents for further biomedical applications.

An "all-in-one" antitumor and anti-recurrence/metastasis nanomedicine with multi-drug co-loading and burst drug release for multi-modality therapy

Drug-loading often suffers from tedious procedures, limited loading efficiency, slow release, and therefore a low curative effect. Cancer easily recurs and metastasizes even after a solid tumor is removed. Herein, we report a simple strategy with multi-drug co-loading and burst drug release for a high curative effect and anti-recurrence/metastasis. CuS nanoparticles, protoporphyrin IX, and doxorubicin were added to the precursors of ZIF-8 with one-pot co-loading during the formation of ZIF-8 for chemo-, photothermal-, and photodynamic-therapy to eliminate solid tumors. Negative CpG, as a kind of immune adjuvant, was adsorbed on the positive surface of ZIF-8 to inhibit the recurrence and metastasis of tumors with its long-term immune response. Precision treatment with one-pot multi-drug co-loading, controllable drug delivery, and multi-modality therapy may be anticipated by this versatile strategy.

A redox-activated theranostic nanoagent: toward multi-mode imaging guided chemo-photothermal therapy

Development of tumor microenvironment responsive and modulating theranostic nano-systems is of great importance for specific and efficient cancer therapy. Herein, we report a redox-sensitive nanoagent combining manganese dioxide (MnO2) and gold nanoshell coated silicon nanoparticles for synergistic chemo-photothermal therapy of hypoxia solid tumors. In highly reducing tumor tissues, the outer MnO2 nanosheet with the loaded drug would be dissociated by intracellular glutathione (GSH), resulting in on-demand drug release, as well as generating Mn2+ ions which provided high contrast magnetic resonance imaging (MRI), and fluorescence imaging (FI) in vitro and in vivo. While upon near-infrared (NIR) light irradiation, the gold nanoshell modulated the hypoxic tumor microenvironment via increasing blood flow, achieving enhanced photothermal therapy (PTT) and chemotherapy. After tail vein injection into tumor-bearing mice and monitoring in real time, the intelligent redox-activated nanoagent exhibited high tumor accumulation and powerful synergistic chemo-photothermal therapy efficiency. The proposed work developed a noninvasive strategy to modulate the tumor microenvironment and enhance the anticancer therapeutic effect. We believe that this single nano-platform exhibits promising potential as a comprehensive theranostic agent to enhance the efficacies of synergistic cancer therapy.

Dihydroartemisinin increases gemcitabine therapeutic efficacy in ovarian cancer by inducing reactive oxygen species

Ovarian cancer is the major cause of death in women gynecological malignancy and gemcitabine (GEM) is commonly used in related chemotherapy. However, more than 90% GEM is catalyzed into an inactive metabolite 2'-deoxy-2',2'-difluorouridine by stromal and cellular cytidine deaminase (CDA). Dihydroartemisinin (DHA), which possesses an intramolecular endoperoxide bridge, could be activated by heme or ferrous iron to produce reactive oxygen species (ROS). The excess ROS generation will excite expression of heme oxygenase-1 and suppress CDA expression. Under low CDA expression, the inactivation of GEM is decreased in turn to exert excellent therapeutic efficiency. Herein, we first studied the ROS generation by DHA in vitro with A2780 cells by means of flow cytometry and confocal laser scanning microscopy. Furthermore, cytotoxicity assay in vitro showed that DHA + GEM had synergistic effect, with molar ratio of DHA and GEM at 10. Eventually, in A2780 ovarian cancer xenograft tumor model, DHA + GEM exhibited significant antitumor efficiency with lower blood toxicity than GEM alone. Noteworthy, the combination treatment group completely eliminated the tumors on day 14.

Theranostic Mn-Porphyrin Metal-Organic Frameworks for Magnetic Resonance Imaging-Guided Nitric Oxide and Photothermal Synergistic Therapy

Chemotherapy remains restricted by its toxic adverse effects and resistance to drugs. The treatment of nitric oxide (NO) combined with imaging-guided physical therapy is a promising alternative for clinical applications. Herein, we report nanoscale metal-organic framework (NMOF) systems to integrate magnetic resonance (MR) imaging, spatiotemporally controllable NO delivery, and photothermal therapy (PTT) as a new means of cancer theranostics. As a proof of concept, the NMOFs are prepared with biocompatible Zr⁴⁺ ions and Mn-porphyrin as a bridging ligand. By inserting paramagnetic Mn ions into porphyrin rings, Mn-porphyrin renders the NMOFs strong T₁-weighted MR contrast capacity and high photothermal conversion for efficient PTT. S-Nitrosothiol (SNO) is conjugated to the surfaces of the NMOFs for heat-sensitive NO generation. Moreover, single near-infrared (NIR) light triggers the controllable NO release and PTT simultaneously for their efficient synergistic therapy with one-step operation. Upon intravenous injection, NMOF-SNO shows effective tumor accumulation as exposed by the MR images of the tumor-bearing mice. When exposed to the NIR laser, the tumors of mice injected with NMOF-SNO are completely inhibited, verifying the efficiency of NMOF-SNO. For the first time, Mn-porphyrin NMOFs are developed to be an effective theranostic system for MR imaging-guided controllable NO release and photothermal synergetic therapy under single NIR irradiation.

Paclitaxel-Induced Ultrasmall Gallic Acid-Fe@BSA Self-Assembly with Enhanced MRI Performance and Tumor Accumulation for Cancer Theranostics

Ultrasmall nanoparticles have attracted great attention because of their efficient renal clearance. However, their bioapplication is still severely hampered by the poor performance derived from low tumor accumulation. Here, a large, self-assembled nanoparticle was designed for cancer theranostics and used with paclitaxel (PTX) to assemble bovine serum albumin-coated ultrasmall gallic acid-Fe(III) (GA-Fe@BSA-PTX) nanoparticles by the hydrophobic effect. The GA-Fe@BSA-PTX self-assembled nanoparticles featured appropriate size (∼115 nm), high water dispersity and stability, and low cell toxicity. Importantly, the magnetic resonance imaging performance and tumor accumulation of GA-Fe@BSA-PTX self-assembled nanoparticles were much better than those of the ultrasmall GA-Fe@BSA nanoparticles. Furthermore, the GA-Fe@BSA-PTX self-assembled nanoparticles exhibited an excellent therapeutic effect on tumors, owing to the combined chemo- and photothermal effects. This work highlights the great potential of the as-synthesized GA-Fe@BSA-PTX self-assembled nanoparticles as a multifunctional theranostic nanoplatform, offering compelling opportunities for theranostic applications in the clinic.

Multifunctional nanozymes: enzyme-like catalytic activity combined with magnetism and surface plasmon resonance

Over decades, as alternatives to natural enzymes, highly-stable and low-cost artificial enzymes have been widely explored for various applications. In the field of artificial enzymes, functional nanomaterials with enzyme-like characteristics, termed as nanozymes, are currently attracting immense attention. Significant progress has been made in nanozyme research due to the exquisite control and impressive development of nanomaterials. Since nanozymes are endowed with unique properties from nanomaterials, an interesting investigation is multifunctionality, which opens up new potential applications for biomedical sensing and sustainable chemistry due to the combination of two or more distinct functions of high-performance nanozymes. To highlight the progress, in this review, we discuss two representative types of multifunctional nanozymes, including iron oxide nanomaterials with magnetic properties and metal nanomaterials with surface plasmon resonance. The applications are also covered to show the great promise of such multifunctional nanozymes. Future challenges and prospects are discussed at the end of this review.

All-in-One Theranostic Nanoagent with Enhanced Reactive Oxygen Species Generation and Modulating Tumor Microenvironment Ability for Effective Tumor Eradication

Despite regulation of the reactive oxygen species (ROS) level is an intelligent strategy for cancer therapy, the therapeutic effects of ROS-mediated therapy (including photodynamic therapy (PDT) and chemodynamic therapy (CDT)) are limited by oxygen reliance, inherent flaws of traditional photosensitizers, and strict reaction conditions of effective Fenton reaction. Herein, we reported biocompatible copper ferrite nanospheres (CFNs) with enhanced ROS production under irradiation with a 650 nm laser through direct electron transfer and photoenhanced Fenton reaction and high photothermal conversion efficiency upon exposure to an 808 nm laser, exhibiting a considerable improved synergistic treatment effect. Importantly, by exploiting the properties of O₂ generation and glutathione (GSH) depletion of CFNs, CFNs relieve the hypoxia and antioxidant capability of the tumor, achieving photoenhanced CDT and improved PDT. The high relaxivity of 468.06 mM^-1 s^-1 enables CFNs to act as an outstanding contrast agent for MRI in vitro and in vivo. These findings certify the potential of such "all in one" nanotheranostic agent integrated PDT, photoenhanced CDT, photothermal therapy (PTT), and MRI imaging capabilities along with modulating the tumor microenvironment function in theranostics of cancer.

Dual-triggered oxygen self-supply black phosphorus nanosystem for enhanced photodynamic therapy

Nonspecific distribution of photosensitizer and the intrinsic hypoxic condition in the tumor microenvironment are two key factors limiting the efficacy of O₂-dependent photodynamic therapy (PDT). Herein, a dual-triggered oxygen self-supported nanosystem using black phosphorus nanosheet (BPNS) as both photosensitizer and nanocarrier was developed to enhance PDT for tumors within hypoxic microenvironment. The BPNS platform was functionalized with folate and a blocker DNA duplex of 5'-Cy5-aptamer-heme/3'-heme labeled oligonucleotides. The resulting heme dimer could passivate its peroxidase activity. After specific recognition of aptamer-target, the quenched fluorescence is "turned" on by cellular adenosine triphosphate. The passivated nanosystem then activates the catalytic function towards excessive intracellular H₂O₂ to generate O₂ essential to sustain BPNS-mediated PDT, leading to 8.7-fold and 7.5-fold increase of PDT efficacy in treating the hypoxic cell and tumor, respectively. Therefore, the dual-triggered oxygen self-supply nanosystem not only exerts tumor microenvironment-associated stimulus for enhanced PDT but also surmounts hypoxia-associated therapy resistance.

Marriage of artificial catalase and black phosphorus nanosheets for reinforced photodynamic antitumor therapy

Pt nanoparticle-based artificial catalase is decorated on black phosphorus nanosheets, achieving reinforced photodynamic antitumor performance.