Recent Advances on NIR-II Light-Enhanced Chemodynamic Therapy

Chemodynamic therapy (CDT) is a particular oncological therapeutic strategy by generates the highly toxic hydroxyl radical (•OH) from the dismutation of endogenous hydrogen peroxide (H2O2) via Fenton or Fenton-like reactions. However, single CDT therapies have been limited by unsatisfactory efficacy. Enhanced chemodynamic therapy (ECDT) triggered by near-infrared (NIR) is a novel therapeutic modality based on light energy to improve the efficiency of Fenton or Fenton-like reactions. However, the limited penetration and imaging capability of the visible (400-650 nm) and traditional NIR-I region (650-900 nm) light-amplified CDT restrict the prospects for its clinical application. Combined with the high penetration/high precision imaging characteristics of the second near-infrared (NIR-II,) nanoplatform, it is expected to kill deep tumors efficiently while imaging the treatment process in real-time, and more notably, the NIR-II region radiation with wavelengths above 1000 nm can minimize the irradiation damage to normal tissues. Such NIR-II ECDT nanoplatforms have greatly improved the effectiveness of CDT therapy and demonstrated extraordinary potential for clinical applications. Accordingly, various strategies have been explored in the past years to improve the efficiency of NIR-II Enhanced CDT. In this review, the mechanisms and strategies used to improve the performance of NIR-II-enhanced CDT are outlined.

Monophenylboryl aza-BODIPY with free rotation of the B-phenyl group for enhanced photothermal conversion

Owing to the efficient non-radiative relaxation by the free rotation of the B-phenyl moiety, monophenyl substituted aza-BODIPY on the boron centre with near-infrared absorption has high photothermal conversion efficiency, which is highly desirable for a photothermal therapy agent.

All-in-one HN@Cu-MOF nanoparticles with enhanced reactive oxygen species generation and GSH depletion for effective tumor treatment

Non-invasive cancer therapies, especially those based on reactive oxygen species, including photodynamic therapy (PDT), have gained much interest. As emerging photodynamic nanocarriers, metal-organic frameworks (MOFs) based on porphyrin can release reactive oxygen species (ROS) to destroy cancer cells. However, due to the inefficient production of ROS by photosensitizers and the over-expression of glutathione (GSH) in the tumor microenvironment (TME), their therapeutic effect is not satisfactory. Therefore, herein, we developed a multi-functional nanoparticle, HN@Cu-MOF, to enhance the efficacy of PDT. We combined chemical dynamic therapy (CDT) and nitric oxide (NO) therapy by initiating sensitization to PDT and cell apoptosis in the treatment of tumors. The Cu2+-doped MOF reacted with GSH to form Cu+, exhibiting a strong CDT ability to generate hydroxyl radicals (˙OH). The Cu-MOF was coated with HN, which is hyaluronic acid (HA) modified by a nitric oxide donor. HN can target tumor cells over-expressing the CD44 receptor and consume GSH in the cells to release NO. Both cell experiments and in vivo experiments showed an excellent tumor inhibitory effect upon the treatment. Overall, the HN@Cu-MOF nanoparticle-integrated NO gas therapy and CDT with PDT led to a significant enhancement in GSH consumption and a remarkable elevation in ROS production.

The construction of hierarchical assemblies with in situ generation of chemotherapy drugs to enhance the efficacy of chemodynamic therapy for multi-modal anti-tumor treatments

The effectiveness of chemodynamic therapy (CDT) in cancer treatment is limited by insufficient endogenous H2O2 levels in tumor tissue and an increasing ratio of high valence metal ions. To overcome these challenges, a novel nanotherapeutic approach, named GOx-CuCaP-DSF, has been proposed. This approach involves the design of nanotherapeutics that aim to self-supply H2O2 within cancer cells and provide a supplement of low valence metal ions to enhance the performance of CDT. GOx-CuCaP-DSF nanotherapeutics are engineered by incorporating glucose oxidase (GOx) into Ca2+-doped calcium phosphate (CaP) nanoparticles and loading disulfiram (DSF) through surface adsorption. Under the tumor microenvironment, GOx catalyzes the conversion of tumor-overexpressed glucose (Glu) to liberate H2O2. The degradation of CaP further lowers the pH, facilitating the release of Cu2+ ions and DSF. The rapid reaction between Cu2+ and DSF leads to the generation of Cu+, increasing the Cu+/Cu2+ ratio and promoting the Cu+-based Fenton reaction, which enhances the efficiency of CDT. Simultaneously, DSF undergoes conversion to diethyldithiocarbamate acid (ET), forming a copper(II) complex (Cu(II)ET) by strong chelation with Cu ions. This Cu(II)ET complex, a potent chemotherapeutic drug, exhibits a synergistic therapeutic effect in combination with CDT. Moreover, the elevated Cu+ species resulting from DSF reaction promotes the aggregation of toxic mitochondrial proteins, leading to cell cuproptosis. Overall, the strategy of integrating the chemodynamic therapy efficiency of the Fenton reaction with the activation of efficacious cuproptosis using a chemotherapeutic drug presents a promising avenue for enhancing the effectiveness of multi-modal anti-tumor treatments.

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.

pH-Activatable copper-axitinib coordinated multifunctional nanoparticles for synergistic chemo-chemodynamic therapy against aggressive cancers

Chemodynamic therapy (CDT) is an emerging oncological treatment that eliminates tumor cells by generating lethal hydroxyl radicals (˙OH) through Fenton or Fenton-like reactions within tumors. However, the effectiveness of CDT is limited by the overexpression of glutathione (GSH) and low reaction efficiency in the tumor microenvironment (TME). To address these challenges and enhance tumor treatment, we developed a novel pH-activatable metal ion-drug coordinated nanoparticle (Cu-AXB NPs) system, incorporating a CDT agent (Cu2+) and a chemotherapeutic agent (axitinib, AXB). The obtained Cu-AXB NPs exhibited exceptional characteristics, including ultrahigh drug loading capacity (87.55%) and an average size of 180 nm. These nanoparticles also demonstrated excellent plasma stability and pH-responsive drug release, enabling prolonged circulation in the bloodstream and targeted therapy at weakly acidic tumor sites. Upon release, AXB acted as a chemotherapeutic agent, effectively eliminating tumor cells, while Cu2+ ions were reduced to Cu+ by GSH, further generating toxic ˙OH with hydrogen peroxide (H2O2) for CDT through a Fenton-like reaction. Additionally, the Cu-AXB NPs efficiently disrupted the copper metabolic balance and increased the intracellular Cu content, further amplifying the therapeutic impact of CDT. In vitro studies assessing cytotoxicity and apoptosis confirmed the superior tumor cell-killing efficacy of the Cu-AXB NPs. This enhanced efficacy can be attributed to the synergistic effect of CDT and chemotherapy. Moreover, the Cu-AXB NPs exhibited excellent tumor targeting capabilities, resulting in significant tumor inhibition (77.53% inhibition) while maintaining favorable biocompatibility in tumor-bearing mice. In conclusion, this study presents a promising and safe strategy for cancer therapy by combining CDT with chemotherapy, offering a potential breakthrough in the field of oncology.

BODIPY as a Multifunctional Theranostic Reagent in Biomedicine: Self-Assembly, Properties, and Applications

The use of boron dipyrromethene (BODIPY) in biomedicine is reviewed. To open, its synthesis and regulatory strategies are summarized, and inspiring cutting-edge work in post-functionalization strategies is highlighted. A brief overview of assembly model of BODIPY is then provided: BODIPY is introduced as a promising building block for the formation of single- and multicomponent self-assembled systems, including nanostructures suitable for aqueous environments, thereby showing the great development potential of supramolecular assembly in biomedicine applications. The frontier progress of BODIPY in biomedical application is thereafter described, supported by examples of the frontiers of biomedical applications of BODIPY-containing smart materials: it mainly involves the application of materials based on BODIPY building blocks and their assemblies in fluorescence bioimaging, photoacoustic imaging, disease treatment including photodynamic therapy, photothermal therapy, and immunotherapy. Lastly, not only the current status of the BODIPY family in the biomedical field but also the challenges worth considering are summarized. At the same time, insights into the future development prospects of biomedically applicable BODIPY are provided.

Tracking tumor heterogeneity and progression with near-infrared II fluorophores

Heterogeneous cells are the main feature of tumors with unique genetic and phenotypic characteristics, which can stimulate differentially the progression, metastasis, and drug resistance. Importantly, heterogeneity is pervasive in human malignant tumors, and identification of the degree of tumor heterogeneity in individual tumors and progression is a critical task for tumor treatment. However, current medical tests cannot meet these needs; in particular, the need for noninvasive visualization of single-cell heterogeneity. Near-infrared II (NIR-II, 1000-1700 nm) imaging exhibits an exciting prospect for non-invasive monitoring due to the high temporal-spatial resolution. More importantly, NIR-II imaging displays more extended tissue penetration depths and reduced tissue backgrounds because of the significantly lower photon scattering and tissue autofluorescence than traditional the near-infrared I (NIR-I) imaging. In this review, we summarize systematically the advances made in NIR-II in tumor imaging, especially in the detection of tumor heterogeneity and progression as well as in tumor treatment. As a non-invasive visual inspection modality, NIR-II imaging shows promising prospects for understanding the differences in tumor heterogeneity and progression and is envisioned to have the potential to be used clinically.

Stimuli-Responsive Boron-Based Materials in Drug Delivery

Drug delivery systems, which use components at the nanoscale level as diagnostic tools or to release therapeutic drugs to particular target areas in a regulated manner, are a fast-evolving field of science. The active pharmaceutical substance can be released via the drug delivery system to produce the desired therapeutic effect. The poor bioavailability and irregular plasma drug levels of conventional drug delivery systems (tablets, capsules, syrups, etc.) prevent them from achieving sustained delivery. The entire therapy process may be ineffective without a reliable delivery system. To achieve optimal safety and effectiveness, the drug must also be administered at a precision-controlled rate and the targeted spot. The issues with traditional drug delivery are overcome by the development of stimuli-responsive controlled drug release. Over the past decades, regulated drug delivery has evolved considerably, progressing from large- and nanoscale to smart-controlled drug delivery for several diseases. The current review provides an updated overview of recent developments in the field of stimuli-responsive boron-based materials in drug delivery for various diseases. Boron-containing compounds such as boron nitride, boronic acid, and boron dipyrromethene have been developed as a moving field of research in drug delivery. Due to their ability to achieve precise control over drug release through the response to particular stimuli (pH, light, glutathione, glucose or temperature), stimuli-responsive nanoscale drug delivery systems are attracting a lot of attention. The potential of developing their capabilities to a wide range of nanoscale systems, such as nanoparticles, nanosheets/nanospheres, nanotubes, nanocarriers, microneedles, nanocapsules, hydrogel, nanoassembly, etc., is also addressed and examined. This review also provides overall design principles to include stimuli-responsive boron nanomaterial-based drug delivery systems, which might inspire new concepts and applications.

Injectable Tissue-Adhesive Hydrogel for Photothermal/Chemodynamic Synergistic Antibacterial and Wound Healing Promotion

It is an exigent need for the development of hydrogel dressings with desirable injectability, good adhesive, antibacterial, and wound healing promotion properties. Herein, the multifunctional injectable hydrogels with good tissue adhesion are designed based on Ag-doped Mo₂C-derived polyoxometalate (AgPOM) nanoparticles, urea, gelatin, and tea polyphenols (TPs) for antibacterial and wound healing acceleration. After being injected into the tissue, urea diffuses out under the concentration gradient, and TPs and gelatin chains recombine to trigger the in situ formation of hydrogel with excellent adhesiveness. AgPOM fixed in the hydrogel could not only react with hydrogen peroxide in the infection site to generate singlet oxygen to kill the bacteria but also convert near-infrared light into heat under 1060 nm laser irradiation to realize sterilization. In vitro studies display the high bactericidal ability of the hydrogel against drug-resistant Staphylococcus aureus and also exhibit a prominent therapeutic effect on infected wounds through synergistic photothermal/chemodynamic therapy and accelerate wound healing. Hence, the injectable hydrogel with AgPOM as the antimicrobial agent can be a novel therapeutic agent for drug-resistant bacteria-infected wounds and wound healing promotion.

Recent advances in small molecule dye-based nanotheranostics for NIR-II photoacoustic imaging-guided cancer therapy

Photoacoustic (PA) imaging in the second near-infrared (NIR-II) window has gained more and more attention in recent years and showed great potential in the field of bioimaging. Until now, numerous materials have been developed as contrast agents for NIR-II PA imaging. Among them, small molecule dyes hold unique advantages such as definite structures and capability of fast clearance from body. By virtue of these advantages, small molecule dyes-constructed nanoparticles have relatively small size and show promise in the clinical translation. Thus, in this minireview, we summarize recent advances in small molecule dyes-based nanotheranostics for NIR-II PA imaging and cancer therapy. Studies about NIR-II PA imaging-guided phototherapy are first introduced. Then, NIR-II PA imaging-guided phototherapy-based combination therapeutic systems are reviewed. Finally, the conclusion and perspectives of this field are summarized and discussed.

Hyaluronic Acid-Enwrapped Polyoxometalate Complex for Synergistic Near Infrared-II Photothermal/Chemo-Therapy and Chemodynamic Therapy

To enhance the efficacy of tumor therapy, the collection of functional components into a targeting system shows advantages over most homogeneous materials in inducing apoptosis of cancer cells. The security and targeting of therapeutic agents also require the effect combination of additional components. However, the construction of multifunctional composites in a simple system with intelligent cooperative responsiveness remains a challenge. Herein, a reduced polyanionic cluster (rP₂W₁₈) bearing the absorption at the near infrared (NIR) II region is used as a core carrier to bind the positively charged doxorubicin hydrochloride (DOX) through ionic interaction. To reduce the physiological toxicity, hyaluronic acid grafting β-cyclodextrin side chains is used to cover the ionic complex through host-guest inclusion to DOX. When the nanocomposite is activated by local laser exposure, the final three-component therapeutic agent is demonstrated to present targeted photothermal conversion capability and chemodynamic activity together with chemotherapy. With the controlled release of DOX under the stimulation of mild acidity in the tumor region and photothermal effect, the exposed rP₂W₁₈ is aroused by hydrogen peroxide overexpressed in a tumor microenvironment to produce toxic reactive oxygen species, ¹O₂. This work presents an opportunity for the development of a nanocomposite in NIR-II photothermal/chemo-therapy and chemodynamic synergistic therapy.

TME-triggered MnSiO3@Met@GOx nanosystem for ATP dual-inhibited starvation/chemodynamic synergistic therapy

Adenosine triphosphate (ATP) is an essential substance for maintaining tumor cell survival and proliferation. Inhibiting the ATP-producing pathways has emerged as a promising cancer treatment strategy. However, the antitumor efficiency of ATP inhibitors is compromised by the inter-compensation of multiple ATP-producing pathways in tumor cells and biological barriers in the complex tumor microenvironment (TME). Herein, we developed metformin (Met) and glucose oxidase (GOx) co-loaded manganese silicon nanoplatform MnSiO3@Met@GOx (MMG) for TME-responsive ATP dual inhibited starvation/chemodynamic synergistic therapy. Under the mildly acidic conditions in TME, MMG was decomposed, releasing Met and GOx for effective ATP suppression by inhibiting oxidative phosphorylation (OXPHOS) and aerobic glycolysis pathways, respectively. Meanwhile, GOx-catalyzed glucose oxidation increased tumor acidity and hydrogen peroxide (H2O2) concentration in tumors, which not only accelerated MMG decomposition and drug release but also promoted manganese ions-mediated Fenton-like reaction. In vitro and in vivo experiments further demonstrated the effectiveness and biosafety of MMG-based synergistic therapy. This study provides a novel strategy for tumor treatment based on tumor metabolism regulation.

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.

Recent Advances in Single Fe-Based Nanoagents for Photothermal-Chemodynamic Cancer Therapy

Monomodal cancer therapies are often unsatisfactory, leading to suboptimal treatment effects that result in either an inability to stop growth and metastasis or prevent relapse. Thus, synergistic strategies that combine different therapeutic modalities to improve performance have become the new research trend. In this regard, the integration of photothermal therapy (PTT) with chemodynamic therapy (CDT), especially PTT/CDT in the second near-infrared (NIR-II) biowindow, has been demonstrated to be a highly efficient and relatively safe concept. With the rapid development of nanotechnology, nanoparticles can be designed from specific elements, such as Fe, that are equipped with both PTT and CDT therapeutic functions. In this review, we provide an update on the recent advances in Fe-based nanoplatforms for combined PTT/CDT. The perspectives on further improvement of the curative efficiency are described, highlighting the important scientific obstacles that require resolution in order to reach greater heights of clinical success. We hope this review will inspire the interest of researchers in developing novel Fe-based nanomedicines for multifunctional theranostics.

One-Step Integration of Tumor Microenvironment-Responsive Calcium and Copper Peroxides Nanocomposite for Enhanced Chemodynamic/Ion-Interference Therapy

Recently, various metal peroxide nanomaterials have drawn increasing attention as an efficient hydrogen peroxide (H₂O₂) self-supplying agent for enhanced tumor therapy. However, a single kind of metal peroxide is insufficient to achieve more effective antitumor performance. Here, a hyaluronic acid modified calcium and copper peroxides nanocomposite has been synthesized by a simple one-step strategy. After effective accumulation at the tumor site due to the enhanced permeability and retention (EPR) effect and specific recognition of hyaluronate acid with CD44 protein on the surface of tumor cells, plenty of Ca²⁺, Cu²⁺, and H₂O₂ can be simultaneously released in acid and hyaluronidase overexpressed tumor microenvironment (TME), generating abundant hydroxyl radical through enhanced Fenton-type reaction between Cu²⁺ and self-supplying H₂O₂ with the assistance of glutathione depletion. Overloaded Ca²⁺ can lead to mitochondria injury and thus enhance the oxidative stress in tumor cells. Moreover, an unbalanced calcium transport channel caused by oxidative stress can further promote tumor calcification and necrosis, which is generally defined as ion-interference therapy. As a result, the synergistic effect of Fenton-like reaction by Cu²⁺ and mitochondria dysfunction by Ca²⁺ in ROS generation is performed. Therefore, a TME-responsive calcium and copper peroxides nanocomposite based on one-step integration has been successfully established and exhibits a more satisfactory antitumor efficiency than any single kind of metal peroxide.

NIR-II Functional Materials for Photoacoustic Theranostics

Photoacoustic imaging (PAI) has attracted great attention in the diagnosis and treatment of diseases due to its noninvasive properties. Especially in the second near-infrared (NIR-II) window, PAI can effectively avoid the interference of tissue spontaneous fluorescence and light scattering, and obtain high resolution images with deeper penetration depth. Because of its ideal spectral absorption and high conversion efficiency, NIR-II PA contrast agents overcome the absorption or emission of NIR-II light by endogenous biomolecules. In recent years, a series of NIR-II PA contrast agents have been developed to improve the performance of PAI in disease diagnosis and treatment. In this paper, the research progress of NIR-II PA contrast agents and their applications in biomedicine are reviewed. PA contrast agents are classified according to their composition, including inorganic contrast agents, organic contrast agents, and hybrid organic-inorganic contrast agents. The applications of NIR-II PA contrast agents in medical imaging are described, such as cancer imaging, inflammation detection, brain disease imaging, blood related disease imaging, and other biomedical application. Finally, the research prospects and breakthrough of NIR-II PA contrast agents are discussed.

An Adenosine Triphosphate-Responsive Metal-Organic Framework Decorated with Palladium Nanosheets for Synergistic Tri-Modal Therapy

A multifunctional nanoplatform is urgently desired for the development of the highly efficient anticancer therapeutic agents. Here, a class of palladium nanosheets (Pd NSs)-laden MIL-101-NH2 (MIL@Pd) nanostructure encapsulated with doxorubicin...

Electron-acceptor density adjustments for preparation conjugated polymers with NIR-II absorption and brighter NIR-II fluorescence and 1064 nm active photothermal/gas therapy

Designing conjugated polymers (CPs) with both efficient second near-infrared wavelength (NIR-II) fluorescence and NIR-II photothermal therapy performance remains a huge challenge, as the introduction of excessively strong electron donor and acceptor units significantly increase non-radiative decay. Herein, we describe an "electron acceptor density adjustment" strategy to address this problem, since a lower electron acceptor density in the conjugated polymer backbone can enhance the radiative rate constant and improve NIR-II fluorescence brightness. We used quaterthiophene (4T) with four repeated thiophene chain units and bithiophene (2 TC) modified with long alkyl side chains to reduce the electron acceptor density in the conjugated polymer backbone. The resultant 1064 nm absorption polymer, TTQ-2TC-4T displayed approximately 7.30-folds enhancement in NIR-II emission intensity compared to that of undoped TTQ-1T at the same mass concentration in toluene solution. Furthermore nanoparticles (TTQ-MnCO NPs) based on TTQ-2TC-4T and CO donors (Mn₂(CO)₁₀) were developed to realize NIR-II FI-guided 1064 nm laser-triggered NIR-II PTT/Gas synergistic therapy. The TTQ-MnCO NPs nanoparticles exhibited high photothermal conversion efficiency (η) of 44.43% at 1064 nm and high specific NIR-II fluorescence imaging of the cerebral vasculature of live mice. The in vivo results demonstrate that TTQ-MnCO NPs nanoparticles have excellent PTT/Gas synergistic therapeutic effects in MCF-7 tumor-bearing mice under 1064 nm laser irradiation. This study provides a new approach for optimizing both NIR-II fluorescence and NIR-II photothermal performance of NIR-II absorption conjugated polymers.

3D Boranil Complexes with Aggregation-Amplified Circularly Polarized Luminescence

The development of small organic CPL-active molecules with large luminescent dissymmetry factors is highly demanded due to their promising applications in chiroptical devices and sensors. This work describes the design and synthesis of a new family of CPL-active BF₂ complexes, (R_p)/(S_p)-3a-3e, which were constructed by fusing a N̂O-chelated BF₂ complex with [2.2]paracyclophane. These complexes display aggregation-amplified CPL with moderate dissymmetry factors values and moderate quantum yields both in solution and in the solid state. In addition, these photophysical properties were rationalized via X-ray diffraction and TD-DFT calculations.

All-in-One Nanomedicine: Multifunctional Single-Component Nanoparticles for Cancer Theranostics

The development of cancer diagnostic imaging and treatment is a major concern worldwide. By integrating imaging and therapy into one theranostic nanoplatform for simultaneously detecting tumors, evaluating the targeting ability and timely monitoring therapeutic responses provide more opportunities for precision medicine. Among various theranostic nanosystems, a series of single-component nanoparticles (NPs) have been developed for "all-in-one" theranostics, which presents the unique properties of facile preparation, simple composition, defined structure, high reproducibility, and excellent biocompatibility. Specifically, utilizing single-component NPs for both diagnostics and therapeutics can reduce the possible numerous untoward side effects and risks to the living body. In this review, the recent progress of multifunctional single-component NPs in the applications of cancer theranostics is systematically summarized. Notably, the structure design, categories of NPs, targeted strategies, biomedical applications, potential barriers, challenges, and prospects for the future clinical practice of this rapidly growing field are discussed.

Ferroptosis in cancer therapeutics: a materials chemistry perspective

Ferroptosis, distinct from apoptosis, is a regulated form of cell death caused by lipid peroxidation that has attracted extensive research interest since it was first defined in 2012. Over the past five years, an increasing number of studies have revealed the close relationship between ferroptosis and materials chemistry, in particular nanobiotechnology, and have concluded that nanotechnology-triggered ferroptosis is an efficient and promising antitumor strategy that provides an alternative therapeutic approach, especially for apoptosis-resistant tumors. In this review, we summarize recent advances in ferroptosis-induced tumor therapy at the intersection of materials chemistry, redox biology, and tumor biology. The biological features and molecular mechanisms of ferroptosis are first outlined, followed by a summary of the feasible strategies to induce ferroptosis using nanomaterials and the applications of ferroptosis in combined tumor therapy. Finally, the existing challenges and future development directions in this emerging field are discussed, with the aim of promoting the progress of ferroptosis-based oncotherapy in materials science and nanoscience and enriching the antitumor arsenal.

NIR-II Organic Nanotheranostics for Precision Oncotherapy

Precision oncotherapy can remove tumors without causing any apparent iatrogenic damage or irreversible side effects to normal tissues. Second near-infrared (NIR-II) nanotheranostics can simultaneously perform diagnostic and therapeutic modalities in a single nanoplatform, which exhibits prominent perspectives in tumor precision treatment. Among all NIR-II nanotheranostics, NIR-II organic nanotheranostics have shown an exceptional promise for translation in clinical tumor treatment than NIR-II inorganic nanotheranostics in virtue of their good biocompatibility, excellent reproducibility, desirable excretion, and high biosafety. In this review, recent progress of NIR-II organic nanotheranostics with the integration of tumor diagnosis and therapy is systematically summarized, focusing on the theranostic modes and performances. Furthermore, the current status quo, problems, and challenges are discussed, aiming to provide a certain guiding significance for the future development of NIR-II organic nanotheranostics for precision oncotherapy.

Structural effect of NIR-II absorbing charge transfer complexes and its application on cysteine-depletion mediated ferroptosis and phototherapy

Second near-infrared (NIR-II) absorbing organic photothermal agents (PTAs) usually suffer from laborious and time-consuming synthesis; therefore, it is of importance to develop a simple and easy-to-handle method for the preparation of NIR-II PTAs. Charge-transfer complexes (CTCs) can be easily used to construct NIR-II absorbing PTAs, although the relationship between their molecular structure and photophysical properties is yet to be uncovered. Herein, three kinds of electron donors with different substitutions (chloroethyl, ethyl, and methyl) were synthesized and assembled with electron-deficient F4TCNQ to afford corresponding CTC nanoparticles (Cl-F4, Et-F4, and Me-F4 NPs). The large energy gap (>0.61 eV) between HOMO of the donor and LUMO of the acceptor made the CTCs exhibit high charge transfer (>0.93) and dramatic differences in photophysical properties. Additionally, Et-F4 NPs possess the highest NIR-II absorption ability and best photothermal effect because of different packing modes (mass extinction coefficient of 11.0 L g^-1 cm^-1 and photothermal conversion efficiency of 40.2% at 1060 nm). The mixed stacking mode formed strong charge-transfer absorption bands, indicating that the photophysical properties of CTCs can be tailored by changing the molecular structure and aggregate behaviors. Furthermore, Et-F4 NPs with cyano groups could specifically react with cysteine to block the intracellular biosynthesis of GSH and result in ROS accumulation and ferroptosis. Et-F4 NPs possess outstanding antitumor efficacy for the combined actions of NIR-II triggered photothermal killing effect and ferroptosis in vivo.

Thienylpiperidine Donor NIR Xanthene-Based Dye for Photoacoustic Imaging

Few xanthene-based near-infrared (NIR) photoacoustic (PA) dyes with absorbance >800 nm exist. As accessibility to these dyes requires long and tedious synthetic steps, we designed a NIR dye (XanthCR-880) with thienylpiperidine donors and a xanthene acceptor that is accessible in 3-4 synthetic steps. The dye boasts a strong PA signal at 880 nm with good biological compatibility and photostability, yields multiplexed imaging with an aza-BODIPY reference dye, and is detected at a depth of 4 cm.

The tumor phototherapeutic application of nanoparticles constructed by the relationship between PTT/PDT efficiency and 2,6- and 3,5-substituted BODIPY derivatives

BODIPY dyes have recently been used for photothermal and photodynamic therapy of tumors. However, complex multi-material systems, multiple excitation wavelengths and the unclear relationship between BODIPY structures and their PTT/PDT efficiency are still major issues. In our study, nine novel BODIPY near-infrared dyes were designed and successfully synthesized and then, the relationships between BODIPY structures and their PTT/PDT efficiency were investigated in detail. The results showed that modifications at position 3,5 of the BODIPY core with conjugated structures have better effects on photothermal and photodynamic efficiency than the modifications at position 2,6 with halogen atoms. Density functional theory (DFT) calculations showed that this is mainly due to the extension of the conjugated chain and the photoinduced electron transfer (PET) effect. By encapsulating BDPX-M with amphiphilic DSPE-PEG₂₀₀₀-RGD and lecithin, the obtained NPs not only show good water solubility and biological stability, but also could act as superior agents for photothermal and photodynamic synergistic therapy of tumors. Finally, we obtained BODIPY NPs that exhibited excellent photothermal and photodynamic effects at the same time under single irradiation with an 808 nm laser (photothermal conversion efficiency: 42.76%, A/A₀: ∼0.05). In conclusion, this work provides a direction to design and construct phototherapeutic nanoparticles based on BODIPY dyes for tumor treatment.

Leveraging BODIPY nanomaterials for enhanced tumor photothermal therapy

In the past ten years, photothermal therapy (PTT) has attracted widespread attention in tumor treatment due to its non-invasiveness and little side effects. PTT utilizes heat produced by photothermal agents under the irradiation of near-infrared light to kill tumor cells. Boron-dipyrromethene (BODIPY), an organic phototherapy agent, has been widely used in tumor phototherapy due to its higher molar extinction coefficient, robust photostability and good phototherapy effect. However, there are some issues in the application of BODIPY for tumor PTT, such as low photothermal conversion efficiency and short absorption wavelength. In this review, we focus on the latest development of BODIPY nanomaterials for overcoming the above problems and enhancing the PTT effect.

Stimuli-activated molecular photothermal agents for cancer therapy

Taking advantage of activatable and imaging-guided properties, stimuli-activated molecular photothermal agents (MPTAs) have drawn great attention in photothermal therapy (PTT) over the past decades. In this review, the recent progress in the study of stimuli-activated MPTAs is summarized from different stimuli, including pH, bioactive small molecules, and enzymes. The features and challenges of stimuli-activated MPTAs are also discussed. This review aims to motivate readers to design and synthesise more efficient MPTAs.

Recent development of near-infrared photoacoustic probes based on small-molecule organic dye

Photoacoustic imaging (PAI), which integrates the higher spatial resolution of optical imaging and the deeper penetration depth of ultrasound imaging, has attracted great attention. Various photoacoustic probes including inorganic and organic agents have been well fabricated in last decades. Among them, small-molecule based agents are most promising candidates for preclinical/clinical applications due to their favorite in vivo features and facile functionalization. In recent years, PAI, in the near-infrared region (NIR, 700-1700 nm) has developed rapidly and has made remarkable achievements in the biomedical field. Compared with the visible light region (400-700 nm), it can significantly reduce light scattering and meanwhile provide deeper tissue penetration. In this review, we discuss the recent developments of near-infrared photoacoustic probes based on small molecule dyes, which focus on their "always on" and "activatable" form in biomedicine. Further, we also suggest current challenges and perspectives.

CuWO4 Nanodots for NIR-Induced Photodynamic and Chemodynamic Synergistic Therapy

Dynamic therapy, such as photodynamic therapy (PDT) or chemodynamic therapy (CDT), is one of the most promising therapeutic strategies for tumors. Integrating the advantages of near-infrared-induced PDT and CDT can potentially improve the therapeutic performance. A single primitive nanostructure, CuWO₄ nanodots, was developed. It could generate reactive oxygen species under 808 nm light irradiation and release copper ions into the acid tumor microenvironment, thereby boosting Fenton-like reactions. The PDT and CDT would occur when the nanodots were introduced into the tumor tissue and irradiated under 808 nm light. The results of combined PDT and CDT antitumor studies showed the effective inhibition of tumor tissue growth, thereby suggesting that the nanodots are candidate agents for synergistic antitumor applications.

Facile synthesis of Fe-baicalein nanoparticles for photothermal/chemodynamic therapy with accelerated FeIII/FeII conversion

Fe²⁺-baicalein-polyethylene glycol (Fe-BaP) nanoparticles were synthesized by a room temperature wet chemical method via coordination between Fe²⁺ and baicalein. Fe-BaP possessed high photothermal conversion efficiency (η = 45.6%) and excellent antitumor efficacy was achieved with the synergistic photothermal/chemodynamic tumor therapy.

Characterization of Triphenylamine and Ferrocenyl Donor-π-Donor Vinyl BODIPY Derivatives as Photoacoustic Contrast Agents†

The photophysical and electrochemical properties for a series of BODIPY dyes with incremental 3- and 3,5-vinyl conjugation, as well as incremental electron-donating groups (anisole < triphenylamine < ferrocenyl), are presented. Insight into the influence of each vinyl-conjugated electron-donating group on both vis-NIR absorption and fluorescence emission properties is provided. These trends are further corroborated by density functional theory computational analysis. Two of this series containing the 3,5-bis(vinyltriphenylamine) and 3,5-bis(vinylferrocenyl) substituents exhibit significant absorption cross sections in the biological transparency window justifying further investigation of their photoacoustic emission properties via both optical photoacoustic z-scan and photoacoustic tomography experiments. Both the 3,5-bis(vinyltriphenylamine) and 3,5-bis(vinylferrocenyl) substituted BODIPY dyes exhibit quantitative photoacoustic quantum yields. Relative to the commercially available methylene blue and indocyanine green molecular photoacoustic contrast agents, the 3,5-bis(vinyltriphenylamine)-derived BODIPY exhibits the greatest photoacoustic emission and contrast upon excited-state absorption at 685 nm excitation at a low power laser fluence (<20 mJ cm^-2 ).

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.

Recent advances in pH-responsive nanomaterials for anti-infective therapy

The design and synthesis of pH-responsive antibacterial nanomaterials and their applications in anti-infective therapy.

An acidity-responsive polyoxometalate with inflammatory retention for NIR-II photothermal-enhanced chemodynamic antibacterial therapy

W/Mo-based polyoxometalate was developed for local photothermal-enhanced chemodynamic antibacterial therapy in the second near-infrared region.