Repurposing indocyanine green: exploring the potential of an old drug in modern medicine

The repurposing of existing drugs, referred to as theranostics, has made profound impacts on precision medicine. Indocyanine green (ICG), a well-established and clinical dye, has continued to be a star agent, described as a multifunctional molecule with concurrent photo- or sono-sensitiveness capabilities and co-delivery accessibility, showing remarkable potential in the area of unimodal or multimodal imaging-guided therapy of various diseases, leading to the extensive consideration of immediate clinical translations. In this review, we strive to bring the understanding of repurposing performance assessment for ICG into practice by clarifying the relationships between its features and applicability. Specifically, we address the obstacles encountered in the process of developing an ICG repurposing strategy, as well as the noteworthy advancements made in the field of ICG repurposing. We also go into detail about the structure-function correlations of drugs containing ICG and how different structural groups significantly affect the physicochemical properties.

Layered Double Hydroxides: Recent Progress and Promising Perspectives Toward Biomedical Applications

Layered double hydroxides (LDHs) have been widely studied for biomedical applications due to their excellent properties, such as good biocompatibility, degradability, interlayer ion exchangeability, high loading capacity, pH-responsive release, and large specific surface area. Furthermore, the flexibility in the structural composition and ease of surface modification of LDHs makes it possible to develop specifically functionalized LDHs to meet the needs of different applications. In this review, the recent advances of LDHs for biomedical applications, which include LDH-based drug delivery systems, LDHs for cancer diagnosis and therapy, tissue engineering, coatings, functional membranes, and biosensors, are comprehensively discussed. From these various biomedical research fields, it can be seen that there is great potential and possibility for the use of LDHs in biomedical applications. However, at the same time, it must be recognized that the actual clinical translation of LDHs is still very limited. Therefore, the current limitations of related research on LDHs are discussed by combining limited examples of actual clinical translation with requirements for clinical translation of biomaterials. Finally, an outlook on future research related to LDHs is provided.

Osteosarcoma-targeted Cu and Ce based oxide nanoplatform for NIR II fluorescence/magnetic resonance dual-mode imaging and ros cascade amplification along with immunotherapy

BACKGROUND

As the lethal bone tumor, osteosarcoma often frequently occurs in children and adolescents with locally destructive and high metastasis. Distinctive kinds of nanoplatform with high therapeutical effect and precise diagnosis for osteosarcoma are urgently required. Multimodal optical imaging and programmed treatment, including synergistic photothermal-chemodynamic therapy (PTT-CDT) elicits immunogenetic cell death (ICD) is a promising strategy that possesses high bio-imaging sensitivity for accurate osteosarcoma delineating as well as appreciable therapeutic efficacy with ignorable side-effects.

METHODS AND RESULTS

In this study, mesoporous Cu and Ce based oxide nanoplatform with Arg-Gly-Asp (RGD) anchoring is designed and successfully constructed. After loading with indocyanine green, this nanoplatform can be utilized for precisely targeting and efficaciously ablating against osteosarcoma via PTT boosted CDT and the closely following ICD stimulation both in vitro and in vivo. Besides, it provides off-peak fluorescence bio-imaging in the second window of near-infrared region (NIR II, 1000-1700 nm) and Magnetic resonance signal, serves as the dual-mode contrast agents for osteosarcoma tissue discrimination.

CONCLUSION

Tumor targeted Cu&Ce based mesoporous nanoplatform permits efficient osteosarcoma suppression and dual-mode bio-imaging that opens new possibility for effectively diagnosing and inhibiting the clinical malignant osteosarcoma.

Advances of Layered Double Hydroxide-Based Materials for Tumor Imaging and Therapy

Layered double hydroxides (LDH) are a class of functional anionic clays that typically consist of orthorhombic arrays of metal hydroxides with anions sandwiched between the layers. Due to their unique properties, including high chemical stability, good biocompatibility, controlled drug loading, and enhanced drug bioavailability, LDHs have many potential applications in the medical field. Especially in the fields of bioimaging and tumor therapy. This paper reviews the research progress of LDHs and their nanocomposites in the field of tumor imaging and therapy. First, the structure and advantages of LDH are discussed. Then, several commonly used methods for the preparation of LDH are presented, including co-precipitation, hydrothermal and ion exchange methods. Subsequently, recent advances in layered hydroxides and their nanocomposites for cancer imaging and therapy are highlighted. Finally, based on current research, we summaries the prospects and challenges of layered hydroxides and nanocomposites for cancer diagnosis and therapy.

Strategies to engineer various nanocarrier-based hybrid catalysts for enhanced chemodynamic cancer therapy

Chemodynamic therapy (CDT) is a newly developed cancer-therapeutic modality that kills cancer cells by the highly toxic hydroxyl radical (˙OH) generated from the in situ triggered Fenton/Fenton-like reactions in an acidic and H2O2-overproduced tumor microenvironment (TME). By taking the advantage of the TME-activated catalytic reaction, CDT enables a highly specific and minimally-invasive cancer treatment without external energy input, whose efficiency mainly depends on the reactant concentrations of both the catalytic ions and H2O2, and the reaction conditions (including pH, temperature, and amount of glutathione). Unfortunately, it suffers from unsatisfactory therapy efficiency for clinical application because of the limited activators (i.e., mild acid pH and insufficient H2O2 content) and overexpressed reducing substance in TME. Currently, various synergistic strategies have been elaborately developed to increase the CDT efficiency by regulating the TME, enhancing the catalytic efficiency of catalysts, or combining with other therapeutic modalities. To realize these strategies, the construction of diverse nanocarriers to deliver Fenton catalysts and cooperatively therapeutic agents to tumors is the key prerequisite, which is now being studied but has not been thoroughly summarized. In particular, nanocarriers that can not only serve as carriers but are also active themselves for therapy are recently attracting increasing attention because of their less risk of toxicity and metabolic burden compared to nanocarriers without therapeutic capabilities. These therapy-active nanocarriers well meet the requirements of an ideal therapy system with maximum multifunctionality but minimal components. From this new perspective, in this review, we comprehensively summarize the very recent research progress on nanocarrier-based systems for enhanced CDT and the strategies of how to integrate various Fenton agents into the nanocarriers, with particular focus on the studies of therapy-active nanocarriers for the construction of CDT catalysts, aiming to guide the design of nanosystems with less components and more functionalities for enhanced CDT. Finally, the challenges and prospects of such a burgeoning cancer-theranostic modality are outlooked to provide inspirations for the further development and clinical translation of CDT.

Sulfur-Doped NiFe Hydroxide Nanobowls with Wrinkling Patterns for Photothermal Cancer Therapy

Hierarchical multiscale wrinkling nanostructures have shown great promise for many biomedical applications, such as cancer diagnosis and therapy. However, synthesizing these materials with precise control remains challenging. Here, we report a sulfur doping strategy to synthesize sub-1 nm NiFe hydroxide ultrathin nanosheets (S-NiFe HUNs). The introduction of sulfur affects the reduction of the band gap and the adjustment of the electronic structure, thereby improving the light absorption ability of the S-NiFe HUNs. Additionally, S-NiFe HUNs show a multilayered nanobowl-like structure that enables multiple reflections of incident light inside the nanostructure, which improved the utilization of incident light and achieved high photothermal conversion. As a result, the as-prepared product with hydrophilic modification (dS-NiFe HUNs) demonstrated enhanced tumor-killing ability in vitro. In a mouse model of breast cancer, dS-NiFe HUNs combined with near-infrared light irradiation greatly inhibited tumor growth and prolonged the mice survival. Altogether, our study demonstrates the great potential of dS-NiFe HUNs for cancer photothermal therapy applications.

pH-Activated Ce-Doped Molybdenum Oxide Nanoclusters for Tumor Microenvironment Responsive Photothermal and Chemodynamic Therapy

Molybdenum-based nanomaterials have shown promise for anticancer treatment due to their strong photothermal and redox-activated capabilities. Herein, we have fabricated cerium-doped MoO_x (Ce-MoO_v) with tunable Mo/Ce molar ratios by a one-pot method and investigated their effect on chemodynamic therapy (CDT) and photothermal therapy (PTT). It is found that Ce-MoO_v can self-assemble into nanoclusters in acidic conditions and the increasing Ce amount will generate oxygen vacancy defects and induce the valence change of Mo⁶⁺/Mo⁵⁺ and Ce⁴⁺/Ce³⁺, which leads to strong near-infrared absorption with high photothermal conversion efficiency of 71.31 and 49.86% for 808 and 1064 nm. Other than photothermal conversion, the materials demonstrate pH-/glutathione (GSH)-activated photoacoustic (PA) imaging capability in vitro. In addition, Ce-MoO_v acts as a CDT reagent capable of converting endogenous H₂O₂ to two types of reactive oxygen species (^•OH, ¹O₂) while depleting GSH. Ce-MoO_v demonstrates an excellent therapeutic effect against HCT116 cells and effectively reduces the intracellular GSH level and significantly increases the number of reactive radicals under 1064 nm laser irradiation as compared with the no-laser group in vitro. This work provides a new paradigm using lanthanide-doped polymetallic oxides for pH-/GSH-responsive photothermal/chemodynamic therapy with PA imaging ability.

Multifunctional Layered Double Hydroxides for Drug Delivery and Imaging

Two-dimensional nanomaterials, particularly layered double hydroxides (LDHs), have been widely applied in the biomedical field owing to their biocompatibility, biodegradability, controllable drug release/loading ability, and enhanced cellular permeability. Since the first study analyzing intercalative LDHs in 1999, numerous studies have investigated their biomedical applications, including drug delivery and imaging; recent research has focused on the design and development of multifunctional LDHs. This review summarizes the synthetic strategies and in-vivo and in-vitro therapeutic actions and targeting properties of single-function LDH-based nanohybrids and recently reported (from 2019 to 2023) multifunctional systems developed for drug delivery and/or bio-imaging.

Carrier-Free H2 O2 Self-Supplier for Amplified Synergistic Tumor Therapy

Chemodynamic therapy (CDT) utilizes Fenton or Fenton-like reactions to convert hydrogen peroxide (H₂ O₂ ) into cytotoxic hydroxyl radicals (•OH) and draws extensive interest in tumor therapy. Nevertheless, high concentrations of glutathione (GSH) and insufficient endogenous H₂ O₂ often cause unsatisfactory therapeutic efficacy. Herein, a GSH-depleting and H₂ O₂ self-providing carrier-free nanomedicine that can efficiently load indocyanine green (ICG), β-lapachone (LAP), and copper ion (Cu²⁺ ) (ICG-Cu²⁺ -LAP, LICN) to mediate synergetic photothermal and chemotherapy in enhanced chemodynamic therapy is designed. The results show that  LICNs successfully enter tumors owing to the enhanced permeability and retention effect. Through the reductive intracellular environment, Cu²⁺ in LICN can react with intracellular GSH, alleviate the antioxidant capacity of tumor tissues, and trigger the release of drugs. When LICN is subjected to near-infrared (NIR) irradiation, enhanced photothermal effect and upregulated expression of NAD(P)H quinone oxidoreductase-1 (NQO1) are observed. Meanwhile, the released LAP not only supports chemotherapy but also catalyzes NQO1 and produces sufficient endogenous H₂ O₂ , thereby increasing the efficiency of Cu⁺ -based Fenton-like reaction. Notably, GSH depletion and H₂ O₂ self-sufficiency generate sufficient •OH and kill tumor cells with high specificity. Overall, the study provides an innovative strategy to self-regulate GSH and H₂ O₂ levels for effective anticancer therapy.

Nanoceria: an innovative strategy for cancer treatment

Nanoceria or cerium oxide nanoparticles characterised by the co-existing of Ce³⁺ and Ce⁴⁺ that allows self-regenerative, redox-responsive dual-catalytic activities, have attracted interest as an innovative approach to treating cancer. Depending on surface characteristics and immediate environment, nanoceria exerts either anti- or pro-oxidative effects which regulate reactive oxygen species (ROS) levels in biological systems. Nanoceria mimics ROS-related enzymes that protect normal cells at physiological pH from oxidative stress and induce ROS production in the slightly acidic tumour microenvironment to trigger cancer cell death. Nanoceria as nanozymes also generates molecular oxygen that relieves tumour hypoxia, leading to tumour cell sensitisation to improve therapeutic outcomes of photodynamic (PDT), photothermal (PTT) and radiation (RT), targeted and chemotherapies. Nanoceria has been engineered as a nanocarrier to improve drug delivery or in combination with other drugs to produce synergistic anti-cancer effects. Despite reported preclinical successes, there are still knowledge gaps arising from the inadequate number of studies reporting findings based on physiologically relevant disease models that accurately represent the complexities of cancer. This review discusses the dual-catalytic activities of nanoceria responding to pH and oxygen tension gradient in tumour microenvironment, highlights the recent nanoceria-based platforms reported to be feasible direct and indirect anti-cancer agents with protective effects on healthy tissues, and finally addresses the challenges in clinical translation of nanoceria based therapeutics.

Hollow Mesoporous CeO2-Based Nanoenzymes Fabrication for Effective Synergistic Eradication of Malignant Breast Cancer via Photothermal–Chemodynamic Therapy

CeO₂-based nanoenzymes present a very promising paradigm in cancerous therapy, as H₂O₂ can be effectively decomposed under the electron transmit between Ce³⁺ and Ce⁴⁺. However, the limitations of endogenous H₂O₂ and intracellular low Fenton-like reaction rate lead to single unsatisfied chemodynamic therapy (CDT) efficacy. Other therapeutic modalities combined with chemodynamic therapy are generally used to enhance the tumor eradiation efficacy. Here, we have synthesized a novel hollow pH-sensitive CeO₂ nanoenzyme after a cavity is loaded with indocyanine green (ICG), as well as with surface modification of tumor targeting peptides, Arg-Gly-Asp (denoted as HCeO₂@ICG-RGD), to successfully target tumor cells via α_vβ₃ recognition. Importantly, in comparison with single chemodynamic therapy, a large amount of reactive oxygen species in cytoplasm were induced by enhanced chemodynamic therapy with photothermal therapy (PTT). Furthermore, tumor cells were efficiently killed by a combination of photothermal and chemodynamic therapy, revealing that synergistic therapy was successfully constructed. This is mainly due to the precise delivery of ICG and release after HCeO₂ decomposition in cytoplasm, in which effective hyperthermia generation was found under 808 nm laser irradiation. Meanwhile, our HCeO₂@ICG-RGD can act as a fluorescent imaging contrast agent for an evaluation of tumor tissue targeting capability in vivo. Finally, we found that almost all tumors in HCeO₂@ICG-RGD+laser groups were completely eradicated in breast cancer bearing mice, further proving the effective synergistic effect in vivo. Therefore, our novel CeO₂-based PTT agents provide a proof-of-concept argumentation of tumor-precise multi-mode therapies in preclinical applications.

Exploring the Antibacterial Properties of Lignin-coated Magnetic Nanoparticles Synthesized in a One-pot Process

Given the current grave problems with antibiotic resistance, the discovery of novel, unconventional antibacterial drugs are not just important, but also urgent. In this contribution, we report on the synthesis and testing of several composite nanomaterials that may find applications as therapeutic drugs or surface disinfectants. These materials are based on magnetic nanostructures coated with lignin, for example, lignin@FeCo. The magnetic properties of these nanocomposites facilitate removal or localization, while the lignin shell provides biocompatibility. These nanomaterials are mild antibacterials in the absence of light, but when illuminated become powerful antibacterial agents with typically ≥6 log units bacterial reduction in 1 to 5 minutes of irradiation. These materials are strongly absorbing, including in the very useful NIR biological window, which we illustrate using 810 nm LED irradiation. We also show that in the short time required for antibacterial action, thermal changes are very small (≤5°C). Further, biocompatibility tests using fibroblasts show very limited cell damage and no enhanced adverse effect during 810 nm NIR illumination. As a surface coating for the active material, lignin provides a "trojan horse" strategy to facilitate the antibacterial action.

Ultra-thin layered double hydroxide-mediated photothermal therapy combine with asynchronous blockade of PD-L1 and NR2F6 inhibit hepatocellular carcinoma

Background

The efficacy of immune checkpoint blockade (ICB), in the treatment of hepatocellular carcinoma (HCC), is limited due to low levels of tumor-infiltrating T lymphocytes and deficient checkpoint blockade in this immunologically "cool" tumor. Thus, combination approaches are needed to increase the response rates of ICB and induce synergistic antitumor immunity.

Methods

Herein, we designed a pH-sensitive multifunctional nanoplatform based on layered double hydroxides (LDHs) loaded with siRNA to block the intracellular immune checkpoint NR2F6, together with the asynchronous blockade surface receptor PD-L1 to induce strong synergistic antitumor immunity. Moreover, photothermal therapy (PTT) generated by LDHs after laser irradiation modified an immunologically “cold” microenvironment to potentiate Nr2f6-siRNA and anti-PD-L1 immunotherapy. Flow cytometry was performed to assess the immune responses initiated by the multifunctional nanoplatform.

Results

Under the slightly acidic tumor extracellular environment, PEG detached and the re-exposed positively charged LDHs enhanced tumor accumulation and cell uptake. The accumulated siRNA suppressed the signal of dual protumor activity in both immune and H22 tumor cells by silencing the NR2F6 gene, which further reduced the tumor burden and enhanced systemic antitumor immunity. The responses include enhanced tumor infiltration by CD4⁺ helper T cells, CD8⁺ cytotoxic T cells, and mature dendritic cells; the significantly decreased level of immune suppressed regulator T cells. The therapeutic responses were also attributed to the production of IL-2, IFN-γ, and TNF-α. The prepared nanoparticles also exhibited potential magnetic resonance imaging (MRI) ability, which could serve to guide synergistic immunotherapy treatment.

Conclusions

In summary, the three combinations of PTT, NR2F6 gene ablation and anti-PD-L1 can promote a synergistic immune response to inhibit the progression of primary HCC tumors and prevent metastasis. This study can be considered a proof-of-concept for the targeting of surface and intracellular immune checkpoints to supplement the existing HCC immunotherapy treatments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01565-9.

A superlattice composite of Zn-Fe layered double hydroxide and graphene oxide for antitumor application

A superlattice composite of Zn-Fe layered double hydroxide and graphene oxide was fabricated on the titanium surface and showed lamellar morphology. It was found for the first time that this superlattice composite could inhibit cell adhesion and proliferation, and cause cell death of the cholangiocarcinoma cell line RBE cells in vitro and show tumor inhibition effect in vivo.

Layered double hydroxide-based nanomaterials for biomedical applications

Against the backdrop of increased public health awareness, inorganic nanomaterials have been widely explored as promising nanoagents for various kinds of biomedical applications. Layered double hydroxides (LDHs), with versatile physicochemical advantages including excellent biocompatibility, pH-sensitive biodegradability, highly tunable chemical composition and structure, and ease of composite formation with other materials, have shown great promise in biomedical applications. In this review, we comprehensively summarize the recent advances in LDH-based nanomaterials for biomedical applications. Firstly, the material categories and advantages of LDH-based nanomaterials are discussed. The preparation and surface modification of LDH-based nanomaterials, including pristine LDHs, LDH-based nanocomposites and LDH-derived nanomaterials, are then described. Thereafter, we systematically describe the great potential of LDHs in biomedical applications including drug/gene delivery, bioimaging diagnosis, cancer therapy, biosensing, tissue engineering, and anti-bacteria. Finally, on the basis of the current state of the art, we conclude with insights on the remaining challenges and future prospects in this rapidly emerging field.

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

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

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.

Two-Dimensional Nanomaterial-based catalytic Medicine: Theories, advanced catalyst and system design

Two-dimensional nanomaterial-based catalytic medicines that associate the superiorities of novel catalytic mechanisms with nanotechnology have emerged as absorbing therapeutic strategies for cancer therapy. Catalytic medicines featuring high efficiency and selectivity have been widely used as effective anticancer strategies without applying traditional nonselective and highly toxic chemodrugs. Moreover, two-dimensional nanomaterials are characterized by distinctive physicochemical properties, such as a sizeable bandgap, good conductivity, fast electron transfer and photoelectrochemical activity. The introduction of two-dimensional nanomaterials into catalytic medicine provides a more effective, controllable, and precise antitumor strategy. In this review, different types of two-dimensional nanomaterial-based catalytic nanomedicines are generalized, and their catalytic theories, advanced catalytic pathways and catalytic nanosystem design are also discussed in detail. Notably, future challenges and obstacles in the design and further clinical transformation of two-dimensional nanomaterial-based catalytic nanomedicine are prospected.

Gadolinium Doped Layered Double Hydroxides for Simultaneous Drug Delivery and Magnetic Resonance Imaging

In this study, gadolinium (Gd) doped MgAl layered double hydroxides (LDHs) were synthesized via a ‘bottom-up’ method and fully characterized by X-ray diffraction, infrared spectroscopy and relaxivity measurements. Two cytotoxic agents were then intercalated via ion-exchange. X-ray diffraction patterns exhibit expanded interlayer spacings as a result of successful drug intercalation. Infrared spectra also showed characteristic peaks of the incorporated methotrexate (MTX) or 5-fluorouracil (5-FU). The LDHs were found to be highly stable under physiological conditions, while in acidic conditions a small proportion of Gd was freed into the immersion medium. Dissolution tests revealed that both 5FU and MTX were rapidly released from the LDH carrier. The longitudinal relaxivity of Gd-LDHs remains largely stable during drug release over 24 h, and was higher in acidic environments. Overall, the drug-loaded Gd-LDH systems prepared in this study could serve as pH-sensitive theranostic platforms for MRI-guided anti-cancer therapy.

Chemodynamic Therapy via Fenton and Fenton-Like Nanomaterials: Strategies and Recent Advances

Chemodynamic therapy (CDT), a novel cancer therapeutic strategy defined as the treatment using Fenton or Fenton-like reaction to produce •OH in the tumor region, was first proposed by Bu, Shi, and co-workers in 2016. Recently, with the rapid development of Fenton and Fenton-like nanomaterials, CDT has attracted tremendous attention because of its unique advantages: 1) It is tumor-selective with low side effects; 2) the CDT process does not depend on external field stimulation; 3) it can modulate the hypoxic and immunosuppressive tumor microenvironment; 4) the treatment cost of CDT is low. In addition to the Fe-involved CDT strategies, the Fenton-like reaction-mediated CDT strategies have also been proposed, which are based on many other metal elements including copper, manganese, cobalt, titanium, vanadium, palladium, silver, molybdenum, ruthenium, tungsten, cerium, and zinc. Moreover, CDT has been combined with other therapies like chemotherapy, radiotherapy, phototherapy, sonodynamic therapy, and immunotherapy for achieving enhanced anticancer effects. Besides, there have also been studies that extend the application of CDT to the antibacterial field. This review introduces the latest advancements in the nanomaterials-involved CDT from 2018 to the present and proposes the current limitations as well as future research directions in the related field.

Magnetic mediators for ultrasound theranostics

The theranostics paradigm is based on the concept of combining therapeutic and diagnostic modalities into one platform to improve the effectiveness of treatment. Combinations of multiple modalities provide numerous medical advantages and are enabled by nano- and micron-sized mediators. Here we review recent advancements in the field of ultrasound theranostics and the use of magnetic materials as mediators. Several subdisciplines are described in detail, including controlled drug delivery and release, ultrasound hyperthermia, magneto-ultrasonic heating, sonodynamic therapy, magnetoacoustic imaging, ultrasonic wave generation by magnetic fields, and ultrasound tomography. The continuous progress and improvement in theranostic materials, methods, and physical computing models have created undeniable possibilities for the development of new approaches. We discuss the prospects of ultrasound theranostics and possible expansions of other studies to the theranostic context.

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.

Hierarchical Two-Dimensional Layered Double Hydroxide Coated Polydopamine Nanocarriers for Combined Chemodynamic and Photothermal Tumor Therapy

The combination of chemodynamic therapy (CDT) and photothermal therapy (PTT) has proven to be successful in combating the challenges associated with cancer therapy. A combination of these therapies can maximize the benefits of each therapeutic modality through endogenous reduction-oxidation (redox) reaction and external laser power induction. In the current work, we have designed a copper-aluminum layered double hydroxide (CuAl-LDH) loaded doxorubicin (DOX) by a co-precipitation method; the surface was coated with polydopamine (PDA). The synthesized CuAl-LDH@DOX@PDA nanocarrier (NC) served as a Fenton-like catalyst with photothermal properties. It is well known that metal ion incorporated NCs can induce intracellular depletion of reduced glutathione (GSH) levels along with the reduction of Cu2+ to Cu+. The Cu+ ions in turn react with DOX leading to the generation of intracellular hydrogen peroxide (H2O2) molecules to produce the highly toxic hydroxyl radicals (•OH) through a Fenton-like reaction. The enhanced absorption of CuAl@DOX@PDA at 810 nm, greatly improved the photothermal efficiency in comparison with bare CuAl-LDH and CuAl-LDH@DOX. In vitro studies revealed the tremendous CDT/PTT efficacy of CuAl@DOX@PDA in suppressing A549 cancer cells. Furthermore, reactive oxygen species (ROS) assays and intracellular levels of various ROS cascade biomolecules support our findings in the efficient destruction of cancer cells through synergistic CDT/PTT therapy.

Ferrous ions doped layered double hydroxide: smart 2D nanotheranostic platform with imaging-guided synergistic chemo/photothermal therapy for breast cancer

Developing simple and efficient nanotheranostic platforms with behavior responsive to the acid microenvironment of a tumor is of great significance for accurate tumor diagnosis and therapy. In this study, a smart 2D nanotheranostic platform has been successfully fabricated by doping functional ferrous ions into as-synthesized MgAl-layered double hydroxide (LDH) with doxurubicin (DOX) loading to form Fe-LDH/DOX NPs, which achieved magnetic resonance imaging (MRI)-guided synergistic chemo/photothermal therapy for breast cancer. The doping of ferrous ions into Fe-LDH/DOX enabled a strong photo-induced heating ability with a high photothermal conversion efficiency of 45.67%, which could be combined with the antitumor drug DOX to achieve the synergistic effect of photothermal therapy (PTT) and chemotherapy for killing tumor cells. Additionally, its in vitro pH-dependent degradation behavior and T₂-weighted MRI effect revealed that the as-prepared Fe-LDH/DOX is sensitive to the tumor acid microenvironment. Most importantly, the growth rate of tumors in 4T1 bearing mice could be effectively inhibited after the synergistic treatment of PTT and chemotherapy by Fe-LDH/DOX. These results show that doping functional metal ions into LDH NPs may open a novel approach to fabricating an LDH NP-based nanotheranostics platform with advanced diagnostic and therapeutic performances.

Emerging indocyanine green-integrated nanocarriers for multimodal cancer therapy: a review

Nanotechnology is a branch of science dealing with the development of new types of nanomaterials by several methods. In the biomedical field, nanotechnology is widely used in the form of nanotherapeutics. Therefore, the current biomedical research pays much attention to nanotechnology for the development of efficient cancer treatment. Indocyanine green (ICG) is a near-infrared tricarbocyanine dye approved by the Food and Drug Administration (FDA) for human clinical use. ICG is a biologically safe photosensitizer and it can kill tumor cells by producing singlet oxygen species and photothermal heat upon NIR irradiation. ICG has some limitations such as easy aggregation, rapid aqueous degradation, and a short half-life. To address these limitations, ICG is further formulated with nanoparticles. Therefore, ICG is integrated with organic nanomaterials (polymers, micelles, liposomes, dendrimers and protein), inorganic nanomaterials (magnetic, gold, mesoporous, calcium, and LDH based), and hybrid nanomaterials. The combination of ICG with nanomaterials provides highly efficient therapeutic effects. Nowadays, ICG is used for various biomedical applications, especially in cancer therapeutics. In this review, we mainly focus on ICG-based combined cancer nanotherapeutics for advanced cancer treatment.