Triggering Sequential Catalytic Fenton Reaction on 2D MXenes for Hyperthermia-Augmented Synergistic Nanocatalytic Cancer Therapy

Design of nanosystems for melanoma treatment

Melanoma is a prevalent and concerning form of skin cancer affecting millions of individuals worldwide. Unfortunately, traditional treatments can be invasive and painful, prompting the need for alternative therapies with improved efficacy and patient outcomes. Nanosystems offer a promising solution to these obstacles through the rational design of nanoparticles (NPs) which are structured into nanocomposite forms, offering efficient approaches to cancer treatment procedures. A range of NPs consisting of polymeric, metallic and metal oxide, carbon-based, and virus-like NPs have been studied for their potential in treating skin cancer. This review summarizes the latest developments in functional nanosystems aimed at enhancing melanoma treatment. The fundamentals of these nanosystems, including NPs and the creation of various functional nanosystem types, facilitating melanoma treatment are introduced. Then, the advances in the applications of functional nanosystems for melanoma treatment are summarized, outlining both their benefits and the challenges encountered in implementing nanosystem therapies.

Advanced Preparation Methods and Biomedical Applications of Single-Atom Nanozymes

Metal nanoparticles with inherent defects can harness biomolecules to catalyze reactions within living organisms, thereby accelerating the advancement of multifunctional diagnostic and therapeutic technologies. In the quest for superior catalytic efficiency and selectivity, atomically dispersed single-atom nanozymes (SANzymes) have garnered significant interest recently. This review concentrates on the development of SANzymes, addressing potential challenges such as fabrication strategies, surface engineering, and structural characteristics. Notably, we elucidate the catalytic mechanisms behind some key reactions to facilitate the biomedical application of SANzymes. The diverse biomedical uses of SANzymes including in cancer therapy, wound disinfection, biosensing, and oxidative stress cytoprotection are comprehensively summarized, revealing the link between material structure and catalytic performance. Lastly, we explore the future prospects of SANzymes in biomedical fields.

Catalytic Biomaterials-Activated In Situ Chemical Reactions: Strategic Modulation and Enhanced Disease Treatment

Chemical reactions underpin biological processes, and imbalances in critical biochemical pathways within organisms can lead to the onset of severe diseases. Within this context, the emerging field of "Nanocatalytic Medicine" leverages nanomaterials as catalysts to modulate fundamental chemical reactions specific to the microenvironments of diseases. This approach is designed to facilitate the targeted synthesis and localized accumulation of therapeutic agents, thus enhancing treatment efficacy and precision while simultaneously reducing systemic side effects. The effectiveness of these nanocatalytic strategies critically hinges on a profound understanding of chemical kinetics and the intricate interplay of reactions within particular pathological microenvironments to ensure targeted and effective catalytic actions. This review methodically explores in situ catalytic reactions and their associated biomaterials, emphasizing regulatory strategies that control therapeutic responses. Furthermore, the discussion encapsulates the crucial elements-reactants, catalysts, and reaction conditions/environments-necessary for optimizing the thermodynamics and kinetics of these reactions, while rigorously addressing both the biochemical and biophysical dimensions of the disease microenvironments to enhance therapeutic outcomes. It seeks to clarify the mechanisms underpinning catalytic biomaterials and evaluate their potential to revolutionize treatment strategies across various pathological conditions.

In situ thermosensitive H2O2/NO self-sufficient hydrogel for photothermal ferroptosis of triple-negative breast cancer

L-Arginine (LA), a semi-essential amino acid in the human body, holds significant potential in cancer therapy due to its ability to generate nitric oxide (NO) continuously in the presence of inducible NO synthase (iNOS) or reactive oxygen species (ROS). However, the efficiency of NO production in tumor tissue is severely constrained by the hypoxic and H2O2-deficient tumor microenvironment (TME). To address this issue, we have developed calcium peroxide (CaO2) nanoparticles capable of supplying O2/H2O2, which encapsulate and oxidize an LA-modified lipid bilayer to enable controlled localized NO generation in the presence of ROS, synergising with a ferroptosis inducer, RSL-3 (CPIR NPs). The synthesized nanoparticles were tested in vitro for their anticancer activity in 4T1 cells. To address challenges related to specificity and frequent dosing, we developed an in situ thermosensitive injectable hydrogel incorporating CPIR nanoparticles. Cross-linking at 60 °C creates a self-sufficient formulation, releasing NO/H2O2 to combat tumor hypoxia. RSL-3 induces ferroptosis, contributing to a synergistic photothermal effect and eliminating tumor in vivo.

Catalytic Nanoparticles in Biomedical Applications: Exploiting Advanced Nanozymes for Therapeutics and Diagnostics

Catalytic nanoparticles (CNPs) as heterogeneous catalyst reveals superior activity due to their physio-chemical features, such as high surface-to-volume ratio and unique optical, electric, and magnetic properties. The CNPs, based on their physio-chemical nature, can either increase the reactive oxygen species (ROS) level for tumor and antibacterial therapy or eliminate the ROS for cytoprotection, anti-inflammation, and anti-aging. In addition, the catalytic activity of nanozymes can specifically trigger a specific reaction accompanied by the optical feature change, presenting the feasibility of biosensor and bioimaging applications. Undoubtedly, CNPs play a pivotal role in pushing the evolution of technologies in medical and clinical fields, and advanced strategies and nanomaterials rely on the input of chemical experts to develop. Herein, a systematic and comprehensive review of the challenges and recent development of CNPs for biomedical applications is presented from the viewpoint of advanced nanomaterial with unique catalytic activity and additional functions. Furthermore, the biosafety issue of applying biodegradable and non-biodegradable nanozymes and future perspectives are critically discussed to guide a promising direction in developing span-new nanozymes and more intelligent strategies for overcoming the current clinical limitations.

Tumor-Targeting Multiple Metabolic Regulations for Bursting Antitumor Efficacy of Chemodynamic Therapy

Interfering with intratumoral metabolic processes is proven to effectively sensitize different antitumor treatments. Here, a tumor-targeting catalytic nanoplatform (CQ@MIL-GOX@PB) loading with autophagy inhibitor (chloroquine, CQ) and glucose oxidase (GOX) is fabricated to interfere with the metabolisms of tumor cells and tumor-associated macrophages (TAMs), then realizing effective antitumor chemodynamic therapy (CDT). Once accumulating in the tumor site with the navigation of external biotin, CQ@MIL-GOX@PB will release Fe ions and CQ in the acid lysosomes of tumor cells, the latter can sensitize Fe ions-involved antitumor CDT by blocking the autophagy-dependent cell repair. Meanwhile, the GOX component will consume glucose, which not only generates many H2O2 for CDT but also once again decelerates the tumor repair process by reducing energy metabolism. What is more, the release of CQ can also drive the NO anabolism of TAMs to further sensitize CDT. This strategy of multiple metabolic regulations is evidenced to significantly improve the antitumor effect of traditional CDT nanoagents and might provide a new sight to overcome the bottlenecks of different antitumor treatments.

MXene-Mediated Catalytic Redox Reactions for Biomedical Applications

Reactive oxygen species (ROS) play a crucial role in orchestrating a myriad of physiological processes within living systems. With the advent of materdicine, an array of nanomaterials has been intricately engineered to influence the redox equilibrium in biological milieus, thereby pioneering a distinctive therapeutic paradigm predicated on ROS-centric biochemistry. Among these, two-dimensional carbides, nitrides, and carbonitrides, collectively known as MXenes, stand out due to their multi-valent and multi-elemental compositions, large surface area, high conductivity, and pronounced local surface plasmon resonance effects, positioning them as prominent contributors in ROS modulation. This review aims to provide an overview of the advancements in harnessing MXenes for catalytic redox reactions in various biological applications, including tumor, anti-infective, and anti-inflammatory therapies. The emphasis lies on elucidating the therapeutic mechanism of MXenes, involving both pro-oxidation and anti-oxidation processes, underscoring the redox-related therapeutic applications facilitated by self-catalysis, photo-excitation, and sono-excitation properties of MXenes. Furthermore, this review highlights the existing challenges and outlines future development trends in leveraging MXenes for ROS-involving disease treatments, marking a significant step towards the integration of these nanomaterials into clinical practice.

Bi2S3/Ti3C2-TPP nano-heterostructures induced by near-infrared for photodynamic therapy combined with photothermal therapy on hypoxic tumors

BACKGROUND

Photodynamic therapy (PDT) efficacy of bismuth sulfide (Bi2S3) semiconductor has been severely restricted by its electron-hole pairs (e--h+) separation inefficiency and oxygen (O2) deficiency in tumors, which greatly hinders reactive oxygen species (ROS) generation and further clinical application of Bi2S3 nanoparticles (NPs) in biomedicine.

RESULTS

Herein, novel Bi2S3/titanium carbide (Ti3C2) two-dimensional nano-heterostructures (NHs) are designed to realize multimode PDT of synchronous O2 self-supply and ROS generation combined with highly efficient photothermal tumor elimination for hypoxic tumor therapy. Bi2S3/Ti3C2 NHs were synthesized via the in situ synthesis method starting from Ti3C2 nanosheets (NSs), a classical type of MXene nanostructure. Compared to simple Bi2S3 NPs, Bi2S3/Ti3C2 NHs significantly extend the absorption to the near-infrared (NIR) region and enhance the photocatalytic activity owing to the improved photogenerated carrier separation, where the hole on the valence band (VB) of Bi2S3 can react with water to supply O2 for the electron on the Ti3C2 NSs to generate ·O2- and ·OH through electron transfer. Furthermore, they also achieve 1O2 generation through energy transfer due to O2 self-supply. After the modification of triphenylphosphium bromide (TPP) on Bi2S3/Ti3C2 NHs, systematic in vitro and in vivo evaluations were conducted, revealing that the synergistic-therapeutic outcome of this nanoplatform enables complete eradication of the U251 tumors without recurrence by NIR laser irradiation, and it can be used for computed tomography (CT) imaging because of the strong X-ray attenuation ability.

CONCLUSION

This work expands the phototherapeutic effect of Bi2S3-based nanoplatforms, providing a new strategy for hypoxic tumor theranostics.

CeO2 and Glucose Oxidase Co-Enriched Ti3C2Tx MXene for Hyperthermia-Augmented Nanocatalytic Cancer Therapy

Foreseen as foundational in forthcoming oncology interventions are multimodal therapeutic systems. Nevertheless, the tumor microenvironment (TME), marked by heightened glucose levels, hypoxia, and scant concentrations of endogenous hydrogen peroxide could potentially impair their effectiveness. In this research, two-dimensional (2D) Ti3C2 MXene nanosheets are engineered with CeO2 nanozymes and glucose oxidase (GOD), optimizing them for TME, specifically targeting cancer therapy. Following our therapeutic design, CeO2 nanozymes, embodying both peroxidase-like and catalase-like characteristics, enable transformation of H2O2 into hydroxyl radicals for catalytic therapy while also producing oxygen to mitigate hypoxia. Concurrently, GOD metabolizes glucose, thereby augmenting H2O2 levels and disrupting the intracellular energy supply. When subjected to a near-infrared laser, 2D Ti3C2 MXene accomplishes photothermal therapy (PTT) and photodynamic therapy (PDT), additionally amplifying cascade catalytic treatment via thermal enhancement. Empirical evidence demonstrates robust tumor suppression both in vitro and in vivo by the CeO2/Ti3C2-PEG-GOD nanocomposite. Consequently, this integrated approach, which combines PTT/PDT and enzymatic catalysis, could offer a valuable blueprint for the development of advanced oncology therapies.

Post-Graphene 2D Materials: Structures, Properties, and Cancer Therapy Applications

Cancer is one of the most serious diseases challenging human health and life span. Cancer has claimed millions of lives worldwide. Early diagnosis and effective treatment of cancer are very important for the survival of patients. In recent years, 2D nanomaterials have shown great potential in the development of anticancer treatment by combining their inherent physicochemical properties after surface modification. 2D nanomaterials have attracted great interest due to their unique nanosheet structure, large surface area, and extraordinary physicochemical properties. This article reviews the advantages and application status of emerging 2D nanomaterials for targeted tumor synergistic therapy compared with traditional therapeutic strategies. In order to investigate novel potential anticancer strategies, this paper focuses on the surface modification, cargo delivery capability, and unique optical properties of emerging 2D nanomaterials. Finally, the current problems and challenges in cancer treatment are summarized and prospected.

Multifunctional nano MOF drug delivery platform in combination therapy

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

MXene-Based Functional Platforms for Tumor Therapy

Recently, 2D transition metal carbide, nitride, and carbonitrides (MXenes) materials stand out in the field of tumor therapy, particularly in the construction of functional platforms for optimal antitumor therapy due to their high specific surface area, tunable performance, strong absorption of near-infrared light as well as preferable surface plasmon resonance effect. In this review, the progress of MXene-mediated antitumor therapy is summarized after appropriate modifications or integration procedures. The enhanced antitumor treatments directly performed by MXenes, the significant improving effect of MXenes on different antitumor therapies, as well as the MXene-mediated imaging-guided antitumor strategies are discussed in detail. Moreover, the existing challenges and future development directions of MXenes in tumor therapy are presented.

Rare-earth hydroxide/MXene hybrid: a promising agent for near-infrared photothermy and magnetic resonance imaging

Layered gadolinium hydroxide (LGdH) and Ti3C2 monolayers were assembled into a LGdH/Ti3C2 (GTC) hybrid. The hybrid demonstrated enhanced near-infrared (NIR) light absorption properties and superior photothermal performance. Moreover, the GTC hybrid achieved an excellent T1-weighted magnetic resonance imaging (MRI) effect.

RuCu Nanosheets with Ultrahigh Nanozyme Activity for Chemodynamic Therapy

Nanoenzymes have been widely explored for chemodynamic therapy (CDT) in cancer treatment. However, poor catalytic efficiency of nanoenzymes, especially in the tumor microenvironment with insufficient H2 O2 and mild acidity, limits the effect of CDT. Herein, a new ultrathin RuCu nanosheet (NS) based nanoenzyme which has a large specific surface area and abundant channels and defects is developed. The RuCu NSs show superb catalytic efficiency for the oxidation of peroxidase substrate H2 O2 at a wide range of pH and their catalytic efficiency (kcat /Km = 177.2 m-1  s-1 ) is about 14.9 times higher than that of the single-atom catalyst FeN3 P. Besides being an efficient nanozyme as peroxidase, the RuCu NSs possess other two enzyme activities, not only disproportionating superoxide anion to produce H2 O2 but also consuming glutathione to keep a high concentration of H2 O2 in the tumor microenvironment for Fenton reaction. With these advantages, the RuCu NSs exhibit good performance to kill cancer cells and inhibit tumor growth in mice, demonstrating a promising potential as new CDT reagent.

Recent trends in MXene-based material for biomedical applications

MXene is a magical class of 2D nanomaterials and emerging in many applications in diverse fields. Due to the multiple advantageous characteristics of its fundamental components, such as structural, physicochemical, optical, and occasionally even biological characteristics. However, it is limited in the biomedical industry due to poor physiological stability, decomposition rate, and lack of controlled and sustained drug release. These limitations can be overcome when MXene forms composites with other 2D materials. The efficiency of pure MXene in biomedicine is inferior to that of MXene-based composites. The availability of functionality on the exterior part of MXene has a key role in the modification of their surface and their characteristics. This review provides an extensive discussion on the synthesizing of MXene and the role of the surface functionalities on the efficiency of MXene. In addition, a detailed discussion of the biomedical applications of MXene, including antibacterial activity, regenerative medicine, CT scan capability, drug delivery, diagnostics, MRI and biosensing capability. Furthermore, an outline of the future problems and challenges of MXene-based materials for biomedical applications was narrated. Thus, these salient features showcase the potential of MXene-based material and will be a breakthrough in biomedical applications in the near future.

Cytocompatibility of Ti3C2Tx MXene with Red Blood Cells and Human Umbilical Vein Endothelial Cells and the Underlying Mechanisms

Two-dimensional (2D) nanomaterials have been widely used in biomedical applications because of their biocompatibility. Considering the high risk of exposure of the circulatory system to Ti3C2Tx, we studied the cytocompatibility of Ti3C2Tx MXene with red blood cells (RBCs) and human umbilical vein endothelial cells (HUVECs) and showed that Ti3C2Tx had excellent compatibility with the two cell lines. Ti3C2Tx at a concentration as high as 200 μg/mL caused a negligible percent hemolysis of 0.8%. By contrast, at the same treatment concentration, graphene oxide (GO) caused a high percent hemolysis of 50.8%. Scanning electron microscopy revealed that RBC structures remained intact in the Ti3C2Tx treatment group, whereas those in the GO group completely deformed, sunk, and shrunk, which resulted in the release of cell contents. This difference can be largely ascribed to the distinct surficial properties of the two nanosheets. In specific, the fully covered surface-terminating -O and -OH groups leading to Ti3C2Tx had a very hydrophilic surface, thereby hindering its penetration into the highly hydrophobic interior of the cell membrane. However, the strong direct van der Waals attractions coordinated with hydrophobic interactions between the unoxidized regions of GO and the lipid hydrophobic tails can still damage the integrity of the cell membranes. In addition, the sharp and keen-edged corners of GO may also facilitate its relatively strong cell membrane damage effects than Ti3C2Tx. Thus, the excellent cell membrane compatibility of Ti3C2Tx nanosheets and their ultraweak capacity to provoke excessive ROS generation endowed them with much better compatibility with HUVECs than GO nanosheets. These results indicate that Ti3C2Tx has much better cytocompatibility than GO and provide a valuable reference for the future biomedical applications of Ti3C2Tx.

Recent Advances in Well-Designed Therapeutic Nanosystems for the Pancreatic Ductal Adenocarcinoma Treatment Dilemma

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant tumor with an extremely poor prognosis and low survival rate. Due to its inconspicuous symptoms, PDAC is difficult to diagnose early. Most patients are diagnosed in the middle and late stages, losing the opportunity for surgery. Chemotherapy is the main treatment in clinical practice and improves the survival of patients to some extent. However, the improved prognosis is associated with higher side effects, and the overall prognosis is far from satisfactory. In addition to resistance to chemotherapy, PDAC is significantly resistant to targeted therapy and immunotherapy. The failure of multiple treatment modalities indicates great dilemmas in treating PDAC, including high molecular heterogeneity, high drug resistance, an immunosuppressive microenvironment, and a dense matrix. Nanomedicine shows great potential to overcome the therapeutic barriers of PDAC. Through the careful design and rational modification of nanomaterials, multifunctional intelligent nanosystems can be obtained. These nanosystems can adapt to the environment's needs and compensate for conventional treatments' shortcomings. This review is focused on recent advances in the use of well-designed nanosystems in different therapeutic modalities to overcome the PDAC treatment dilemma, including a variety of novel therapeutic modalities. Finally, these nanosystems' bottlenecks in treating PDAC and the prospect of future clinical translation are briefly discussed.

Construction nanoenzymes with elaborately regulated multi-enzymatic activities for photothermal-enhanced catalytic therapy of tumor

In order to solve the limitation of tumor microenvironment on the anticancer effect of nanozymes, a multifunctional nanoenzyme Co/La-PB@MOF-199/GOx was designed in this work. By doping Co²⁺ and La³⁺ in different proportions, Co/La-PB with the optimal photothermal-enhanced catalytic performance was screened, which can catalyze H₂O₂ to generate more hydroxyl radicals (•OH) and oxygen, showing peroxidase (POD)-like and catalase(CAT)-like property. Through MOF-199 coating and loading glucose oxidase (GOx), a multifunctional nanoenzyme Co/La-PB@MOF-199/GOx was achieved. Due to the pH response of MOF-199, GOx can be accurately released into tumors to catalyze the reaction of glucose and oxygen to produce H₂O₂. In this process, the oxygen consumption can be compensated by the CAT-like property to realize continuous consumption of glucose and self-supply of H₂O₂ to continuously produce •OH. In the presence of high oxidation state metal ions (Co³⁺ and Fe³⁺), GSH consumption is accelerated to avoid weakening of •OH, showing the glutathione oxidase (GPx-like) activity. Besides, magnetic resonance imaging (MRI) experiments showed the potential application in imaging guided therapy. In vivo anti-tumor experiments showed a satisfactory anti-cancer effect through multi-enzymatic activities.

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.

Two-dimensional nanomaterials for tumor microenvironment modulation and anticancer therapy

The development of two-dimensional (2D) nanomaterials for cancer therapy has attracted increasing attention due to their high specific surface area, unique ultrathin structure, electronic and photonic properties. For biomedical applications, investigations into the family of 2D materials have been sparked by graphene and its derivatives. Many 2D nanomaterials, including layered double hydroxides, transition metal dichalcogenides, nitrides and carbonitrides, black phosphorus nanosheets, and metal-organic framework nanosheets, are extensively explored as cancer theranostic platforms. In addition to the high drug loading, 2D nanomaterials are featured with improved physiological properties of drugs, prolonged blood circulation, and increased tumor accumulation and bioavailability. As a consequence, 2D nanomaterials have been widely examined in pre-clinical tumor therapy, particularly through the tumor microenvironment (TME) modulation. This review summarizes recent progresses in developing 2D nanomaterials for TME modulating-based cancer diagnosis and therapy. It is anticipated that this review will benefit researchers to obtain a deeper understanding of interactions between 2D nanomaterials and TME components and develop rational and reliable 2D nanomedicines for pre/clinical cancer theranostics.

Ti3C2 nanosheets with broad-spectrum antioxidant activity for cytoprotection against oxidative stress

Redox regulation in biological systems represents a fascinating method for treatment and prevention of oxidative stress induced diseases. The key and difficult point is to find ideal materials with excellent antioxidant capability and good biocompatibility. To this end, ultra-thin two-dimensional MXene (Ti3C2) nanosheets (NSs) were investigated for their antioxidant capability. It is found that Ti3C2 NSs can scavenge efficiently reactive oxygen and nitrogen species (˙OH, H2O2, and ˙NO), ABTS+˙ and DPPH˙ free radicals in a concentration dependent manner, showing broad-spectrum antioxidant activities. Ti3C2 NSs exhibit higher antioxidant activity and broader antioxidant capability than natural antioxidant molecules. The significant role of PEG modified Ti3C2 with good stability in preventing cell damage against oxidative stress was demonstrated. Upon treatment of H2O2 induced oxidative stress with Ti3C2, the intracellular ROS level decreases and the cell survival rate increases significantly. An antioxidant mechanism based on gradient oxidation was proposed to account for the superior antioxidant activity of Ti3C2. Our result proves that ultra-thin MXenes as antioxidants have great potential in preventing oxidative stress caused biological damage.

Two-Dimensional Nanostructures in the World of Advanced Oxidation Processes

Two-dimensional compounds with nanostructural features are attracting attention from researchers worldwide. Their multitude of applications in various fields and vast potential for future technology advancements are successively increasing the research progress. Wastewater treatment and preventing dangerous substances from entering the environment have become important aspects due to the increasing environmental awareness, and increasing consumer demands have resulted in the appearance of new, often nonbiodegradable compounds. In this review, we focus on using the most promising 2D materials, such as MXenes, Bi2WO6, and MOFs, as catalysts in the modification of the Fenton process to degrade nonbiodegradable compounds. We analyze the efficiency of the process, its toxicity, previous environmental applications, and the stability and reusability of the catalyst. We also discuss the catalyst’s mechanisms of action. Collectively, this work provides insight into the possibility of implementing 2D material-based catalysts for industrial and urban wastewater treatment.

From Microenvironment Remediation to Novel Anti-Cancer Strategy: The Emergence of Zero Valent Iron Nanoparticles

Accumulated studies indicate that zero-valent iron (ZVI) nanoparticles demonstrate endogenous cancer-selective cytotoxicity, without any external electric field, lights, or energy, while sparing healthy non-cancerous cells in vitro and in vivo. The anti-cancer activity of ZVI-based nanoparticles was anti-proportional to the oxidative status of the materials, which indicates that the elemental iron is crucial for the observed cancer selectivity. In this thematic article, distinctive endogenous anti-cancer mechanisms of ZVI-related nanomaterials at the cellular and molecular levels are reviewed, including the related gene modulating profile in vitro and in vivo. From a material science perspective, the underlying mechanisms are also analyzed. In summary, ZVI-based nanomaterials demonstrated prominent potential in precision medicine to modulate both programmed cell death of cancer cells, as well as the tumor microenvironment. We believe that this will inspire advanced anti-cancer therapy in the future.

Recent advances in multifunctional nanomaterials for photothermal-enhanced Fenton-based chemodynamic tumor therapy

Photothermal (PT)-enhanced Fenton-based chemodynamic therapy (CDT) has attracted a significant amount of research attention over the last five years as a highly effective, safe, and tumor-specific nanomedicine-based therapy. CDT is a new emerging nanocatalyst-based therapeutic strategy for the in situ treatment of tumors via the Fenton reaction or Fenton-like reaction, which has got fast progress in recent years because of its high specificity and activation by endogenous substances. A variety of multifunctional nanomaterials such as metal-, metal oxide-, and metal-sulfide-based nanocatalysts have been designed and constructed to trigger the in situ Fenton or Fenton-like reaction within the tumor microenvironment (TME) to generate highly cytotoxic hydroxyl radicals (•OH), which is highly efficient for the killing of tumor cells. However, research is still required to enhance the curative outcomes and minimize its side effects. Specifically, the therapeutic efficiency of certain CDTs is still hindered by the TME, including low levels of endogenous hydrogen peroxide (H2O2), overexpression of reduced glutathione (GSH), and low catalytic efficacy of Fenton or Fenton-like reactions (pH 5.6-6.8), which makes it difficult to completely cure cancer using monotherapy. For this reason, photothermal therapy (PTT) has been utilized in combination with CDT to enhance therapeutic efficacy. More interestingly, tumor heating during PTT not only causes damage to the tumor cells but can also accelerate the generation of •OH via the Fenton and Fenton-like reactions, thus enhancing the CDT efficacy, providing more effective cancer treatment when compared with monotherapy. Currently, synergistic PT-enhanced CDT using multifunctional nanomaterials with both PT and chemodynamic properties has made enormous progress in cancer theranostics. However, there has been no comprehensive review on this subject published to date. In this review, we first summarize the recent progress in PT-enhanced Fenton-based CDT for cancer treatment. We then discuss the potential and challenges in the future development of PT-enhanced Fenton-based nanocatalytic tumor therapy for clinical application.

Active-passive Strategy for Enhanced Synergistic Photothermal-Ferroptosis Therapy in NIR-I/II Biowindows

Ferroptosis therapy (FT) is an attractive strategy to selectively damage cancer cells by lipid peroxides (LPO) over accumulation. However, this therapy suffers from poor therapeutic efficacy due to the limited...

MXene-based hybrid system exhibits excellent synergistic antibiosis

MXenes are a group of inorganic two-dimensional (2D) nanomaterial, and have raised significant interests in biomedical areas. Ti₃C₂T_x, as an important member of MXene family, is widely studied because of its biodegradability and low-cytotoxicity. However, their single antibacterial mechanism and poor stability in aqueous solution need to be improved, especially for the antimicrobial applications. In this work, a MXene-based hybrid antibacterial system (M-HAS) was developed and its synergistic antibacterial activity was investigated. In the M-HAS, 2D few-layer Ti₃C₂T_x(FL-Ti₃C₂T_x) was modified with hydrophilic polymers and thereby used as carriers for silver nanoparticles (Ag NPs). By assembling these two substrates, photodynamic performance of the prepared system is significantly improved with a large amount of reactive oxygen species produced under 660 nm laser. Antibacterial effects of the M-HAS are enhanced by over 4 times with irradiation. In another word, the developed hybrid system displays excellent photodynamic antibacterial synergistic properties. This work takes advantage of the photodynamic properties of each component in the M-HAS to achieve efficient antibacterial activity and proposes an innovative approach to develop the 2D FL-Ti₃C₂T_x-based antibacterial platform.

Emerging 2D Nanomaterials for Biomedical Applications

Two-dimensional (2D) nanomaterials are an emerging class of biomaterials with remarkable potential for biomedical applications. The planar topography of these nanomaterials confers unique physical, chemical, electronic and optical properties, making them attractive candidates for therapeutic delivery, biosensing, bioimaging, regenerative medicine, and additive manufacturing strategies. The high surface-to-volume ratio of 2D nanomaterials promotes enhanced interactions with biomolecules and cells. A range of 2D nanomaterials, including transition metal dichalcogenides (TMDs), layered double hydroxides (LDHs), layered silicates (nanoclays), 2D metal carbides and nitrides (MXenes), metal-organic framework (MOFs), covalent organic frameworks (COFs) and polymer nanosheets have been investigated for their potential in biomedical applications. Here, we will critically evaluate recent advances of 2D nanomaterial strategies in biomedical engineering and discuss emerging approaches and current limitations associated with these nanomaterials. Due to their unique physical, chemical, and biological properties, this new class of nanomaterials has the potential to become a platform technology in regenerative medicine and other biomedical applications.

PDA@Ti3 C2 Tx as a novel carrier for pesticide delivery and its application in plant protection: NIR-responsive controlled release and sustained antipest activity

BACKGROUND

Stimuli-responsive pesticide controlled release system provides a new strategy for the development of high-efficiency pesticides formulation.

RESULTS

In this article, we report a novel polydopamine surface modified MXene-Ti₃ C₂ T_x nanocarrier for pesticide delivery and plant protection. Polydopamine modified Ti₃ C₂ T_x (PDA@Ti₃ C₂ T_x ) nanocarrier was prepared by biomimetic self-polymerization of dopamine on the surface of Ti₃ C₂ T_x . A typical pesticide, emamectin benzoate (EB), was loaded on PDA@Ti₃ C₂ T_x through physisorption process, with a high pesticide loading rate of 45.37%. PDA@Ti₃ C₂ T_x exhibited excellent photothermal conversion effect (η = 34.5%). Under the irradiation of near-infrared (NIR) laser, EB would sustained release from PDA@Ti₃ C₂ T_x nanocarrier to surrounding medium. Compared with free EB, EB@PDA@Ti₃ C₂ T_x exhibited prolonged persistence period, which can keep antipest activity at 14 days post spraying. In addition, PDA@Ti₃ C₂ T_x nanocarrier and EB@PDA@Ti₃ C₂ T_x nanoformulation are of good safety, showing no side effect to the seed germination and seedling growth.

CONCLUSION

This research developed a novel nanocarrier for water-insoluble pesticide delivery, realizing NIR-responsive controlled release and sustained antipest activity.

Two-dimensional biomaterials: material science, biological effect and biomedical engineering applications

To date, nanotechnology has increasingly been identified as a promising and efficient means to address a number of challenges associated with public health. In the past decade, two-dimensional (2D) biomaterials, as a unique nanoplatform with planar topology, have attracted explosive interest in various fields such as biomedicine due to their unique morphology, physicochemical properties and biological effect. Motivated by the progress of graphene in biomedicine, dozens of types of ultrathin 2D biomaterials have found versatile bio-applications, including biosensing, biomedical imaging, delivery of therapeutic agents, cancer theranostics, tissue engineering, as well as others. The effective utilization of 2D biomaterials stems from the in-depth knowledge of structure-property-bioactivity-biosafety-application-performance relationships. A comprehensive summary of 2D biomaterials for biomedicine is still lacking. In this comprehensive review, we aim to concentrate on the state-of-the-art 2D biomaterials with a particular focus on their versatile biomedical applications. In particular, we discuss the design, fabrication and functionalization of 2D biomaterials used for diverse biomedical applications based on the up-to-date progress. Furthermore, the interactions between 2D biomaterials and biological systems on the spatial-temporal scale are highlighted, which will deepen the understanding of the underlying action mechanism of 2D biomaterials aiding their design with improved functionalities. Finally, taking the bench-to-bedside as a focus, we conclude this review by proposing the current crucial issues/challenges and presenting the future development directions to advance the clinical translation of these emerging 2D biomaterials.

Encapsulation of Enzymes in Metal-Phenolic Network Capsules for the Trigger of Intracellular Cascade Reactions

Nanoengineered capsules encapsulated with functional cargos (e.g., enzymes) are of interest for various applications including catalysis, bioreactions, sensing, and drug delivery. Herein, we report a facile strategy to engineer enzyme-encapsulated metal-phenolic network (MPN) capsules using enzyme-loaded zeolitic imidazolate framework nanoparticles (ZIF-8 NPs) as templates, which can be removed in a mild condition (e.g., ethylenediaminetetraacetic acid (EDTA) solution). The capsule size (from 250 nm to 1 μm) and thickness (from 9.8 to 33.7 nm) are well controlled via varying the template size and coating time, respectively. Importantly, MPN capsules encapsulated with enzymes (i.e., glucose oxidase) can trigger the intracellular cascade reaction via the exhaustion of glucose to produce H₂O₂ and subsequently generate toxic hydroxyl radicals (^•OH) based on the Fenton reaction via the reaction between H₂O₂ and iron ions in MPN coatings. The intracellular cascade reaction for the generation of ^•OH is efficient to inhibit cancer cell viability, which is promising for the application in chemodynamic therapy.

Two-Dimensional Silicene/Silicon Nanosheets: An Emerging Silicon-Composed Nanostructure in Biomedicine

Silicon-composed nanomedicines are one of the most representative inorganic nanosystems in theranostic biomedicine. The emerging of new family members of silicon-composed nanosystems substantially contributes to their further clinical translation. 2D silicene/silicon nanosheets have recently been developed as an emerging topology of silicon-composed nanoparticles, which features unique planar nanostructure with large surface area, abundant surface chemistry, specific physiochemical property, and desirable biological effects. This progress report highlights and discusses the state-of-art developments of the elaborate construction of 2D silicene/silicon nanosheets for versatile biomedical applications, including top-down fabrication, multifunctionalization, surface engineering, and their available biomedical applications in tumor theranostics (e.g., bioimaging, photothermal ablation, chemotherapy, chemoreactive nanotherapy, radiotherapy, and synergistic nanotherapy) and antibacteria. Their large surface area originating from 2D nanostructure not only enables efficient loading and delivery of chemotherapeutic drugs, but also guarantees the multifunctionalization. Especially, 2D silicene/silicon nanosheets harness desirable photothermal-conversion performance for photonic hyperthermia and photoacoustic imaging in the near infrared biowindow, accompanied with the desirable biodegradability and biocompatibility, which is typically not possessed in other silicon-composed counterparts. The multivariate analysis on the facing challenges and future developments of these 2D silicene/silicon nanosheets have also been conducted and outlooked for further underpinning their clinical translations.

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.

Chemodynamic nanomaterials for cancer theranostics

It is of utmost urgency to achieve effective and safe anticancer treatment with the increasing mortality rate of cancer. Novel anticancer drugs and strategies need to be designed for enhanced therapeutic efficacy. Fenton- and Fenton-like reaction-based chemodynamic therapy (CDT) are new strategies to enhance anticancer efficacy due to their capacity to generate reactive oxygen species (ROS) and oxygen (O2). On the one hand, the generated ROS can damage the cancer cells directly. On the other hand, the generated O2 can relieve the hypoxic condition in the tumor microenvironment (TME) which hinders efficient photodynamic therapy, radiotherapy, etc. Therefore, CDT can be used together with many other therapeutic strategies for synergistically enhanced combination therapy. The antitumor applications of Fenton- and Fenton-like reaction-based nanomaterials will be discussed in this review, including: (iþ) producing abundant ROS in-situ to kill cancer cells directly, (ii) enhancing therapeutic efficiency indirectly by Fenton reaction-mediated combination therapy, (iii) diagnosis and monitoring of cancer therapy. These strategies exhibit the potential of CDT-based nanomaterials for efficient cancer 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.

Exploiting cyanine dye J-aggregates/monomer equilibrium in hydrophobic protein pockets for efficient multi-step phototherapy: an innovative concept for smart nanotheranostics

After several decades of development in the field of near-infrared (NIR) dyes for photothermal therapy (PTT), indocyanine green (ICG) still remains the only FDA-approved NIR contrast agent. However, upon NIR light irradiation ICG can react with molecular oxygen to form reactive oxygen species and degrade the ICG core, losing the convenient dye properties. In this work, we introduce a new approach for expanding the application of ICG in nanotheranostics, which relies on the confinement of self-organized J-type aggregates in hydrophobic protein domains acting as monomer depots. Upon the fast photobleaching, while the dye is irradiated, this strategy permits the equilibrium-driven monomer replacement after each irradiation cycle that radically increases the systems' effectivity and applicability. Gadolinium-doped casein micelles were designed to prove this novel concept at the same time as endowing the nanosystems with further magnetic resonance imaging (MRI) ability for dual-modal imaging-guided PTT. By teaching a new trick to a very old dog, the clinical prospect of ICG will undoubtedly be boosted laying the foundation for novel therapeutics. It is anticipated that future research could be expanded to other relevant J-aggregates-forming cyanine dyes or nanocrystal formulations of poorly water-soluble photosensitizers.

Tumor Microenvironment-Activatable Cyclic Cascade Reaction to Reinforce Multimodal Combination Therapy by Destroying the Extracellular Matrix

The optimal therapy effect of tumors is frequently restricted by the dense extracellular matrix (ECM) and anoxia. Herein, an intelligent BPNs-Arg-GOx@MnO₂ (BAGM) nanozyme is innovatively designed as a multimodal synergistic therapeutic paradigm that possesses both nitric oxide (NO) self-supplying and ECM degradation properties to reinforce the therapy effect by a tumor microenvironment (TME)-activatable cyclic cascade catalytic reaction. This theranostic nanoplatform is constructed by using polyethyleneimine-modified black phosphorus nanosheets as a "fishnet" to attach l-Arginine (l-Arg) and glucose oxidase (GOx) and then depositing mini-sized MnO₂ nanosheets (MNs) on the surface by a facile situ biomineralization method. As an intelligent "switch", the MNs can effectively trigger the cascade reaction by disintegrating intracellular H₂O₂ to release O₂. Then, the conjugated GOx can utilize O₂ production to catalyze intracellular glucose to generate H₂O₂, which not only starves the tumor cells but also promotes oxidation of l-Arg to NO. Thereafter, matrix metalloproteinases will be activated by NO production to degrade the dense ECM and transform matrix collagen into a loose state. In turn, a loose ECM can enhance the accumulation of the BAGM nanozyme and thereby reinforce synergistic photothermal therapy/starvation therapy/NO gas therapy. Both in vitro and in vivo results indicate that the TME-tunable BAGM therapeutic nanoplatform with cascade anticancer property and satisfactory biosecurity shows potential in nanomedicine.

Emerging Nanomedicine-Enabled/Enhanced Nanodynamic Therapies beyond Traditional Photodynamics

The rapid knowledge growth of nanomedicine and nanobiotechnology enables and promotes the emergence of distinctive disease-specific therapeutic modalities, among which nanomedicine-enabled/augmented nanodynamic therapy (NDT), as triggered by either exogenous or endogenous activators on nanosensitizers, can generate reactive radicals for accomplishing efficient disease nanotherapies with mitigated side effects and endowed disease specificity. As one of the most representative modalities of NDT, traditional light-activated photodynamics suffers from the critical and unsurmountable issues of the low tissue-penetration depth of light and the phototoxicity of the photosensitizers. To overcome these obstacles, versatile nanomedicine-enabled/augmented NDTs have been explored for satisfying varied biomedical applications, which strongly depend on the physicochemical properties of the involved nanomedicines and nanosensitizers. These distinctive NDTs refer to sonodynamic therapy (SDT), thermodynamic therapy (TDT), electrodynamic therapy (EDT), piezoelectric dynamic therapy (PZDT), pyroelectric dynamic therapy (PEDT), radiodynamic therapy (RDT), and chemodynamic therapy (CDT). Herein, the critical roles, functions, and biological effects of nanomedicine (e.g., sonosensitizing, photothermal-converting, electronic, piezoelectric, pyroelectric, radiation-sensitizing, and catalytic properties) for enabling the therapeutic procedure of NDTs, are highlighted and discussed, along with the underlying therapeutic principle and optimization strategy for augmenting disease-therapeutic efficacy and biosafety. The present challenges and critical issues on the clinical translations of NDTs are also discussed and clarified.

Knittable and Sewable Spandex Yarn with Nacre-Mimetic Composite Coating for Wearable Health Monitoring and Thermo- and Antibacterial Therapies

The emerging personal healthcare has significantly propelled the development of advanced wearable electronics with novel functions of providing diagnostic information and point-of-care therapies for specific diseases. However, it is still challenging to simultaneously achieve high sensitivity for health biomonitoring and multifunction integration for point-of-care therapies in a one single flexible, lightweight yet robust fiber-based device. Here, a knittable and sewable spandex yarn with conductive nacre-mimetic composite coating has been developed through an alternant dip-coating method employing MXene nanosheets as the "brick" and polydopamine (PDA)/Ni²⁺ as the "mortar". The resultant spandex yarn coating with MXene/PDA/Ni²⁺ (MPNi@Spandex) can be assembled as a strain sensor with high sensitivity (up to 5.7 × 10⁴ for the gauge factor), wide sensing range (∼61.2%), and low detection limit (0.11%) to monitor the biological activities of the human body. Furthermore, MPNi@Spandex displays great potential to give on-demand thermotherapy by virtue of the fast response to near-infrared irradiation, controllable surface temperature, and applicability even under sewing conditions. In addition, MPNi@Spandex knitted textiles demonstrate a strong antibacterial effect due to the sharp edges, anionic, and hydrophilic nature of MXene nanosheets. Remarkably, near-infrared irradiation further improves the bacteria-killing efficiency of an MPNi@Spandex knitted textile to more than 99.9%. This work paves the way for the design of multifunctional wearable electronics with an all-in-one theranostic platform for personal healthcare.

Smart Textiles with Self-Disinfection and Photothermochromic Effects

Self-disinfecting textile materials employing combined photodynamic/photothermal effects enable the prevention of microbial infections, a property that has great potential in healthcare applications. However, smart textiles with stimulus responses to ambient temperature are marvelous materials for enhancing their photothermal applications with additional functions. It is still challenging to realize vivid and contrasting color changes as temperature indicators. Herein, through the in situ growth of PCN-224 metal-organic frameworks (MOFs), the electrospraying of a Ti₃C₂ MXene colloid, and the screen printing of a thermochromic dye, a smart photothermochromic self-disinfecting textile has been fabricated. An antibacterial inactivation study revealed 99.9999% inactivation toward gram-negative (Escherichia coli ATCC 8099) and gram-positive (Staphylococcus aureus ATCC 6538) bacteria in 30 min. A mechanism study revealed that light-driven singlet oxygen and heat are the main reasons for bacterial inactivation. Interestingly, the fabrics presented photothermal effects not only under a handheld 780 nm NIR laser but also under visible Xe lamp (λ ≥ 420 nm) illumination. The color of the fabrics (S-CF@PCN_0.08) changed completely from dark green to dark red when the temperature exceeded 45 °C under Xe lamp illumination. Furthermore, the photothermochromic effect occurred in just 1 s under a 780 nm laser. Taken together, this smart photothermochromic self-disinfecting textile permits a new way to feedback the timely signal of temperature by color change and provides novel insights into the development of self-disinfecting textiles.

Biodistribution, inter-/intra-cellular localization and respiratory dysfunction induced by Ti3C2 nanosheets: Involvement of surfactant protein down-regulation in alveolar epithelial cells

Two-dimensional Ti₃C₂ nanosheets have been extensively used in biomedical fields and are mostly designed to enter the circulatory system. However, few studies have focused on the in vivo anatomical location and physiological function of major organs on exposure to Ti₃C₂ nanosheets. This study attempts to determine whether and how Ti₃C₂ nanosheets disrupt the physiological function of the involved organs. Our studies demonstrated that Ti₃C₂ nanosheets were mainly distributed in the lungs and liver after entering circulation. In the lungs, they were retained in the cytoplasm of alveolar epithelial cells and endothelial cells, and inhibited pulmonary surfactant protein B (SP-B) expression on alveolar epithelial cell, causing increased airway resistance-induced respiratory disorder following a 28-day Ti₃C₂ nanosheet exposure. Furthermore, our data showed that Ti₃C₂ nanosheets did not cause abnormal proinflammatory cytokines and histopathological changes. These findings demonstrated that Ti₃C₂ nanosheets might disturb respiration without inflammatory responses and pathological lesions, suggesting that these effects may occur by decreasing SP-B-mediated airway resistance. This indicates that organ function maintenance differs from biological safety for Ti₃C₂ nanosheets, an important consideration during potential clinical application and human exposure.

Biomimetic Anti-PD-1 Peptide-Loaded 2D FePSe3 Nanosheets for Efficient Photothermal and Enhanced Immune Therapy with Multimodal MR/PA/Thermal Imaging

Metal phosphorous trichalcogenides (MPX3) are novel 2D nanomaterials that have recently been exploited as efficient photothermal-chemodynamic agents for cancer therapy. As a representative MPX3, FePSe3 has the potential to be developed as magnetic resonance imaging (MRI) and photoacoustic imaging (PAI) agents due to the composition of Fe and the previously revealed PA signal. Here, a FePSe3-based theranostic agent, FePSe3@APP@CCM, loaded with anti-PD-1 peptide (APP) as the inner component and CT26 cancer cell membrane (CCM) as the outer shell is reported, which acts as a multifunctional agent for MR and PA imaging and photothermal and immunotherapy against cancer. FePSe3@APP@CCM induces highly efficient tumor ablation and suppresses tumor growth by photothermal therapy under near-infrared laser excitation, which further activates immune responses. Moreover, APP blocks the PD-1/PD-L1 pathway to activate cytotoxic T cells, causing strong anticancer immunity. The combined therapy significantly prolongs the lifespan of experimental mice. The multimodal imaging and synergistic therapeutic effects of PTT and its triggered immune responses and APP-related immunotherapy are clearly demonstrated by in vitro and in vivo experiments. This work demonstrates the potential of MPX3-based biomaterials as novel theranostic agents.

Folic acid-appended galactoxyloglucan-capped iron oxide nanoparticles as a biocompatible nanotheranostic agent for tumor-targeted delivery of doxorubicin

Iron oxide nanoparticles (IONPs) are employed as MRI contrast agents and as effective drug delivery vehicles. However, the limited solubility and biodegradability of these nanoparticles need to be improved for safer biomedical applications. In an attempt to improve the bottlenecks associated with IONPs, the current study focuses on the synthesis of folic acid conjugated, galactoxyloglucan-iron oxide nanoparticles (FAPIONPs), for the loading and controlled release of the encapsulated chemotherapeutic agent doxorubicin (DOX). The as-designed DOX@FAPIONPs induced a dose-dependent increase in cytotoxicity in folate receptor-positive cells through a caspase-mediated programmed cell death pathway while bare DOX demonstrated a non-targeted toxicity profile. Using LC-MS/MS analysis, several major biological processes altered in treated cells, from which, cell cycle, cellular function and maintenance were the most affected. Detailed toxicity studies in healthy mice indicated the absence of any major side effects while bare drugs created substantial organ pathology. Gadolinium-based contrast agents have a risk of adverse effects, including nephrogenic systemic fibrosis overcome by the administration of DOX@FAPIONPs in xenograft mice model. Tumor-targeted biodistribution pattern with a favorable DOX pharmacokinetics will be the driving factor behind the appealing tumor reduction capacity and increased survival benefits demonstrated on solid tumor-bearing mice.

Nanoplatform-based cascade engineering for cancer therapy

Various therapeutic techniques have been studied for treating cancer precisely and effectively, such as targeted drug delivery, phototherapy, tumor-specific catalytic therapy, and synergistic therapy, which, however, evoke numerous challenges due to the inherent limitations of these therapeutic modalities and intricate biological circumstances as well. With the remarkable advances of nanotechnology, nanoplatform-based cascade engineering, as an efficient and booming strategy, has been tactfully introduced to optimize these cancer therapies. Based on the designed nanoplatforms, pre-supposed cascade processes could be triggered under specific conditions to generate/deliver more therapeutic species or produce stronger tumoricidal effects inside tumors, aiming to achieve cancer therapy with increased anti-tumor efficacy and diminished side effects. In this review, the recent advances in nanoplatform-based cascade engineering for cancer therapy are summarized and discussed, with an emphasis on the design of smart nanoplatforms with unique structures, compositions and properties, and the implementation of specific cascade processes by means of endogenous tumor microenvironment (TME) resources and/or exogenous energy inputs. This fascinating strategy presents unprecedented potential in the enhancement of cancer therapies, and offers better controllability, specificity and effectiveness of therapeutic functions compared to the corresponding single components/functions. In the end, challenges and prospects of such a burgeoning strategy in the field of cancer therapy will be discussed, hopefully to facilitate its further development to meet the personalized treatment demands.

GSH-Depleted Nanozymes with Hyperthermia-Enhanced Dual Enzyme-Mimic Activities for Tumor Nanocatalytic Therapy

Nanocatalytic therapy, using artificial nanoscale enzyme mimics (nanozymes), is an emerging technology for therapeutic treatment of various malignant tumors. However, the relatively deficient catalytic activity of nanozymes in the tumor microenvironment (TME) restrains their biomedical applications. Here, a versatile and bacteria-like PEG/Ce-Bi@DMSN nanozyme is developed by coating uniform Bi₂ S₃ nanorods (NRs) with dendritic mesoporous silica (Bi₂ S₃ @DMSN) and then decorating ultrasmall ceria nanozymes into the large mesopores of Bi₂ S₃ @DMSN. The nanozymes exhibit dual enzyme-mimic catalytic activities (peroxidase-mimic and catalase-mimic) under acidic conditions that can regulate the TME, that is, simultaneously elevate oxidative stress and relieve hypoxia. In addition, the nanozymes can effectively consume the overexpressed glutathione (GSH) through redox reaction. Photothermal therapy (PTT) is introduced to synergistically improve the dual enzyme-mimicking catalytic activities and depletion of the overexpressed GSH in the tumors by photonic hyperthermia. This is achieved by taking advantage of the desirable light absorbance in the second near-infrared (NIR-II) window of the PEG/Ce-Bi@DMSN nanozymes. Subsequently the reactive oxygen species (ROS)-mediated therapeutic efficiency is significantly improved. Therefore, this study provides a proof of concept of hyperthermia-augmented multi-enzymatic activities of nanozymes for tumor ablation.