Near-Infrared Light Triggered H2 Generation for Enhanced Photothermal/Photodynamic Therapy against Hypoxic Tumor

Black Titania Janus Mesoporous Nanomotor for Enhanced Tumor Penetration and Near-Infrared Light-Triggered Photodynamic Therapy

Thanks to their excellent photoelectric characteristics to generate cytotoxic reactive oxygen species (ROS) under the light-activation process, TiO2 nanomaterials have shown significant potential in photodynamic therapy (PDT) for solid tumors. Nevertheless, the limited penetration depth of TiO2-based photosensitizers and excitation sources (UV/visible light) for PDT remains a formidable challenge when confronted with complex tumor microenvironments (TMEs). Here, we present a H2O2-driven black TiO2 mesoporous nanomotor with near-infrared (NIR) light absorption capability and autonomous navigation ability, which effectively enhances solid tumor penetration in NIR light-triggered PDT. The nanomotor was rationally designed and fabricated based on the Janus mesoporous nanostructure, which consists of a NIR light-responsive black TiO2 nanosphere and an enzyme-modified periodic mesoporous organosilica (PMO) nanorod that wraps around the TiO2 nanosphere. The overexpressed H2O2 can drive the nanomotor in the TME under catalysis of catalase in the PMO domain. By precisely controlling the ratio of TiO2 and PMO compartments in the Janus nanostructure, TiO2&PMO nanomotors can achieve optimal self-propulsive directionality and velocity, enhancing cellular uptake and facilitating deep tumor penetration. Additionally, by the decomposition of endogenous H2O2 within solid tumors, these nanomotors can continuously supply oxygen to enable highly efficient ROS production under the NIR photocatalysis of black TiO2, leading to intensified PDT effects and effective tumor inhibition.

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.

Nanoplatform-based strategies for enhancing the lethality of current antitumor PDT

Photodynamic therapy (PDT) exhibits great application prospects in future clinical oncology due to its spatiotemporal controllability and good biosafety. However, the antitumor efficacy of PDT is seriously hindered by many factors, including tumor hypoxia, limited light penetration ability, and strong defense mechanisms of tumors. Considering that it is difficult to completely solve the first two problems, enhancing the lethality of antitumor PDT has become a good idea to extend its clinical application. Herein, we summarize the nanoplatform-involved strategies to effectively amplify the tumoricidal capability of current PDT and then discuss the present bottlenecks and prospects of the nanoplatform-based PDT sensitization strategies in tumor therapy. We hope this review will provide some references for others to design high-performance PDT nanoplatforms for tumor therapy.

NIR light-facilitated bone tissue engineering

In the last decades, near-infrared (NIR) light has attracted considerable attention due to its unique properties and numerous potential applications in bioimaging and disease treatment. Bone tissue engineering for bone regeneration with the help of biomaterials is currently an effective means of treating bone defects. As a controlled light source with deeper tissue penetration, NIR light can provide real-time feedback of key information on bone regeneration in vivo utilizing fluorescence imaging and be used for bone disease treatment. This review provides a comprehensive overview of NIR light-facilitated bone tissue engineering, from the introduction of NIR probes as well as NIR light-responsive materials, and the visualization of bone regeneration to the treatment of bone-related diseases. Furthermore, the existing challenges and future development directions of NIR light-based bone tissue engineering are also discussed. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement.

Plant-derived nanovesicles as an emerging platform for cancer therapy

Plant-derived nanovesicles (PDNVs) derived from natural green products have emerged as an attractive nanoplatform in biomedical application. They are usually characterized by unique structural and biological functions, such as the bioactive lipids/proteins/nucleic acids as therapeutics and targeting groups, immune-modulation, and long-term circulation. With the rapid development of nanotechnology, materials, and synthetic chemistry, PDNVs can be engineered with multiple functions for efficient drug delivery and specific killing of diseased cells, which represent an innovative biomaterial with high biocompatibility for fighting against cancer. In this review, we provide an overview of the state-of-the-art studies concerning the development of PDNVs for cancer therapy. The original sources, methods for obtaining PDNVs, composition and structure are introduced systematically. With an emphasis on the featured application, the inherent anticancer properties of PDNVs as well as the strategies in constructing multifunctional PDNVs-based nanomaterials will be discussed in detail. Finally, some scientific issues and technical challenges of PDNVs as promising options in improving anticancer therapy will be discussed, which are expected to promote the further development of PDNVs in clinical translation.

An Activatable Prodrug Nanosystem for Ultrasound-Driven Multimodal Tumor Therapy and Metastasis Inhibition

Ultrasound, featuring deep tissue penetration and noninvasiveness, offers a new opportunity to activate functional materials in a tumor-selective manner. However, very few direct ultrasound-responsive redox systems are applicable under therapeutic ultrasound (1 MHz). Herein, the investigations on nanoprodrug of DHE@PEG-SS-DSPE are reported, which exhibit glutathione-activated release of dihydroethidium (DHE) in tumor cells. DHE is stable with good biosafety and is transformed into cytotoxic ethidium to induce DNA damage under medical ultrasound irradiation, accompanied by the generation of reactive oxygen species. Further, DHE@PEG-SS-DSPE could effectively induce ferroptosis through glutathione depletion, lipid peroxide accumulation, and downregulation of glutathione peroxidase 4. In vivo studies confirmed that DHE@PEG-SS-DSPE nanoparticles effectively inhibit both the growth of solid tumors and the expression of metastasis-related proteins in mice, thus effectively inhibiting lung metastasis. This DHE-based prodrug nanosystem could lay a foundation for the design of ultrasound-driven therapeutic agents.

Iridium(III)-Based Infrared Two-Photon Photosensitizers: Systematic Regulation of Their Photodynamic Therapy Efficacy

Cyclometalated iridium(III) complexes are of significant importance in the field of antitumor photodynamic therapy (PDT), whether they exist as single molecules or are incorporated into nanomaterials. Nevertheless, a comprehensive examination of the relationship between their molecular structure and PDT effectiveness remains awaited. The influencing factors of two-photon excited PDT can be anticipated to be further multiplied, particularly in relation to intricate nonlinear optical properties. At present, a comprehensive body of research on this topic is lacking, and few discernible patterns have been identified. In this study, through systematic structure regulation, the nitro-substituted styryl group and 1-phenylisoquinoline ligand containing YQ2 was found to be the most potent infrared two-photon excitable photosensitizer in a 4 × 3 combination library of cyclometalated Ir(III) complexes. YQ2 could enter cells via an energy-dependent and caveolae-mediated pathway, bind specifically to mitochondria, produce 1O2 in response to 808 nm LPL irradiation, activate caspases, and induce apoptosis. In vitro, YQ2 displayed a remarkable phototherapy index for both malignant melanoma (>885) and non-small-cell lung cancer (>1234) based on these functions and was minimally deleterious to human normal liver and kidney cells. In in vivo antitumor phototherapy, YQ2 inhibited tumor growth by an impressive 85% and could be eliminated from the bodies of mice with a half-life as short as 43 h. This study has the potential to contribute significantly to the development of phototherapeutic drugs that are extremely effective in treating large, profoundly located solid tumors as well as the understanding of the structure-activity relationship of Ir(III)-based PSs in PDT.

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.

Nanoparticle-Based Photothermal Therapy for Breast Cancer Noninvasive Treatment

Rapid advancements in materials science and nanotechnology, intertwined with oncology, have positioned photothermal therapy (PTT) as a promising noninvasive treatment strategy for cancer. The breast's superficial anatomical location and aesthetic significance render breast cancer a particularly pertinent candidate for the clinical application of PTT following melanoma. This review comprehensively explores the research conducted on the various types of nanoparticles employed in PTT for breast cancer and elaborates on their specific roles and mechanisms of action. The integration of PTT with existing clinical therapies for breast cancer is scrutinized, underscoring its potential for synergistic outcomes. Additionally, the mechanisms underlying PTT and consequential modifications to the tumor microenvironment after treatment are elaborated from a medical perspective. Future research directions are suggested, with an emphasis on the development of integrative platforms that combine multiple therapeutic approaches and the optimization of nanoparticle synthesis for enhanced treatment efficacy. The goal is to push the boundaries of PTT toward a comprehensive, clinically applicable treatment for breast cancer.

A Glucose Metabolic Intervention Nanoplatform for Enhanced Chemodynamic Therapy and Sensitized Photothermal Therapy of Hepatocellular Carcinoma

Traditional treatments for hepatocellular carcinoma (HCC) still lack effectiveness. Recently, the combined mode of chemodynamic therapy (CDT) and photothermal therapy (PTT) has shown great potential against HCC. However, insufficient Fenton reaction rates and hyperthermia-induced heat shock responses greatly impair their efficiency, hindering their further clinical application. Here, we constructed a cascade-amplified PTT/CDT nanoplatform by coating an IR780-embedded red blood cell membrane on glucose oxidase (GOx)-loaded Fe₃O₄ nanoparticles for effective HCC treatment. On the one hand, the nanoplatform interfered with glucose metabolism through the action of GOx to reduce the synthesis of ATP, which reduced the expression of heat shock proteins, thereby sensitizing the IR780-mediated PTT. On the other hand, hydrogen peroxide generated during GOx catalysis and the thermal effect of PTT accelerated the Fe₃O₄-mediated Fenton reaction, realizing enhanced CDT. Consequently, the sensitized PTT and enhanced CDT for HCC management could be simultaneously achieved by interfering with glucose metabolism, providing an alternative strategy for the effective treatment of tumors.

Piezoelectric Metal-Organic Frameworks Based Sonosensitizer for Enhanced Nanozyme Catalytic and Sonodynamic Therapies

The regulation of electrostatic electric fields through electrical stimulation is an efficient method to increase the catalytic activity of nanozymes and improve the therapeutic effect of nanozyme catalytic therapy. Piezoelectric materials, which are capable of generating a built-in electric field under ultrasound (US), not only improve the activity of nanozymes but also enable piezoelectric sonodynamic therapy (SDT). In this study, a sonosensitizer based on a Hf-based metal-organic framework (UIO-66) and Au nanoparticles (NPs) was produced. Under US irradiation, UIO-66 can generate a built-in electric field inside the materials, which promotes electron-hole separation and produces reactive oxygen species (ROS). The introduction of Au NPs facilitated the electron transfer, which inhibited the recombination of the electron-hole pairs and improved the piezoelectric properties of UIO-66. The value of the piezoelectric constant (d₃₃) increased from 71 to 122 pmV^-1 after the deposition of Au NPs. In addition, the intrinsic catalase and peroxidase activities of the Au NPs were increased 2-fold after the stimulation from the built-in electric field induced through US exposure. In vivo and in vitro experiments revealed that the proposed sonosensitizer can kill cancer cells and inhibit tumor growth in mice through the enhanced piezoelectric SDT and nanozyme catalytic therapy. The piezoelectric sensitizer proposed in this work proved to be an efficient candidate that can be used for multiple therapeutic modalities in tumor therapy.

High aspect ratio plasmonic Au/Ag nanorods-mediated NIR-II photothermally enhanced nanozyme catalytic cancer therapy

Chemodynamic therapy (CDT) is based on the endogenous generation of cytotoxic hydroxyl free radicals (·OH) with high specificity and selectivity between cancer and normal cells. However, its efficacy is often limited by the relatively deficient catalytic activity of nanozymes in the tumor microenvironment (TME). Therefore, the combination of CDT with other strategy to realize synergistic therapy is necessary. Herein, a versatile plasmonic Au/Ag nanorods (abbreviated as Au/Ag NRs) via anisotropic Ag overgrowth on Au nanobipyramids was rationally devised to achieve synergistic nanozyme catalytic therapy and near infrared II (NIR-II) light induced photothermal therapy (PTT) with the guidance of computed tomography (CT) imaging. As TME contains high concentrations of H⁺ and H₂O₂, Au/Ag NRs exhibited peroxidase (POD) activity to catalyze H₂O₂ to produce ·OH, inducing cancer cell death. Meanwhile, Au/Ag NRs showed a preeminent NIR-II photothermal effect. More importantly, the enhanced ·OH generation by in-situ heating up resulting from PTT could conversely inhibit the expression of heat shock proteins (HSPs) to abate their resistance to PTT, realizing self-augmented synergistic effect. The NIR-II photothermally enhanced nanozyme catalytic cancer therapy validly inhibited the cancer proliferation, as demonstrated via both cell and animal assays. Moreover, ideal high-contrast CT imaging was realized, owing to the X-ray attenuation capability of elemental Au. The multifunctional Au/Ag NRs hold potential in oncotherapy with imaging capability, high efficiency and low side effects.

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.

Photothermal Hydrogels for Promoting Infected Wound Healing

Photothermal therapies (PTT), with spatiotemporally controllable antibacterial capabilities without inducing resistance, have shown encouraging prospects in the field of infected wound treatments. As an important platform for PTT, photothermal hydrogels exhibit attractive advantages in the field of infected wound treatment due to their excellent biochemical properties and have been intensively explored in recent years. This review summarizes the progress of the photothermal hydrogels for promoting infected wound healing. Three major elements of photothermal hydrogels, i.e., photothermal materials, hydrogel matrix, and construction methods, are introduced. Furthermore, different strategies of photothermal hydrogels in the treatment of infected wounds are summarized. Finally, the challenges and prospects in the clinical treatment of photothermal hydrogels are discussed.

Photoresponsive polymeric microneedles: An innovative way to monitor and treat diseases

Microneedles (MN) technology is an emerging technology for the transdermal delivery of therapeutics. When combined with photoresponsive (PR) materials, MNs can deliver therapeutics precisely and effectively with enhanced efficacy or synergistic effects. This review systematically summarizes the therapeutic applications of PRMNs in cancer therapy, wound healing, diabetes treatment, and diagnostics. Different PR approaches to activate and control the release of therapeutic agents from MNs are also discussed. Overall, PRMNs are a powerful tool for stimuli-responsive controlled-release therapeutic delivery to treat various diseases.

Research Progress of Nanomedicine-Based Mild Photothermal Therapy in Tumor

With the booming development of nanomedicine, mild photothermal therapy (mPTT, 42-45°C) has exhibited promising potential in tumor therapy. Compared with traditional PTT (>50°C), mPTT has less side effects and better biological effects conducive to tumor treatment, such as loosening the dense structure in tumor tissues, enhancing blood perfusion, and improving the immunosuppressive microenvironment. However, such a relatively low temperature cannot allow mPTT to completely eradicate tumors, and therefore, substantial efforts have been conducted to optimize the application of mPTT in tumor therapy. This review extensively summarizes the latest advances of mPTT, including two sections: (1) taking mPTT as a leading role to maximize its effect by blocking the cell defense mechanisms, and (2) regarding mPTT as a supporting role to assist other therapies to achieve synergistic antitumor curative effect. Meanwhile, the special characteristics and imaging capabilities of nanoplatforms applied in various therapies are discussed. At last, this paper puts forward the bottlenecks and challenges in the current research path of mPTT, and possible solutions and research directions in future are proposed correspondingly.