Soft X-Ray Stimulated Lanthanide@MOF Nanoprobe for Amplifying Deep Tissue Synergistic Photodynamic and Antitumor Immunotherapy

Multifunctional nano MOF drug delivery platform in combination therapy

Recent preclinical and clinical studies have demonstrated that for cancer treatment, combination therapies are more effective than monotherapies in reducing drug-related toxicity, decreasing drug resistance, and improving therapeutic efficacy. With the rapid development of nanotechnology, the combination of metal-organic frameworks (MOFs) and multi-mode therapy offers a realistic possibility to further improve the shortcomings of cancer treatment. This article focuses on the latest developments, achievements, and treatment strategies of representative multifunctional MOF combination therapies for cancer treatment in recent years, which include not only bimodal combination therapies, but also multi-modal synergistic therapies, further demonstrating the effectiveness and superiority of the MOF drug delivery systems in cancer treatment.

Nanoscale metal-organic framework delivers rapamycin to induce tissue immunogenic cell death and potentiates cancer immunotherapy

Rapamycin has great potential in the antitumor application, but its therapeutic effect is seriously affected by poor water solubility, targeting ability, and low bioavailability. Here, we constructed a novel composite nanomaterial with PCN-224 as a drug carrier and loaded rapamycin, named R@BP@HA. The nanoplate not only improves targeting, but also synergizes rapamycin with PCN-224 to effectively promote tumor cell apoptosis, which subsequently causes immunogenic cell death (ICD), and shows strong therapeutic effect in 4T1 breast cancer model. The treatment effect depends on three main points:(i)Proapoptotic effect of rapamycin on tumor cells;(ii)ROS production by PCN-224-mediated photodynamic therapy;(iii)ICD induced DC maturation, increased immune response and promoted T cell proliferation and differentiation. This nanoplate offers potential antitumor efficacy in combination with chemotherapy, photodynamic therapy, and immunotherapy.

NIR-II Light-Activated Gold Nanorods for Synergistic Thermodynamic and Photothermal Therapy of Tumor

There are tricky challenges in tumor therapy due to the hypoxic tumor microenvironment, inevitably inhibiting the treatment efficacy of the traditional photodynamic therapy (PDT), radiation therapy (RT), and sonodynamic therapy (SDT). Herein, to overcome tumor hypoxia limitation, we constructed a near-infrared II (NIR-II) light-triggered thermodynamic therapy (TDT) nanoplatform of Au@mSiO₂-AIPH@PCM/PEG (ASAPP) by integrating the Au nanorods (Au NRs) and thermally activated alkyl free radical-releasing molecules (AIPH). Au NRs@mSiO₂ was used as a photothermally responsive material and AIPH carrier, and the hot-melt phase-change material (PCM) was used as a capping agent to prevent leakage of AIPH during blood circulation. Upon NIR-II light irradiation, heat-triggered free radical release from AIPH was successfully achieved for killing cancer cells in vitro and in vivo without oxygen dependence, leading to synergistically enhanced antitumor therapy.

Metal-Organic Frameworks Applications in Synergistic Cancer Photo-Immunotherapy

Conventional cancer therapies, such as radiotherapy and chemotherapy, can have long-term side effects. Phototherapy has significant potential as a non-invasive alternative treatment with excellent selectivity. Nevertheless, its applicability is restricted by the availability of effective photosensitizers and photothermal agents, and its low efficacy when it comes to avoiding metastasis and tumor recurrence. Immunotherapy can promote systemic antitumoral immune responses, acting against metastasis and recurrence; however, it lacks the selectivity displayed by phototherapy, sometimes leading to adverse immune events. The use of metal-organic frameworks (MOFs) in the biomedical field has grown significantly in recent years. Due to their distinct properties, including their porous structure, large surface area, and inherent photo-responsive properties, MOFs can be particularly useful in the fields of cancer phototherapy and immunotherapy. MOF nanoplatforms have successfully demonstrated their ability to address several drawbacks associated with cancer phototherapy and immunotherapy, enabling an effective and low-side-effect combinatorial synergistical treatment for cancer. In the coming years, new advancements in MOFs, particularly regarding the development of highly stable multi-function MOF nanocomposites, may revolutionize the field of oncology.

Hybrid Nanomaterials for Cancer Immunotherapy

Nano-immunotherapy has been recognized as a highly promising strategy for cancer treatment in recent decades, which combines nanotechnology and immunotherapy to combat against tumors. Hybrid nanomaterials consisting of at least two constituents with distinct compositions and properties, usually organic and inorganic, have been engineered with integrated functions and enormous potential in boosting cancer immunotherapy. This review provides a summary of hybrid nanomaterials reported for cancer immunotherapy, including nanoscale metal-organic frameworks, metal-phenolic networks, mesoporous organosilica nanoparticles, metallofullerene nanomaterials, polymer-lipid, and biomacromolecule-based hybrid nanomaterials. The combination of immunotherapy with chemotherapy, chemodynamic therapy, radiotherapy, radiodynamic therapy, photothermal therapy, photodynamic therapy, and sonodynamic therapy based on hybrid nanomaterials is also discussed. Finally, the current challenges and the prospects for designing hybrid nanomaterials and their application in cancer immunotherapy are outlined.

Advancing X-ray Luminescence for Imaging, Biosensing, and Theragnostics

X-ray luminescence is an optical phenomenon in which chemical compounds known as scintillators can emit short-wavelength light upon the excitation of X-ray photons. Since X-rays exhibit well-recognized advantages of deep penetration toward tissues and a minimal autofluorescence background in biological samples, X-ray luminescence has been increasingly becoming a promising optical tool for tackling the challenges in the fields of imaging, biosensing, and theragnostics. In recent years, the emergence of nanocrystal scintillators have further expanded the application scenarios of X-ray luminescence, such as high-resolution X-ray imaging, autofluorescence-free detection of biomarkers, and noninvasive phototherapy in deep tissues. Meanwhile, X-ray luminescence holds great promise in breaking the depth dependency of deep-seated lesion treatment and achieving synergistic radiotherapy with phototherapy.In this Account, we provide an overview of recent advances in developing advanced X-ray luminescence for applications in imaging, biosensing, theragnostics, and optogenetics neuromodulation. We first introduce solution-processed lead halide all-inorganic perovskite nanocrystal scintillators that are able to convert X-ray photons to multicolor X-ray luminescence. We have developed a perovskite nanoscintillator-based X-ray detector for high-resolution X-ray imaging of the internal structure of electronic circuits and biological samples. We further advanced the development of flexible X-ray luminescence imaging using solution-processable lanthanide-doped nanoscintillators featuring long-lived X-ray luminescence to image three-dimensional irregularly shaped objects. We also outline the general principles of high-contrast in vivo X-ray luminescence imaging which combines nanoscintillators with functional biomolecules such as aptamers, peptides, and antibodies. High-quality X-ray luminescence nanoprobes were engineered to achieve the high-sensitivity detection of various biomarkers, which enabled the avoidance of interference from the biological matrix autofluorescence and photon scattering. By marrying X-ray luminescence probes with stimuli-responsive materials, multifunctional theragnostic nanosystems were constructed for on-demand synergistic gas radiotherapy with excellent therapeutic effects. By taking advantage of the capability of X-rays to penetrate the skull, we also demonstrated the development of controllable, wireless optogenetic neuromodulation using X-ray luminescence probes while obviating damage from traditional optical fibers. Furthermore, we discussed in detail some challenges and future development of X-ray luminescence in terms of scintillator synthesis and surface modification, mechanism studies, and their other potential applications to provide useful guidance for further advancing the development of X-ray luminescence.

Oxidative Stress Amplifiers as Immunogenic Cell Death Nanoinducers Disrupting Mitochondrial Redox Homeostasis for Cancer Immunotherapy

Reactive oxygen species (ROS)-induced oxidative stress in the endoplasmic reticulum (ER) is generally believed to be an important prerequisite for immunogenic cell death (ICD) which can trigger antitumor immune responses for cancer immunotherapy. However, thus far, little is known between the oxidative stress in a certain organelle other than ER and ICD. Herein, polymers for preparing ROS-responsive nanoparticles (NP-I-CA-TPP) with mitochondrial targeting performance as ICD nanoinducers are designed. It is believed that NP-I-CA-TPP can target mitochondria which are extremely important organelles intimately involved in cellular stress signaling to play an important role in the induction of ICD. NP-I-CA-TPP can amplify cinnamaldehyde (CA)-induced ROS damage by iodo-thiol click chemistry-mediated glutathione depletion in cancer cells. Finally, NP-I-CA-TPP is shown to disrupt mitochondrial redox homeostasis, amplify mitochondrial oxidative stress, promote cancer cell apoptosis via inducing ICD, and triggering the body's antitumor immune response for cancer immunotherapy.

Importance of Rose Bengal Loaded with Nanoparticles for Anti-Cancer Photodynamic Therapy

Rose Bengal (RB) is a photosensitizer (PS) used in anti-cancer and anti-bacterial photodynamic therapy (PDT). The specific excitation of this PS allows the production of singlet oxygen and oxygen reactive species that kill bacteria and tumor cells. In this review, we summarize the history of the use of RB as a PS coupled by chemical or physical means to nanoparticles (NPs). The studies are divided into PDT and PDT excited by X-rays (X-PDT), and subdivided on the basis of NP type. On the basis of the papers examined, it can be noted that RB used as a PS shows remarkable cytotoxicity under the effect of light, and RB loaded onto NPs is an excellent candidate for nanomedical applications in PDT and X-PDT.

Oxygen-Generating Hydrogels Overcome Tumor Hypoxia to Enhance Photodynamic/Gas Synergistic Therapy

Hypoxic environment is a bottleneck of photodynamic therapy (PDT) in tumor treatment, as oxygen is the critical substrate for photosensitivity reaction. Herein, a sustained oxygen supply system based on cerium nanoparticles and hydrogel (GHCAC) was explored for enhanced synergistic PDT and gas therapy. Ceria nanoparticles were prepared as a drug carrier by self-assembly mediated by hyaluronic acid (HA), a targeting for CD44 on cervical cancer cells, followed by photosensitizer and l-arginine (l-Arg) loading. Then, the GHCAC system was developed by incorporating a prepared nanocarrier (HCePA) and O₂-evolving agent calcium peroxide (CaO₂) into the hydrogel (Gel) developed by a poloxamer. Gel in the system could moderately infiltrate H₂O to react with CaO₂ and generate sustained oxygen using the catalase-like activity of HCePA. The system could efficiently alleviate hypoxia in tumor environments for up to 7 days, meeting the "once injection, repeat irradiation" strategy and enhanced PDT efficacy. Besides, the generated singlet oxygen (¹O₂) in the PDT process could also oxidize l-Arg into high concentrations of nitric oxide for synergistic gas therapy. The developed oxygen supplied and drug delivery Gel system is a new strategy for synergistic PDT/gas therapy to overcome cervical cancer.