Schottky heterojunction CeO2@MXene nanosheets with synergistic type I and type II PDT for anti-osteosarcoma

Photodynamic therapy (PDT) has shown great potential for tumor treatment as the method is noninvasive, highly selective, and causes minimal side effects. However, conventional type II PDT, which relies on 1O2, presents poor therapeutic efficacy for hypoxic tumors due to its reliance on oxygen. Here, CeO2/Ti3C2-MXene (CeO2@MXene) hybrids were successfully designed by growing CeO2in situ using Ti3C2-MXene (MXene) nanosheets. CeO2@MXene serves as a reduction-oxidation (REDOX) center due to the presence of Ce in the lattice of CeO2 nanoparticles. This REDOX center reacts with H2O2 to generate oxygen and weakens the hypoxic tumor cell environment, achieving type II PDT. At the same time, many other ROS (such as ⋅O2- and ⋅OH) can be produced via a type I photodynamic mechanism (electron transfer process). The CeO2@MXene heterojunction performs nanoenzymatic functions for synergistic type I and type II PDT, which improves cancer treatment.

Recent Advances in Photothermal Therapy at Near-Infrared-II Based on 2D MXenes

The use of photothermal therapy (PTT) with the near-infrared II region (NIR-II: 1000-1700 nm) is expected to be a powerful cancer treatment strategy. It retains the noninvasive nature and excellent temporal and spatial controllability of the traditional PTT, and offers significant advantages in terms of tissue penetration depth, background noise, and the maximum permissible exposure standards for skin. MXenes, transition-metal carbides, nitrides, and carbonitrides are emerging inorganic nanomaterials with natural biocompatibility, wide spectral absorption, and a high photothermal conversion efficiency. The PTT of MXenes in the NIR-II region not only provides a valuable reference for exploring photothermal agents that respond to NIR-II in 2D inorganic nanomaterials, but also be considered as a promising biomedical therapy. First, the synthesis methods of 2D MXenes are briefly summarized, and the laser light source, mechanism of photothermal conversion, and evaluation criteria of photothermal performance are introduced. Second, the latest progress of PTT based on 2D MXenes in NIR-II are reviewed, including titanium carbide (Ti3 C2 ), niobium carbide (Nb2 C), and molybdenum carbide (Mo2 C). Finally, the main problems in the PTT application of 2D MXenes to NIR-II and future research directions are discussed.

Integrated metabolomics revealed the photothermal therapy of melanoma by Mo2C nanosheets: toward rehabilitated homeostasis in metabolome combined lipidome

Melanoma, the most aggressive and life-threatening form of skin cancer, lacks innovative therapeutic approaches and deeper bioinformation. In this study, we developed a photothermal therapy (PTT) based on Mo2C nanosheets to eliminate melanoma while utilizing integrated metabolomics to investigate the metabolic shift of metabolome combined lipidome during PTT at the molecular level. Our results demonstrated that 1 mg ml-1 Mo2C nanosheets could efficiently convert laser energy into heat with a strong and stable photothermal effect (74 ± 0.9 °C within 7 cycles). Furthermore, Mo2C-based PTT led to a rapid decrease in melanoma volume (from 3.299 to 0 cm2) on the sixth day, indicating the effective elimination of melanoma. Subsequent integrated metabolomics analysis revealed significant changes in aqueous metabolites (including organic acids, amino acids, fatty acids, and amines) and lipid classes (including phospholipids, lysophospholipids, and sphingolipids), suggesting that melanoma caused substantial fluctuations in both metabolome and lipidome, while Mo2C-based PTT helped improve amino acid metabolism-related biological events (such as tryptophan metabolism) impaired by melanoma. These findings suggest that Mo2C nanosheets hold significant potential as an effective therapeutic agent for skin tumors, such as melanoma. Moreover, through exploring multidimensional bioinformation, integrated metabolomics technology provides novel insights for studying the metabolic effects of tumors, monitoring the correction of metabolic abnormalities by Mo2C nanosheet therapy, and evaluating the therapeutic effect on tumors.

Multifunctional MXene-Based Bioactive Materials for Integrated Regeneration Therapy

The reconstruction engineering of tissue defects accompanied by major diseases including cancer, infection, and inflammation is one of the important challenges in clinical medicine. The development of innovative tissue engineering strategies such as multifunctional bioactive materials presents a great potential to overcome the challenge of disease-impaired tissue regeneration. As the major representative of two-dimensional nanomaterials, MXenes have shown multifunctional physicochemical properties and have been diffusely studied as multimodal nanoplatforms in the field of biomedicine. This review summarized the recent advances in the multifunctional properties of MXenes and integrated regeneration-therapy applications of MXene-based biomaterials, including tissue regeneration-tumor therapy, tissue regeneration-infection therapy, and tissue regeneration-inflammation therapy. MXenes have been recognized as good candidates for promoting tissue regeneration and treating diseases through photothermal therapy, regulating cell behavior, and drug and gene delivery. The current challenges and future perspectives of MXene-based biomaterials in integrated regeneration-therapy are also discussed well in this review. In summary, MXene-based biomaterials have shown promising potential for integrated tissue regeneration and disease treatment due to their favorable physicochemical properties and bioactive functions. However, there are still many obstacles and challenges that must be addressed for the regeneration-therapy applications of MXene-based biomaterials, including understanding the bioactive mechanism, ensuring long-term biosafety, and improving their targeting therapy capacity.

State-of-the-art: MXene structures in nano-oncology

Cancer nanomedicine has been investigated widely and boomed in the last two decades, resulting in designing nanostructures with biofunctionalization, giving rise to an "All-in-One" multifunctional platform. The development of rational design technology with extended functionalities brought interdisciplinary researchers to work continuously, aiming to find a prevent or effectively treat the deadly disease of the century. Thus, it led to some Food and Drug Administration (FDA)-approving nano-based formulations for cancer treatment and opening a vast area of promising discoveries by exploiting different nanomaterials. Two-dimensional (2D) materials have recently gained tremendous interest among scientists because of their outstanding structural, optical, electronic, thermal, and mechanical characteristics. Among various 2D nanomaterials, MXenes are a widely studied nanosystem because of their close similarity to graphene analogs. So, it is synthesized using multiple approaches and exploits their inherited properties. But in most cases, surface functionalization techniques are carried out for targeting, site-specific drug clearance, renal clearance, and biocompatible with healthy cells. Thus, fabricating a multimodal agent for mono or combined therapies is also an image-guided diagnostic agent. This review will explain the recent and emerging advancements of MXenes-based composites as a multifunctional theragnostic agent and discuss the possibilities of transferring laboratory research to clinical translation.

Roles of MXenes in biomedical applications: recent developments and prospects

....With the development of nanomedical technology, the application of various novel nanomaterials in the biomedical field has been greatly developed in recent years. MXenes, which are new inorganic nanomaterials with ultrathin atomic thickness, consist of layered transition metal carbides and nitrides or carbonitrides and have the general structural formula M_n+1X_nT_x (n = 1-3). Based on the unique structural features of MXenes, such as ultrathin atomic thickness and high specific surface area, and their excellent physicochemical properties, such as high photothermal conversion efficiency and antibacterial properties, MXenes have been widely applied in the biomedical field. This review systematically summarizes the application of MXene-based materials in biomedicine. The first section is a brief summary of their synthesis methods and surface modification strategies, which is followed by a focused overview and analysis of MXenes applications in biosensors, diagnosis, therapy, antibacterial agents, and implants, among other areas. We also review two popular research areas: wearable devices and immunotherapy. Finally, the difficulties and research progress in the clinical translation of MXene-based materials in biomedical applications are briefly discussed.

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.

Functional two-dimensional MXenes as cancer theranostic agents

Recently, MXenes, as a kind of two-dimensional (2D) layered materials with exceptional performance, have become the research hotspots owing to their unique structural, electronic, and chemical properties. They have potential applications in electrochemical storage, photocatalysis, and biosensors. Furthermore, they have certain characteristics such as large surface area, favorable biocompatibility, and ideal mechanical properties, which can expand their applications in biomedical fields, especially in cancer therapy. To date, several researchers have explored the applications of MXenes in tumor elimination, which exhibited other fantastic properties of those 2D MXenes, such as efficient in vivo photothermal ablation, low phototoxicity, high biocompatibility, etc. In this review, the structures, properties, modifications, and preparation methods are introduced respectively. More importantly, the multifunctional platforms for cancer therapy based on MXenes nanosheets (NSs) are reviewed in detail, including single-modality and combined-modality cancer therapy. Finally, the prospects and challenges of MXenes are prospected and discussed. STATEMENT OF SIGNIFICANCE: In this review, the structures, properties, modifications, and preparation methods of MXenes nanomaterials are introduced, respectively. In addition, the preparation conditions and morphological characterizations of some common MXenes for therapeutic platforms are also summarized. More importantly, the practical applications of MXenes-based nanosheets are reviewed in detail, including drug delivery, biosensing, bioimaging, and multifunctional tumor therapy platforms. Finally, the future prospects and challenges of MXenes are prospected and discussed.

MXenes in Cancer Nanotheranostics

MXenes encompass attractive properties such as a large surface area, unique chemical structures, stability, elastic mechanical strength, excellent electrical conductivity, hydrophilicity, and ease of surface functionalization/modifications, which make them one of the broadly explored two-dimensional materials in the world. MXene-based micro- and nanocomposites/systems with special optical, mechanical, electronic, and excellent targeting/selectivity features have been explored for cancer nanotheranostics. These materials exhibit great diagnostic and therapeutic potential and offer opportunities for cancer photoacoustic imaging along with photodynamic and photothermal therapy. They can be applied to targeted anticancer drug delivery while being deployed for the imaging/diagnosis of tumors/cancers and malignancies. MXene-based systems functionalized with suitable biocompatible or bioactive agents have suitable cellular uptake features with transferring potential from vascular endothelial cells and specific localization, high stability, and auto-fluorescence benefits at different emission-excitation wavelengths, permitting post-transport examination and tracking. The surface engineering of MXenes can improve their biocompatibility, targeting, bioavailability, and biodegradability along with their optical, mechanical, and electrochemical features to develop multifunctional systems with cancer theranostic applications. However, challenges still persist in terms of their environmentally benign fabrication, up-scalability, functionality improvement, optimization conditions, surface functionalization, biocompatibility, biodegradability, clinical translational studies, and pharmacokinetics. This manuscript delineates the recent advancements, opportunities, and important challenges pertaining to the cancer nanotheranostic potential of MXenes and their derivatives.

Integrated metabolomics revealed the fibromyalgia-alleviation effect of Mo2C nanozyme through regulated homeostasis of oxidative stress and energy metabolism

Fibromyalgia (FM), the most common cause of chronic musculoskeletal pain in the general public, lacks advanced therapeutic methodology and detailed bioinformation. However, acting as a newly developed and important transition metal carbide or carbonitride, the Mo2C nanozyme has provided a novel iatrotechnique with excellent bioactivity in a cell/animal model, which also exhibits potential prospects for future clinical applications. In addition, high-content and high-throughput integrated metabolomics (including aqueous metabolomics, lipidomics, and desorption electrospray ionization-mass spectrometry imaging) also specializes in qualitative and quantitative analysis of metabolic shifts at the molecular level. In this work, the FM-alleviation effect of Mo2C nanozyme was investigated through integrated metabolomics in a mouse model. An advanced platform combining gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry and bioinformatics was utilized to study the variation in the mouse metabolome and lipidome. The results revealed that Mo2C treatment could effectively enhance energy metabolism-related biological events impaired by FM, leading to homeostasis of oxidative stress and energy metabolism toward the control levels. During this process, Mo2C facilitated the elimination of ROS in plasma and cells and the rehabilitation of mice from oxidative stress and mitochondrial dysfunction. It was believed that such an integrated metabolomics study on the FM-alleviation effect of Mo2C nanozyme could provide another excellent alternative to traditional Mo2C-based research with numerous pieces of bioinformation, further supporting research area innovation, material modification, and clinical application.

Advances of MXenes; Perspectives on Biomedical Research

The last decade witnessed the emergence of a new family of 2D transition metal carbides and nitrides named MXenes, which quickly gained momentum due to their exceptional electrical, mechanical, optical, and tunable functionalities. These outstanding properties also rendered them attractive materials for biomedical and biosensing applications, including drug delivery systems, antimicrobial applications, tissue engineering, sensor probes, auxiliary agents for photothermal therapy and hyperthermia applications, etc. The hydrophilic nature of MXenes with rich surface functional groups is advantageous for biomedical applications over hydrophobic nanoparticles that may require complicated surface modifications. As an emerging 2D material with numerous phases and endless possible combinations with other 2D materials, 1D materials, nanoparticles, macromolecules, polymers, etc., MXenes opened a vast terra incognita for diverse biomedical applications. Recently, MXene research picked up the pace and resulted in a flood of literature reports with significant advancements in the biomedical field. In this context, this review will discuss the recent advancements, design principles, and working mechanisms of some interesting MXene-based biomedical applications. It also includes major progress, as well as key challenges of various types of MXenes and functional MXenes in conjugation with drug molecules, metallic nanoparticles, polymeric substrates, and other macromolecules. Finally, the future possibilities and challenges of this magnificent material are discussed in detail.

Thermal Properties of MXenes and Relevant Applications

The properties and applications of MXenes (a family of layered transition metal carbides, nitrides, and carbonitrides) have aroused enormous research interests for a decade since the successful synthesis of few-layer transition metal carbides in 2011. Though MXenes, as the building blocks, have already been applied in various fields (such as wearable electronics) owing to the distinctive optical, mechanical and electrical properties, their thermal stability and intrinsic thermal properties were less thoroughly investigated compared to other characteristics in early reports. The pioneering theoretical prediction of the thermoelectric nature of MXenes was performed in 2013 while the first experiment-based report concerning the degradation behavior of the 2D structure at elevated temperatures in a controlled atmosphere was published in 2015, followed by numerous discoveries regarding the thermal properties of MXenes. Herein, after a brief description of the synthesis, this Review summarized the latest insights into the thermal stability and thermophysical properties of MXenes, and further associated these unique properties with relevant applications by multiple examples. Finally, current hurdles and challenges in this field were provided along with some advices on potential research directions in the future.

Progress of Nanomaterials in Photodynamic Therapy Against Tumor

Photodynamic therapy (PDT) is an advanced therapeutic strategy with light-triggered, minimally invasive, high spatiotemporal selective and low systemic toxicity properties, which has been widely used in the clinical treatment of many solid tumors in recent years. Any strategies that improve the three elements of PDT (light, oxygen, and photosensitizers) can improve the efficacy of PDT. However, traditional PDT is confronted some challenges of poor solubility of photosensitizers and tumor suppressive microenvironment. To overcome the related obstacles of PDT, various strategies have been investigated in terms of improving photosensitizers (PSs) delivery, penetration of excitation light sources, and hypoxic tumor microenvironment. In addition, compared with a single treatment mode, the synergistic treatment of multiple treatment modalities such as photothermal therapy, chemotherapy, and radiation therapy can improve the efficacy of PDT. This review summarizes recent advances in nanomaterials, including metal nanoparticles, liposomes, hydrogels and polymers, to enhance the efficiency of PDT against malignant tumor.

2D MXenes for combatting COVID-19 Pandemic: A perspective on latest developments and innovations

The COVID-19 pandemic has adversely affected the world, causing enormous loss of lives. A greater impact on the economy was also observed worldwide. During the pandemic, the antimicrobial aprons, face masks, sterilizers, sensor processed touch-free sanitizers, and highly effective diagnostic devices having greater sensitivity and selectivity helped to foster the healthcare facilities. Furthermore, the research and development sectors are tackling this emergency with the rapid invention of vaccines and medicines. In this regard, two-dimensional (2D) nanomaterials are greatly explored to combat the extreme severity of the pandemic. Among the nanomaterials, the 2D MXene is a prospective element due to its unique properties like greater surface functionalities, enhanced conductivity, superior hydrophilicity, and excellent photocatalytic and/or photothermal properties. These unique properties of MXene can be utilized to fabricate face masks, PPE kits, face shields, and biomedical instruments like efficient biosensors having greater antiviral activities. MXenes can also cure comorbidities in COVID-19 patients and have high drug loading as well as controlled drug release capacity. Moreover, the remarkable biocompatibility of MXene adds a feather in its cap for diverse biomedical applications. This review briefly explains the different synthesis processes of 2D MXenes, their biocompatibility, cytotoxicity and antiviral features. In addition, this review also discusses the viral cycle of SARS-CoV-2 and its inactivation mechanism using MXene. Finally, various applications of MXene for combatting the COVID-19 pandemic and their future perspectives are discussed.

The 10th anniversary of MXenes: Challenges and prospects for their surface modification toward future biotechnological applications

A broad family of two-dimensional (2D) materials - carbides, nitrides, and carbonitrides of early transition metals, called MXenes, became a newcomer in the flatland at the turn of 2010 and 2011 (over ten years ago). Their unique physicochemical properties made them attractive for many applications, highly boosting the development of various fields, including biotechnological. However, MXenes' functional features that impact their bioactivity and toxicity are still not fully well understood. This study discusses the essentials for MXenes's surface modifications toward their application in modern biotechnology and nanomedicine. We survey modification strategies in context of cytotoxicity, biocompatibility, and most prospective applications ready to implement in medical practice. We put the discussion on the material-structure-chemistry-property relationship into perspective and concentrate on overarching challenges regarding incorporating MXenes into nanostructured organic/inorganic bioactive architectures. It is another emerging group of materials that are interesting from the biomedical point of view as well. Finally, we present an influential outlook on the growing demand for future research in this field.

MXenes in photomedicine: Advances and prospects

MXenes and their related nanocomposites with superior physicochemical properties such as high surface area, ease of synthesis and functionalization, high drug loading capacity, collective therapy potentials, pH-triggered drug release behavior,...

Functionalized MoS2 Nanoflowers with Excellent Near-Infrared Photothermal Activities for Scavenging of Antibiotic Resistant Bacteria

Presently, antibiotic resistant bacteria (ARB) have been commonly found in environment, such as air, soil and lakes. Therefore, it is urgent and necessary to prepare antimicrobial agents with excellent anti-antibiotic resistant bacteria. In our research, poly-ethylene glycol functionalized molybdenum disulfide nanoflowers (PEG-MoS2 NFs) were synthesized via a one-step hydrothermal method. As-prepared PEG-MoS2 NFs displayed excellent photothermal conversion efficiency (30.6%) and photothermal stability. Under 808 nm NIR laser irradiation for 10 min, the inhibition rate of tetracycline-resistant Bacillus tropicalis and Stenotrophomonas malphilia reached more than 95% at the concentration of 50 μg/mL. More interestingly, the photothermal effect of PEG-MoS2 NFs could accelerate the oxidation of glutathione, resulting in the rapid death of bacteria. A functionalized PEG-MoS2 NFs photothermal anti-antibiotic resistant system was constructed successfully.

NIR-driven intracellular photocatalytic oxygen-supply on metallic molybdenum carbide@N-carbon for hypoxic tumor therapy

The intracellular O₂-supply not only can relieve tumor hypoxia but also enhance the effects of photodynamic therapy (PDT). In this work, metallic Mo₂C@N-carbon@PEG nanoparticles were constructed to reveal the near infrared (NIR)-photocatalytic O₂ generation and promote photodynamic therapy (PDT). Here, (NH₄)₆Mo₇O₂₄·4H₂O nanorods and urea were adopted as resources that were calcined to obtain Mo₂C@N-carbon nanoparticles (20 nm). All samples displayed high NIR absorption as well as photothermal conversion efficiency of up to 52.7 % (Mo₂C@N-Carbon-3@PEG). The density functional theory calculations demonstrated the metallic characteristic of Mo₂C and that the consecutive interband/intraband charge-transition was responsible for the high NIR harvest and redox ability of electron-hole pairs, making the NIR-photocatalytic O₂ and reactive oxygen species (ROS) generation. In comparison with the pure Mo₂C, the heterostructure displayed twice the performance due to the enhanced charge-segregation between Mo₂C and N-carbon. Given the high X-ray absorption coefficient and photothermal ability, the nanocomposite could be used in novel computer tomography and photothermal imaging contrast. Furthermore, the novel biodegradation and metabolism behaviors of nanocomposites were investigated, which were reflected as elimination from the body (mouse) via feces and urine within 14 days. The as-synthesized Mo₂C@N-Carbon@PEG nanocomposites integrated the dual-model imaging, intracellular O₂-supply, and phototherapy into one nanoplatform, revealing its potential for anti-cancer therapy.

Fascinating MXene nanomaterials: emerging opportunities in the biomedical field

In recent years, there has been rapid progress in MXene research due to its distinctive two-dimensional structure and outstanding properties. Especially in biomedical applications, MXenes have attracted widespread favor with numerous studies on biosafety, bioimaging, therapy, and biosensing, although their development is still in the experimental stage. A comprehensive understanding of the current status of MXenes in biomedicine will promote their use in clinical applications. Here, we review advances in MXene research. First, we introduce the methods of synthesis, surface modification and functionalization of MXenes. Then, we summarize the biosafety and biocompatibility, paving the way for specific biomedical applications. On this basis, MXene nanostructures are described with respect to their use in antibacterial, bioimaging, cancer therapy, tissue regeneration and biosensor applications. Finally, we discuss MXene as a promising candidate material for further applications in biomedicine.

Overcoming barriers in photodynamic therapy harnessing nano-formulation strategies

Photodynamic therapy (PDT) has been extensively investigated for decades for tumor treatment because of its non-invasiveness, spatiotemporal selectivity, lower side-effects, and immune activation ability. It can be a promising treatment modality in several medical fields, including oncology, immunology, urology, dermatology, ophthalmology, cardiology, pneumology, and dentistry. Nevertheless, the clinical application of PDT is largely restricted by the drawbacks of traditional photosensitizers, limited tissue penetrability of light, inefficient induction of tumor cell death, tumor resistance to the therapy, and the severe pain induced by the therapy. Recently, various photosensitizer formulations and therapy strategies have been developed to overcome these barriers. Significantly, the introduction of nanomaterials in PDT, as carriers or photosensitizers, may overcome the drawbacks of traditional photosensitizers. Based on this, nanocomposites excited by various light sources are applied in the PDT of deep-seated tumors. Modulation of cell death pathways with co-delivered reagents promotes PDT induced tumor cell death. Relief of tumor resistance to PDT with combined therapy strategies further promotes tumor inhibition. Also, the optimization of photosensitizer formulations and therapy procedures reduces pain in PDT. Here, a systematic summary of recent advances in the fabrication of photosensitizers and the design of therapy strategies to overcome barriers in PDT is presented. Several aspects important for the clinical application of PDT in cancer treatment are also discussed.

Cu2-xSe/Bi2Se3@PEG Z-scheme heterostructure: a multimode bioimaging guided theranostic agent with enhanced photo/chemodynamic and photothermal therapy

Photodynamic therapy (PDT) can be defined as a kind of intracellular photocatalysis. Inspired by the design of photocatalysts, the construction of the heterojunction also is expected to improve the production of reactive oxygen species (ROS) for PDT. Herein, the Cu2-xSe/Bi2Se3@PEG (CB3@PEG) nano-heterostructure has been prepared by a cation-exchange process, where the interaction between the host and exchange agent is vital. CB3@PEG exhibits the near-infrared (NIR)-triggered hydroxyl radical and singlet oxygen (˙OH and 1O2) generation, which is more than 6 times in contrast with that of pure Cu2-xSe@PEG, attributed to the Z-scheme charge transfer mechanism with the high redox ability and great charge separation. Moreover, with the narrower band gap of Bi2Se3, CB3@PEG exhibits enhanced NIR harvest as well as high photothermal conversion efficiency (60.4%). Due to the Fenton reaction caused by the Cu ion, CB3@PEG is endowed with the chemodynamic therapy (CDT) and signal-enhanced T1-weight magnetic resonance imaging (MRI) capacity. In addition, the great photothermal ability and X-ray absorption coefficient provide outstanding contrast in photothermal imaging (PTI) and computerized tomography (CT) imaging. Finally, the multi-imaging combined with the synergistic treatment (PTT/CDT/PDT) makes CB3@PEG achieve enhanced efficiency in anticancer therapy.

MXenes for Cancer Therapy and Diagnosis: Recent Advances and Current Challenges

MXenes endowed with several attractive physicochemical attributes, namely, specific large surface area, significant electrical conductivity, magnetism, low toxicity, luminescence, and high biocompatibility, have been considered as promising candidates for cancer therapy and theranostics. These two-dimensional (2D) nanostructures endowed with photothermal, chemotherapeutic synergistic, and photodynamic effects have shown promising potential for decidedly effectual and noninvasive anticancer treatments. They have been explored for photothermal/chemo-photothermal therapy (PTT) and for targeted anticancer drug delivery. Remarkably, MXenes with their unique optical properties have been employed for bioimaging and biosensing, and their excellent light-to-heat transition competence renders them an ideal biocompatible and decidedly proficient nanoscaled agent for PTT appliances. However, several important challenging issues still linger regarding their stability in physiological environments, sustained/controlled release of drugs, and biodegradability that need to be addressed. This Perspective emphasizes the latest advancements of MXenes and MXene-based materials in the domain of targeted cancer therapy/diagnosis, with a focus on the current trends, important challenges, and future perspectives.

Low-work-function LaB6 for realizing photodynamic-enhanced photothermal therapy

There is great potential for photodynamic therapy (PDT)-enhanced photothermal therapy (PTT) to be used for tumor therapy, especially for the single material-mediated process that could greatly simplify the experimental arrangements. This study presents a new cancer phototherapeutic agent consisting of low-work-function lanthanum hexaboride particles, which are excellent light absorbers in the near-infrared (NIR) region. The photothermal effect and reactive oxygen species production were realized by LaB6 under NIR light irradiation. Theoretical calculations based on density functional theory confirmed that the strong NIR light absorption by LaB6 was attributed to the local plasmonic resonance effect and the excellent photodynamic effect derived from the low work function. In vivo treatment of HepG2 tumor-bearing mice revealed that LaB6-mediated phototherapy resulted in excellent tumor inhibitory effects, and no adverse effects on mice were observed. These results indicate that LaB6 is a promising phototherapeutic agent for cancer synergetic phototherapy.

Molybdenum-based hetero-nanocomposites for cancer therapy, diagnosis and biosensing application: Current advancement and future breakthroughs

In recent years, there have been significant advancements in the nanotechnology for cancer therapy. Even though molybdenum disulphide (MoS2)-based nanocomposites demonstrated extensive applications in biosensing, bioimaging, phototherapy, the review article focusing on MoS2 nanocomposite platform has not been accounted for yet. The review summarizes recent strategies on design and fabrication of MoS2-based nanocomposites and their modulated properties in cancer treatment. The review also discussed several therapeutic strategies (photothermal, photodynamic, immunotherapy, gene therapy and chemotherapy) and their combinations for efficient cancer therapy along with certain case studies. The review also inculcates various diagnostic techniques viz. magnetic resonance imaging, computed tomography, photoacoustic imaging and fluorescence imaging for diagnosis of cancer.

Recent advances in ultrathin two-dimensional materials and biomedical applications for reactive oxygen species generation and scavenging

Graphene and graphene-like two-dimensional (2D) nanomaterials, such as black phosphorus (BP), transition metal carbides/carbonitrides (MXene) and transition metal dichalcogenides (TMD), have been extensively studied in recent years due to their unique physical and chemical properties. With atomic-scale thickness, these 2D materials and their derivatives can react with ROS and even scavenge ROS in the dark. With excellent biocompatibility and biosafety, they show great application potential in the antioxidant field and ROS detection for diagnosis. They can also generate ROS under light and be applied in antibacterial, photodynamic therapy (PDT), and other biomedical fields. Understanding the degradation mechanism of 2D nanomaterials by ROS generated under ambient conditions is crucial to developing air stable devices and expanding their application ranges. In this review, we summarize recent advances in 2D materials with a focus on the relationship between their intrinsic structure and the ROS scavenging or generating ability. We have also highlighted important guidelines for the design and synthesis of highly efficient ROS scavenging or generating 2D materials along with their biomedical applications.

Magnetically responsive peptide coacervates for dual hyperthermia and chemotherapy treatments of liver cancer

Liver cancer is an aggressive malignancy associated with high levels of mortality and morbidity. Doxorubicin (Dox) is often used to slow down liver cancer progression; however its efficacy is limited, and its severe side effects prevent its routine use at therapeutic concentrations. We present a biomimetic peptide that coacervates into micro-droplets, within which both Dox and magnetic nanoparticles (MNPs) can be sequestered. These Dox-loaded Magnetic Coacervates (DMCs) can be used for thermo-chemotherapy, with the controlled release of Dox triggered by an external Alternating Magnetic Field (AMF). The DMCs are internalized by the cells via an energy-independent mechanism which is not based on endocytosis. Application of AMF generates a temperature of 45 °C within the DMCs, triggering their disassembly and the simultaneous release of Dox, thereby resulting in dual hyperthermia and chemotherapy for more efficient cancer therapy. In vitro studies conducted under AMF reveal that DMCs are cytocompatible and effective in inducing HepG2 liver cancer cell death. Thermo-chemotherapy treatment against HepG2 cells is also shown to be more effective compared to either hyperthermia or chemotherapy treatments alone. Thus, our novel peptide DMCs can open avenues in theranostic strategies against liver cancer through programmable, wireless, and remote control of Dox release. STATEMENT OF SIGNIFICANCE: Simultaneous administration of chemical and thermal therapy (thermo-chemotherapy) is more effective in inducing liver cancer cell death and improving survival rate. Thus, there is a keen interest in developing suitable carriers for thermo-chemotherapy. Coacervate micro-droplets display significant advantages, including high loading capacity, fast self-assembly in aqueous environments, and liquid-like behavior. However, they have not yet been explored as carriers for thermo-chemotherapy. Here, we demonstrate that peptide coacervate micro-droplets can co-encapsulate Dox and magnetic nanoparticles and cross the cell membrane. Applying an alternating magnetic field to cells containing drug-loaded coacervates triggers the release of Dox as well as the localized heating by magnetic hyperthermia, resulting in efficient liver cancer cell death by dual thermo-chemotherapy.

Cell-cargo mediated ZrN nanoparticle for the synergetic phototherapy on both of mice and rabbits

Realization of phototherapy on the big animal modal with orthotopic tumor is of considerable significance in view of its great clinical relevance to the human deep tumor treatment. Herein, near infrared (NIR)-active ZrN nanoparticles were chosen for both of photothermal and photodynamic purposes to achieve the synergetic phototherapy on mice with subcutaneous tumor and even rabbits bearing with orthotopic tumor. Broad and strong photoabsorption, photosensitive ROS generation and photothermal effect of ZrN nanoparticles together made it to be ideal candidate for the effective tumor photoablation. Meanwhile, cell-cargo of macrophage enables targeted delivery of ZrN nanoparticles without influence on its photophysical properties. Resultantly, macrophage loaded ZrN could efficiently mediate synergetic phototherapeutic outcome as proved by complete removal of solid tumor from mice and rabbits. In this work, we also introduced B-mode ultrasonography and contrast-enhanced ultrasound technique for monitoring the evolution process of deep orthotopic tumor on rabbits post-treatment and confirmed the pathological changes of vascular degeneration and liquefaction necrosis post phototherapy.

Overview of the application of inorganic nanomaterials in cancer photothermal therapy

Cancer photothermal therapy (PTT) has captured the attention of researchers worldwide due to its localized and trigger-activated therapeutic effect.

Body-clearable chromium nitride for synergetic photothermal and photodynamic treatment

Cr₂N could realize photothermal and photodynamic outcomes simultaneously, as well as in vivo degradation and excretion.

A biodegradable nanodrug of molybdenum silicide for photothermal oncotherapy

MoSi₂ is a clearable photothermal nanodrug that can be metabolized and excreted from the body via feces and urine.

Photodynamic Therapy Based on Graphene and MXene in Cancer Theranostics

Cancer is one of the leading causes of death in the world. Therefore, the development of new advanced and targeted strategies in cancer research for early diagnosis and treatment has become essential to improve diagnosis outcomes and reduce therapy side effects. Graphene and more recently, MXene, are the main representatives of the family of two-dimensional (2D) materials and are widely studied as multimodal nanoplatforms for cancer diagnostics and treatment, in particular leveraging their potentialities as photodynamic therapeutic agents. Indeed, due to their irreplaceable physicochemical properties, they are virtuous allies for photodynamic therapy (PDT) in combination with bioimaging, photothermal therapy, as well as drug and gene delivery. In this review, the rapidly progressing literature related to the use of these promising 2D materials for cancer theranostics is described in detail, highlighting all their possible future advances in PDT.