Hydrogen gas improves photothermal therapy of tumor and restrains the relapse of distant dormant tumor

NIR-II Absorption/Emission Dual Function Based 2D Targeted Nanotheranostics for Tunable Hydrogenothermal Therapy

Photothermal therapy (PTT) is a promising approach for treating tumors that offers multiple advantages. Nevertheless, its practical use in clinical settings faces several limitations, such as suboptimal delivery efficiency, uneven heat distribution, and challenges in predicting optimal treatment duration. In addition, the localized hyperthermia generated by the PTT method to induce cell apoptosis can result in the production of excessive reactive oxygen species (ROS) and the release of inflammatory cytokines, which can pose a threat to the healthy tissues surrounding the tumor. To address the above challenges, this work designs an integrated H2 delivery nanoplatform for multimodal imaging H2 thermal therapy. The combination of the second near-infrared window (NIR-II) fluorescence imaging (FL) agent (CQ4T) and the photothermal and photoacoustic (PA) properties of Ti3C2 (TC) enables real-time monitoring of the tumor area and guides photothermal treatment. Simultaneously, due to the acid-responsive H2 release characteristics of the nanoplatform, H2 can be utilized for synergistic photothermal therapy to eradicate tumor cells effectively. Significantly, acting as an antioxidant and anti-inflammatory agent, Ti3C2-BSA-CQ4T-H2 (TCBCH) protects peritumoral normal cells from damage. The proposed technique utilizing H2 gas for combination therapies and multimodal imaging integration exhibits prospects for effective and secure treatment of tumors in future clinical applications.

Hydrogen Therapy Reverses Cancer-Associated Fibroblasts Phenotypes and Remodels Stromal Microenvironment to Stimulate Systematic Anti-Tumor Immunity

Tumor microenvironment (TME) plays an important role in the tumor progression. Among TME components, cancer-associated fibroblasts (CAFs) show multiple tumor-promoting effects and can induce tumor immune evasion and drug-resistance. Regulating CAFs can be a potential strategy to augment systemic anti-tumor immunity. Here, the study observes that hydrogen treatment can alleviate intracellular reactive oxygen species of CAFs and reshape CAFs' tumor-promoting and immune-suppressive phenotypes. Accordingly, a controllable and TME-responsive hydrogen therapy based on a CaCO3 nanoparticles-coated magnesium system (Mg-CaCO3) is developed. The hydrogen therapy by Mg-CaCO3 can not only directly kill tumor cells, but also inhibit pro-tumor and immune suppressive factors in CAFs, and thus augment immune activities of CD4+ T cells. As implanted in situ, Mg-CaCO3 can significantly suppress tumor growth, turn the "cold" primary tumor into "hot", and stimulate systematic anti-tumor immunity, which is confirmed by the bilateral tumor transplantation models of "cold tumor" (4T1 cells) and "hot tumor" (MC38 cells). This hydrogen therapy system reverses immune suppressive phenotypes of CAFs, thus providing a systematic anti-tumor immune stimulating strategy by remodeling tumor stromal microenvironment.

Near-infrared-driven upconversion nanoparticles with photocatalysts through water-splitting towards cancer treatment

Water splitting is promising, especially for energy and environmental applications; however, there are limited studies on the link between water splitting and cancer treatment. Upconversion nanoparticles (UCNPs) can be used to convert near-infrared (NIR) light to ultraviolet (UV) or visible (Vis) light and have great potential for biomedical applications because of their profound penetration ability, theranostic approaches, low self-fluorescence background, reduced damage to biological tissue, and low toxicity. UCNPs with photocatalytic materials can enhance the photocatalytic activities that generate a shorter wavelength to increase the tissue penetration depth in the biological microenvironment under NIR light irradiation. Moreover, UCNPs with a photosensitizer can absorb NIR light and convert it into UV/vis light and emit upconverted photons, which excite the photoinitiator to create H2, O2, and/or OH˙ via water splitting processes when exposed to NIR irradiation. Therefore, combining UCNPs with intensified photocatalytic and photoinitiator materials may be a promising therapeutic approach for cancer treatment. This review provides a novel strategy for explaining the principles and mechanisms of UCNPs and NIR-driven UCNPs with photocatalytic materials through water splitting to achieve therapeutic outcomes for clinical applications. Moreover, the challenges and future perspectives of UCNP-based photocatalytic materials for water splitting for cancer treatment are discussed in this review.

Nanomaterials-Induced Redox Imbalance: Challenged and Opportunities for Nanomaterials in Cancer Therapy

Cancer cells typically display redox imbalance compared with normal cells due to increased metabolic rate, accumulated mitochondrial dysfunction, elevated cell signaling, and accelerated peroxisomal activities. This redox imbalance may regulate gene expression, alter protein stability, and modulate existing cellular programs, resulting in inefficient treatment modalities. Therapeutic strategies targeting intra- or extracellular redox states of cancer cells at varying state of progression may trigger programmed cell death if exceeded a certain threshold, enabling therapeutic selectivity and overcoming cancer resistance to radiotherapy and chemotherapy. Nanotechnology provides new opportunities for modulating redox state in cancer cells due to their excellent designability and high reactivity. Various nanomaterials are widely researched to enhance highly reactive substances (free radicals) production, disrupt the endogenous antioxidant defense systems, or both. Here, the physiological features of redox imbalance in cancer cells are described and the challenges in modulating redox state in cancer cells are illustrated. Then, nanomaterials that regulate redox imbalance are classified and elaborated upon based on their ability to target redox regulations. Finally, the future perspectives in this field are proposed. It is hoped this review provides guidance for the design of nanomaterials-based approaches involving modulating intra- or extracellular redox states for cancer therapy, especially for cancers resistant to radiotherapy or chemotherapy, etc.

Current trends in gas-synergized phototherapy for improved antitumor theranostics

Phototherapy, such as photothermal therapy (PTT) and photodynamic therapy (PDT), has been considered an elegant solution to eradicate tumors due to its minimal invasiveness and low systemic toxicity. Nevertheless, it is still challenging for phototherapy to achieve ideal outcomes and clinical translation due to its inherent drawbacks. Owing to the unique biological functions, diverse gases have attracted growing attention in combining with phototherapy to achieve super-additive therapeutic effects. Specifically, gases such as nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S) have been proven to kill tumor cells by inducing mitochondrial damage in synergy with phototherapy. Additionally, several gases not only enhance the thermal damage in PTT and the reactive oxygen species (ROS) production in PDT but also improve the tumor accumulation of photoactive agents. The inflammatory responses triggered by hyperthermia in PTT are also suppressed by the combination of gases. Herein, we comprehensively review the latest studies on gas-synergized phototherapy for cancer therapy, including (1) synergistic mechanisms of combining gases with phototherapy; (2) design of nanoplatforms for gas-synergized phototherapy; (3) multimodal therapy based on gas-synergized phototherapy; (4) imaging-guided gas-synergized phototherapy. Finally, the current challenges and future opportunities of gas-synergized phototherapy for tumor treatment are discussed. STATEMENT OF SIGNIFICANCE: 1. The novelty and significance of the work with respect to the existing literature. (1) Strategies to design nanoplatforms for gas-synergized anti-tumor phototherapy have been summarized for the first time. Meanwhile, the integration of various imaging technologies and therapy modalities which endow these nanoplatforms with advanced theranostic capabilities has been summarized. (2) The mechanisms by which gases synergize with phototherapy to eradicate tumors are innovatively and comprehensively summarized. 2. The scientific impact and interest. This review elaborates current trends in gas-synergized anti-tumor phototherapy, with special emphases on synergistic anti-tumor mechanisms and rational design of therapeutic nanoplatforms to achieve this synergistic therapy. It aims to provide valuable guidance for researchers in this field.

Stimuli-responsive nanoparticles delivered by a nasal-brain pathway alleviate depression-like behavior through extensively scavenging ROS

Depression is one of the most common mental diseases, which seriously affects patients' physical and mental health. Emerging evidence has indicated that oxidative stress (OS) is a major cause of neurodegeneration involved in the pathogenesis of depression. Consequently, targeted reactive oxygen species (ROS) elimination is regarded as a promising strategy for efficient depression therapy. In addition, insufficient brain drug delivery is the main obstacle to depression therapy owing to the presence of the blood-brain barrier (BBB). To achieve the goals of bypassing the BBB and promoting antioxidant therapy for depression, a broad-spectrum ROS scavenging NPs was rationally designed through a nasal-brain pathway developed for combined ROS scavenging and brain drug delivery. A hexa-arginine (R6) modified ROS-responsive dextran (DEX) derivate was synthesized for antidepressant olanzapine (Olz) and H2 donor amino borane (AB) loading to prepare Olz/RDPA nanoparticles (NPs). Subsequently, the NPs were dispersed into a thermoresponsive hydrogel system based on poloxamer. In vitro and in vivo results demonstrated that Olz/RDPA in situ thermoresponsive hydrogel system could effectively deliver NPs to the brain via the nasal-brain pathway and alleviate depression-like behaviors through combined ROS depletion and inhibition of 5-HT dysfunction of the oxidative stress-induced. The proposed ROS-scavenging nanotherapeutic would open a new window for depression treatment. STATEMENT OF SIGNIFICANCE: ROS is an innovative therapeutic target involving the pathology of depression whereas targeted delivery of ROS scavenging has not been achieved yet. In the current study, ROS-responsive nanoparticles (Olz/RDPA NPs) were prepared and dispersed in a thermosensitive hydrogel for delivery through the nasal-brain pathway for the treatment of depression. Sufficient ROS depletion and improvement of delivery capacity by the nasal-brain pathway effectively could reverse oxidative stress and alleviate depressive-like behavior. Collectively, these nanoparticles may represent a promising strategy for the treatment of depression.

Current Advances of Atomically Dispersed Metal-Centered Nanozymes for Tumor Diagnosis and Therapy

Nanozymes, which combine enzyme-like catalytic activity and the biological properties of nanomaterials, have been widely used in biomedical fields. Single-atom nanozymes (SANs) with atomically dispersed metal centers exhibit excellent biological catalytic activity due to the maximization of atomic utilization efficiency, unique metal coordination structures, and metal-support interaction, and their structure-activity relationship can also be clearly investigated. Therefore, they have become an emerging alternative to natural enzymes. This review summarizes the examples of nanocatalytic therapy based on SANs in tumor diagnosis and treatment in recent years, providing an overview of material classification, activity modulation, and therapeutic means. Next, we will delve into the therapeutic mechanism of SNAs in the tumor microenvironment and the advantages of synergistic multiple therapeutic modalities (e.g., chemodynamic therapy, sonodynamic therapy, photothermal therapy, chemotherapy, photodynamic therapy, sonothermal therapy, and gas therapy). Finally, this review proposes the main challenges and prospects for the future development of SANs in cancer diagnosis and therapy.

Palladium-based multifunctional nanoparticles for combined chemodynamic/photothermal and calcium overload therapy of tumors

Due to the high mortality and incidence rates associated with tumors and the specificity of the tumor microenvironment (TME), it is difficult to achieve a complete cure for tumors using a single therapy. In this study, calcium carbonate-modified palladium hydride nanoparticles (PdH@CaCO3) were prepared and utilized for the combined treatment of tumors through chemodynamic therapy (CDT)/photothermal therapy (PTT) and calcium overload therapy. After entering tumor cells, PdH@CaCO3 releases calcium ions (Ca2+) and PdH once it reaches the TME due to the pH reactivity of the calcium carbonate coating. The mitochondrial membrane potential is lowered by the Ca2+, leading to irreversible cell damage. Meanwhile, PdH reacts with excessive hydrogen peroxide (H2O2) in the TME via the Fenton reaction, generating hydroxyl radicals (·OH). Moreover, PdH is an excellent photothermal agent that can kill tumor cells under laser irradiation, leading to significant anti-tumor effects. In vitro and in vivo studies have demonstrated that PdH@CaCO3 could combine CDT/PTT and calcium overload therapy, exhibiting great clinical potential in the treatment of tumors.

Gas-assisted phototherapy for cancer treatment

Phototherapies, mainly including photodynamic and photothermal therapy, have made considerable strides in the field of cancer treatment. With the aid of phototherapeutic agents, reactive oxygen species (ROS) or heat are generated under light irradiation to selectively damage cancer cells. However, sole-modality phototherapy faces certain drawbacks, such as limited penetration of phototherapeutic agents into tumor tissues, inefficient ROS generation due to hypoxia, treatment-induced inflammation and resistance of tumor to treatment (e.g., high levels of antioxidants, expression of heat shock protein). Gas therapy, an emerging therapy approach that damages cancer cells by improving the level of certain gas at the tumor site, shows potential to overcome the challenges associated with phototherapies. In addition, with the rapid development of nanotechnology, gas-assisted phototherapy based on nanomedicines has emerged as a promising strategy to enhance the treatment efficacy. This review summarizes recent advances in gas-assisted phototherapy and discusses the prospects and challenges of this strategy in cancer phototherapy.

Anti-inflammatory strategies for photothermal therapy of cancer

High temperature generated by photothermal therapy (PTT) can trigger an inflammatory response at the tumor site, which not only limits the efficacy of PTT but also increases the risk of tumor metastasis and recurrence. In light of the current limitations posed by inflammation in PTT, several studies have revealed that inhibiting PTT-induced inflammation can significantly improve the efficacy of cancer treatment. In this review, we summarize the research progress made in combining anti-inflammatory strategies to enhance the effectiveness of PTT. The goal is to offer valuable insights for developing better-designed photothermal agents in clinical cancer therapy.

Small-size Ti3C2Tx MXene nanosheets coated with metal-polyphenol nanodots for enhanced cancer photothermal therapy and anti-inflammation

As a controllable, simple method with few side effects, near-infrared (NIR) light-based photothermal therapy (PTT) has been proven an effective cancer therapeutic approach. However, PTT-induced inflammation is a potential negative factor. And the overexpressed heat shock proteins (HSPs) by cancer cells can protect them from hyperthermia during PTT. In this work, small-size Ti₃C₂T_x MXene nanosheets with high photothermal conversion efficiency in the region of NIR, high cargo loading capability and good free radical scavenging capability were chosen for cancer PTT and anti-inflammation. And (-)-epigallocatechin gallate (EGCG) was applied to form EGCG/Fe metal-polyphenol nanodots on the nanosheets. EGCG being released in acid cancer cells could reduce the expression of HSPs and could be used for anti-inflammation. As a result, the complex nanosheets named MXene@EGCG could achieve enhanced cancer PTT and be anti-inflammatory. Both in vitro and in vivo studies proved the good photothermal ability of MXene@EGCG and demonstrated that it could inhibit the expression of HSPs in tumor cells and relieve PTT-induced inflammation. Therefore, the nanosheets show good results in tumor ablation with a low level of inflammation, which provides another possibility for cancer therapy. STATEMENT OF SIGNIFICANCE: Photothermal therapy (PTT)-induced inflammation plays an essential role in some important stages of tumor development and is unfavorable for cancer treatment. And hyperthermia leads to the overexpression of heat shock proteins (HSPs) in cancer cells, which limits the therapeutic effect of PTT. Therefore, we coated small-size Ti₃C₂T_x MXene nanosheets with (-)-epigallocatechin gallate (EGCG)/Fe metal-polyphenol nanodots and named them as MXene@EGCG. This system shows a good photothermal conversion efficiency at 808 nm. And it can release EGCG in cancer cells to inhibit the expression of HSPs, thus achieving an enhanced cancer PTT. Both MXene and EGCG can also diminish the PTT-trigged inflammation. Both in vitro and in vivo studies prove the good anti-cancer PTT effect and anti-inflammation capability of MXene@EGCG.

Injectable carboxymethyl chitosan-based hydrogel for simultaneous anti-tumor recurrence and anti-bacterial applications

The postoperative recurrence has adversely affected the treatment of tumors. Besides, the potential bacterial infection at the wound site may lead to a series of tissue necrosis. Here, we developed an injectable γ-polyglutamic acid/carboxymethyl chitosan/polydopamine hydrogel (PCP) for simultaneously reducing the postoperative infection and preventing the tumor recurrence. On the one hand, the aqueous solution of carboxymethyl chitosan oxidized the dopamine into polydopamine; on the other, the carboxymethyl chitosan was cross-linked with the activated γ-polyglutamic acid to form a hydrogel. After local implantation, the PCP hydrogel effectively killed tumor cells and bacteria under 808 nm laser irradiation. In addition, carboxymethyl chitosan rendered the hydrogel with anti-bacterial properties as well as anti-tumor efficiencies. The anti-tumor recurrence and anti-bacterial efficiencies of PCP hydrogel were proved on a tumor-removed mouse model and a Staphylococcus aureus-infected mouse model, respectively. Moreover, the hydrogel has the advantages of good biocompatibility and simple preparation, and thus has potential application prospects in the prevention of tumor recurrence and wound bacterial infection.

Rational Design of Platinum-Bismuth Sulfide Schottky Heterostructure for Sonocatalysis-Mediated Hydrogen Therapy

Conventional sonodynamic therapy is unavoidably limited by the tumor microenvironment, although many sonosensitizers have been developed to improve them to a certain extent. Given this, a concept of sonocatalytic hydrogen evolution is proposed, which is defined as an oxygen-independent therapeutics. To demonstrate the feasibility of the concept, the narrow-bandgap semiconductor bismuth sulfide (Bi₂ S₃ ) is selected as the sonocatalyst and platinum (Pt) nanoparticles are grown in situ to optimize their catalytic performance. In this nanocatalytic system, the Pt nanoparticles help to capture sonoexcited electrons, whereas intratumoral overexpressed glutathione (GSH), as a natural hole sacrificial agent, can consume sonoexcited holes, which greatly improves the charge-separation efficiency and promotes controllable and sustainable H₂  generation. Even under hypoxic conditions, the Pt-Bi₂ S₃  nanoparticles can also produce sufficient H₂  under ultrasound irradiation. Mechanistically, mitochondrial dysfunction caused by H₂  and intratumoral redox homeostasis destruction by GSH depletion synergistically damage DNA to induce tumor cells apoptosis. At the same time, the Pt nanoparticles and holes can also trigger the decomposition of hydrogen peroxide into O₂  to relieve tumor hypoxia, thus being synergistic with GSH depletion to reverse tumor immunosuppressive microenvironment. The proposed sonocatalysis-mediated therapy will provide a new direction to realize facile and efficient cancer therapy.

Near-infrared band responsive ROS regulator selectively inhibits breast cancer cells by programming combination phototherapy

Catalytic therapy can effectively kill tumor cells and inhibit tumor growth by producing highly toxic reactive oxygen species (ROS). However, the long-term catalysis of nanozymes easily lead to ROS breaking through the boundary in tumor tissues, resulting in spillover and injuring normal cells. Therefore, how to control the threshold of ROS production from nanozymes in tumor tissues is an unsolved problem. In this work, to prevent the boundary effect of the photosensitizer ([Ru(bpy)2(tip)]²⁺, RBT) during ROS generation, we used the sensitivity of RBT and PdH_0.2-Ir with different wavelengths of near-infrared light (NIR) to generate ROS and H₂, respectively. Therefore, an intelligent nanosystem PdH_0.2-Ir@RBT(PIH@R) was constructed to precisely control ROS generation by adjusting the NIR laser wavelength. The palladium-iridium alloy (Pd-Ir) nanoparticles as the core can co-load hydrogen (H₂) and RBT and show NIR-responsive behaviors. Under 808 nm laser irradiation, PIH@R produces ROS with the photocatalysis of RBT, while under 1064 nm laser irradiation PIH@R will quickly activate and release H₂ to eliminate ROS. Interestingly, in vitro and in vivo experiments showed that PIH@R acted like a "Trojan horse": PIH@R can destroy the mitochondria of 4T1 cells to destroy their redox homeostasis system, resulting in cancer cells relying on exogenous PIH@R to change their reactive oxygen species levels. Subsequently, when PIH@R is activated into a harmful oxidation state, it can easily crush the redox homeostasis system of cancer cells and induce cancer cell apoptosis.

Calcium Hydride-Based Dressing to Promote Wound Healing

Wound microenvironment with excess reactive oxygen species (ROS) can significantly inhibit wound healing. Encouraged by hydrogen molecules (H₂ ) with effective ROS scavenging and calcium hydride (CaH₂ ) with sufficient H₂ supply, the authors for the first time employed CaH₂ as a therapeutic H₂ donor and starch as a diluent to construct CaH₂ pulvis dressing for wound healing treatment. It has been found that CaH₂ by generating H₂ exhibited excellent ROS scavenging performance, favorable for preserving the oxidative-stress-induced cell death. After being applied onto the skin wound, the CaH₂ pulvis dressing with the unique ROS-scavenging ability can accelerate skin wound healing in healthy/diabetic mice (small animal models) and Bama mini-pigs (large animal model). Such CaH₂ dressing can release H₂ to relieve the inflammation levels, decrease the secretion of pro-inflammatory cytokines, increase the infiltration of inflammation-suppressive immune cells, and promote the regeneration of new blood vessels and collagens, thereby accelerating wound healing. This work highlighted that the integration of anti-oxidation and anti-inflammation functions based on CaH₂ dressing endowed it with a promising possibility for the treatment of inflammatory diseases.

Copper-Based Metal-Organic Framework Induces NO Generation for Synergistic Tumor Therapy and Antimetastasis Activity

The interaction between platelets and circulating tumor cells (CTCs) contributes to distal tumor metastasis by protecting CTCs from immunological assault and shear stress, which can be disrupted by nitric oxide (NO) through inhibiting platelet-mediated adhesion. To eradicate primitive tumors and inhibit CTC-based pulmonary metastasis, a novel biomimetic nanomedicine (mCuMNO) is designed by encapsulating Cu⁺ -responsive S-nitrosoglutathione as a NO donor into a copper-based metal-organic framework (CuM). This work discovers that mCuMNO can target tumor regions and deplete local glutathione (GSH) to reduce Cu²⁺ to Cu⁺ , followed by triggering NO release and hydroxyl radicals (·OH) production, thereby interrupting platelet/CTC interplay and contributing to chemodynamic therapy. Detailed studies demonstrate that mCuMNO exhibits high efficiency and safety in tumor therapy and antimetastasis activity, sheding new light on the development of CuM-based tumor synthetic therapy.

Recent advances in near-infrared-II hollow nanoplatforms for photothermal-based cancer treatment

Near-infrared-II (NIR-II, 1000–1700 nm) light-triggered photothermal therapy (PTT) has been regarded as a promising candidate for cancer treatment, but PTT alone often fails to achieve satisfactory curative outcomes. Hollow nanoplatforms prove to be attractive in the biomedical field owing to the merits including good biocompatibility, intrinsic physical-chemical nature and unique hollow structures, etc. On one hand, hollow nanoplatforms themselves can be NIR-II photothermal agents (PTAs), the cavities of which are able to carry diverse therapeutic units to realize multi-modal therapies. On the other hand, NIR-II PTAs are capable of decorating on the surface to combine with the functions of components encapsulated inside the hollow nanoplatforms for synergistic cancer treatment. Notably, PTAs generally can serve as good photoacoustic imaging (PAI) contrast agents (CAs), which means such kind of hollow nanoplatforms are also expected to be multifunctional all-in-one nanotheranostics. In this review, the recent advances of NIR-II hollow nanoplatforms for single-modal PTT, dual-modal PTT/photodynamic therapy (PDT), PTT/chemotherapy, PTT/catalytic therapy and PTT/gas therapy as well as multi-modal PTT/chemodynamic therapy (CDT)/chemotherapy, PTT/chemo/gene therapy and PTT/PDT/CDT/starvation therapy (ST)/immunotherapy are summarized for the first time. Before these, the typical synthetic strategies for hollow structures are presented, and lastly, potential challenges and perspectives related to these novel paradigms for future research and clinical translation are discussed.

Fluorescent COFs with a Highly Conjugated Structure for Combined Starvation and Gas Therapy

Covalent organic frameworks (COFs) show great potential in biomedicine, but the synthesis of fluorescent ones with a highly conjugated structure in mild conditions remains a challenge. Herein, we reported a facile method to synthesize a nanosized, highly conjugated, and N-enriched COF material with bright fluorescence and further integrated it as a novel nanoplatform for efficient cancer starvation/gas therapy. High surface area and a porous structure endowed COFs with large loading capacity for both glucose oxidase and l-arginine, while conjugated monomer and N-doping guaranteed bright fluorescence and relatively strong interactions between loaded cargos. Well-designed size allowed easy cell uptake of drug-loaded COFs, which finally resulted in a highly efficient starvation therapy by consuming large amounts of glucose in cancer cells. H₂O₂, the byproduct during glucose consumption, was made full use of oxidizing l-arginine to generate toxic NO. This constructed combined starvation and gas therapy and exhibited emerging antimigration performance. Both in vitro and in vivo experiments confirmed an excellent cancer therapeutic effect than a single therapy, and the novel therapeutic platform showed good biocompatibility. Detailed mechanism study demonstrated that cell apoptosis and lysosomal damage contributed most to the synergistic treatment. Our study developed a new strategy to synthesize highly conjugated COFs with fluorescence and reported the potential applications in cancer therapy.

Advances in nanobiotechnology-propelled multidrug resistance circumvention of cancer

Multidrug resistance (MDR) is one of the main reasons for the failure of tumor chemotherapy and has a negative influence on the therapeutic effect. MDR is primarily attributable to two mechanisms: the activation of efflux pumps for drugs, which can transport intracellular drug molecules from cells, and other mechanisms not related to efflux pumps, e.g., apoptosis prevention, strengthened DNA repair, and strong oxidation resistance. Nanodrug-delivery systems have recently attracted much attention, showing some unparalleled advantages such as drug targeting and reduced drug efflux, drug toxicity and side effects in reversing MDR. Notably, in drug-delivery platforms based on nanotechnology, multiple therapeutic strategies are integrated into one system, which can compensate for the limitations of individual strategies. In this review, the mechanisms of tumor MDR as well as common vectors and nanocarrier-combined therapy strategies to reverse MDR were summarized to promote the understanding of the latest progress in improving the efficiency of chemotherapy and synergistic strategies. In particular, the adoption of nanotechnology has been highlighted and the principles underlying this phenomenon have been elucidated, which may provide guidance for the development of more effective anticancer strategies.

Precisely NIR-II-activated and pH-responsive cascade catalytic nanoreactor for controlled drug release and self-enhanced synergetic therapy

Mesoporous polydopamine (MPDA) and MPDA-based nanosystems have been widely used in the field of photothermal therapy (PTT) and drug delivery. However, synthesis of the corresponding nanoplatforms for efficient PTT and controlled drug release simultaneously in the second near infrared (NIR-II) region remains a great challenge. Herein, a NIR-II and pH dual-responsive HMPDA@Cu_2-xSe cascade catalytic nanoplatform was constructed by assembling hollow mesoporous polydopamine (HMPDA) with ultra-small Cu_2-xSe, which could compensate the inadequate NIR-II-induced PTT effect of HMPDA and enhance the efficacy of chemodynamic therapy (CDT) simultaneously under NIR-II laser irradiation. Meanwhile, doxorubicin (DOX) and glucose oxidase (GOx) were encapsulated into the synthesized HMPDA@Cu_2-xSe using the photothermal-induced phase change material (PCM) tetradecyl (1-TD) as a gatekeeper to achieve the controlled release of the cargo. Under 1064 nm laser, the generated heat could cause 1-TD melting, resulting in the release of large amounts of DOX and GOx. The released GOx could further catalyze glucose to H₂O₂ and gluconic acid, which in turn promoted the effects of PTT/CDT and the release of drugs. In vitro and in vivo experiments showed that the synthesized HMPDA@Cu_2-xSe-DOX-GOx@PCM (HMPC-D/G@PCM) nanosystem exhibited a significant tumor cell inhibition effect by combining different treatment modes. Thus, this smart nanoplatform with multiple stimuli-activated cascade reactions provided a new idea for designing effective multi-modal combination therapy for tumors.

Recent progress in upconversion nanomaterials for emerging optical biological applications

The recent advances of upconversion nanoparticles (UCNPs) have made them the ideal "partner" for a variety of biological applications. In this review, we describe the emerging biological optical applications of UCNPs, focus on their potential therapeutic advantages. Firstly, we briefly review the development and mechanisms of upconversion luminescence, including organic and inorganic UCNPs. Next, in the section on UCNPs for imaging and detection, we list the development of UCNPs in visualization, temperature sensing, and detection. In the section on therapy, recent results are described concerning optogenetics and neurotherapy. Tumor therapy is another major part of this section, including the synergistic application of phototherapy such as photoimmunotherapy. In a special section, we briefly cover the integration of UCNPs in therapeutics. Finally, we present our understanding of the limitations and prospects of applications of UCNPs in biological fields, hoping to provide a more comprehensive understanding of UCNPs and attract more attention.

The Advancement of Gas-Generating Nanoplatforms in Biomedical Fields: Current Frontiers and Future Perspectives

Diverse gases (NO, CO, H₂ S, H₂ , etc.) have been widely applied in the medical intervention of various diseases, including cancer, cardiovascular disease, ischemia-reperfusion injury, bacterial infection, etc., attributing to their inherent biomedical activities. Although many gases have many biomedical activities, their clinical use is still limited due to the rapid and free diffusion behavior of these gases molecules, which may cause potential side effects and/or ineffective treatment. Gas-generating nanoplatforms (GGNs) are effective strategies to address the aforementioned challenges of gas therapy by preventing gas production or release at nonspecific sites, enhancing GGNs accumulation at targeted sites, and controlling gas release in response to exogenous (UV, NIR, US, etc.) or endogenous (H₂ O₂ , GSH, pH, etc.) stimuli at the lesion site, further maintaining gas concentration within the effective range and achieving the purpose of disease treatment. This review comprehensively summarizes the advancements of "state-of-the-art" GGNs in the recent three years, with emphasis on the composition, structure, preparation process, and gas release mechanism of the nanocarriers. Furthermore, the therapeutic effects and limitations of GGNs in preclinical studies using cell/animal models are discussed. Overall, this review enlightens the further development of this field and promotes the clinical transformation of gas therapy.

Bacteria-Elicited Specific Thrombosis Utilizing Acid-Induced Cytolysin A Expression to Enable Potent Tumor Therapy

Given the special microenvironment of solid tumors, live microorganisms have emerged as drug delivery vehicles and therapeutic agents. Here, an acid-induced therapeutic platform is constructed using attenuated Escherichia coli to express the cytolysin A protein. The bacteria can target and colonize tumor tissues without causing notable host toxicity. Bacterial infection can disrupt blood vessels and trigger thrombosis in tumor tissues, resulting in the cut-off of nutrient supply to tumor cells and the arrest of tumor growth. The expression of cytolysin A induced by the acidic tumor microenvironment further strengthens thrombosis and provides a complementary therapeutic option due to its pore-forming function. In a xenograft mouse tumor model, this strategy reduces tumor proliferation by 79% and significantly prevents tumor metastasis, thus paving a new avenue for bacteria-based tumor therapy.

Magnesium galvanic cells produce hydrogen and modulate the tumor microenvironment to inhibit cancer growth

Hydrogen can be used as an anti-cancer treatment. However, the continuous generation of H₂ molecules within the tumor is challenging. Magnesium (Mg) and its alloys have been extensively used in the clinic as implantable metals. Here we develop, by decorating platinum on the surface of Mg rods, a Mg-based galvanic cell (MgG), which allows the continuous generation of H₂ in an aqueous environment due to galvanic-cell-accelerated water etching of Mg. By implanting MgG rods into a tumor, H₂ molecules can be generated within the tumor, which induces mitochondrial dysfunction and intracellular redox homeostasis destruction. Meanwhile, the Mg(OH)₂ residue can neutralize the acidic tumor microenvironment (TME). Such MgG rods with the micro-galvanic cell structure enable hydrogen therapy to inhibit the growth of tumors, including murine tumor models, patient-derived xenografts (PDX), as well as VX₂ tumors in rabbits. Our research suggests that the galvanic cells for hydrogen therapy based on implantable metals may be a safe and effective cancer treatment.

The production of hydrogen inside cells can stimulate cell death. Here, the authors made magnesium galvanic rods that continuously produce hydrogen and result in tumor inhibition in vitro and in vivo.

Surgical Tumor-Derived Photothermal Nanovaccine for Personalized Cancer Therapy and Prevention

Recent breakthroughs in cell membrane-fabricated nanovaccine offer innovateive therapeutic options for preventing tumor metastasies and recurrence, yet the treatment of patient-specific solid tumor remained challenging owing to the immunosuppressive tumor microenvironment. Herein, we developed a personalized photothermal nanovaccine based on the surgical tumor-derived cell membranes (CMs) coating resiquimod (R848) loaded mesoporous polydopamine (MPDA) nanoparticles for targeting tumor photothermal immunotherapy and prevention. The fabricated photothermal nanovaccine MPDA-R848@CM (MR@C) demonstrates outstanding imaging-guided photothermal immunotherapy efficacy to eradicate solid tumors under near-IR laser irradiation and further inhibiting metastasis tumors by the resulted antitumor immunities, especially in combination with programmed death-ligand 1 antibody therapy (aPD-L1). Furthermore, from in vivo prophylactic testing results, it is confirmed that the 4T1 cells rechallenge can be prevented 100% in postsurgical tumor model after vaccination of the photothermal nanovaccine. Our work fabricates a personalized photothermal nanovaccine that possesses great potential for tumor-specific treatment and for preventing postoperative tumor recurrence.

A comprehensive update of micro- and nanobubbles as theranostics in oncology

Advances in diagnostic and imaging capabilities have allowed cancers to be detected earlier and characterized more robustly. These strategies have recently branched into theranostics whereby contrast agents traditionally used for imaging have been co-loaded with therapeutics to simultaneously diagnose and treat cancers in a patient-specific manner. Microbubbles (MB) and nanobubbles (NB) are contrast agents which can be modulated to meet the theranostic needs particularly in the realm of oncology. The current review focuses on the ultrasound-responsive MB/NB platforms used as a theranostic tool in oncology. We discuss in detail the key parameters that influence the utility of MB/NB formulations and implications of such treatment modalities. Recent advances in composition strategies, latest works in the pre-clinical stages and multiple paradigm-shifting innovations in the field of MB/NB are discussed in-depth in this review. The clinical application of MB/NB is currently limited to diagnostic imaging. Surface chemistry modification strategies will help tune the formulations toward therapeutic applications. It is also anticipated that MB/NB will see increased use to deliver gas therapeutics. Scalability and stability considerations will be at the forefront as these particles get introduced into the clinical theranostic toolbox.

Near-infrared light-triggered nano-prodrug for cancer gas therapy

Gas therapy (GT) has attracted increasing attention in recent years as a new cancer treatment method with favorable therapeutic efficacy and reduced side effects. Several gas molecules, such as nitric oxide (NO), carbon monoxide (CO), hydrogen (H2), hydrogen sulfide (H2S) and sulfur dioxide (SO2), have been employed to treat cancers by directly killing tumor cells, enhancing drug accumulation in tumors or sensitizing tumor cells to chemotherapy, photodynamic therapy or radiotherapy. Despite the great progress of gas therapy, most gas molecules are prone to nonspecific distribution when administered systemically, resulting in strong toxicity to normal tissues. Therefore, how to deliver and release gas molecules to targeted tissues on demand is the main issue to be considered before clinical applications of gas therapy. As a specific and noninvasive stimulus with deep penetration, near-infrared (NIR) light has been widely used to trigger the cleavage and release of gas from nano-prodrugs via photothermal or photodynamic effects, achieving the on-demand release of gas molecules with high controllability. In this review, we will summarize the recent progress in cancer gas therapy triggered by NIR light. Furthermore, the prospects and challenges in this field are presented, with the hope for ongoing development.

Controlled release of hydrogen by implantation of magnesium induces P53-mediated tumor cells apoptosis

Hydrogen has been used to suppress tumor growth with considerable efficacy. Inhalation of hydrogen gas and oral ingestion of hydrogen-rich saline are two common systemic routes of hydrogen administration. We have developed a topical delivery method of hydrogen at targeted sites through the degradation of magnesium-based biomaterials. However, the underlying mechanism of hydrogen's role in cancer treatment remains ambiguous. Here, we investigate the mechanism of tumor cell apoptosis triggered by the hydrogen released from magnesium-based biomaterials. We find that the localized release of hydrogen increases the expression level of P53 tumor suppressor proteins, as demonstrated by the in vitro RNA sequencing and protein expression analysis. Then, the P53 proteins disrupt the membrane potential of mitochondria, activate autophagy, suppress the reactive oxygen species in cancer cells, and finally result in tumor suppression. The anti-tumor efficacy of magnesium-based biomaterials is further validated in vivo by inserting magnesium wire into the subcutaneous tumor in a mouse. We also discovered that the minimal hydrogen concentration from magnesium wires to trigger substantial tumor apoptosis is 91.2 μL/mm³ per day, which is much lower than that required for hydrogen inhalation. Taken together, these findings reveal the release of H₂ from magnesium-based biomaterial exerts its anti-tumoral activity by activating the P53-mediated lysosome-mitochondria apoptosis signaling pathway, which strengthens the therapeutic potential of this biomaterial as localized anti-tumor treatment.

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The feasibility of using Mg implants is explored for localized delivery of hydrogen against colorectal tumors.

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This approach is advantageous over conventional chemotherapy/H₂ inhalation due to the portability, high H₂-loading capacity and efficient delivery of H₂ gas to tumors.

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We provide a molecularly detailed and mechanistic understanding of how H₂ could activate the antitumor pathway above certain threshold concentrations of H₂, which inspires more effective therapy against tumors.

Gas and gas-generating nanoplatforms in cancer therapy

Gas therapy is the usage of certain gases with special therapeutic effects for the treatment of diseases. Hydrogen (H₂), nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H₂S) acting as gas signalling molecules are representative gases in cancer therapy. They act directly on mitochondria or nuclei to lead to cell apoptosis. They can also alleviate immuno-suppression in the tumour microenvironment and promote phenotype conversion of tumour-associated macrophages. Moreover, the combination of gas therapy and other traditional therapy methods can reduce side effects and improve therapeutic efficacy. Here, we discuss the roles of NO, CO, H₂S and H₂ in cancer biology. Considering the rapidly developing nanotechnology, gas-generating nanoplatforms which can achieve targeted delivery and controlled release were also discussed. Finally, we highlight the current challenges and future opportunities of gas-based cancer therapy.

In situ hydrogen nanogenerator for bimodal imaging guided synergistic photothermal/hydrogen therapies

Multifunctional nanoagents integrating multiple therapeutic and imaging functions hold promise in the field of non-invasive and precise tumor therapies. However, the complex preparation process and uncertain drug metabolism of nanoagents loaded with various therapeutic agents or imaging agents greatly hinder its clinical applications. Developing simple and effective nanoagents that integrate multiple therapeutic and imaging functions remain a huge challenge. Therefore, a novel strategy based on in situ hydrogen release is proposed in this work: aminoborane (AB) was loaded onto mesoporous polydopamine nanoparticles (MPDA NPs) as a prodrug for hydrogen production, and then, PEG was modified on the surface of nanoparticles (represented as AB@MPDA-PEG). MPDA NPs not only act as photothermal agents (PTA) with high photothermal conversion efficiency (808 nm, η = 38.72%) but also as the carriers of AB accumulated in the tumor through enhanced permeability and retention (EPR) effect. H₂ gas generated by AB in the weak acid conditions of the tumor microenvironment (TME) not only was used to treat tumors via a combination of hydrogen and photothermal therapies but also serves as a US and CT contrast agent, providing accurate guidance for tumor treatment. Finally, in vivo and in vitro investigation suggest that the designed multifunctional nanosystem not only showed excellent properties such as high hydrogen-loading capacity, long-lasting sustained hydrogen release ability and excellent biocompatibility but also achieve selective PTT/hydrogen therapies and US/CT bimodal imaging functions, which can effectively guide antitumor therapies. The proposed hydrogen gas-based strategy for combination therapies and bimodal imaging integration holds promise as an efficient and safe tumor treatment for future clinical translation.

Hydrogen-rich water prepared by ammonia borane can enhance rapeseed (Brassica napus L.) seedlings tolerance against salinity, drought or cadmium

Hydrogen agriculture is recently recognized as an emerging and promising approach for low-carbon society. Since shorter retention time for hydrogen gas (H2) in conventional electrolytically produced hydrogen-rich water (HRW) limits its application, seeking a more suitable method to produce and maintain H2 level in HRW for longer time remain a challenge for scientific community. To solve above problems, we compared and concluded that the H2 in HRW prepared by ammonia borane (NH3·BH3) could meet above requirement. The biological effects of HRW prepared by NH3·BH3 were further evaluated in seedlings of rapeseed, the most important crop for producing vegetable oil worldwide. Under our experimental conditions, 2 mg/L NH3·BH3-prepared HRW could confer 3-day-old hydroponic seedlings tolerance against 150 mM sodium chloride (NaCl), 20% polyethylene glycol (PEG; w/v), or 100 μM CdCl2 stress, and intensify endogenous nitric oxide (NO) accumulation under above stresses. The alleviation of seedlings growth stunt was confirmed by reducing cell death and reestablishing redox homeostasis. Reconstructing ion homeostasis, increasing proline content, and reducing Cd accumulation were accordingly observed. Above responses were sensitive to the removal of endogenous NO with its scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-imidazoline-1-1-oxyl-3-oxide (cPTIO; 100 μM), reflecting the requirement of NO functioning in the regulation of plant physiology achieved by NH3·BH3-prepared HRW. The application of 1 mM tungstate, an inhibitor of nitrate reductase (NR; an important NO synthetic enzyme), showed the similar blocking responses in the phenotype, suggesting that NR might be the major source of NO involved in above H2 actions. Together, these results revealed that HRW prepared by NH3·BH3 could enhance rapeseed seedlings tolerance against abiotic stress, thus opening a new window for the application of H2 in agricultural production.

How do bismuth-based nanomaterials function as promising theranostic agents for the tumor diagnosis and therapy?

The complexity of tumor microenvironment and the diversity of tumors seriously affect the therapeutic effect, the focus, therefore, has gradually been shifted from monotherapy to combination therapy in clinical research in order to improve the curative effect. The synergistic enhancement interactions among multiple monotherapies majorly contribute to the birth of the multi-mode cooperative therapy, whose effect of the treatment is clearly stronger than that of any single therapy. In addition, the accurate diagnosis of the tumour location is also crucial to the treatment. Bismuth-based nanomaterials (NMs) hold great properties as promising theranostic platforms based on their many unique features that include low toxicity, excellent photothermal conversion efficiency as well as high ability of X-ray computed tomography imaging and photoacoustic imaging. In this review, we will introduce briefly the main features of tumor microenvironment first and its effect on the mechanism of nanomedicine actions and present the recent advances of bismuth-based NMs for diagnosis and photothermal therapy-based combined therapies using bismuth-based NMs are presented, which may provide a new way for overcoming drug resistance and hypoxia. At the end, further challenges and outlooks regarding this promising field are discussed accompanied with some design tips for bismuth-based NMs, hoping to provide researchers some inspirations to design safe and effective nanotherapeutic agents for the clinical treatments of cancers.

Therapeutic gas delivery strategies

Gas molecules with pharmaceutical effects offer emerging solutions to diseases. In addition to traditional medical gases including O₂ and NO, more gases such as H₂ , H₂ S, SO₂ , and CO have recently been discovered to play important roles in various diseases. Though some issues need to be addressed before clinical application, the increasing attention to gas therapy clearly indicates the potentials of these gases for disease treatment. The most important and difficult part of developing gas therapy systems is to transport gas molecules of high diffusibility and penetrability to interesting targets. Given the particular importance of gas molecule delivery for gas therapy, distinguished strategies have been explored to improve gas delivery efficiency and controllable gas release. Here, we summarize the strategies of therapeutic gas delivery for gas therapy, including direct gas molecule delivery by chemical and physical absorption, inorganic/organic/hybrid gas prodrugs, and natural/artificial/hybrid catalyst delivery for gas generation. The advantages and shortcomings of these gas delivery strategies are analyzed. On this basis, intelligent gas delivery strategies and catalysts use in future gas therapy are discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Utilization of nanotechnology in targeted radionuclide cancer therapy: monotherapy, combined therapy and radiosensitization

The rapid progress of nanomedicine field has a great influence on the different tumor therapeutic trends. It achieves a potential targeting of the therapeutic agent to the tumor site with neglectable exposure of the normal tissue. In nuclear medicine, nanocarriers have been employed for targeted delivery of therapeutic radioisotopes to the malignant tissues. This systemic radiotherapy is employed to overcome the external radiation therapy drawbacks. This review overviews studies concerned with investigation of different nanoparticles as promising carriers for targeted radiotherapy. It discusses the employment of different nanovehicles for achievement of the synergistic effect of targeted radiotherapy with other tumor therapeutic modalities such as hyperthermia and photodynamic therapy. Radiosensitization utilizing different nanosensitizer loaded nanoparticles has also been discussed briefly as one of the nanomedicine approach in radiotherapy.

Engineering a Hydrogen-Sulfide-Based Nanomodulator to Normalize Hyperactive Photothermal Immunogenicity for Combination Cancer Therapy

Photothermal therapy (PTT), one of the most-potent cancer therapeutic strategies known, is highlighted with excessive inflammatory response, while ablating cancer with immunogenic death. This hyperactive immune response may override PTT-triggered immunogenicity, exacerbate skin empyrosis, and incur permanent tissue injury and high-profile tumor regeneration. Therefore, an anticancer balance between pathological and protective immune response is urgently needed for an advanced photothermal therapeutic tactic. Herein, a gas-modulated photothermal immunogenicity strategy is proposed by integrating an amphiphilic-conjugated polymer with a polysulfide-based hydrogen sulfide (H₂ S) donor (2,2'-dipyridyl tetrasulfide@CP-PEG) (where CP = conjugated polymer and PEG = poly(ethylene glycol)). The CP is endowed with NIR-II fluorescence capacity and favorable photothermal effect, tracing the tumor for precise therapeutics. The polysulfide donor can release H₂ S triggered by intracellular glutathione, which elicits mitochondrial dysfunction and robust anti-inflammation effect. Ultimately, this gas-modulated PTT strategy inhibits tumor growth remarkably and limits the magnitude of PTT-induced proinflammatory tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1beta (IL-1β) cytokines. Moreover, the regulated inflammation accelerates PTT-induced wound healing. A H₂ S-modulated PTT with adaptive immune response is thus recommended as an advanced strategy to cancer therapeutics.

Orchestration of biomimetic membrane coating and nanotherapeutics in personalized anticancer therapy

Nanoparticle-based therapeutic and detectable modalities can augment anticancer efficiency, holding potential in capable target and suppressive metastases post administration. However, the individual discrepancies of the current "one-size-fits-all" strategies for anticancer nanotherapeutics have heralded the need for "personalized therapy". Benefiting from the special inherency of various cells, diverse cell membrane-coated nanoparticles (CMCNs) were established on a patient-by-patient basis, which would facilitate the personalized treatment of individual cancer patients. CMCNs in a complex microenvironment can evade the immune system and target homologous tumors with a suppressed immune response, as well as a prolonged circulation time, consequently increasing the drug accumulation at the tumor site and anticancer therapeutic efficacy. This review focuses on the emerging strategies and advances of CMCNs to synergistically integrate the merit of source cells with nanoparticulate delivery systems for the orchestration of personalized anticancer nanotherapeutics, thus discussing their rationalities in facilitating chemotherapy, imaging, immunotherapy, phototherapy, radiotherapy, sonodynamic, magnetocaloric, chemodynamic and gene therapy. Furthermore, the mechanism, challenges and opportunities of CMCNs in personalized anticancer therapy were highlighted to further boost cooperation from different fields, including materials science, chemistry, medicine, pharmacy and biology for the lab-to-clinic translation of CMCNs combined with the individual advantages of source cells and nanotherapeutics.

Biomineralized calcium carbonate nanohybrids for mild photothermal heating-enhanced gene therapy

It is of great significance to develop multifunctional gene carriers to achieve treatments with enhanced therapeutic effects in an inflammation-free manner. In this work, assembled micelles of polysaccharide were utilized for the biomineralization of calcium carbonate to produce one-dimensional Alg-CaCO₃ nanoparticles. In order to introduce both functions of mild hyperthermia and gene transfection, polydopamine (PDA) coating was applied to conjugate cationic polymers on the surface of nanoparticles. The resultant ACDP nanohybrids exhibited enhanced performance as gene carriers under near infrared (NIR) light irradiation at a low power density. Meanwhile, the pH-responsive degradation of gene carriers could further promote gene release for better effectiveness. The enhanced gene therapy induces tumor cell apoptosis, which could prevent inflammatory responses. The feasibility of mild hyperthermia-enhanced gene therapy for tumor treatment was investigated in vitro and in vivo. In addition, dual-modal ultrasound (US) and photoacoustic (PA) imaging was also realized to monitor and guide the treatment processes. The current work provides a new avenue for the construction of multifunctional platform to realize cancer therapy with improved therapeutic effectiveness in an inflammation-free manner.

In Vivo X-ray Triggered Catalysis of H2 Generation for Cancer Synergistic Gas Radiotherapy

To date, hydrogen (H₂ ) therapy has received widespread attention. However, X-ray triggered sustainable H₂ -producing materials with controlled release for cancer treatment have not been reported. Herein, an X-ray triggered sustainable in situ H₂ producing platform, Au NR-TiO₂ @ZnS:Cu,Co-A(Au-TiO₂ @ZnS), composed of Au-amorphous TiO₂ nano-dumbbell-shaped heterostructure coated with long afterglow particles, was developed for cancer synergistic H₂ -radiotherapy. The mechanism of H₂ production was verified by theoretical calculations and in vitro experiments. Changes in the apoptosis pathway caused by the synergistic effect of H₂ and radiotherapy were reported. Guided by its excellent photoacoustic imaging capabilities, mice with orthotopic liver cancer achieved excellent therapeutic effects and low inflammatory side effects, suggesting that Au-TiO₂ @ZnS has promising application potential for cancer treatment and prognosis.

Ultrathin chalcogenide nanosheets for photoacoustic imaging-guided synergistic photothermal/gas therapy

Previous preclinical and clinical studies have shown that using only a single therapy makes it difficult to completely eradicate tumors and restrain cancer metastasis. To overcome this challenge, multi-modal synergistic treatments have attracted considerable attention. Herein, an ultrathin Cu-loaded CoCuFe-selenide (CCFS) was prepared by a facile topotactic transformation from CoCuFe layered double hydroxide (LDH) nanosheets (NSs), followed by surface modification with polyvinyl pyrrolidone (PVP) and l-arginine (L-Arg). The resultant CCFS-PVP-L-Arg (CPA) system shows excellent synergetic photothermal and gas therapy (PTT/GT). The CCFS NSs have strong LSPR absorbance characteristic, with enhanced light absorption in the near-infrared (NIR) region. This endows the CPA nanocomposite with an outstanding photothermal conversion efficiency of 72.0% (pH 7.4) and 81.0% (pH 5.4), among the highest reported for 2D chalcogenide nanomaterials. In addition, NO release from CPA is triggered by decomposition of L-Arg in the H₂O₂-rich and acidic tumor microenvironment, permitting localized NO gas therapy in the tumor site. In vitro experiments revealed 91.8% apoptosis of HepG2 cells, and in vivo studies showed complete tumor elimination upon treatment with the CPA nanocomposite under NIR irradiation. To the best of our knowledge, this is the first report of combined defect-induced high-efficiency PTT with H₂O₂ and pH targeted GT.

Hollow carbon-based nanosystem for photoacoustic imaging-guided hydrogenothermal therapy in the second near-infrared window

Compared with the near-infrared-I spectral window (NIR-I, 650-950 nm), a newly developed imaging and treatment window with a 1000-1700 nm range (defined as the NIR-II bio-window) has attracted much attention owing to its higher spatiotemporal resolution, increased tissue penetration depth and therapeutic efficacy. Herein, we designed a nanotheranostic platform (HC-AB NPs) via loading ammonia borane (AB) into hollow carbon nanoparticles (HCs) for NIR-II photoacoustic (PA) imaging-guided NIR-II hydrogenothermal therapy. Importantly, by exploiting the characteristics of beta zeolite as a hard template and a template-carbonization-corrosion process, the prepared HCs have excellent NIR-II absorption performance and AB loading capacity. With the high biocompatibility of HC-AB NPs, an efficient synergistic anti-tumor strategy has been achieved via high intratumoural accumulation and acid-stimulated H2 release as well as PA-guided precise NIR-II photothermal therapy. The HC-AB NPs as a promising nanotheranostic platform opens a new avenue for high-efficacy NIR-II hydrogenothermal therapy.

New Approaches for Hydrogen Therapy of Various Diseases

Hydrogen therapy has recently received increasing attention as an emerging and promising therapeutic technology due to its selective antioxidant property and cell energy regulatory capability in vivo. To solve the low solubility issue of hydrogen, a variety of nanomaterials and devices for hydrogen supply have recently been developed, aiming to increase the concentration of hydrogen in the specific disease site and realize controlled hydrogen release and combined treatment. In this review, we mainly focus on the latest advances in using hydrogen-generating devices and nanomaterials for hydrogen therapy. These developments include sustained release of H2, controlled release of H2, versatile modalities of synergistic therapy, etc. Also, bio-safety issues and challenges are discussed to further promote the clinical applications of hydrogen therapy and the development of hydrogen medicine.

Hydrogen Gas: A Novel Type of Antioxidant in Modulating Sexual Organs Homeostasis

Sex is a science of cutting edge but bathed in mystery. Coitus or sexual intercourse, which is at the core of sexual activities, requires healthy and functioning vessels to supply the pelvic region, thus contributing to clitoris erection and vaginal lubrication in female and penile erection in male. It is well known that nitric oxide (NO) is the main gas mediator of penile and clitoris erection. In addition, the lightest and diffusible gas molecule hydrogen (H2) has been shown to improve erectile dysfunction (ED), testis injuries, sperm motility in male, preserve ovarian function, protect against uterine inflammation, preeclampsia, and breast cancer in female. Mechanistically, H2 has strong abilities to attenuate excessive oxidative stress by selectively reducing cytotoxic oxygen radicals, modulate immunity and inflammation, and inhibit injuries-induced cell death. Therefore, H2 is a novel bioactive gas molecule involved in modulating sexual organs homeostasis.

Recent advances in the development of metal-organic framework-based nanoplatforms for synergistic cancer therapy

Gas therapy as a burgeoning and promising research field has attracted considerable attention in biomedicine due to its high therapeutic efficacy, biocompatibility, and biosafety. However, the lack of tumor site accumulation and controlled release of therapeutic gas molecules limited the therapeutic efficacy. Therefore, the development of gas-releasing nanoplatforms to realize tumor targeting and controllable release is highly desired. The structural diversity and tailorability and ultrahigh surface area make metal-organic frameworks (MOFs) find potential applications in the delivery and release of gas or gas releasing molecules (GRMs). In this Frontier article, we provide an overview of the recent developments achieved in gas-involving cancer therapy using MOFs or MOF-based materials. The main emphasis is focused on the design of multifunctional MOF-based nanoplatforms for the delivery and release of therapeutic gas molecules, and emphasizing their synergistic mechanism against tumor. Moreover, the challenges, future trends, and prospects of gas-related cancer therapy are also discussed.

Self-Amplification of Tumor Oxidative Stress with Degradable Metallic Complexes for Synergistic Cascade Tumor Therapy

The ferroptosis effect has been illuminated with a clear Fenton reaction mechanism that converts endogenous hydrogen peroxide (H₂O₂) into highly oxidative hydroxyl radicals (·OH) in ROS-amplified tumor therapy. This ferroptosis-related oxidation effect was then further enhanced by the enzyme-like roles of cisplatin (CDDP). This CDDP-induced apoptosis was promoted in reverse by ferroptosis via the depletion of glutathione (GSH) and prevention of DNA damage repair. Here, we have developed degradable metallic complexes (PtH@FeP) containing an Fe(III)-polydopamine (FeP) core and HA-cross-linked CDDP (PtH) shell, exaggerating in situ toxic ROS production via the synergistic effect of CDDP and Fe(III). Taken together, the rationally designed PtH@FeP provided a new strategy for self-amplified synergistic chemotherapy/ferroptosis/photothermal therapy (PTT) antitumor effects with a reduced dosage that facilitates clinical safety.