MSOT/CT/MR imaging-guided and hypoxia-maneuvered oxygen self-supply radiotherapy based on one-pot MnO2-mSiO2@Au nanoparticles

MXene-based nanosheet for enhanced glioma therapy via photonic hyperthermia to boost the abscopal effect of radioimmunotherapy

Radiotherapy (RT) effectiveness is limited by low DNA damage in tumor cells, surrounding tissue harm, and tumor radioresistance with active DNA repair. Herein, we have engineered a two-dimensional nanomaterial consisting of MXene nanosheets at its core, coated with gold nanorods and a cisplatin shell, and further modified with polyvinyl alcohol, referred to as APMP. The APMP exploits its distinctive electronic properties and photothermal effects to augment radiosensitivity and impede DNA damage repair mechanisms. In vitro experiments demonstrate that APMP elevates reactive oxygen species (ROS) production to approximately 2.6 times higher than that achieved with radiotherapy alone, thereby significantly enhancing the sensitivity to radiotherapy. Combining APMP with photothermal therapy (PTT) and RT is a promising glioblastoma treatment strategy, achieving tumor destruction via localized hyperthermia and overcoming radioresistance. This approach achieves precise tumor targeting, reducing side effects and enhancing therapeutic response in preclinical models. The novel core-shell design enables potent radiotherapy-specific radiosensitizers that drive immunogenic cell death, enhancing glioblastoma combination immunotherapy. This universal strategy heralds a new era in integrating radiotherapy sensitizers with immunotherapy.

Harnessing stimuli-responsive biomaterials for advanced biomedical applications

Cell behavior is intricately intertwined with the in vivo microenvironment and endogenous pathways. The ability to guide cellular behavior toward specific goals can be achieved by external stimuli, notably electricity, light, ultrasound, and magnetism, simultaneously harnessed through biomaterial-mediated responses. These external triggers become focal points within the body due to interactions with biomaterials, facilitating a range of cellular pathways: electrical signal transmission, biochemical cues, drug release, cell loading, and modulation of mechanical stress. Stimulus-responsive biomaterials hold immense potential in biomedical research, establishing themselves as a pivotal focal point in interdisciplinary pursuits. This comprehensive review systematically elucidates prevalent physical stimuli and their corresponding biomaterial response mechanisms. Moreover, it delves deeply into the application of biomaterials within the domain of biomedicine. A balanced assessment of distinct physical stimulation techniques is provided, along with a discussion of their merits and limitations. The review aims to shed light on the future trajectory of physical stimulus-responsive biomaterials in disease treatment and outline their application prospects and potential for future development. This review is poised to spark novel concepts for advancing intelligent, stimulus-responsive biomaterials.

X-ray triggered bimetallic nanoassemblies as radiosensitizers and STING agonists for a CDT/radio-immunotherapy strategy

Radiotherapy (RT) is a cornerstone of cancer therapy, but its effectiveness is constrained by dose-limiting toxicity and inadequate systemic immune activation. To overcome these limitations, we have engineered an X-ray-responsive nanoassembly (sMnAu NAs) by cross-linking monodisperse MnAu nanoparticles (NPs) with radiation-responsive diselenide-containing linkers. MnAu alloy NPs not only provide Au NPs for radiosensitization, but also control Mn (0) release, which stimulates Fenton-like reaction for chemodynamic therapy and is transferred into Mn2+ to activate the STING pathway for immunotherapy. The responsive design not only improves tumor accumulation via EPR effect during circulation, but also achieves deep penetration of MnAu NPs following X-ray induced disassembly. The synergistic combination of chemodynamic therapy, radiotherapy and immunotherapy exhibits remarkable inhibition of tumor growth and metastasis. Overall, our sMnAu NAs represent a promising radiosensitizer for chemodynamic therapy and radiotherapy to enhance immunotherapy. STATEMENT OF SIGNIFICANCE: As a principal treatment modality in cancer management, RT is limited due to the co-irradiation of organs at risk and subsequent normal tissue toxicities. This study reported an X-ray responsive radiosensitizer prepared by cross-linking monodisperse MnAu NPs with diselenide-containing linkers. Upon X-ray irradiation, sMnAu NAs accumulate in tumors and disassemble into MnAu NPs, enabling deeper penetration. The increased surface area of MnAu NPs enhances the exposure of Mn(0), which reacts into Mn2+ and enhances ROS generation. The released Mn2+ activates the STING pathway, potentiating the X-ray-induced immune response. The synergistic integration of CDT, RT, and immunotherapy results in a potent suppression of tumor growth and metastasis. Collectively, this X-ray activatable CDT/radio-immunotherapy strategy holds great potential for effective cancer treatment.

Utilisation of High Molecular Weight and Ultra-High Molecular Weight Hyaluronan in Management of Glioblastoma

HA (hyaluronan) has been considered in recent years as a naturally occurring modifiable gel-like scaffold that has the capability to absorb and release drugs over an extended period of time making it suitable as a potential chemotherapeutic delivery agent. Considering the limited treatment options available in the treatment of glioblastoma, in this review, we discuss the novel utilisation of ultra-high molecular weight HA-originally identified as a mechanism for maintaining longevity in the naked mole-rat-as both a protective and extracellular matrix-optimizing colloidal scaffold, and a means to deliver therapy in resected brain tumours. The unique properties of this unique form of HA cross-linked gel indicate potential future use in the prevention and treatment of both proliferative-based and inflammation-driven disease.

Multimodal optoacoustic imaging: methods and contrast materials

Optoacoustic (OA) imaging offers powerful capabilities for interrogating biological tissues with rich optical absorption contrast while maintaining high spatial resolution for deep tissue observations. The spectrally distinct absorption of visible and near-infrared photons by endogenous tissue chromophores facilitates extraction of diverse anatomic, functional, molecular, and metabolic information from living tissues across various scales, from organelles and cells to whole organs and organisms. The primarily blood-related contrast and limited penetration depth of OA imaging have fostered the development of multimodal approaches to fully exploit the unique advantages and complementarity of the method. We review the recent hybridization efforts, including multimodal combinations of OA with ultrasound, fluorescence, optical coherence tomography, Raman scattering microscopy and magnetic resonance imaging as well as ionizing methods, such as X-ray computed tomography, single-photon-emission computed tomography and positron emission tomography. Considering that most molecules absorb light across a broad range of the electromagnetic spectrum, the OA interrogations can be extended to a large number of exogenously administered small molecules, particulate agents, and genetically encoded labels. This unique property further makes contrast moieties used in other imaging modalities amenable for OA sensing.

Electrically activated polymetallic nanocrystals for long-term tumor suppression via oxygen-independent ROS generation and electro-immunotherapy

The low oxidation level and immunosuppressive microenvironment within hypoxic tumor tissue are critical factors contributing to the inefficacy of various anti-tumor strategies. Herein, we have designed a novel intravenous injection nanoplatform to conduct electro-immunotherapy, based on phospholipid-modified PtPd nanocrystals loaded with the immunoregulator IPI549 (LP@Pt-Pd@IPI549 nanoparticles, LPPI). LPPI responds to reactive oxygen species (ROS), triggering a cascade of therapeutic effects that overcome hypoxia-related resistance and effectively eradicate hypoxic tumors. Firstly, under electric field exposure, LPPI relied on water rather than oxygen to generate abundant ROS under hypoxic conditions for tumor electrodynamic therapy (EDT). Moreover, the generated ROS further induced the disintegration of the outer phospholipid membrane of LPPI, leading to the release of the immunoregulator and inhibition of myeloid-derived suppressor cells (MDSCs), triggering cascade immune responses. Additionally, the immunomodulatory effects of IPI549, in synergy with the immunogenic cell death (ICD) induced by EDT, reversed the immunosuppressive microenvironment contributing to tumor resistance. In summary, EDT transiently killed tumor cells while simultaneously generating antigen release, instigating an adaptive immune response for electro-immunotherapy, resulting in a potent and long-lasting tumor inhibition effect.

Manganese Dioxide-Based Nanomaterials for Medical Applications

Manganese dioxide (MnO2) nanomaterials can react with trace hydrogen peroxide (H2O2) to produce paramagnetic manganese (Mn2+) and oxygen (O2), which can be used for magnetic resonance imaging and alleviate the hypoxic environment of tumors, respectively. MnO2 nanomaterials also can oxidize glutathione (GSH) to produce oxidized glutathione (GSSG) to break the balance of intracellular redox reactions. As a consequence of the sensitivity of the tumor microenvironment to MnO2-based nanomaterials, these materials can be used as multifunctional diagnostic and therapeutic platforms for tumor imaging and treatment. Importantly, when MnO2 nanomaterials are implanted along with other therapeutics, synergetic tumor therapy can be achieved. In addition to tumor treatment, MnO2-based nanomaterials display promising prospects for tissue repair, organ protection, and the treatment of other diseases. Herein, we provide a thorough review of recent progress in the use of MnO2-based nanomaterials for biomedical applications, which may be helpful for the design and clinical translation of next-generation MnO2 nanomaterials.

Advancing Cancer Treatment: Enhanced Combination Therapy through Functionalized Porous Nanoparticles

Cancer remains a major global health challenge, necessitating the development of innovative treatment strategies. This review focuses on the functionalization of porous nanoparticles for combination therapy, a promising approach to enhance cancer treatment efficacy while mitigating the limitations associated with conventional methods. Combination therapy, integrating multiple treatment modalities such as chemotherapy, phototherapy, immunotherapy, and others, has emerged as an effective strategy to address the shortcomings of individual treatments. The unique properties of mesoporous silica nanoparticles (MSN) and other porous materials, like nanoparticles coated with mesoporous silica (NP@MS), metal-organic frameworks (MOF), mesoporous platinum nanoparticles (mesoPt), and carbon dots (CDs), are being explored for drug solubility, bioavailability, targeted delivery, and controlled drug release. Recent advancements in the functionalization of mesoporous nanoparticles with ligands, biomaterials, and polymers are reviewed here, highlighting their role in enhancing the efficacy of combination therapy. Various research has demonstrated the effectiveness of these nanoparticles in co-delivering drugs and photosensitizers, achieving targeted delivery, and responding to multiple stimuli for controlled drug release. This review introduces the synthesis and functionalization methods of these porous nanoparticles, along with their applications in combination therapy.

Therapeutic application of manganese-based nanosystems in cancer radiotherapy

Radiotherapy is an important therapeutic modality in the treatment of cancers. Nevertheless, the characteristics of the tumor microenvironment (TME), such as hypoxia and high glutathione (GSH), limit the efficacy of radiotherapy. Manganese-based (Mn-based) nanomaterials offer a promising prospect for sensitizing radiotherapy due to their good responsiveness to the TME. In this review, we focus on the mechanisms of radiosensitization of Mn-based nanosystems, including alleviating tumor hypoxia, increasing reactive oxygen species production, increasing GSH conversion, and promoting antitumor immunity. We further illustrate the applications of these mechanisms in cancer radiotherapy, including the development and delivery of radiosensitizers, as well as their combination with other therapeutic modalities. Finally, we summarize the application of Mn-based nanosystems as contrast agents in realizing precision therapy. Hopefully, the present review will provide new insights into the biological mechanisms of Mn-based nanosystems, as well as their applications in radiotherapy, in order to address the difficulties and challenges that remain in their clinical application in the future.

Multispectral optoacoustic tomography is more sensitive than micro-computed tomography for tracking gold nanorod labelled mesenchymal stromal cells

Tracking the fate of therapeutic cell types is important for assessing their safety and efficacy. Bioluminescence imaging (BLI) is an effective cell tracking technique, but poor spatial resolution means it has limited ability to precisely map cells in vivo in 3D. This can be overcome by using a bimodal imaging approach that combines BLI with a technique capable of generating high-resolution images. Here we compared the effectiveness of combining either multispectral optoacoustic tomography (MSOT) or micro-computed tomography (micro-CT) with BLI for tracking the fate of luciferase+ human mesenchymal stromal cells (MSCs) labelled with gold nanorods. Following subcutaneous administration in mice, the MSCs could be readily detected with MSOT but not with micro-CT. We conclude that MSOT is more sensitive than micro-CT for tracking gold nanorod-labelled cells in vivo and depending on the route of administration, can be used effectively with BLI to track MSC fate in mice.

Recent theranostic applications of hydrogen peroxide-responsive nanomaterials for multiple diseases

It is well established that hydrogen peroxide (H2O2) is associated with the initiation and progression of many diseases. With the rapid development of nanotechnology, the diagnosis and treatment of those diseases could be realized through a variety of H2O2-responsive nanomaterials. In order to broaden the application prospects of H2O2-responsive nanomaterials and promote their development, understanding and summarizing the design and application fields of such materials has attracted much attention. This review provides a comprehensive summary of the types of H2O2-responsive nanomaterials including organic, inorganic and organic-inorganic hybrids in recent years, and focused on their specific design and applications. Based on the type of disease, such as tumors, bacteria, dental diseases, inflammation, cardiovascular diseases, bone injury and so on, key examples for above disease imaging diagnosis and therapy strategies are introduced. In addition, current challenges and the outlook of H2O2-responsive nanomaterials are also discussed. This review aims to stimulate the potential of H2O2-responsive nanomaterials and provide new application ideas for various functional nanomaterials related to H2O2.

New insights into nanosystems for non-small-cell lung cancer: diagnosis and treatment

Lung cancer is caused by a malignant tumor that shows the fastest growth in both incidence and mortality and is also the greatest threat to human health and life. At present, both in terms of incidence and mortality, lung cancer is the first in male malignant tumors, and the second in female malignant tumors. In the past two decades, research and development of antitumor drugs worldwide have been booming, and a large number of innovative drugs have entered clinical trials and practice. In the era of precision medicine, the concept and strategy of cancer from diagnosis to treatment are experiencing unprecedented changes. The ability of tumor diagnosis and treatment has rapidly improved, the discovery rate and cure rate of early tumors have greatly improved, and the overall survival of patients has benefited significantly, with a tendency to transform to a chronic disease with tumor. The emergence of nanotechnology brings new horizons for tumor diagnosis and treatment. Nanomaterials with good biocompatibility have played an important role in tumor imaging, diagnosis, drug delivery, controlled drug release, etc. This article mainly reviews the advancements in lipid-based nanosystems, polymer-based nanosystems, and inorganic nanosystems in the diagnosis and treatment of non-small-cell lung cancer (NSCLC).

Application of nano-radiosensitizers in combination cancer therapy

Radiosensitizers are compounds or nanostructures, which can improve the efficiency of ionizing radiation to kill cells. Radiosensitization increases the susceptibility of cancer cells to radiation-induced killing, while simultaneously reducing the potentially damaging effect on the cellular structure and function of the surrounding healthy tissues. Therefore, radiosensitizers are therapeutic agents used to boost the effectiveness of radiation treatment. The complexity and heterogeneity of cancer, and the multifactorial nature of its pathophysiology has led to many approaches to treatment. The effectiveness of each approach has been proven to some extent, but no definitive treatment to eradicate cancer has been discovered. The current review discusses a broad range of nano-radiosensitizers, summarizing possible combinations of radiosensitizing NPs with several other types of cancer therapy options, focusing on the benefits and drawbacks, challenges, and future prospects.

Oxygen-generating biocatalytic nanomaterials for tumor hypoxia relief in cancer radiotherapy

Radiotherapy (RT), the most commonly used treatment method in clinics, shows unique advantages such as strong penetration, high energy intensity, and low systemic side effects. However, in vivo tumor hypoxia seriously hinders the therapeutic effect of RT. Hypoxia is a common characteristic of locally advanced solid tumor microenvironments, which leads to the proliferation, invasion and metastasis of tumor cells. In addition, oxygen consumption during RT will further aggravate tumor hypoxia, causing a variety of adverse side effects. In recent years, various biocatalytic nanomaterials (BCNs) have been explored to regulate and reverse tumor hypoxia microenvironments during RT. In this review, the most recent efforts toward developing oxygen-generating BCNs in relieving tumor hypoxia in RT are focused upon. The classification, engineering nanocatalytical activity of oxygen-generating BCNs and combined therapy based on these BCNs are systematically introduced and discussed. The challenges and prospects of these oxygen-generating BCNs in RT applications are also summarized.

Novel strategies for tumor radiosensitization mediated by multifunctional gold-based nanomaterials

Radiotherapy (RT) is one of the most effective and commonly used cancer treatments for malignant tumors. However, the existing radiosensitizers have a lot of side effects and poor efficacy, which limits the curative effect and further application of radiotherapy. In recent years, emerging nanomaterials have shown unique advantages in enhancing radiosensitization. In particular, gold-based nanomaterials, with high X-ray attenuation capacity, good biocompatibility, and promising chemical, electronic and optical properties, have become a new type of radiotherapy sensitizer. In addition, gold-based nanomaterials can be used as a carrier to load a variety of drugs and immunosuppressants; in particular, its photothermal therapy, photodynamic therapy and multi-mode imaging functions aid in providing excellent therapeutic effect in coordination with RT. Recently, many novel strategies of radiosensitization mediated by multifunctional gold-based nanomaterials have been reported, which provides a new idea for improving the efficacy and reducing the side effects of RT. In this review, we systematically summarize the recent progress of various new gold-based nanomaterials that mediate radiosensitization and describe the mechanism. We further discuss the challenges and prospects in the field. It is hoped that this review will help researchers understand the latest progress of gold-based nanomaterials for radiosensitization, and encourage people to optimize the existing methods or explore novel approaches for radiotherapy.

Advances in Single-component inorganic nanostructures for photoacoustic imaging guided photothermal therapy

Phototheranostic based on photothermal therapy (PTT) and photoacoustic imaging (PAI), as one of avant-garde medical techniques, have sparked growing attention because it allows noninvasive, deeply penetrative, and highly selective and effective therapy. Among a variety of phototheranostic nanoagents, single-component inorganic nanostructures are found to be novel and attractive PAI and PTT combined nanotheranostic agents and received tremendous attention, which not only exhibit structural controllability, high tunability in physiochemical properties, size-dependent optical properties, high reproducibility, simple composition, easy functionalization, and simple synthesis process, but also can be endowed with multiple therapeutic and imaging functions, realizing the superior therapy result along with bringing less foreign materials into body, reducing systemic side effects and improving the bioavailability. In this review, according to their synthetic components, conventional single-component inorganic nanostructures are divided into metallic nanostructures, metal dichalcogenides, metal oxides, carbon based nanostructures, upconversion nanoparticles (UCNPs), metal organic frameworks (MOFs), MXenes, graphdiyne and other nanostructures. On the basis of this category, their detailed applications in PAI guide PTT of tumor treatment are systematically reviewed, including synthesis strategies, corresponding performances, and cancer diagnosis and therapeutic efficacy. Before these, the factors to influence on photothermal effect and the principle of in vivo PAI are briefly presented. Finally, we also comprehensively and thoroughly discussed the limitation, potential barriers, future perspectives for research and clinical translation of this single-component inorganic nanoagent in biomedical therapeutics.

Prospects for hypoxia-based drug delivery platforms for the elimination of advanced metastatic tumors: From 3D modeling to clinical concepts

Hypoxia is a unique characteristic of the solid tumor microenvironment. Hypoxia contributes to multi-drug resistance, metastasis and cancer relapse through numerous molecular pathways, but at the same time provides an opportunity for the development of novel drugs or modalities specifically targeting hypoxic tumor regions. Given the high significance of tumor hypoxia in therapeutic results, we here discuss a variety of hypoxia-adopted strategies, and their potential and utility in the treatment of deep-seated hypoxic tumor cells. We discuss the merits and demerits of these approaches, as well as their combination with other approaches such as photodynamic therapy. We also survey the currently available 3D hypoxia modeling systems, in particular organoid-based microfluidics. Finally, we discuss the potential and the current status of preclinical tumor hypoxia approaches in clinical trials for advanced cancer. We believe that multi-modal imaging and therapeutic hypoxia adopted drug delivery platforms could provide better efficacy and safety profiles, and more importantly personalized therapy. Determining the hypoxia status of tumors could offer a second chance for the clinical translation of hypoxia-based agents, such as hypoxia activated prodrugs (HAPs) from bench to bedside.

Nanoparticles for MRI-guided radiation therapy: a review

The development of nanoparticle agents for MRI-guided radiotherapy is growing at an increasing pace, with clinical trials now underway and many pre-clinical evaluation studies ongoing. Gadolinium and iron-oxide-based nanoparticles remain the most clinically advanced nanoparticles to date, although several promising candidates are currently under varying stages of development. Goals of current and future generation nanoparticle-based contrast agents for MRI-guided radiotherapy include achieving positive signal contrast on T1-weighted MRI scans, local radiation enhancement at clinically relevant concentrations and, where applicable, avoidance of uptake by the reticuloendothelial system. Exploiting the enhanced permeability and retention effect or the use of active targeting ligands on nanoparticle surfaces is utilised to promote tumour uptake. This review outlines the current status of promising nanoparticle agents for MRI-guided radiation therapy, including several platforms currently undergoing clinical evaluation or at various stages of the pre-clinical development process. Challenges facing nanoparticle agents and possible avenues for current and future development are discussed.

Hyaluronic Acid-Based Nanomaterials Applied to Cancer: Where Are We Now?

Cancer cells normally develop the ability to rewire or reprogram themselves to become resistant to treatments that were previously effective. Despite progress in understanding drug resistance, knowledge gaps remain regarding the underlying biological causes of drug resistance and the design of cancer treatments to overcome it. So, resistance acquisition remains a major problem in cancer treatment. Targeted therapeutics are considered the next generation of cancer therapy because they overcome many limitations of traditional treatments. Numerous tumor cells overexpress several receptors that have a high binding affinity for hyaluronic acid (HA), while they are poorly expressed in normal body cells. HA and its derivatives have the advantage of being biocompatible and biodegradable and may be conjugated with a variety of drugs and drug carriers for developing various formulations as anticancer therapies such as micelles, nanogels, and inorganic nanoparticles. Due to their stability in blood circulation and predictable delivery patterns, enhanced tumor-selective drug accumulation, and decreased toxicity to normal tissues, tumor-targeting nanomaterial-based drug delivery systems have been shown to represent an efficacious approach for the treatment of cancer. In this review, we aim to provide an overview of some in vitro and in vivo studies related to the potential of HA as a ligand to develop targeted nanovehicles for future biomedical applications in cancer treatment.

Multifunctional Nanosnowflakes for T1-T2 Double-Contrast Enhanced MRI and PAI Guided Oxygen Self-Supplementing Effective Anti-Tumor Therapy

Introduction

Accurate tumor diagnosis is essential to achieve the ideal therapeutic effect. However, it is difficult to accurately diagnose cancer using a single imaging method because of the technical limitations. Multimodal imaging plays an increasingly important role in tumor treatment. Photodynamic therapy (PDT) has received widespread attention in tumor treatment due to its high specificity and controllable photocytotoxicity. Nevertheless, PDT is susceptible to tumor microenvironment (TME) hypoxia, which greatly reduces the therapeutic effect of tumor treatment.

Methods

In this study, a novel multifunctional nano-snowflake probe (USPIO@MnO2@Ce6, UMC) for oxygen-enhanced photodynamic therapy was developed. We have fabricated the honeycomb-like MnO2 to co-load chlorin e6 (Ce6, a photosensitizer) and ultrasmall superparamagnetic iron oxide (USPIO, T1-T2 double contrast agent). Under the high H2O2 level of tumor cells, UMC efficiently degraded and triggered the exposure of photosensitizers to the generated oxygen, accelerating the production of reactive oxygen species (ROS) during PDT. Moreover, the resulting USPIO and Mn2+ allow for MR T1-T2 imaging and transformable PAI for multimodal imaging-guided tumor therapy.

Results

TEM and UV-vis spectroscopy results showed that nano-snowflake probe (UMC) was successfully synthesized, and the degradation of UMC was due to the pH/ H2O2 responsive properties. In vitro results indicated good uptake of UMC in 4T-1 cells, with maximal accumulation at 4 h. In vitro and in vivo experimental results showed their imaging capability for both T1-T2 MR and PA imaging, providing the potential for multimodal imaging-guided tumor therapy. Compared to the free Ce6, UMC exhibited enhanced treatment efficiency due to the production of O2 with the assistance of 660 nm laser irradiation. In vivo experiments confirmed that UMC achieved oxygenated PDT under MR/PA imaging guidance in tumor-bearing mice and significantly inhibited tumor growth in tumor-bearing mice, exhibiting good biocompatibility and minimal side effects.

Conclusion

The multimodal imaging contrast agent (UMC) not only can be used for MR and PA imaging but also has oxygen-enhanced PDT capabilities. These results suggest that UMC may have a good potential for further clinical application in the future.

Dual-Mode Tumor Imaging Using Probes That Are Responsive to Hypoxia-Induced Pathological Conditions

Hypoxia in solid tumors is associated with poor prognosis, increased aggressiveness, and strong resistance to therapeutics, making accurate monitoring of hypoxia important. Several imaging modalities have been used to study hypoxia, but each modality has inherent limitations. The use of a second modality can compensate for the limitations and validate the results of any single imaging modality. In this review, we describe dual-mode imaging systems for the detection of hypoxia that have been reported since the start of the 21st century. First, we provide a brief overview of the hallmarks of hypoxia used for imaging and the imaging modalities used to detect hypoxia, including optical imaging, ultrasound imaging, photoacoustic imaging, single-photon emission tomography, X-ray computed tomography, positron emission tomography, Cerenkov radiation energy transfer imaging, magnetic resonance imaging, electron paramagnetic resonance imaging, magnetic particle imaging, and surface-enhanced Raman spectroscopy, and mass spectrometric imaging. These overviews are followed by examples of hypoxia-relevant imaging using a mixture of probes for complementary single-mode imaging techniques. Then, we describe dual-mode molecular switches that are responsive in multiple imaging modalities to at least one hypoxia-induced pathological change. Finally, we offer future perspectives toward dual-mode imaging of hypoxia and hypoxia-induced pathophysiological changes in tumor microenvironments.

Intelligent Bi2Se3@Cu2-xSe heterostructures with enhanced photoabsorption and photoconversion efficiency for tri-modal imaging guided combinatorial cancer therapy by near-infrared Ⅱ light

A novel nanoplatform that supports multimodal imaging has been designed for deep tumor therapy. In this study, Bi₂Se₃@Cu_2-xSe heterojunction nanocomposites with tunable spectral absorption, effective electron-hole separation and high photothermal conversion efficiency were prepared for the combination therapy of phototherapy (PT), chemodynamic therapy (CDT) and radiotherapy (RT). By adjusting the doping ratio, the heterojunction nanoparticles show obvious tunable ability of local surface plasmon resonance and the ability to promote electron-hole separation with significantly enhanced reactive oxygen species production capacity. The band structure and charge density difference calculated by density functional theory further reveal that the change of band gap and the decrease of free carriers can regulate the spectral absorption of nanomaterials and promote electron-hole separation. In addition, the photothermal conversion properties of low carrier density semiconductors are related to their inherent deep level defects. The formation of heterojunctions making the Se atoms deviate from the Bi₂Se₃ lattice, resulting in more deep level defects and stronger photothermal conversion properties. Meanwhile, this nanoplatform presented features similar to catalase activities and glutathione (GSH) consumption characteristics, which was capable of effectively alleviate the tumor-specific hypoxia environment to enhance the efficacy of O₂-dependent photodynamic therapy (PDT) and radiotherapy (RT) and depletion GSH to prevent the reduction of therapeutic efficacy due to the clearance of reactive oxygen species. In addition to therapeutic enhancement, heterojunction nanomaterials have excellent nuclear magnetic resonance imaging (MRI), infrared thermal imaging (IR) and computed tomography (CT) properties due to their significant paramagnetism and excellent photothermal conversion and X-ray attenuation capacities. In conclusion, our findings provide a new strategy for designing multi-function and efficient nanoplatform to treat tumor.

Facile Synthesis of Multifunctional Magnetoplasmonic Au-MnO Hybrid Nanocomposites for Cancer Theranostics

Significant attention is paid to the design of magnetoplasmonic nanohybrids, which exploit synergistic properties for biomedical applications. Here, a facile method was employed to prepare plasmonic magnetic Au-MnO heterostructured hybrid nanoparticles for imaging-guided photothermal therapy of cancers in vitro, with the view to reducing the serious drawbacks of chemotherapy and gadolinium-based contrast agents. The biocompatibility of the prepared Au-MnO nanocomposites was further enhanced by Food and Drug Administration (FDA)-approved triblock copolymers Pluronic^® F-127 and chitosan oligosaccharide (COS), with complementary support to enhance the absorption in the near-infrared (NIR) region. In addition, synthesized COS-PF127@Au-MnO nanocomposites exhibited promising contrast enhancement in T₁ MR imaging with a good r₁ relaxivity value (1.2 mM^-1 s^-1), demonstrating a capable substitute to Gd-based toxic contrast agents. In addition, prepared COS-PF127@Au-MnO hybrid nanoparticles (HNPs) produced sufficient heat (62 °C at 200 μg/mL) to ablate cancerous cells upon 808 nm laser irradiation, inducing cell toxicity, and apoptosis. The promising diagnostic and photothermal therapeutic performance demonstrated the appropriateness of the COS-PF127@Au-MnO HNPs as a potential theranostic agent.

Recent Technical Advances in Accelerating the Clinical Translation of Small Animal Brain Imaging: Hybrid Imaging, Deep Learning, and Transcriptomics

Small animal models play a fundamental role in brain research by deepening the understanding of the physiological functions and mechanisms underlying brain disorders and are thus essential in the development of therapeutic and diagnostic imaging tracers targeting the central nervous system. Advances in structural, functional, and molecular imaging using MRI, PET, fluorescence imaging, and optoacoustic imaging have enabled the interrogation of the rodent brain across a large temporal and spatial resolution scale in a non-invasively manner. However, there are still several major gaps in translating from preclinical brain imaging to the clinical setting. The hindering factors include the following: (1) intrinsic differences between biological species regarding brain size, cell type, protein expression level, and metabolism level and (2) imaging technical barriers regarding the interpretation of image contrast and limited spatiotemporal resolution. To mitigate these factors, single-cell transcriptomics and measures to identify the cellular source of PET tracers have been developed. Meanwhile, hybrid imaging techniques that provide highly complementary anatomical and molecular information are emerging. Furthermore, deep learning-based image analysis has been developed to enhance the quantification and optimization of the imaging protocol. In this mini-review, we summarize the recent developments in small animal neuroimaging toward improved translational power, with a focus on technical improvement including hybrid imaging, data processing, transcriptomics, awake animal imaging, and on-chip pharmacokinetics. We also discuss outstanding challenges in standardization and considerations toward increasing translational power and propose future outlooks.

Developing Smart Nanoparticles Responsive to the Tumor Micro-Environment for Enhanced Synergism of Thermo-Chemotherapy With PA/MR Bimodal Imaging

With the development of nanotechnology, a theranostics nanoplatform can have broad applications in multimodal image-guided combination treatment in cancer precision medicine. To overcome the limitations of a single diagnostic imaging mode and a single chemotherapeutic approach, we intend to combat tumor growth and provide therapeutic interventions by integrating multimodal imaging capabilities and effective combination therapies on an advanced platform. So, we have constructed IO@MnO₂@DOX (IMD) hybrid nanoparticles composed of superparamagnetic iron oxide (IO), manganese dioxide (MnO₂), and doxorubicin (DOX). The nano-platform could achieve efficient T2-T1 magnetic resonance (MR) imaging, switchable photoacoustic (PA) imaging, and tumor microenvironment (TME)-responsive DOX release and achieve enhanced synergism of magnetic hyperthermia and chemotherapy with PA/MR bimodal imaging. The results show that IMD has excellent heating properties when exposed to an alternating magnetic field (AMF). Therefore, it can be used as an inducer for tumor synergism therapy with chemotherapy and hyperthermia. In the TME, the IMD nanoparticle was degraded, accompanied by DOX release. Moreover, in vivo experimental results show that the smart nanoparticles had excellent T2-T1 MR and PA imaging capabilities and an excellent synergistic effect of magnetic hyperthermia and chemotherapy. IMD nanoparticles could significantly inhibit tumor growth in tumor-bearing mice with negligible side effects. In conclusion, smart IMD nanoparticles have the potential for tumor diagnosis and growth inhibition as integrated diagnostic nanoprobes.

Trojan-Horse Diameter-Reducible Nanotheranostics for Macroscopic/Microscopic Imaging-Monitored Chemo-Antiangiogenic Therapy

Although nanotheranostics have displayed striking potential toward precise nanomedicine, their targeting delivery and tumor penetration capacities are still impeded by several biological barriers. Besides, the current antitumor strategies mainly focus on killing tumor cells rather than antiangiogenesis. Enlightened by the fact that the smart transformable self-targeting nanotheranostics can enhance their targeting efficiency, tumor penetration, and cellular uptake, we herein report carrier-free Trojan-horse diameter-reducible metal-organic nanotheranostics by the coordination-driven supramolecular sequential co-assembly of the chemo-drug pemetrexed (PEM), transition-metal ions (Fe^III), and antiangiogenesis pseudolaric acid B. Such nanotheranostics with both a high dual-drug payload efficiency and outstanding physiological stability are responsively decomposed into numerous ultra-small-diameter nanotheranostics under stimuli of the moderate acidic tumor microenvironment and then internalized into tumor cells through tumor-receptor-mediated self-targeting, synergistically enhancing tumor penetration and cellular uptake. Besides, such nanotheranostics enable visualization of self-targeting capacity under the macroscopic monitor of computed tomography/magnetic resonance imaging, thereby realizing efficient oncotherapy. Moreover, tumor microvessels are precisely monitored by optical coherence tomography angiography/laser speckle imaging during chemo-antiangiogenic therapy in vivo, visually verifying that such nanotheranostics possess an excellent antiangiogenic effect. Our work will provide a promising strategy for further tumor diagnosis and targeted therapy.

A Comprehensive Evaluation of ZrC Nanoparticle in Combined Photothermal and Radiation Therapy for Treatment of Triple-Negative Breast Cancer

Because of the difficulty in treating triple-negative breast cancer (TNBC), the search for treatments has never stopped. Treatment opinions remain limited for triple-negative breast cancer (TNBC). The current treatment approach of using photothermal therapy (PTT) is often imprecise and has limited penetration below the surface of the skin. On the other hand, radiation therapy (RT) has its unavoidable disadvantages, such as side effects or ineffectiveness against hypoxic tumor microenvironment (TME). In this study, we proposed the use of ZrC nanoparticles in conjunction with RT/PTT to enhance antitumor and antimetastatic effect. We modified the ZrC nanoparticle with bovine serum albumin (BSA) and folic acid (FA), sizing desirable about 100nm. The photothermal conversion efficiency was calculated to be 40.51% and sensitizer enhancement ration (SER) was 1.8. With addition of ZrC NPs, more DNA were damaged in γ-H2AX and more ROS were detected with immunofluorescence. In vitro and vivo, the combined therapy with ZrC NPS showed the best effect of tumor cell inhibition and safety. Our results provide evidence that the combination of ZrC NPs, PT, and RT is effective in of TNBC, making it a great potential application for cancer therapy in clinic.

A cerium oxide@metal-organic framework nanoenzyme as a tandem catalyst for enhanced photodynamic therapy

An O2 self-evolving core-shell theranostic nanohybrid was developed by encapsulating a nanoenzyme cerium oxide (CeOx) in a metal-organic framework (MOF). The hybrid reveals a 9-fold higher apoptotic percentage than bare CeOx in a harsh hypoxic microenvironment through tandem homogenous catalysis. Simultaneously, the oxygen-promoted therapeutic efficiency was self-monitored by the hybrid with caspase-3 activation, paving the way for MOF-functionalized nanoenzymes in theranostics.

Enzymatically synthesised MnO2 nanoparticles for efficient near-infrared photothermal therapy and dual-responsive magnetic resonance imaging

Manganese dioxide (MnO2) nanoparticles (NPs) are highly attractive for biomedical applications due to their biocompatibility, stimuli-responsive magnetic resonance imaging (MRI) properties and capability to modulate the hypoxic tumour microenvironment (TME). However, conventional MnO2 NPs do not possess photothermal therapy (PTT) functions except for hybrids with other photothermal materials. Herein, we first reveal the extraordinary photothermal conversion efficiency (44%) of enzymatically synthesised MnO2 NPs (Bio-MnO2 NPs), which are distinct from chemically synthesised MnO2 NPs. In addition, the Bio-MnO2 NPs revealed high thermal recycling stability and solubility as well as dual pH- and reduction-responsive MRI enhancement for tumour theragnosis. These NPs were prepared through a facile MnxEFG enzyme-mediated biomineralization process. The MnxEFG complex from Bacillus sp. PL-12 is the only manganese mineralization enzyme that could be heterologously overexpressed in its active form to achieve Bio-MnO2 NPs without a bacterial host. The hexagonal layer symmetry of the Bio-MnO2 NPs is the key feature facilitating the high photothermal conversion efficiency and TME-responsive T1-weighted MRI. Evaluations both in vitro at the cellular level and in vivo in a systematic tumour-bearing mouse xenograft model demonstrated the high photothermal ablation efficacy of the Bio-MnO2 NPs, which achieved complete tumour eradication with high therapeutic biosafety without obvious reoccurrence. Moreover, stimuli-responsive MR enhancement potentially allows imaging-guided precision PTT. With their excellent biocompatibility, mild synthesis conditions and relatively simple composition, Bio-MnO2 NPs hold great translational promise.

Albumin-Templated Bi2Se3-MnO2 Nanocomposites with Promoted Catalase-Like Activity for Enhanced Radiotherapy of Cancer

Novel and effective radiosensitizers that can enhance radiosensitivity of tumor tissues and increase the local radiation dose are highly desirable. In this work, templated by bovine serum albumin (BSA), Bi2Se3-MnO2 nanocomposites (Bi2Se3-MnO2@BSA) were fabricated via biomineralization, while Bi2Se3 nanodots act as radiosensitizers to increase the local radiation dosage because of their strong X-ray attenuation ability, and MnO2 with catalase-like activity can increase the oxygen concentration in tumors by triggering the decomposition of tumor endogenous H2O2 so as to improve the hypoxia-associated radioresistance of tumors. Owing to the interaction of the two components in the interface, Bi2Se3-MnO2@BSA showed promoted catalytic activity compared to MnO2@BSA, favoring tumor radiotherapy (RT) sensitization. BSA templating enabled the nanocomposites with high colloidal stability and biocompatibility as well as satisfactory tumor targeting both in vitro and in vivo; thus, an enhanced RT efficacy was obtained. Moreover, the proposed Bi2Se3-MnO2@BSA exhibited excellent performances in computerized tomography and magnetic resonance imaging. Thus, this work provides a tumor microenvironment-responsive multifunctional theranostic nanoagent with an improved performance for imaging-guided tumor RT sensitization.

Folic Acid-Conjugated Gold Nanostars for Computed Tomography Imaging and Photothermal/Radiation Combined Therapy

Fabrication of multifunctional nanoprobes, which integrate tumor targeting, imaging, and effective treatment, has been widely explored in nanomedicine. In the present study, we fabricated tumor-targeting polymer folic acid-terminated polyethylene glycol thiol-modified gold nanostars (GNS-FA), which could realize X-ray computed tomography (CT) imaging and PTT/RT synergistic therapy. The synthesized GNS-FA exhibited good biocompatibility. GNS-FA could be used as a CT imaging contrast agent due to the strong X-ray attenuation of Au. GNS-FA exhibited good near-infrared (NIR) light absorption and excellent photothermal conversion performance, making them promising photothermal transduction agents (PTAs). Furthermore, GNS-FA could be used as an RT sensitizer to enhance the radio-mediated cell death due to the high atomic number (high Z) of gold. Hence, GNS-FA were used as the CT imaging agent, PTA, and radiosensitizer in this work. The in vitro antitumor experiments showed that the PTT/RT combined treatment had enhanced anticancer efficacy compared with the monotherapy (PTT or RT). Our results indicated that the bioconjugated GNS could offer an excellent nanoplatform for CT imaging-guided PTT/RT combined cancer therapy in the future.

An Ultra-Stable, Oxygen-Supply Nanoprobe Emitting in Near-Infrared-II Window to Guide and Enhance Radiotherapy by Promoting Anti-Tumor Immunity

Currently, radiotherapy (RT) is the main method for cancer treatment. However, the hypoxic environment of solid tumors is likely to cause resistance or failure of RT. Moreover, high-dose radiation may cause side effects to surrounding normal tissues. In this study, a new type of nanozyme is developed by doping Mn (II) ions into Ag₂ Se quantum dots (QDs) emitting in the second near-infrared window (NIR-II, 1000-1700 nm). Through the catalysis of Mn (II) ions, the nanozymes can trigger the rapid decomposition of H₂ O₂ and produce O₂ . Conjugated with tumor-targeting arginine-glycine-aspartate (RGD) tripeptides and polyethylene glycol (PEG) molecules, the nanozymes are then constructed into in vivo nanoprobes for NIR-II imaging-guided RT of tumors. Owing to the radiosensitive activity of the element Ag, the nanoprobes can promote radiation energy deposition. The specific tumor-targeting and NIR-II emitting abilities of the nanoprobes facilitate the precise tumor localization, which enables precise RT with low side effects. Moreover, their ultra-stability in the living body ensures that the nanoprobes continuously produce oxygen and relieve the hypoxia of tumors to enhance RT efficacy. Guided by real-time and high-clarity imaging, the nanoprobe-mediated RT promotes anti-tumor immunity, which significantly inhibits the growth of tumors or even cures them completely.

Multifunctional MnO2 nanoparticles for tumor microenvironment modulation and cancer therapy

Tumor microenvironment (TME) is generally featured by low pH values, high glutathione (GSH) concentrations, overproduced hydrogen peroxide (H₂ O₂ ), and severe hypoxia. These characteristics could provide an interior environment for origination and residence of tumor cells and would lead to tumor progression, metastasis, and drug resistance. Therefore, the development of TME-responsive smart nanosystems has shown significant potential to enhance the efficacy of current cancer treatments. Manganese dioxide (MnO₂ )-based nanosystems have attracted growing attentions for applications in cancer treatment as an excellent TME-responsive theranostic platform, due to their tunable structures/morphologies, pH responsive degradation, and excellent catalytic activities. In this review, we mainly summarize the strategies of MnO₂ and its nanocomposites to modulate TME, such as tumor hypoxia relief, excessive GSH depletion, glucose consumption, and tumor immunosuppressive microenvironment moderation. Such MnO₂ -based TME modulation would be beneficial for a wide range of cancer therapies including photodynamic therapy, radiotherapy, sonodynamic therapy, chemodynamic therapy, starvation therapy, and immunotherapy. Next, some representative designs of MnO₂ -based nanoplatforms in other tumor therapies are highlighted. Moreover, we will discuss the challenges and future perspectives of these MnO₂ -based nanosystems for enhanced tumor treatment. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Self-assembly of hyaluronic acid-mediated tumor-targeting theranostic nanoparticles

Theranostic nanoparticles (NPs) have emerged as promising candidates for cancer diagnosis and treatment. Manganese dioxide (MnO₂)-based NPs are potential contrast agents with excellent paramagnetic property and biocompatibility, exhibiting satisfactory magnetic resonance imaging (MRI) effects and biological safety. Recently, hyaluronic acid (HA) has gained increasing interest due to its tumor-targeting ability, which can improve the tumor affinity of manganese dioxide (MnO₂)-based NPs. In this study, HA-coated and albumin (BSA)-templated MnO₂ and polydopamine hybrid nanoparticles (HMDNs) with tumor-targeting and superior imaging capability were fabricated via modifying the nanoparticles prepared by integrating dopamine polymerization and MnO₂ biomineralization. The modification was found to enhance the cellular uptake of HMDNs by cancer cells. The prepared HMDN had high MRI contrasting capability with a longitudinal relaxivity of 22.2 mM^-1 s^-1 and strong photothermal therapy (PTT) effects with nearly complete tumor ablation under laser irradiation in vivo. HMDNs also showed effective clearance through kidneys, with no toxicity to important tissues. Therefore, HMDNs with superior imaging and PTT capability presented a new method to prepare tumor-targeting multifunctional nanotheranostics.

Three-dimensional assembly and disassembly of Fe3O4-decorated porous carbon nanocomposite with enhanced transversal relaxation for magnetic resonance sensing of bisphenol A

The design and construction of a novel magnetic resonance sensor (MRS) is presented for bisphenol A (BPA) detection. The MRS has been built based on the core component of magnetic Fe₃O₄ nanoparticles (~ 40 nm), which were uniformly distributed in nanoporous carbon (abbreviated as Fe₃O₄@NPC). The synthesis was derived from the calcination of the metal organic framework (MOF) precursor of Fe-MIL-101 at high temperature. Fe₃O₄@NPC was confirmed with enhanced transversal relaxation with r₂ value of 118.2 mM^-1 s^-1, which was around 1.7 times higher than that of the naked Fe₃O₄ nanoparticle. This enhancement is attributed to the excellent proton transverse relaxation rate of Fe₃O₄@NPC caused by the reduced self-diffusion coefficient of water molecules in the vicinity of Fe₃O₄ nanoparticles in the nanoporous carbon. BPA antibody (Ab) and antigen (Ag)-ovalbumin (OVA) were immobilized onto the Fe₃O₄@NPC to form Ab-Fe₃O₄@NPC and Ag-Fe₃O₄@NPC, respectively. These two composites can cause the three-dimensional assembly of Fe₃O₄@NPC via immunological recognition. The presence of BPA can compete with antigen-OVA to combine with Ab-Fe₃O₄@NPC, thereby breaking the assembly process (disassembly). The difference in the change of the T₂ value before and after adding BPA can thus be used to monitor BPA. The proposed MRS not only revealed a wide linear range of BPA concentration from 0.05 to 50 ng mL^-1 with an extremely low detection limit of 0.012 ng mL^-1 (S/N = 3), but also displayed high selectivity towards matrix interferences. The recoveries of BPA ranged from 95.6 to 108.4% for spiked tea π, and 93.4 to 104.7% for spiked canned oranges samples, respectively, and the RSD (n = 3) was less than 4.4% for 3 successive assays. The versatility of Fe₃O₄@NPC with customized relaxation responses provides the possibility for the adaptation of magnetic resonance platforms for food safety development. The magnetic Fe3O4 nanoparticles are uniformly dispersed in the nanoporous carbon (Fe3O4@NPC), which derived from the calcinating of the metal organic framework (MOF) precursor of Fe-MIL-101. And the magnetic Fe₃O₄@NPCs are adopted for the construction of magnetic resonance sensor (MRS) for bisphenol A (BPA) detection.

Multi-scale optoacoustic molecular imaging of brain diseases

The ability to non-invasively visualize endogenous chromophores and exogenous probes and sensors across the entire rodent brain with the high spatial and temporal resolution has empowered optoacoustic imaging modalities with unprecedented capacities for interrogating the brain under physiological and diseased conditions. This has rapidly transformed optoacoustic microscopy (OAM) and multi-spectral optoacoustic tomography (MSOT) into emerging research tools to study animal models of brain diseases. In this review, we describe the principles of optoacoustic imaging and showcase recent technical advances that enable high-resolution real-time brain observations in preclinical models. In addition, advanced molecular probe designs allow for efficient visualization of pathophysiological processes playing a central role in a variety of neurodegenerative diseases, brain tumors, and stroke. We describe outstanding challenges in optoacoustic imaging methodologies and propose a future outlook.

Nanotheranostics for Cancer Therapy and Detection: State of the Art

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

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.

Light-activatable liposomes for repetitive on-demand drug release and immunopotentiation in hypoxic tumor therapy

External stimuli-responsive nanomedicine with desirable repetitive on-demand drug release character is postulated to greatly accommodate patients' flexible medication regime. To this object, light-activatable liposomes (Pt/Ce6-LP) integrated with both a Ce6 photodynamic component and a tetravalent platinum prodrug (Pt(IV)) chemotherapeutic component are engineered. This multifunctional system was rationally designed using unsaturated phospholipid to achieve repetitive on-demand drug release under discontinuous light irradiation, thus performing chemo-photodynamic therapy effect and immunopotentiation in hypoxic tumor. Furthermore, glutathione (GSH) consumption during transformation from Pt(IV) prodrug to Pt(II) can avoid depletion of reactive oxygen species (ROS) in photodynamic therapy (PDT). Note this positive feedback loop appears to remodel the redox balance of H₂O₂ and GSH in tumors, alleviating the hypoxic tumor microenvironment. The alleviated hypoxia is found to be critical to the enhancement of PDT efficacy, reversal of cisplatin resistance in tumors, and polarization of tumor-associated macrophages (TAMs) to the immunocompetent M1-phynotype. Pt/Ce6-LP with light radiation demonstrates significant antitumor effect and persistent post-medication inhibition in patient-derived tumor xenograft model of hepatocellular carcinoma.

Multifunctional Hf/Mn-TCPP Metal-Organic Framework Nanoparticles for Triple-Modality Imaging-Guided PTT/RT Synergistic Cancer Therapy

Background

Recent studies have validated and confirmed the great potential of nanoscale metal-organic framework (NMOF) in the biomedical field, especially in improving the efficiency of cancer diagnosis and therapy. However, most previous studies only utilized either the metal cluster or the organic ligand of the NMOF for cancer treatments and merely reported limited theranostic functions, which may not be optimized. As a highly designable and easily functionalized material, prospective rational design offers a powerful way to extract the maximum benefit from NMOF for cancer theranostic applications.

Materials and Methods

A NMOF based on hafnium (Hf) cluster and Mn(III)-porphyrin ligand was rational designed and synthesized as a high-performance multifunctional theranostic agent. The folic acid (FA) was modified on the NMOF surface to enhance the cancer targeting efficacy. The proposed “all-in-one” FA-Hf-Mn-NMOF (fHMNM) was characterized and identified using various analytical techniques. Then, in vitro and in vivo studies were performed to further explore the effects of fHMNM both as the magnetic resonance imaging (MRI)/computed tomography (CT)/photoacoustic imaging (PAI) contrast agent and as the photothermal therapy (PTT)/radiotherapy (RT) agent.

Results

A tumour targeting multifunctional fHMNM was successfully synthesized with high performance for MRI/CT/PAI enhancements and image-guided PTT/RT synergistic therapy properties. Compared with the current clinical CT and MR contrast agents, the X-ray attenuation and T₁ relaxation rate of this integrated nanosystem increased 1.7-fold and 3–5-fold, respectively. More importantly, the catalase-like Mn(III)-porphyrin ligand can decompose H₂O₂ into O₂ in tumour microenvironments to improve the synergistic treatment efficiency of PTT and RT. Significant tumour growth inhibition was achieved in mouse cancer models without obvious damage to the other organs.

Conclusion

This work highlights the potential of fHMNM as an easily designable material for biomedical applications, could be an effective tool for in vivo detection and subsequent treatment of tumour.

Nanostructured manganese dioxide for anticancer applications: preparation, diagnosis, and therapy

Nanostructured manganese dioxide (MnO₂) has attracted extensive attention in the field of anticancer applications. As we all know, the tumor microenvironment is usually characterized by a high glutathione (GSH) concentration, overproduced hydrogen peroxide (H₂O₂), acidity, and hypoxia, which affect the efficacy of many traditional treatments such as chemotherapy, radiotherapy, and surgery. Fortunately, as one kind of redox-active nanomaterial, nanostructured MnO₂ has many excellent properties such as strong oxidation ability, excellent catalytic activity, and good biodegradability. It can be used effectively in diagnosis and treatment when it reacts with some harmful substances in the tumor site. It can not only enhance the therapeutic effect but also adjust the tumor microenvironment. Therefore, it is necessary to present the recent achievements and progression of nanostructured MnO₂ for anticancer applications, including preparation methods, diagnosis, and treatment. Special attention was paid to photodynamic therapy (PDT), bioimaging and cancer diagnosis (BCD), and drug delivery systems (DDS). This review is expected to provide helpful guidance on further research of nanostructured MnO₂ for anticancer applications.

Diagnostic prospects and preclinical development of optical technologies using gold nanostructure contrast agents to boost endogenous tissue contrast

Numerous developments in optical biomedical imaging research utilizing gold nanostructures as contrast agents have advanced beyond basic research towards demonstrating potential as diagnostic tools; some of which are translating into clinical applications. Recent advances in optics, lasers and detection instrumentation along with the extensive, yet developing, knowledge-base in tailoring the optical properties of gold nanostructures has significantly improved the prospect of near-infrared (NIR) optical detection technologies. Of particular interest are optical coherence tomography (OCT), photoacoustic imaging (PAI), multispectral optoacoustic tomography (MSOT), Raman spectroscopy (RS) and surface enhanced spatially offset Raman spectroscopy (SESORS), due to their respective advancements. Here we discuss recent technological developments, as well as provide a prediction of their potential to impact on clinical diagnostics. A brief summary of each techniques' capability to distinguish abnormal (disease sites) from normal tissues, using endogenous signals alone is presented. We then elaborate on the use of exogenous gold nanostructures as contrast agents providing enhanced performance in the above-mentioned techniques. Finally, we consider the potential of these approaches to further catalyse advances in pre-clinical and clinical optical diagnostic technologies.

Optical biomedical imaging research utilising gold nanostructures as contrast agents has advanced beyond basic science, demonstrating potential in various optical diagnostic tools; some of which are currently translating into clinical applications.

Enhanced radiotherapy using photothermal therapy based on dual-sensitizer of gold nanoparticles with acid-induced aggregation

The damaged DNA strands caused by radiotherapy (RT) can repair by themselves. A gold nanoparticles (GNPs) system with acid-induced aggregation was developed into a dual sensitizer owing to its high radioactive rays attenuation ability and enhanced photothermal heating efficiency after GNPs aggregation to achieve a combination therapy of RT and photothermal therapy (PTT). In this combination therapy, the formed GNP aggregates firstly showed a higher sensitize enhancement ratio (SER) value (1.52). Importantly, the self-repair of damaged DNA strands was inhibited by mild PTT through down-regulating the expression of DNA repair protein, thus resulting in a much higher SER value (1.68). Anti-tumor studies further demonstrated that this combination therapy exhibited ideal anti-tumor efficacy. Furthermore, the imaging signals of GNPs in computed tomography and photoacoustic were significantly improved following the GNPs aggregation. Therefore, a dual sensitizer with multimodal imaging was successfully developed and can be further applied as a new anti-tumor therapy.

Manganese Oxide Nanomaterials: Synthesis, Properties, and Theranostic Applications

Despite the comprehensive applications in bioimaging, biosensing, drug/gene delivery, and tumor therapy of manganese oxide nanomaterials (MONs including MnO₂ , MnO, Mn₂ O₃ , Mn₃ O₄ , and MnO_x ) and their derivatives, a review article focusing on MON-based nanoplatforms has not been reported yet. Herein, the representative progresses of MONs on synthesis, heterogene, properties, surface modification, toxicity, imaging, biodetection, and therapy are mainly introduced. First, five kinds of primary synthetic methods of MONs are presented, including thermal decomposition method, exfoliation strategy, permanganates reduction method, adsorption-oxidation method, and hydro/solvothermal. Second, the preparations of hollow MONs and MON-based composite materials are summarized specially. Then, the chemical properties, surface modification, and toxicity of MONs are discussed. Next, the diagnostic applications including imaging and sensing are outlined. Finally, some representative rational designs of MONs in photodynamic therapy, photothermal therapy, chemodynamic therapy, sonodynamic therapy, radiotherapy, magnetic hyperthermia, chemotherapy, gene therapy, starvation therapy, ferroptosis, immunotherapy, and various combination therapy are highlighted.

Polydopamine protected hollow nanosphere with AuAg-nanoframe-core@Carbon@AuAg-nanocrystals-satellite hybrid nanostructure (AuAg@C@AuAg/PDA) for enhancing nanocatalysis

This work reported a facile method for fabricating multi-layered polydopamine (PDA) encapsulated AuAg@C@AuAg core/shell nanosphere with a hollow interior. During the synthetic process, the preliminary Ag@C nanosphere is easily covered by an AuAg/PDA hybrid layer through the in situ redox-oxidized polymerization to form the Ag-AuAg@C@AuAg/PDA precursor, in which the AuAg bimetallic nanocrystals are simultaneously obtained via the electrochemical substitution reaction. After etching the residue Ag core, the final AuAg@C@AuAg/PDA hybrid nanosphere is achieved and the inner AuAg shows a unique nanoframe-like nanostructure. The carbon shell plays an important role for the formation and structure evolution of the AuAg@C@AuAg/PDA, and the composition can be modulated by varying the polymerization process. Owing to the well distributed AuAg nanocrystals and inner AuAg nanoframes, the AuAg@C@AuAg/PDA shows better performance than Ag-AuAg@C@AuAg/PDA precursor in catalyzing 4-nitrophenol, and the rate constant (K) to catalyst weight ratio reaches as high as 3.63 min^-1 •mg^-1. As a result, this work not only offers a hybrid bi-metallic nanocatalyst with excellent performance, but also has valuable implications for compositional modulation of hollow interior multi-layered nanostructure in adsorption, drug delivery, and nanocatalysis.

Multifunctional two-dimensional nanocomposites for photothermal-based combined cancer therapy

Two-dimensional (2D) nanocomposites have been widely used in biomedical applications during the past few years due to their extraordinary physicochemical properties, which has proved their importance in the field of nanomedicine. Benefiting from the excellent optical absorption in the near-infrared window and large specific surface area, many efforts have been devoted to fabricating 2D nanomaterial-based multifunctional nanoplatforms to realize photothermal therapy (PTT)-based or chemotherapy-based synergistic treatment, which exhibits obvious anti-tumor effects and significantly enhances the therapeutic efficiency of cancer compared with monotherapy. In particular, 2D nanocomposites are usually fabricated as intelligent nanoplatforms for stimuli-responsive nanocarriers, whose therapeutic effects could be specifically activated by the tumor microenvironment (TME). In addition, different fluorescent probes and functional inorganic nanomaterials could be absorbed on the surface of 2D nanomaterials to fabricate multifunctional hybrid nanomaterials with satisfactory magnetic, optical, or other properties that are widely used for multimodal imaging-guided cancer therapy. In this review, the latest development of multifunctional 2D nanocomposites for combination therapy is systematically summarized, mainly focusing on PTT-based synergistic cancer therapy, and the other forms and potential forms of synergistic cancer therapy are also simply summarized. Furthermore, the design principles of 2D nanocomposites are particularly emphasized, and the current challenges and future prospects of 2D nanocomposites for cancer theranostics are discussed simultaneously.