Biodegradable Manganese-Doped Calcium Phosphate Nanotheranostics for Traceable Cascade Reaction-Enhanced Anti-Tumor Therapy

Glucose oxidase and Fe3O4/TiO2/Ag3PO4 co-embedded biomimetic mineralization hydrogels as controllable ROS generators for accelerating diabetic wound healing

The hyperglycemic environment and the presence of bacterial infections delay the healing of diabetic wounds. Herein, glucose oxidase (GOx) and Fe₃O₄/TiO₂/Ag₃PO₄ were embedded in a polyacrylic acid-calcium phosphate (PAA-CaPs@Nps@GOx) hydrogel through an in situ biomimetic mineralization approach. The GOx encapsulation efficiency was 96.75% and exhibited exceptional enzyme activity stability. Moreover, the co-immobilization of GOx and Fe₃O₄/TiO₂/Ag₃PO₄ nanoparticles generated a simple and multifunctional antibacterial platform with the advantages of decreasing blood glucose concentration and efficiently producing reactive oxygen species (ROS). In addition, the degradation rate of the hydrogel was controlled by regulating the concentration of phosphate thus controlling the release of Fe₃O₄/TiO₂/Ag₃PO₄ and GOx. As a result, both the potential toxicity and oxidative stress associated with the antimicrobial biomaterial can be controlled within the body therefore potentially preventing detriment. In vivo results indicated that the PAA-CaPs@Nps@GOx hydrogel effectively promoted diabetic wound healing and showed great potential for clinical applications of chronic wound management.

Biomimetic Nanoreactor for Cancer Eradication via Win-Win Cooperation between Starvation/Photo/Chemodynamic Therapies

Combining phototherapy with the cancer cell metabolic pathway altering strategies, that is, glucose starvation, would be a promising approach to accomplish high curative efficiency of cancer treatment. Accordingly, herein, we sought to construct a multifunctional biomimetic hybrid nanoreactor by fastening nanozyme AuNPs (glucose oxidase activity) and PtNPs (catalase and peroxidase activity) and photosensitizer Indocyanine green (ICG) onto the polydopamine (PDA) surface (ICG/Au/Pt@PDA-PEG) to attain superior cancer cell killing efficiency though win-win cooperation between starvation therapy, phototherapy, and chemodynamic therapy. The as-synthesized ICG/Au/Pt@PDA-PEG has shown excellent light-to-heat conversion (photothermal therapy) and reactive oxygen species generation (photodynamic therapy) properties upon laser irradiation and also red-shifted ICG absorption (from 780 to 800 nm) and enhanced its photostability. Further, the ICG/Au/Pt@PDA-PEG NRs have reduced the solution glucose concentration and slightly increased solution oxygen levels and also enhanced 3,3',5,5'-tetramethylbenzidine oxidation in the presence of glucose through a cascade of enzymatic activities. The in vitro results demonstrated that the ICG/Au/Pt@PDA-PEG NRs have superior therapeutic efficacy against cancer cells via the cooperative effect between starvation/photo/chemodynamic therapies and not much toxicity to normal cells.

Construction of Novel Nanocomposites (Cu-MOF/GOD@HA) for Chemodynamic Therapy

The emerging chemodynamic therapy (CDT) has received an extensive attention in recent years. However, the efficiency of CDT is influenced due to the limitation of H2O2 in tumor. In this study, we designed and synthesized a novel core-shell nanostructure, Cu-metal organic framework (Cu-MOF)/glucose oxidase (GOD)@hyaluronic acid (HA) (Cu-MOF/GOD@HA) for the purpose of improving CDT efficacy by increasing H2O2 concentration and cancer cell targeting. In this design, Cu-MOF act as a CDT agent and GOD carrier. Cu(II) in Cu-MOF are reduced to Cu(I) by GSH to obtain Cu(I)-MOF while GSH is depleted. The depletion of GSH reinforces the concentration of H2O2 in tumor to improve the efficiency of CDT. The resultant Cu(I)-MOF catalyze H2O2 to generate hydroxyl radicals (·OH) for CDT. GOD can catalyze glucose (Glu) to supply H2O2 for CDT enhancement. HA act as a targeting molecule to improve the targeting ability of Cu-MOF/GOD@HA to the tumor cells. In addition, after loading with GOD and coating with HA, the proportion of Cu(I) in Cu-MOF/GOD@HA is increased compared with the proportion of Cu(I) in Cu-MOF. This phenomenon may shorten the reactive time from Cu-MOF to Cu(I)-MOF. The CDT enhancement as a result of GOD and HA effects in Cu-MOF/GOD@HA was evidenced by in vitro cell and in vivo animal studies.

Cell membrane inspired nano-shell enabling long-acting Glucose Oxidase for Melanoma starvation therapy via microneedles-based percutaneous delivery

Rationale: Glucose oxidase (GOx) has gained tremendous research interest recently as a glucose-consuming enzyme for tumor starvation therapy, while its in vivo applications are strictly limited by rapid deactivation, as well as side effects of non-specific catalysis.

Methods: To address these issues, here we report a protective nano-shell to encapsule GOx for localized melanoma therapy delivered by dissolving microneedles (MNs). Inspired by cell membrane that separates and protects cell organelles and components from outside environment while selectively ingesting nutrition sources, we designed polydopamine (PDA)-structured nano-shell to allow free transportation of glucose for catalytic reaction, while impede the penetration of GOx, proteinase, and other GOx-deactivating macromolecules across the shell membrane.

Results: GOx was well protected in core layer with persistent catalytic activity for at least 6 d under various biological matrixes (e.g., PBS, serum, and cell lysate) and surviving different harsh conditions (e.g., acid/base treatments, and proteinase-induced degradation). Such long-acting nano-catalyst can be easily integrated into MNs as topical delivery carrier for effective glucose consumption in melanoma tissue, achieving significant tumor growth inhibition via starvation therapy with minimized side effects as compared to systemic administration.

Conclusion: This work provides an elegant platform for in vivo delivery of GOx, and our cell-mimicking nano-system can also be applied for other enzyme-based therapeutics.

Biodegradable cascade nanocatalysts enable tumor-microenvironment remodeling for controllable CO release and targeted/synergistic cancer nanotherapy

Gas therapy as an emerging therapeutic modality for cancer treatment is still facing critical challenges such as precise delivery and controllable release of therapeutic gas. Herein, we report a "tumor-microenvironment remodeling" strategy for in situ sustained release of CO gas and magnetic resonance imaging (MRI)-monitored targeted/synergistic cancer gas/starvation nanotherapy by engineering cascade biodegradable nanocatalyst. The nanocatalyst integrates the enzyme catalyst glucose oxidase (GOD) and H₂O₂-sensitive molecule manganese carbonyl (MnCO) entrapped biodegradable hollow mesoporous organosilica nanoparticles (HMONs). Especially, GOD is initially exploited as a gatekeeper, followed by surface engineering with arginine-glycine-aspartic acid (RGD) for specifically targeting α_vβ₃ integrin-overexpressed cancer cells. The GOD is dissociated under reduced pH to release the loaded MnCO, and sequentially produce gluconic acid and H₂O₂ to remodel the TME for facilitating the in situ generation of CO/Mn²⁺. As systematically demonstrated both at cellular level and in an animal tumor xenograft model, the engineered nanocatalyst achieves superior theranostics performance via combinatorial CO gas and starving-like nanotherapy. This work provides an effective strategy for augmenting CO-mediated antitumor efficacy by remodeling the tumor microenvironment.

Chemodynamic nanomaterials for cancer theranostics

It is of utmost urgency to achieve effective and safe anticancer treatment with the increasing mortality rate of cancer. Novel anticancer drugs and strategies need to be designed for enhanced therapeutic efficacy. Fenton- and Fenton-like reaction-based chemodynamic therapy (CDT) are new strategies to enhance anticancer efficacy due to their capacity to generate reactive oxygen species (ROS) and oxygen (O2). On the one hand, the generated ROS can damage the cancer cells directly. On the other hand, the generated O2 can relieve the hypoxic condition in the tumor microenvironment (TME) which hinders efficient photodynamic therapy, radiotherapy, etc. Therefore, CDT can be used together with many other therapeutic strategies for synergistically enhanced combination therapy. The antitumor applications of Fenton- and Fenton-like reaction-based nanomaterials will be discussed in this review, including: (iþ) producing abundant ROS in-situ to kill cancer cells directly, (ii) enhancing therapeutic efficiency indirectly by Fenton reaction-mediated combination therapy, (iii) diagnosis and monitoring of cancer therapy. These strategies exhibit the potential of CDT-based nanomaterials for efficient cancer therapy.

Inorganic nanomaterials with rapid clearance for biomedical applications

Inorganic nanomaterials that have inherently exceptional physicochemical properties (e.g., catalytic, optical, thermal, electrical, or magnetic performance) that can provide desirable functionality (e.g., drug delivery, diagnostics, imaging, or therapy) have considerable potential for application in the field of biomedicine. However, toxicity can be caused by the long-term, non-specific accumulation of these inorganic nanomaterials in healthy tissues, preventing their large-scale clinical utilization. Over the past several decades, the emergence of biodegradable and clearable inorganic nanomaterials has offered the potential to prevent such long-term toxicity. In addition, a comprehensive understanding of the design of such nanomaterials and their metabolic pathways within the body is essential for enabling the expansion of theranostic applications for various diseases and advancing clinical trials. Thus, it is of critical importance to develop biodegradable and clearable inorganic nanomaterials for biomedical applications. This review systematically summarizes the recent progress of biodegradable and clearable inorganic nanomaterials, particularly for application in cancer theranostics and other disease therapies. The future prospects and opportunities in this rapidly growing biomedical field are also discussed. We believe that this timely and comprehensive review will stimulate and guide additional in-depth studies in the area of inorganic nanomedicine, as rapid in vivo clearance and degradation is likely to be a prerequisite for the future clinical translation of inorganic nanomaterials with unique properties and functionality.

Cyclic reactions-mediated self-supply of H2O2 and O2 for cooperative chemodynamic/starvation cancer therapy

Hydroxyl radical (·OH)-mediated chemodynamic therapy (CDT) and glucose oxidase (GOx)-based starvation therapy (ST) are two emerging antitumor strategies, limited by acid/H₂O₂ deficiency and tumor hypoxia, respectively. Herein, we developed a liposomal nanoplatform co-delivering Fe(OH)₃-doped CaO₂ nanocomposites and GOx molecules for synergistic CDT/ST with a complementary effect. Based on Fenton reactions initiated by iron ions, CaO₂-supplied H₂O₂ could not only generate ·OH for H₂O₂-sufficient CDT, but also produce O₂ to promote the catalytic efficiency of GOx under hypoxia. In return, the enhanced ST generated gluconic acid and H₂O₂, further amplifying CDT. Through in vitro and in vivo experiments, we demonstrated that such a mutually reinforced modality based on the cyclic Fenton/starvation reactions provided a novel and potent anticancer mechanism for the effective treatment of hypoxic cancers.

Liposome-Coated Arsenic-Manganese Complex for Magnetic Resonance Imaging-Guided Synergistic Therapy Against Carcinoma

Purpose

A liposome-coated arsenic-manganese complex, denoted as LP@MnAs_x was constructed for the targeted delivery of arsenic trioxide (ATO) against carcinoma.

Methods

Arsenite, the prodrug of ATO, was encapsulated within a liposome via electrostatic interaction with the manganese ions. The as-prepared material was characterized with dynamic light scattering and transmission electron microscopy. The entrapment efficiency and drug loading of arsenic in the carrier were measured using inductively coupled plasma spectrometry. The in vitro release of arsenic was evaluated by using the dialysis bag method. Furthermore, the Fenton-like activity and in vitro cytodynamics research of LP@MnAs_x were monitored in this work. And the cellular uptake study was used to investigate the in vitro entry mechanism. Furthermore, the cytotoxicity, cell apoptosis and cell cycle study were performed to evaluate the tumor-killing efficiency. Also, the pharmacokinetic and antitumor studies were investigated in HepG2 tumor-bearing nude mice.

Results

The as-prepared LP@MnAs_x possessed a spherical morphology, uniformly distributed hydrodynamic diameter, and excellent drug-loading efficiency. LP@MnAs_x displayed robust stability and sustained-release profile under physiological environments. LP@MnAs_x could degrade with high sensitivity to the pH variation in the tumor microenvironment. As such, this could lead to a burst release profile of Mn²⁺ and arsenite to achieve a synergistic therapy of chemodynamic therapy and chemotherapy. When compared to the carrier-free arsenate, in vitro experiments revealed that LP@MnAs_x exhibited enhanced cellular uptake and tumor-killing efficiency. LP@MnAs_x also demonstrated significantly enhanced tumor-specific in vivo distribution of arsenic, prolonged systemic circulation lifetime, and increased accumulation at the tumor site.

Conclusion

Based on the experimental results, LP@MnAs_x is an ideal arsenic-based nanodelivery system, whereby it can improve the non-specific distribution of NaAsO₂ in vivo. Thus, this work can expand the research and application of arsenic trioxide against solid tumors.

Self-preparation system using glucose oxidase-inspired nitroreductase amplification for cascade-responsive drug release and multidrug resistance reversion

Early antitumor therapy is an important determinant of survival in patients with cancer. Utilization of specific pathological states, such as hypoxia, greatly promotes the development of intelligent drug delivery systems (DDSs) for targeted antitumor therapy. However, a slight decrease in oxygen levels in early-stage tumors is not sufficient to trigger hypoxia-responsive drug release. Nitroreductase (NTR) is overexpressed in bioreductive hypoxic cancers, and its expression level has been verified to be directly related to hypoxic status. Herein, using glucose oxidase (GOx) as an O₂-consuming agent to exacerbate hypoxia, a cascade strategy of GOx-induced overexpression of NTR and amplified NTR-catalyzed release was proposed for early antitumor therapy. Briefly, NTR-sensitive p-nitrobenzyl chloroformate (PNZ-Cl) was adopted to conjugate with the polysaccharide chitosan (CS) and self-assemble into CS-PNZ-Cl micelles. These polymer micelles possess the dual abilities to specifically immobilize GOx and load mitoxantrone (MIT) to form the NTR-responsive nanocascade reactor GOx/MIT@CS-PNZ-Cl. First, as a "key", tumor hypoxia triggers the initial release of GOx, which serves as the O₂-consuming agent when catalyzing its reaction with glucose, which is accompanied by H₂O₂ production. Depleted oxygen levels facilitate the expression of NTR, which in turn amplifies the capacity of the nanocascade reactor to decompose into secondary micelles for enhanced intratumoral permeation. GOx-inspired NTR amplification further elicits MIT release, realizing a synergistic "domino effect" cascade. In addition, upregulated H₂O₂ has been shown to effectively reverse GSH-mediated MIT resistance, reaching the superior tumor inhibition rate of 93.08%. This GOx-based NTR-responsive nanocascade reactor provides amplification of the bioreductive hypoxic tumor microenvironment for early antitumor therapy.

Zeolitic Imidazolate Framework Platform for Combinational Starvation Therapy and Oxygen Self-Sufficient Photodynamic Therapy against a Hypoxia Tumor

The antitumor efficacy of photodynamic therapy (PDT) is greatly impeded by the nonspecific targeting of photosensitizers and limited oxygen supply in hypoxic tumors. Aiming to overcome the problem, a dual-locked porphyrin/enzyme-loading zeolitic imidazolate framework (ZIF) nanoplatform was constructed for starvation therapy and O₂ self-sufficient PDT. The fluorescence recovery and PDT of photosensitizers could be cooperatively triggered by dual pathological parameters, the low pH and overexpressed GSH in tumor tissues, which makes the PDT process conduct precisely in a tumor microenvironment. The cascade catalysis of glucose oxidase and catalase promotes the nanoplatform dissociation, inhibits the energy supply of tumors (starvation therapy), and provides enough O₂ to ameliorate the hypoxia and enhance PDT efficacy. In vitro and in vivo studies were performed to confirm the high antitumor efficacy of the porphyrin/enzyme-loading ZIF nanoplatform. Thus, this work offers a path for precise and efficient PDT-based combination therapy against a hypoxia tumor.

Skillfully collaborating chemosynthesis with GOx-enabled tumor survival microenvironment deteriorating strategy for amplified chemotherapy and enhanced tumor ablation

The satisfactory efficient tumor treatment and complete tumor ablation using a mono-therapeutic approach are limited owing to the tumor complexity, diversity, heterogeneity and the multiple pathways involved in tumor pathogenesis. Herein, novel, intelligent and tumor microenvironment (TME)-responsive biotin/R8 peptide co-modified nanocarriers (BRNC) loading paclitaxel (PTX)/glucose oxidase (GOx) were constructed. GOx could catalyze the oxidation of intracellular glucose to gluconic acid and poisonous H2O2 to cause the deterioration of the tumor survival microenvironment, simultaneously achieving starvation and oxidation therapy. The acidic amplification during the GOx-mediated oxidation progress could in turn accelerate the cleavage of the acid-degradable hydrazone bond, promoting the deep penetration of nanocarriers into tumors. Even better, the aforementioned two aspects further increased the tumors' sensitivity to chemotherapeutic agents. Both in vitro and in vivo investigations indicated that the co-administration of GOx-BRNC and PTX-BRNC can remarkably improve the therapeutic efficacy and reduce side effects through the high-specific tumor targeting multimodal synergistic starvation/oxidation/chemotherapy, which would be a promising strategy for the next generation cancer therapy.

Biomimetic nanoreactor for targeted cancer starvation therapy and cascade amplificated chemotherapy

Consuming glucose by glucose oxidase (GOx) has attracted great interest in cancer starvation therapy, but the therapeutic effect is severely limited by the tumor hypoxia environment. Herein, to overcome such limitation, cancer cell membranes disguised biomimetic nanoreactors were elaborately established for synergetic cancer starvation therapy and cascade amplificated hypoxia activated chemotherapy. Via a metallothionein-like self-assembly and infiltration approach, GOx and hypoxia activated prodrug banoxantrone (AQ4N) were efficiently loaded into metal-organic framework ZIF-8 nanocarriers to yield nanoreactor AQ4N/GOx@ZIF-8. Subsequently, the biomimetic nanoreactor (AQ4N/GOx@ZIF-8@CM) was obtained by camouflaging the nanoreactor with cancer cell membrane, which endowed the biomimetic nanoreactor homotypic targeting, immune escape and prolonged blood circulation features. Once targeted accumulating into tumor sites, the acid environment triggered the decomposition of ZIF-8, then encapsulated GOx and AQ4N were released. GOx would rapidly exhaust endogenous glucose and O₂ to shut off the energy supply of tumor cells for starvation treatment. Furthermore, the aggravated tumor intracellular hypoxia environment would activate the cytotoxicity of AQ4N for chemotherapy. In vitro and in vivo results demonstrated that the designed biomimetic nanoreactor exhibited negligible systemic toxicity, besides, the combination of starvation therapy and cascade amplified hypoxia activated chemotherapy significantly inhibited the tumor growth and improved the therapeutic efficacy.

Bioactive metal-containing nanomaterials for ferroptotic cancer therapy

The clinical performance of the current cancer therapies is still far from satisfactory. The emerging ferroptosis-driven therapy strategies reignite the hope of chemotherapy in tumor treatment due to their incredible tumor suppression. Among ferroptosis-based cancer therapies, metal elements have attracted remarkable attention due to their inherent physicochemical properties in inducing ferroptosis of tumor cells quickly and strongly without complex cellular signal transduction. Although the discovery and applications of ferroptosis for tumor treatment have been discussed in many reviews, the unique advantages of metal-containing nanomaterials interfering ferroptotic cancer therapies (MIFCT) have seldom been mentioned. Here, we outline the latest advances of MIFCT comprehensively. Firstly, the functions of different kinds of metal elements or their ions are introduced to illustrate their advantages in MIFCT. Secondly, the emerging metal-containing nanomaterials that are designed to achieve ferroptosis-driven therapy are overviewed, including their ability to boost the Fenton or Fenton-like reaction for reactive oxygen species generation, act as hydrogen peroxide self-providers, damage the reducing system, and disturb cellular communication. Moreover, metal-containing nanomaterials with external energy conversion features for MIFCT are discussed. Finally, the future expectations and challenges of MIFCT for clinical cancer therapy are spotlighted.

Manganese-Dioxide-Coating-Instructed Plasmonic Modulation of Gold Nanorods for Activatable Duplex-Imaging-Guided NIR-II Photothermal-Chemodynamic Therapy

Nanotheranostic agents of gold nanomaterials in the second near-infrared (NIR-II) window have attracted significant attention in cancer management, owing to the reduced background signal and deeper penetration depth in tissues. However, it is still challenging to modulate the localized surface plasmon resonance (LSPR) of gold nanomaterials from the first near-infrared (NIR-I) to NIR-II region. Herein, a plasmonic modulation strategy of gold nanorods (GNRs) through manganese dioxide coating is developed for NIR-II photoacoustic/magnetic resonance (MR) duplex-imaging-guided NIR-II photothermal chemodynamic therapy. GNRs are coated with silica dioxide (SiO2 ) and then covered with magnesium dioxide (MnO2 ) to obtain the final product of GNR@SiO2 @MnO2 (denoted as GSM). The LSPR peak of GNRs could be tuned by adjusting the thickness of the MnO2 layer. Theoretical simulations reveal that this plasmonic modulation is mainly due to the change of refraction index around the GNRs after coating with the MnO2 layer. Additionally, the MnO2 layer is demonstrated to degrade into Mn2+ ions in response to peroxide and acidic protons in the tumor microenvironment, which allows for MR imaging and chemodynamic therapy. This plasmonic modulation strategy can be adapted to other metal nanomaterials and the construction of a new class of NIR-II nanotheranostics.

Hypoxia modulation by dual-drug nanoparticles for enhanced synergistic sonodynamic and starvation therapy

BACKGROUND

Sonodynamic therapy (SDT) is an emerging non-invasive therapeutic technique. SDT-based cancer therapy strategies are presently underway, and it may be perceived as a promising approach to improve the efficiency of anti-cancer treatment. In this work, multifunctional theranostic nanoparticles (NPs) were synthesized for synergistic starvation therapy and SDT by loading glucose oxidase (GOx, termed G) and 5,10,15,20-tetrakis (4-chlorophenyl) porphyrin) Cl (T (p-Cl) PPMnCl, termed PMnC) in Poly (lactic-co-glycolic) acid (PLGA) NPs (designated as MG@P NPs).

RESULTS

On account of the peroxidase-like activity of PMnC, MG@P NPs can catalyze hydrogen peroxide (H2O2) in tumor regions to produce oxygen (O2), thus enhancing synergistic therapeutic effects by accelerating the decomposition of glucose and promoting the production of cytotoxic singlet oxygen (1O2) induced by ultrasound (US) irradiation. Furthermore, the NPs can also serve as excellent photoacoustic (PA)/magnetic resonance (MR) imaging contrast agents, effectuating imaging-guided cancer treatment.

CONCLUSION

Multifunctional MG@P NPs can effectuate the synergistic amplification effect of cancer starvation therapy and SDT by hypoxia modulation, and act as contrast agents to enhance MR/PA dual-modal imaging. Consequently, MG@P NPs might be a promising nano-platform for highly efficient cancer theranostics.

Artificial Bioaugmentation of Biomacromolecules and Living Organisms for Biomedical Applications

The synergistic union of nanomaterials with biomaterials has revolutionized synthetic chemistry, enabling the creation of nanomaterial-based biohybrids with distinct properties for biomedical applications. This class of materials has drawn significant scientific interest from the perspective of functional extension via controllable coupling of synthetic and biomaterial components, resulting in enhancement of the chemical, physical, and biological properties of the obtained biohybrids. In this review, we highlight the forefront materials for the combination with biomacromolecules and living organisms and their advantageous properties as well as recent advances in the rational design and synthesis of artificial biohybrids. We further illustrate the incredible diversity of biomedical applications stemming from artificially bioaugmented characteristics of the nanomaterial-based biohybrids. Eventually, we aim to inspire scientists with the application horizons of the exciting field of synthetic augmented biohybrids.

A Three-in-one ZIFs-Derived CuCo(O)/GOx@PCNs Hybrid Cascade Nanozyme for Immunotherapy/Enhanced Starvation/Photothermal Therapy

Glucose oxidase (GOx) is regarded as an ideal endogenous natural enzyme for tumor starvation therapy and photothermal therapy (PTT) is a promising strategy for the ablation of primary tumor. In this work, Cu-doped cobalt oxide and porous carbon nanocomposites (CuCo(O)@PCNs) were synthesized from double-layered ZIF-8@ZIF-67 and GOx was loaded in the porous carbon to form a CuCo(O)/GOx@PCNs hybrid nanozyme. CuCo(O) was characterized as the Cu_0.3Co_2.7O₄ phase through X-ray diffraction analysis and it can react with H₂O₂ to generate O₂ and alleviate tumor hypoxia, resulting in the recovered enzymatic activity of GOx and the enhanced starvation therapy. The porous nanocarbon can ablate the primary tumor because of its high photothermal conversion efficiency of 40.04%. The three-in-one functions of oxygen supply, glucose consumption, and photothermal conversion were realized in the ZIFs-derived CuCo(O)/GOx@PCNs nanozyme and the starvation therapy effect was improved by PTT and oxygen supplement. Furthermore, the inhibition effect of CuCo(O)/GOx@PCNs on metastatic tumor is similar to combined therapy of the nanozyme and the immune checkpoint-blocking antibody, α-PD-1. The related antitumor immune mechanism was studied through the analysis of immune-related proinflammatory cytokines and the activated T cells. This work may provide new ideas for the development and application of the ZIFs-derived hybrid nanozyme in tumor therapy and the CuCo(O)/GOx@PCNs nanozyme may be a promising alternative to immune checkpoint inhibitors.

Functionalized graphene oxide in situ initiated ring-opening polymerization for highly sensitive sensing of cytokeratin-19 fragment

Improving the sensitivity of detection is crucial to monitor biomarker, assess toxicity, and track therapeutic agent. Herein, a sensitivity-improved immunosensor is reported for the first time via functionalized graphene oxide (GO) and a "grafting-to" ring-opening polymerization (ROP) dual signal amplification strategy. Through the ROP reaction using 2-[(4-ferrocenylbutoxy)methyl] oxirane (FcEpo) as the monomer, lots of electroactive tags are linked in situ from multiple initiation sites on the GO surface modified with ethanol amine (GO-ETA), thereby achieving high sensitivity even in the case of trace amounts of tumor markers. The utmost important factor for achieving this high sensitivity is to select functionalized GO as the initiator that contains a large number of repeated hydroxyl functional groups so as to trigger additional ROP reaction. Under the optimal conditions, the high sensitivity and applicability is demonstrated by the use of GO-ETA-mediated ROP-based immunosensor to detect non-small cell lung cancer (NSCLC)-specific biomarker down to 72.58 ag/mL (equivalent to ~6 molecules in a 5 μL sample). Furthermore, the satisfactory results for the determination of biomarkers in clinical serum samples highlighted that this immunosensor holds a huge potential in practical clinical application. This work described an electrochemical immunosensor for ultrasensitive detection of CYFRA 21-1 via the functionalized graphene oxide (GO) and a "grafting-to" ring-opening polymerization (ROP) dual signal amplification strategy, which hold the merits of high sensitivity, applicability, selectivity, efficiency, easy operation and environmental friendliness.

Construction of Enzyme Nanoreactors to Enable Tumor Microenvironment Modulation and Enhanced Cancer Treatment

Enzymes play pivotal roles in regulating and maintaining the normal functions of all living systems, and some of them are extensively employed for diagnosis and treatment of diverse diseases. More recently, several kinds of enzymes with unique catalytic activities have been found to be promising options to directly suppress tumor growth and/or augment the therapeutic efficacy of other treatments by modulating the hostile tumor microenvironment (TME), which is reported to negatively impair the therapeutic efficacy of different cancer treatments. In this review, first a summary is presented on the chemical approaches utilized for the construction of distinct enzyme nanoreactors with well-retained catalytic performance and reduced immunogenicity. Then, the utilization of such enzyme nanoreactors in attenuating tumor hypoxia, modulating extracellular matrix, and amplifying tumor oxidative stress is discussed in depth. Afterward, some perspectives are presented on the future development of such enzyme nanoreactors in TME modulation and enhanced cancer treatment.

Size controlled fabrication of enzyme encapsulated amorphous calcium phosphate nanoparticle and its intracellular biosensing application

Inorganic-enzyme composites have been widely used for applications in catalysis and analytical science. Amorphous calcium phosphate, as a biocompatible material, can form open hydrated structure to encapsulate and protect enzymes. So far, there have been few progress on size-adjustable amorphous calcium phosphate nanoparticles since the diameter controllability is limited by its natural aggregation characteristics. By co-precipitation and nano-channel extrusion, we developed enzyme-loaded amorphous calcium phosphate nanoparticles with adjustable diameters. These enzyme-loaded particles showed high thermal and chemical stability as well as biocompatibility. The nano-sized enzyme-loaded particles can further expand their application fields and be used as intracellular enzyme probes. Delivering glucose oxidase enzyme by amorphous calcium phosphate nanoparticles enables fluorescent monitoring of glucose levels in living cells, which can be used to study the metabolism rates of cancer cells and normal cells. The nano-channel extrusion method can also be used as a template to encapsulate different kinds of enzymes to expand catalysis and biosensing applications.

Mn-DNA coordination of nanoparticles for efficient chemodynamic therapy

A kind of nanoparticle is developed for highly efficient chemodynamic therapy that only relies on the endogenous H2O2 of cancer cells. For this nanoparticle, high-molecular-weight DNA is used as the biocompatible carrier to load abundant Mn2+ ions. Therefore, the resultant Mn-DNA coordination nanoparticles can efficiently deliver and sensitively release Mn2+ in cancer cells, resulting in high toxicity through the Fenton-like reaction.

Urchin-Shaped Metal Organic/Hydrogen-Bonded Framework Nanocomposite as a Multifunctional Nanoreactor for Catalysis-Enhanced Synergetic Therapy

Ultrasound (US)-induced sonodynamic therapy (SDT) is an efficient and precise method against tumor, and the integration of multiple cancer therapies has been proved as a promising strategy for better therapeutic effects. Herein, for the first time, a multifunctional nanoreactor has been fabricated by integrating Fe-MIL-88B-NH₂, PFC-1, and glucose oxidase (GO_x) to form urchin-like Fe-MIL-88B-NH₂@PFC-1-GO_x (MPG) nanoparticles as Fenton's reagent, a sonosensitizer, and a tumor microenvironment (TME) modulator. In detail, MPG can generate ^•OH for chemodynamic therapy (CDT) and deplete glutathione (GSH) to alleviate the antioxidant ability of cancer cells. Moreover, catalase (CAT)-like MPG can react with H₂O₂ to generate O₂ for relieving hypoxia in TME, enhancing GO_x-catalyzed glucose oxidation to produce H₂O₂ and gluconic acid. Then, the regenerated H₂O₂ can promote the Fenton reaction to achieve GO_x catalysis-enhanced CDT. Owing to its large π-electron conjugated system, MPG also serves as an ideal sonosensitizer, realizing a burst generation of ¹O₂ under US irradiation for efficient SDT. Therefore, the tumor treatment will be notably enhanced by MPG-based synergetic CDT/SDT/starvation therapy via a series of cascade reactions. Overall, this work develops a versatile nanoreactor with improved tumor treatment effectiveness and broadens the application prospects of porous materials in the field of biomedical research.

Light-Triggered Transformable Ferrous Ion Delivery System for Photothermal Primed Chemodynamic Therapy

Chemodynamic therapy (CDT) involves the catalytic generation of highly toxic hydroxyl radicals (^. OH) from hydrogen peroxide (H₂ O₂ ) through metal-ion-mediated Fenton or Fenton-like reactions. Fe²⁺ is a classical catalyst ion, however, it suffers easy oxidation and systemic side-effects. Therefore, the development of a controllable Fe²⁺ delivery system is a challenge to maintain its valence state, reduce toxicity, and improve therapeutic efficacy. Reported here is a near-infrared (NIR) light-triggered Fe²⁺ delivery agent (LET-6) for fluorescence (FL) and photoacoustic (PA) dual-modality imaging guided, photothermal primed CDT. Thermal expansion caused by 808 nm laser irradiation triggers the transformation of LET-6 to expose Fe²⁺ from its hydrophobic layer, which primes the catalytic breakdown of endogenous H₂ O₂ within the tumor microenvironment, thus generating ^. OH for enhanced CDT. LET-6 shows remarkable therapeutic effects, both in vitro and in vivo, achieving 100 % tumor elimination after just one treatment. This high-performance Fe²⁺ delivery system provides a sound basis for future synergistic metal-ion-mediated cancer therapy.

Nanocatalytic Theranostics with Glutathione Depletion and Enhanced Reactive Oxygen Species Generation for Efficient Cancer Therapy

Chemodynamic therapy (CDT) is an emerging therapy method that kills cancer cells by converting intracellular hydrogen peroxide (H₂ O₂ ) into highly toxic hydroxyl radicals (^• OH). To overcome the current limitations of the insufficient endogenous H₂ O₂ and the high concentration of glutathione (GSH) in tumor cells, an intelligent nanocatalytic theranostics (denoted as PGC-DOX) that possesses both H₂ O₂ self-supply and GSH-elimination properties for efficient cancer therapy is presented. This nanoplatform is constructed by a facile one-step biomineralization method using poly(ethylene glycol)-modified glucose oxidase (GOx) as a template to form biodegradable copper-doped calcium phosphate nanoparticles, followed by the loading of doxorubicin (DOX). As an enzyme catalyst, GOx can effectively catalyze intracellular glucose to generate H₂ O₂ , which not only starves the tumor cells, but also supplies H₂ O₂ for subsequent Fenton-like reaction. Meanwhile, the redox reaction between the released Cu²⁺ ions and intracellular GSH will induce GSH depletion and reduce Cu²⁺ to Fenton agent Cu⁺ ions, and then trigger the H₂ O₂ to generate ^• OH by a Cu⁺ -mediated Fenton-like reaction, resulting in enhanced CDT efficacy. The integration of GOx-mediated starvation therapy, H₂ O₂ self-supply and GSH-elimination enhanced CDT, and DOX-induced chemotherapy, endow the PGC-DOX with effective tumor growth inhibition with minimal side effects in vivo.

Tumor-Specific Activatable Nanocarriers with Gas-Generation and Signal Amplification Capabilities for Tumor Theranostics

Multifunctional nanotheranostics are typically designed by integrating multiple functional components. This approach not only complicates the preparation process but also hinders any bioapplication due to the potential toxic effects when each component is metabolized. Here, we report a safe, biodegradable, and tumor-specific nanocarrier that, once activated by the acidic tumor microenvironment (TME), has diagnostic and therapeutic functions suitable for tumor theranostics. Our nanocarrier is composed of biomineralized manganese carbonate (BMC) nanoparticles (NPs) that readily decompose to release Mn²⁺ ions and CO₂ gas in the acidic TME due to its intrinsic pH-dependent solubility. Mn²⁺ and CO₂ release permits magnetic resonance and ultrasound imaging of tumors, respectively. These NPs can be loaded with the anticancer drug doxorubicin (DOX): BMC-DOX has high tumor inhibition effects both in vitro and in vivo due to combined Mn²⁺-mediated chemodynamic therapy and DOX-induced chemotherapy. This tumor-specific actuating nanocarrier might be a promising candidate for clinical translation.

Recent advances in phase change material based nanoplatforms for cancer therapy

Cancer has become a severe threat to human life due to its high mortality and metastatic rate. Effective inhibition and killing of cancer cells using chemotherapeutic drugs have been a promising means in clinical cancer therapy. However, the low selectivity, drug-resistance, uncontrollability and serious side effects of chemotherapy significantly limit its further development. There is an urgent need for new treatment strategies to compensate for deficiencies inherent in chemotherapy alone. A growing body of research shows that combined treatment strategies have the potential to overcome this dilemma by achieving significantly enhanced synergistic effects and reduced side effects. Emerging phase change materials (PCMs) create an ideal nanoplatform for cancer combination therapy due to their universal loading properties, stable and temperature-responsive phase transition capability, and excellent natural biocompatibility/biodegradability. The release of therapeutic agents can be precisely controlled through external, non-intrusive stimuli (such as NIR light and ultrasound), avoiding systemic toxicity associated with conventional chemotherapy. Herein, the construction methods and design principles of PCM-based nanoplatforms serving as strict gatekeeper and smart payload delivery systems are discussed in detail. Moreover, the advantages and disadvantages of these nanoplatforms are provided. A suitable discussion and perspective of the remaining challenges and future opportunities for PCM-based nanoplatforms in cancer treatment are also given in conclusion.

Tumor cell-activated "Sustainable ROS Generator" with homogeneous intratumoral distribution property for improved anti-tumor therapy

Photodynamic therapy (PDT) holds a number of advantages for tumor therapy. However, its therapeutic efficiency is limited by non-sustainable reactive oxygen species (ROS) generation and heterogeneous distribution of photosensitizer (PS) in tumor. Herein, a "Sustainable ROS Generator" (SRG) is developed for efficient antitumor therapy. Methods: SRG was prepared by encapsulating small-sized Mn₃O₄-Ce6 nanoparticles (MC) into dendritic mesoporous silica nanoparticles (DMSNs) and then enveloped with hyaluronic acid (HA). Due to the high concentration of HAase in tumor tissue, the small-sized MC could be released from DMSNs and homogeneously distributed in whole tumor. Then, the released MC would be uptaken by tumor cells and degraded by high levels of intracellular glutathione (GSH), disrupting intracellular redox homeostasis. More importantly, the released Ce6 could efficiently generate singlet oxygen (¹O₂) under laser irradiation until the tissue oxygen was exhausted, and the manganese ion (Mn²⁺) generated by degraded MC would then convert the low toxic by-product (H₂O₂) of PDT to the most harmful ROS (·OH) for sustainable and recyclable ROS generation. Results: MC could be homogeneously distributed in whole tumor and significantly reduced the level of intracellular GSH. At 2 h after PDT, obvious intracellular ROS production was still observed. Moreover, during oxygen recovery in tumor tissue, ·OH could be continuously produced, and the nanosystem could induce 82% of cell death comparing with 30% of cell death induced by free Ce6. For in vivo PDT, SRG achieved a complete inhibition on tumor growth. Conclusion: Based on these findings, we conclude that the designed SRG could induce sustainable ROS generation, homogeneous intratumoral distribution and intracellular redox homeostasis disruption, presenting an efficient strategy for enhanced ROS-mediated anti-tumor therapy.

Dual catalytic cascaded nanoplatform for photo/chemodynamic/starvation synergistic therapy

In this study, manganese dioxide (MnO₂) was attached to prussian blue (PB) by a one-pot method to prepare PBMO. Then, the GOD was loaded onto PBMO through the electrostatic interaction of hyaluronic acid (HA) to form tumor-targeted nanoplatform (PBMO-GH). Hydrogen peroxide (H₂O₂) and gluconic acid were produced through the GOD-catalyzed enzymatic reaction. Meanwhile, PB could not only catalyze H₂O₂ for oxygen generation to further promote glucose consumption but also possess the property of photothermal conversion. As a result, glucose was continuously consumed to achieve the starvation therapy (ST), and the photothermal therapy (PTT) could be realized under near-infrared (NIR) light. Besides, the Mn²⁺ generated by the reaction of MnO₂ with glutathione (GSH) could exert Fenton-like reaction to produce highly toxic hydroxyl radicals (·OH) from H₂O₂, which thereby realized self-reinforcing chemodynamic therapy (CDT). In vitro and in vivo experiments demonstrated that PBMO-GH could effectively inhibit the growth of tumor cells via ST/CDT/PTT synergistic effect. Therefore, the as-prepared nanoplatform for multi-modal therapy will provide a promising paradigm for overcoming cancer.

Biodegradable Multifunctional Nanotheranostic Based on Ag2S-Doped Hollow BSA-SiO2 for Enhancing ROS-Feedback Synergistic Antitumor Therapy

Stimuli-responsive silica nanoparticles are an attractive therapeutic agent for effective tumor ablation, but the responsiveness of silica nanoagents is limited by intrastimulation level and silica framework structure. Herein, a biodegradable hollow SiO₂-based nanosystem (Ag₂S-GOx@BHS NYs) is developed by a novel one-step dual-template (bovine serum albumin (BSA) and cetyltrimethylammonium bromide (CTAB)) synthetic strategy for image-guided therapy. The Ag₂S-GOx@BHS NYs can be specifically activated in the tumor microenvironment via a self-feedback mechanism to achieve reactive oxygen species (ROS)-induced multistep therapy. In response to the inherent acidity and H₂O₂ at the tumor sites, Ag₂S-GOx@BHS would accelerate the structural degradation while releasing glucose oxidase (GOx), which could efficiently deplete intratumoral glucose to copious amounts of gluconic acid and H₂O₂. More importantly, the sufficient H₂O₂ not only acts as a reactant to generate Ag⁺ from Ag₂S for metal-ion therapy and improves the oxidative stress but also combines with gluconic acid results in the self-accelerating degradation process. Moreover, the released Ag₂S nanoparticles can help the Ag₂S-GOx@BHS NYs realize the second near-infrared window fluorescence (NIR-II FL) and photoacoustic (PA) imaging-guided precise photothermal therapy (PTT). Taken together, the development of a self-feedback nanosystem may open up a new dimension for a highly effective multistep tumor therapy.

Nanotheranostics for Cancer Therapy and Detection: State of the Art

Nanotheranostics, an approach of combining both diagnosis and therapy, is one of the latest advances in cancer therapy particularly. Nanocarriers designed and derived from inorganic materials such as like gold nanoparticles, silica nanoparticles, magnetic nanoparticles and carbon nanotubes have been explored for tremendous applications in this area. Similarly, nanoparticles composed of some organic material alone or in combination with inorganic nano-cargos have been developed pre-clinically and possess excellent features desired. Photothermal therapy, MRI, simultaneous imaging and delivery, and combination chemotherapy with a diagnosis are a few of the known methods exploring cancer therapy and detection at organ/tissue/molecular/sub-cellular level. This review comprises an overview of the recent reports meant for nano theranostics purposes. Targeted cancer nanotheranostics have been included for understating tumor micro-environment or cell-specific targeting approach employed. A brief account of various strategies is also included for the readers highlighting the mechanism of cancer therapy.

A tumor-targeted theranostic nanomedicine with strong absorption in the NIR-II biowindow for image-guided multi-gradient therapy

Developing new strategies to enhance drug accumulation in the tumor and therapeutic efficacy is of great importance in the field of tumor therapy. Herein, a peanut-like multifunctional nanomedicine (CuS-PGH NMs) made of CuS nanoparticles encapsulated in poly(l-lysine)(PLL)/glucose oxidase (GOx)-hyaluronic acid (HA) shells has been constructed via layer-by-layer (LbL) assembly, and shows good biocompatibility and effective multi-gradient therapy. Because of the enhanced permeability and retention (EPR) effect, the CuS-PGH NMs could significantly enhance the cellular uptake by tumors overexpressing CD44 receptors, which respond to hyaluronidase (HAase)-triggered surface charge conversion. Once internalized by the tumor, GOx was the first to be exposed and could effectively deplete endogenous glucose for starvation therapy, and the excess H2O2 was then converted into highly toxic hydroxyl radicals (˙OH) via a Cu+-mediated Fenton-like reaction for chemodynamic therapy (CDT). Meanwhile, the as-obtained Cu+ ions accompanied the regenerated less-active Cu2+ ions. Interestingly, the high content of H2O2 could, in turn, accelerate Cu2+/Cu+ conversion to promote the Cu+-H2O2 reaction for enhanced chemodynamic therapy (CDT), thereby achieving efficient tumor growth suppression via synergistic starvation/CDT therapy. Subsequently, owing to the strong NIR-II absorption capability of CuS-PGH NMs, effective photothermal tumor ablation of the weakened tumor cells could be realized with the precise guidance of NIR-II PAI. This multi-gradient therapeutic strategy has been demonstrated to have excellent antitumor activity with minimal nonspecific damages, and offers a new avenue to precise tumor therapy.

Nanoplatform-based cascade engineering for cancer therapy

Various therapeutic techniques have been studied for treating cancer precisely and effectively, such as targeted drug delivery, phototherapy, tumor-specific catalytic therapy, and synergistic therapy, which, however, evoke numerous challenges due to the inherent limitations of these therapeutic modalities and intricate biological circumstances as well. With the remarkable advances of nanotechnology, nanoplatform-based cascade engineering, as an efficient and booming strategy, has been tactfully introduced to optimize these cancer therapies. Based on the designed nanoplatforms, pre-supposed cascade processes could be triggered under specific conditions to generate/deliver more therapeutic species or produce stronger tumoricidal effects inside tumors, aiming to achieve cancer therapy with increased anti-tumor efficacy and diminished side effects. In this review, the recent advances in nanoplatform-based cascade engineering for cancer therapy are summarized and discussed, with an emphasis on the design of smart nanoplatforms with unique structures, compositions and properties, and the implementation of specific cascade processes by means of endogenous tumor microenvironment (TME) resources and/or exogenous energy inputs. This fascinating strategy presents unprecedented potential in the enhancement of cancer therapies, and offers better controllability, specificity and effectiveness of therapeutic functions compared to the corresponding single components/functions. In the end, challenges and prospects of such a burgeoning strategy in the field of cancer therapy will be discussed, hopefully to facilitate its further development to meet the personalized treatment demands.

Highly photostable croconium dye-anchored cell membrane vesicle for tumor pH-responsive duplex imaging-guided photothermal therapy

The development of tumor acidic microenvironment-responsive theranostic agents is a research hotspot. Herein, we developed highly photostable amphiphilic croconium dye-anchored red blood cell membrane vesicle (denoted as LET-5) for tumor pH-responsive near-infrared fluorescence (NIRF) and photoacoustic (PA) duplex imaging-guided photothermal therapy. In tumor acidic microenvironment, both NIRF and PA signals of LET-5 were significantly enhanced and the photothermal effect of LET-5 was activated. Notably, cell membrane-based vesicle with enhanced stability and long blood circulation significantly improved the tumor accumulation of croconium dye, thus achieving better therapeutic effect than free croconium dye. These findings provide a promising approach to construct amphiphilic dye-anchored cell membrane vesicle for cancer theranostics.

Nano-Platelets as an Oxygen Regulator for Augmenting Starvation Therapy Against Hypoxic Tumor

The restriction of a tumor's energy supply is proven to be an effective means of treatment. Glucose oxidase (GOx), an enzyme that catalyzes the conversion of glucose to glucolactone, producing oxygen and hydrogen peroxide in the process, has proved useful in this regard. However, hypoxia, which is implicated in tumor growth, has been found to mediate resistance to this type of tumor starvation. Here, we describe the design and testing of a platelet membrane mimetic, PMS, consisting of mesoporous silica nanoparticles (MSNs) loaded with metformin (MET) as an inner layer and platelet membranes (PM) as an outer layer that inhibits oxygen consumption by the tumor cells' respiratory pathways and enhances the effectiveness of GOx. MET directly inhibits the activity of complex I in mitochondrial electron transport and is thus a potent inhibitor of cell respiration. PMS target tumor tissue effectively and, once internalized, MET can inhibit respiration. When oxygen is plentiful, GOx promotes glucose consumption, allowing amplification of its effects on tumor starvation. This combination of respiratory suppression by PMS and starvation therapy by GOx has been found to be effective in both targeting tumors and inhibiting their growth. It is hoped that this strategy will shed light on the development of next-generation tumor starvation treatments.

Prodrug-Based Nanoreactors with Tumor-Specific In Situ Activation for Multisynergistic Cancer Therapy

Efficient drug delivery into tumor cells while bypassing many biological barriers is still a challenge for cancer therapy. By taking advantage of the palladium (Pd)-mediated in situ activation of a prodrug and the glucose oxidase (GOD)-based β-d-glucose oxidation reaction, we developed a multisynergistic cancer therapeutic platform that combined doxorubicin (DOX)-induced chemotherapy with GOD-mediated cancer-orchestrated oxidation therapy and cancer starvation therapy. In the present work, we first synthesized DOX prodrugs (pDOXs) and temporarily assembled them with β-cyclodextrins to reduce their toxic side effects. Then, a nanoreactor was constructed by synthesizing Pd⁰ nanoparticles in situ within the pores of mesoporous silica nanoparticles for the conversion of pDOX into the active anticancer drug. Furthermore, GOD was introduced to decrease the pH of the tumor microenvironment and induce cancer-orchestrated oxidation/starvation therapy by catalyzing β-d-glucose oxidation to form hydrogen peroxide (H₂O₂) and gluconic acid. Our study provides a new strategy that employs a cascade chemical reaction to achieve combined orchestrated oxidation/starvation/chemotherapy for the synergistic killing of cancer cells and the suppression of tumor growth.

Mesoporous Silica-Coated Silver Nanoframes as Drug-Delivery Vehicles for Chemo/Starvation/Metal Ion Multimodality Therapy

Cutting off the energy supply by glucose oxidase (GOx) to starve cancer cells has been a feasible and efficient oncotherapy strategy. The employment of GOx can effectively starve tumor cells by aerobic hydrolysis of glucose hopefully strengthening the abnormality (including the decrease in pH, the increase of hypoxia, and toxic hydrogen peroxide) in the tumor microenvironment (TME). On this basis, we designed and fabricated a GOx-conjugated yolk-shell Ag@mSiO₂ nanoframe with Ag NPs and GOx-conjugated mesoporous silica as the yolk and the shell, respectively, to make full use of changes the GOx induces in TME. Specifically, lower pH and H₂O₂ could accelerate the transformation of Ag nanoparticles to poisonous Ag ions. At the same time, the anabatic hypoxia condition in turn activated chemotherapy drug tirapazamine (TPZ) to exert a chemotherapeutic effect, thereby achieving effective chemo/starvation and metal ion multimodality therapy. The drug release experiment in vitro demonstrated that the GOx is the key to the nanocarriers, which can activate the whole system. The excellent cellular uptake performances of nanocarriers were corroborated by a confocal laser scanning microscope (CLSM). In addition, its superb cancer-killing effect has been confirmed by cytotoxicity and apoptosis experiments. These results indicated that the drug-delivery system achieved the cascade cancer-killing process in situ and synergistic chemo/starvation/metal ion therapy, which has a bright prospect for treating cancer.

Programmable NIR-II Photothermal-Enhanced Starvation-Primed Chemodynamic Therapy using Glucose Oxidase-Functionalized Ancient Pigment Nanosheets

Chemodynamic therapy (CDT) has attracted considerable attention recently, but the poor reaction kinetics restrict its practical utility in clinic. Herein, glucose oxidase (GOx) functionalized ancient pigment nanosheets (SrCuSi₄ O₁₀ , SC) for programmable near-infrared II (NIR-II) photothermal-enhanced starvation primed CDT is developed. The SC nanosheets (SC NSs) are readily exfoliated from SC bulk suspension in water and subsequently functionalized with GOx to form the nanocatalyst (denoted as SC@G NSs). Upon laser irradiation, the photothermal effect of SC NSs can enhance the catalytic activity of GOx for NIR-II photothermal-enhanced starvation therapy, which effectively eliminates intratumoral glucose and produces abundant hydrogen peroxide (H₂ O₂ ). Importantly, the high photothermal-conversion efficiency (46.3%) of SC@G NSs in second biological window permits photothermal therapy of deep-seated tumors under the guidance of NIR-II photoacoustic imaging. Moreover, the acidity amplification due to gluconic acid generation will in turn accelerate the degradation of SC NSs, facilitating the release of strontium (Sr) and copper (Cu) ions. Both the elevated H₂ O₂ and the released ions will prime the Cu²⁺ /Sr²⁺ -H₂ O₂ reaction for enhanced CDT. Thus, a programmable NIR-II photothermal-enhanced starvation primed CDT is established to combat cancer with minimal side effects.

An intelligent nanodevice based on the synergistic effect of telomerase-triggered photodynamic therapy and gene-silencing for precise cancer cell therapy

The development of intelligent and precise cancer therapy systems that enable accurate diagnosis and specific elimination of cancer cells while protecting normal cells to improve the safety and effectiveness of the treatment is still a challenge. Herein, we report a novel activatable nanodevice for precise cancer therapy. The nanodevice is constructed by adsorbing a DNA duplex probe onto MnO2 nanosheets. After cellular uptake, the DNA duplex probe undergoes telomerase-triggered conformation switching, resulting in a Ce6 "turn-on" signal for the identification of cancer cells. Furthermore, Deoxyribozyme (DNAzyme) is activated to catalyse the cleavage of survivin mRNA, actualizing a precise synergistic therapy in cancer cells involving photodynamic therapy and gene-silencing. The MnO2 nanosheets provide Mn2+ for the DNAzyme and relieve hypoxia to improve the efficiency of the photodynamic therapy. Live cell studies reveal that this nanodevice can diagnose cancer cells and specifically eliminate them without harming normal cells, so making the treatment safer and more effective. The developed DNA-MnO2 nanodevice provides a valuable and general platform for precise cancer therapy.