Synthesis of BSA-Coated BiOI@Bi2 S3 Semiconductor Heterojunction Nanoparticles and Their Applications for Radio/Photodynamic/Photothermal Synergistic Therapy of Tumor

Orthogonally conjugated phthalocyanine-porphyrin oligomer for NIR photothermal-photodynamic antibacterial treatment

With the increase of antibiotic resistance worldwide, there is an urgent demand to develop new fungicides and approaches to address the threat to human health posed by the ineffectiveness of traditional antibiotics. In this work, an orthogonal conjugated uniform oligomer bactericide of SiPc-ddCPP was constructed between silicon phthalocyanine and porphyrin, which can effectively treat infection through photodynamic-photothermal combined therapy without considering drug resistance. Compared with organic photothermal agents induced by unstable H-aggregation with blue-shifted absorption and fluorescence/ROS quenching, this orthogonal-structured uniform SiPc-ddCPP nanoparticle shows remarkably stability and NIR photothermal effect (η = 31.15%) along with fluorescence and ROS generation. Antibacterial studies have shown that both Gram-positive and Gram-negative bacteria could be efficiently annihilated in a few minutes through synergistic PDT-PTT along with satisfactory bacterial targeting. These results suggest SiPc-ddCPP is a multifunctional NIR bactericide, which afford a new approach of synergistic PDT-PTT sterilization to conquer the crisis of antibiotic resistance.

Strong interaction between plasmon and topological surface state in Bi2Se3/Cu2-xS nanowires for solar-driven photothermal applications

Developing high-performance photothermal materials and unraveling the underlying mechanism are essential for photothermal applications. Here, photothermal performance improved by strong interaction between plasmon and topological surface state (TSS) is demonstrated in Bi2Se3/Cu2-xS nanowires. This hybrid, which Cu2-xS nanosheets were grown on Bi2Se3 nanowires, leverages the plasmon resonance and TSS-induced optical property, generating wide and efficient light absorption. A series of tests reveals the strong resonance coupling, TSS-induced hot electron injection, and plasmon-induced hot hole relaxation within the hybrids, endowing the Bi2Se3/Cu2-xS with excellent photothermal performance. By integrating the hybrids into a hydrogel with a thermoelectric module, the Bi2Se3/Cu2-xS evaporator achieves a remarkable water evaporation rate of 3.67 kilograms per square meter per hour with a solar-to-vapor efficiency of 95.2%, and a maximum output power of 1.078 watts per square meter under simulated sunlight irradiation. Moreover, a conical mirror was introduced to the device, which greatly enhances the evaporation rate and maximum output power without additional energy input.

Metal-Protein Hybrid Materials: Unlocking New Frontiers in Biomedical Applications

Metal-protein hybrid materials represent a novel class of functional materials that exhibit exceptional physicochemical properties and tunable structures, rendering them remarkable applications in diverse fields, including materials engineering, biocatalysis, biosensing, and biomedicine. The design and development of multifunctional and biocompatible metal-protein hybrid materials have been the subject of extensive research and a key aspiration for practical applications in clinical settings. This review provides a comprehensive analysis of the design strategies, intrinsic properties, and biomedical applications of these hybrid materials, with a specific emphasis on their potential in cancer therapy, drug and vaccine delivery, antibacterial treatments, and tissue regeneration. Through rational design, stable metal-protein hybrid materials can be synthesized using straightforward methods, enabling them with therapeutic, delivery, immunomodulatory, and other desired functionalities. Finally, the review outlines the existing limitations and challenges associated with metal-protein hybrid materials and evaluates their potential for clinical translation, providing insights into their practical implementation within biomedical applications.

One-Pot Synthesis of Oxygen Vacancy-Rich Amorphous/Crystalline Heterophase CaWO4 Nanoparticles for Enhanced Radiodynamic-Immunotherapy

Radiodynamic therapy that employs X-rays to trigger localized reactive oxygen species (ROS) generation can tackle the tissue penetration issue of phototherapy. Although calcium tungstate (CaWO4) shows great potential as a radiodynamic agent benefiting from its strong X-ray absorption and the ability to generate electron-hole (e--h+) pairs, slow charge carrier transfer and fast e--h+ recombination greatly limit its ROS-generating performance. Herein, via a one-pot wet-chemical method, oxygen vacancy-rich amorphous/crystalline heterophase CaWO4 nanoparticles (Ov-a/c-CaWO4 NPs) with enhanced radiodynamic effect are synthesized for radiodynamic-immunotherapy of cancer. The phase composition and oxygen vacancy content of CaWO4 can be easily tuned by adjusting the solvothermal temperature. More intriguingly, the amorphous/crystalline interfaces and abundant oxygen vacancies accelerate charge carrier transfer and suppress e--h+ recombination, respectively, enabling synergistically improved ROS production from X-ray-irradiated Ov-a/c-CaWO4 NPs. In addition to directly inducing oxidative damage of cancer cells, radiodynamic generation of ROS also boosts immunogenic cell death to provoke a systemic antitumor immune response, thereby allowing the inhibition of both primary and distant tumors as well as cancer metastasis. This study establishes a synergistic enhancement strategy involving the integration of phase and defect engineering to improve the ROS generation capacity of radiodynamic-immunotherapeutic anticancer nanoagents.

Oxygen-defect bismuth oxychloride nanosheets for ultrasonic cavitation effect enhanced sonodynamic and second near-infrared photo-induced therapy of breast cancer

Sonodynamic therapy (SDT) relies heavily on the presence of oxygen to induce cell death. Its effectiveness is thus diminished in the hypoxic regions of tumor tissue. To address this issue, the exploration of ultrasound-based synergistic treatment modalities has become a significant research focus. Here, we report an ultrasonic cavitation effect enhanced sonodynamic and 1208 nm photo-induced cancer treatment strategy based on thermoelectric/piezoelectric oxygen-defect bismuth oxychloride nanosheets (BNs) to realize the high-performance eradication of tumors. Upon ultrasonic irradiation, the local high temperature and high pressure generated by the ultrasonic cavitation effect combined with the thermoelectric and piezoelectric effects of BNs create a built-in electric field. This facilitates the separation of carriers, increasing their mobility and extending their lifetimes, thereby greatly improving the effectiveness of SDT and NIR-Ⅱ phototherapy on hypoxia. The Tween-20 modified BNs (TBNs) demonstrate ∼88.6 % elimination rate against deep-seated tumor cells under hypoxic conditions. In vivo experiments confirm the excellent antitumor efficacy of TBNs, achieving complete tumor elimination within 10 days with no recurrences. Furthermore, due to the high X-ray attenuation of Bi and excellent NIR-Ⅱ absorption, TBNs enable precise cancer diagnosis through photoacoustic (PA) imaging and computed tomography (CT).

Bismuth drug-inspired ultra-small dextran coated bismuth oxide nanoparticles for targeted computed tomography imaging of inflammatory bowel disease

Bismuth (Bi)-based computed tomography (CT) imaging contrast agents (CAs) hold significant promise for diagnosing gastrointestinal diseases due to their cost-effectiveness, heightened sensitivity, and commendable biocompatibility. Nevertheless, substantial challenges persist in achieving an easy synthesis process, remarkable water solubility, and effective targeting ability for the potential clinical transformation of Bi-based CAs. Herein, we show Bi drug-inspired ultra-small dextran coated bismuth oxide nanoparticles (Bi2O3-Dex NPs) for targeted CT imaging of inflammatory bowel disease (IBD). Bi2O3-Dex NPs are synthesized through a simple alkaline precipitation reaction using bismuth salts and dextran as the template. The Bi2O3-Dex NPs exhibit ultra-small size (3.4 nm), exceptional water solubility (over 200 mg mL-1), high Bi content (19.75 %), excellent biocompatibility and demonstrate higher X-ray attenuation capacity compared to clinical iohexol. Bi2O3-Dex NPs not only enable clear visualization of the GI tract outline and intestinal loop structures in CT imaging but also specifically target and accumulate at the inflammatory site in colitis mice after oral administration, facilitating a precise diagnosis and enabling targeted CT imaging of IBD. Our study introduces a novel and clinically promising strategy for synthesizing high-performance Bi2O3-Dex NPs for diagnosing gastrointestinal diseases.

Real-time detection of gastrointestinal leaks via bismuth chelate-enhanced X-ray gastroenterography

Anastomotic leaks are among the most dreaded complications following gastrointestinal (GI) surgery, and contrast-enhanced X-ray gastroenterography is considered the preferred initial diagnostic method for GI leaks. However, from fundamental research to clinical practice, the only oral iodinated contrast agents currently available for GI leaks detection are facing several challenges, including low sensitivity, iodine allergy, and contraindications in patients with thyroid diseases. Herein, we propose a cinematic contrast-enhanced X-ray gastroenterography for the real-time detection of GI leaks with an iodine-free bismuth chelate (Bi-DTPA) for the first time. The Bi-DTPA, synthesized through a straightforward one-pot method, offers distinct advantages such as no need for purification, a nearly 100 % yield, large-scale production capability, and good biocompatibility. The remarkable X-ray attenuation properties of Bi-DTPA enable real-time dynamic visualization of whole GI tract under both X-ray gastroenterography and computed tomography (CT) imaging. More importantly, the leaky site and severity can be both clearly displayed during Bi-DTPA-enhanced gastroenterography in a rat model with esophageal leakage. The proposed movie-like Bi-DTPA-enhanced X-ray imaging approach presents a promising alternative to traditional GI radiography based on iodinated molecules. It demonstrates significant potential in addressing concerns related to iodine-associated adverse effects and offers an alternative method for visually detecting gastrointestinal leaks.

Defect-Engineered Tin Disulfide Nanocarriers as "Precision-Guided Projectile" for Intensive Synergistic Therapy

Nanoformulations with endogenous/exogenous stimulus-responsive characteristics show great potential in tumor cell elimination with minimal adverse effects and high precision. Herein, an intelligent nanotheranostic platform (denoted as TPZ@Cu-SnS2-x/PLL) for tumor microenvironment (TME) and near-infrared light (NIR) activated tumor-specific therapy is constructed. Copper (Cu) doping and the resulting sulfur vacancies can not only improve the response range of visible light but also improve the separation efficiency of photogenerated carriers and increase the carrier density, resulting in the ideal photothermal and photodynamic performance. Density functional theory calculations revealed that the introduction of Cu and resulting sulfur vacancies can induce electron redistribution, achieving favorable photogenerated electrons. After entering cells through endocytosis, the TPZ@Cu-SnS2-x/PLL nanocomposites show the pH responsivity property for the release of the TPZ selectively within the acidic TME, and the released Cu2+ can first interact with local glutathione (GSH) to deplete GSH with the production of Cu+. Subsequently, the Cu+-mediated Fenton-like reaction can decompose local hydrogen peroxide into hydroxyl radicals, which can also be promoted by hyperthermia derived from the photothermal effect for tumor cell apoptosis. The integration of photoacoustic/computed tomography imaging-guided NIR phototherapy, TPZ-induced chemotherapy, and GSH-elimination/hyperthermia enhanced chemodynamic therapy results in synergistic therapeutic outcomes without obvious systemic toxicity in vivo.

Nanoplatform for synergistic therapy constructed via the co-assembly of a reduction-responsive cholesterol-based block copolymer and a photothermal amphiphile

The goal of combination cancer therapy, including chemo-phototherapy, is to achieve highly efficient antitumor effects while minimizing the adverse reactions associated with conventional chemotherapy. Nevertheless, enhancing the contribution of non-chemotherapeutic strategies in combination therapy is often challenging because this requires multiple active ingredients to be encapsulated in a single delivery system. However, most commonly used photothermal reagents are challenging to be loaded in large quantities and have poor biocompatibility. Herein, we developed photothermal co-micelles through a co-assembly strategy using a cholesterol-based liquid crystal block copolymer (LC-BCP) with disulfide bonds in the side chain of the LC blocks and a croconaine-based amphiphile (CBA) containing a cholesterol moiety. This approach allowed the CBA to be effectively embedded within LC-BCPs, serving as the functional component of the drug-loaded carrier. These co-micelles could encapsulate doxorubicin (DOX), showed tunable reduction-responsive drug release, and enabled near-infrared laser-triggered photothermal therapy as well as in vivo fluorescence and photothermal imaging. Following laser irradiation, the photothermal activity of the co-micelles rapidly induced tumor cell death and accelerated drug release. In vitro and in vivo experiments demonstrated that the synergistic photo-chemotherapeutic effects of these drug-loaded co-micelles offer a promising avenue for synergistic precision photothermal-chemotherapy.

Heterojunction semiconductor nanocatalysts as cancer theranostics

Cancer nanotechnology is a promising area of cross-disciplinary research aiming to develop facile, effective, and noninvasive strategies to improve cancer diagnosis and treatment. Catalytic therapy based on exogenous stimulus-responsive semiconductor nanomaterials has shown its potential to address the challenges under the most global medical needs. Semiconductor nanocatalytic therapy is usually triggered by the catalytic action of hot electrons and holes during local redox reactions within the tumor, which represent the response of nontoxic semiconductor nanocatalysts to pertinent internal or external stimuli. However, careful architecture design of semiconductor nanocatalysts has been the major focus since the catalytic efficiency is often limited by facile hot electron/hole recombination. Addressing these challenges is vital for the progress of cancer catalytic therapy. In recent years, diverse strategies have been developed, with heterojunctions emerging as a prominent and extensively explored method. The efficiency of charge separation under exogenous stimulation can be heightened by manipulating the semiconducting performance of materials through heterojunction structures, thereby enhancing catalytic capabilities. This review summarizes the recent applications of exogenous stimulus-responsive semiconducting nanoheterojunctions for cancer theranostics. The first part of the review outlines the construction of different heterojunction types. The next section summarizes recent designs, properties, and catalytic mechanisms of various semiconductor heterojunctions in tumor therapy. The review concludes by discussing the challenges and providing insights into their prospects within this dynamic and continuously evolving field of research.

Bismuth Chelate-Mediated Digital Subtraction Angiography

Digital subtraction angiography (DSA) is considered the "gold standard" for the diagnosis of vascular diseases. However, the contrast agents used in DSA are limited to iodine (I)-based small molecules, which are unsuitable for patients with contraindications. Here, iodine-free DSA utilizing a bismuth (Bi) chelate, Bi-DTPA Dimeglumine, is proposed for vascular visualization for the first time. Bi-DTPA Dimeglumine possesses a simple synthesis process without the need for purification, large-scale production ability (over 200 g in the lab), superior X-ray imaging capability, renal clearance capacity, and good biocompatibility. Bi-DTPA-enhanced DSA can clearly display the arteries of the rabbit's head and lower limbs, with a minimum vascular resolution of 0.5 mm. The displayed integrity of terminal vessels by Bi-DTPA-enhanced DSA is superior to that of iopromide-enhanced DSA. In a rabbit model of thrombotic disease, Bi-DTPA Dimeglumine-enhanced DSA enables the detection of embolism and subsequent reevaluation of vascular conditions after recanalization therapy. This proposed iodine-free DSA provides a promising and universal approach for diagnosing vascular diseases.

Non-invasive fast assessment of hepatic injury through computed tomography imaging with renal-clearable Bi-DTPA dimeglumine

Enhanced computed tomography (CT) imaging with iodinated imaging probes is widely utilized for the diagnosis and evaluation of various liver diseases. However, these iodine-based imaging probes face intractable limitations including allergic reactions and contraindications. Herein, we propose the utilization of renal-clearable iodine-free bismuth chelate (Bi-DTPA dimeglumine) for the non-invasive fast assessment of hepatic ischemia-reperfusion injury (HIRI) via CT imaging for the first time. Bi-DTPA dimeglumine offers several advantages such as simple synthesis, no purification requirement, a yield approaching 100%, large-scale production capability (laboratory synthesis > 100 g), excellent biocompatibility and superior CT imaging performance. In a normal rat model, the administration of Bi-DTPA dimeglumine resulted in a significant 63.79% increase in liver CT value within a very short time period (30 s). Furthermore, in a HIRI rat model, Bi-DTPA dimeglumine enabled the rapid differentiation between healthy and injured areas based on the notable disparity in liver CT values as early as 15 min post-reperfusion, which showed a strong correlation with the histopathological analysis results. Additionally, Bi-DTPA dimeglumine can be almost eliminated from the body via the kidneys within 24 h. As an inherently advantageous alternative to iodinated imaging probes, Bi-DTPA dimeglumine exhibits promising prospects for application in liver disease diagnosis.

Nanoradiosensitizers in glioblastoma treatment: recent advances and future perspectives

Glioblastoma (GBM), a highly invasive type of brain tumor located within the central nervous system, manifests a median survival time of merely 14.6 months. Radiotherapy kills tumor cells through focused high-energy radiation and has become a crucial treatment strategy for GBM, especially in cases where surgical resection is not viable. However, the presence of radioresistant tumor cells limits its clinical effectiveness. Radioresistance is a key factor of treatment failure, prompting the development of various therapeutic strategies to overcome this challenge. With the rapid development of nanomedicine, nanoradiosensitizers provide a novel approach to enhancing the effectiveness of radiotherapy. In this review, we discuss the reasons behind GBM radio-resistance and the mechanisms of radiotherapy sensitization. Then we summarize the primary types of nanoradiosensitizers and recent progress in their application for the radiosensitization of GBM. Finally, we elucidate the factors influencing their practical implementation, along with the challenges and promising prospects associated with multifunctional nanoradiosensitizers.

Ultrathin and Biodegradable Bismuth Oxycarbonate Nanosheets with Massive Oxygen Vacancies for Highly Efficient Tumor Therapy

Nanomaterials doped with high atom number elements can improve the efficacy of cancer radiotherapy, but their clinical application faces obstacles, such as being difficult to degrade in vivo, or still requiring relatively high radiation dose. In this work, a bismuth oxycarbonate-based ultrathin nanosheet with the thickness of 2.8 nm for safe and efficient tumor radiotherapy under low dose of X-ray irradiation is proposed. The high oxygen content (62.5% at%) and selective exposure of the facets of ultrathin 2D nanostrusctures facilitate the escape of large amounts of oxygen atoms on bismuth nanosheets from surface, forming massive oxygen vacancies and generating reactive oxygen species that explode under the action of X-rays. Moreover, the exposure of almost all atoms to environmental factors and the nature of oxycarbonates makes the nanosheets easily degrade into biocompatible species. In vivo studies demonstrate that nanosheets could induce apoptosis in cancer cells after low dose of X-ray irradiation without causing any damage to the liver or kidney. The tumor growth inhibition effect of radiotherapy increases from 49.88% to 90.76% with the help of bismuth oxycarbonate nanosheets. This work offers a promising future for nanosheet-based clinical radiotherapies of malignant cancers.

A review of recent advances in the use of complex metal nanostructures for biomedical applications from diagnosis to treatment

Complex metal nanostructures represent an exceptional category of materials characterized by distinct morphologies and physicochemical properties. Nanostructures with shape anisotropies, such as nanorods, nanostars, nanocages, and nanoprisms, are particularly appealing due to their tunable surface plasmon resonances, controllable surface chemistries, and effective targeting capabilities. These complex nanostructures can absorb light in the near-infrared, enabling noteworthy applications in nanomedicine, molecular imaging, and biology. The engineering of targeting abilities through surface modifications involving ligands, antibodies, peptides, and other agents potentiates their effects. Recent years have witnessed the development of innovative structures with diverse compositions, expanding their applications in biomedicine. These applications encompass targeted imaging, surface-enhanced Raman spectroscopy, near-infrared II imaging, catalytic therapy, photothermal therapy, and cancer treatment. This review seeks to provide the nanomedicine community with a thorough and informative overview of the evolving landscape of complex metal nanoparticle research, with a specific emphasis on their roles in imaging, cancer therapy, infectious diseases, and biofilm treatment. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Diagnostic Tools > Diagnostic Nanodevices.

Implantable, 3D-Printed Alginate Scaffolds with Bismuth Sulfide Nanoparticles for the Treatment of Local Breast Cancer via Enhanced Radiotherapy

Surgical removal of tumor tissue remains the primary clinical approach for addressing breast cancer; however, complete tumor excision is challenging, and the remaining tumor cells can lead to tumor recurrence and metastasis over time, which substantially deteriorates the life quality of the patients. With the aim to improve local cancer radiotherapy, this work reports the fabrication of alginate (Alg) scaffolds containing bovine serum albumin (BSA)-coated bismuth sulfide (Bi2S3@BSA) nanoradiosensitizers using three-dimensional (3D) printing. Under single-dose X-ray irradiation in vitro, Alg-Bi2S3@BSA scaffolds significantly increase the formation of reactive oxygen species, enhance the inhibition of breast cancer cells, and suppress their colony formation capacity. In addition, scaffolds implanted under tumor tissue in murine model show high therapeutic efficacy by reducing the tumor volume growth rate under single-dose X-ray irradiation, while histological observation of main organs reveals no cytotoxicity or side effects. 3D-printed Alg-Bi2S3@BSA scaffolds produced with biocompatible and biodegradable materials may potentially lower the recurrence and metastasis rates in breast cancer patients by inhibiting residual tumor cells following postsurgery as well as exhibit anticancer properties in other solid tumors.

Oxygen Vacancy Defect Enhanced NIR-II Photothermal Performance of BiOxCl Nanosheets for Combined Phototherapy of Cancer Guided by Multimodal Imaging

Narrow photo-absorption range and low carrier utilization are significant barriers that restrict the antitumor efficiency of 2D bismuth oxyhalide (BiOX, X = Cl, Br, I) nanosheets (NSs). Introducing oxygen vacancy (OV) defects can expand the absorption range and improve carrier utilization, which are crucial but also challenging. In this study, a series of BiOxCl NSs with different OV defect concentrations (x = 1, 0.7, 0.5) is developed, which shows full spectrum absorption and strong absorption in the second near-infrared region (NIR-II). Density functional theory calculations are utilized to calculate the crystal structure and density states of BiOxCl, which confirm that part of the carriers is separated by OV enhanced internal electric field to improve carrier utilization. The carriers without redox reaction can be trapped in the OV, leading to great majority of photo-generated carriers promoting the photothermal performance. Triggered by single NIR-II (1064 nm), BiOxCl NSs' bidirectional efficient utilization of carriers achieves synchronously combined phototherapy, leading to enhanced tumor ablation and multimodal diagnostic in vitro and vivo. It is thus believed that this work provides an innovative strategy to design and construct nanoplatforms of indirect band gap semiconductors for clinical phototheranostics.

Achieving Clearance of Drug-Resistant Bacterial Infection and Rapid Cutaneous Wound Regeneration Using an ROS-Balancing-Engineered Heterojunction

Intractable infected microenvironments caused by drug-resistant bacteria stalls the normal course of wound healing. Sono-piezodynamic therapy (SPT) is harnessed to combat pathogenic bacteria, but the superabundant reactive oxygen species (ROS) generated during SPT inevitably provoke severe inflammatory response, hindering tissue regeneration. Consequently, an intelligent nanocatalytic membrane composed of poly(lactic-co-glycolic acid) (PLGA) and black phosphorus /V2C MXene bio-heterojunctions (2D2-bioHJs) is devised. Under ultrasonication, 2D2-bioHJs effectively eliminate drug-resistant bacteria by disrupting metabolism and electron transport chain (ETC). When ultrasonication ceases, they enable the elimination of SPT-generated ROS. The 2D2-bioHJs act as a "lever" that effectively achieves a balance between ROS generation and annihilation, delivering both antibacterial and anti-inflammatory properties to the engineered membrane. More importantly, in vivo assays corroborate that the nanocatalytic membranes transform the stalled chronic wound environment into a regenerative one by eradicating the bacterial population, dampening the NF-κB inflammatory pathway and promoting angiogenesis. As envisaged, this work demonstrates a novel tactic to arm membranes with programmed antibacterial and anti-inflammatory effects to remedy refractory infected wounds from drug-fast bacteria.

Metallic artifacts-free spectral computed tomography angiography based on renal clearable bismuth chelate

Computed tomography angiography (CTA) is one of the most important diagnosis techniques for various vascular diseases in clinic. However, metallic artifacts caused by metal implants and calcified plaques in more and more patients severely hinder its wide applications. Herein, we propose an improved metallic artifacts-free spectral CTA technique based on renal clearable bismuth chelate (Bi-DTPA dimeglumine) for the first time. Bi-DTPA dimeglumine owns the merits of ultra-simple synthetic process, approximately 100% of yield, large-scale production capability, good biocompatibility, and favorable renal clearable ability. More importantly, Bi-DTPA dimeglumine shows superior contrast-enhanced effect in CTA compared with clinical iohexol at a wide range of X-ray energies especially in higher X-ray energy. In rabbits' model with metallic transplants, Bi-DTPA dimeglumine assisted-spectral CTA can not only effectively mitigate metallic artifacts by reducing beam hardening effect under high X-ray energy, but also enables accurate delineation of vascular structure. Our proposed strategy opens a revolutionary way to solve the bottleneck problem of metallic artifacts in CTA examinations.

Design strategies for enhancing antitumor efficacy through tumor microenvironment exploitation using albumin-based nanosystems: A review

The tumor microenvironment (TME) is a complex and dynamic system that plays a crucial role in regulating cancer progression, treatment response, and the emergence of acquired resistance mechanisms. The TME is usually featured by severe hypoxia, low pH values, high hydrogen peroxide (H2O2) concentrations, and overproduction of glutathione (GSH). The current development of intelligent nanosystems that respond to TME has shown great potential to enhance the efficacy of cancer treatment. As one of the functional macromolecules explored in this field, albumin-based nanocarriers, known for their inherent biocompatibility, serves as a cornerstone for constructing diverse therapeutic platforms. In this paper, we present a comprehensive overview of the latest advancements in the design strategies of albumin nanosystems, aiming to enhance cancer therapy by harnessing various features of solid tumors, including tumor hypoxia, acidic pH, the condensed extracellular matrix (ECM) network, excessive GSH, high glucose levels, and tumor immune microenvironment. Furthermore, we highlight representative designs of albumin-based nanoplatforms by exploiting the TME that enhance a broad range of cancer therapies, such as chemotherapy, phototherapy, radiotherapy, immunotherapy, and other tumor therapies. Finally, we discuss the existing challenges and future prospects in direction of albumin-based nanosystems for the practical applications in advancing enhanced cancer treatments.

Emergence and impact of theranostic-nanoformulation of triple therapeutics for combination cancer therapy

Cancer remains a major global health threat necessitating the multipronged approaches for its prevention and management. Traditional approaches in the form of chemotherapy, surgery, and radiotherapy are often encountered with poor patient outcomes evidenced by high mortality and morbidity, compelling the need for precision medicine for cancer patients to enable personalized and targeted cancer treatment. There has been an emergence of smart multimodal theranostic nanoformulation for triple combination cancer therapy in the last few years, which dramatically enhances the overall safety of the nanoformulation for in vivo and potential clinical applications with minimal toxicity. However, it is imperative to gain insight into the limitations of this system in terms of clinical translation, cost-effectiveness, accessibility, and multidisciplinary collaboration. This review paper aims to highlight and compare the impact of the recent theranostic nanoformulations of triple therapeutics in a single nanocarrier for effective management of cancer and provide a new dimension for diagnostic and treatment simultaneously.

Interfacial regulation of BiOI@Bi2S3/MXene heterostructures for enhanced photothermal and photodynamic therapy in antibacterial applications

Developing environmentally friendly, broad-spectrum, and long-lasting antibacterial materials remains challenging. Our ternary BiOI@Bi2S3/MXene composites, which exhibit both photothermal therapy (PTT) and photodynamic therapy (PDT) antibacterial properties, were synthesized through in-situ vulcanization of hollow flower-shaped BiOI on the surface of two-dimensional Ti3C2 MXene. The unique hollow flower-shaped BiOI structure with a high exposure of the (001) crystal plane amplifies light reflection and scattering, offering more active sites to improve light utilization. Under 808 nm irradiation, these composites achieved a photothermal conversion efficiency of 57.8 %, boosting the PTT antibacterial effect. The heterojunction between Bi2S3 and BiOI creates a built-in electric field at the interface, promoting hole and electron transfer. Significantly, the close-contact heterogeneous interface enhances charge transfer and suppresses electron-hole recombination, thereby boosting PDT bacteriostatic performance. EPR experiments confirmed that ∙O2- and •OH radicals play major roles in photocatalytic bacteriostatic reactions. The combined antibacterial action of PTT and PDT led to efficiencies of 99.7 % and 99.8 % against P. aeruginosa and S. aureus, respectively, under 808 nm laser irradiation. This innovative strategy and thoughtful design open new avenues for heterojunction materials in PTT and PDT sterilization. STATEMENT OF SIGNIFICANCE: Photodynamic and photothermal therapy is a promising antibacterial treatment, but its efficiency still limits its application. To overcome this limitation, we prepared three-dimensional heterogeneous BiOI@Bi2S3/MXene nanocomposites through in-situ vulcanization of hollow flower-shaped BiOI with a high exposure of the (001) crystal plane onto the surface of two-dimensional MXene material. The resulting ternary material forms a close-contact heterogeneous interface, which improves charge transfer channels, reduces electron-hole pair recombination, and amplifies photodynamic bacteriostatic performance. These nanocomposites exhibit photothermal conversion efficiency of 57.8 %, enhancing their photothermal bactericidal effects. They demonstrated antibacterial efficiencies of 99.7 % against P. aeruginosa and 99.8 % against S. aureus. Therefore, this study provides a promising method for the synthesis of environmentally friendly and efficient antibacterial materials.

A Cholesterol Metabolic Regulated Hydrogen-Bonded Organic Framework (HOF)-Based Biotuner for Antibody Non-Dependent Immunotherapy Tailored for Glioblastoma

The metabolic reprogramming of glioblastoma (GBM) poses a tremendous obstacle to effective immunotherapy due to its impact on the immunosuppressive microenvironment. In this work, a hydrogen-bonded organic framework (HOF) specifically designed for GBM immunotherapy is developed, taking advantage of the relatively isolated cholesterol metabolism microenvironment in the central nervous system (CNS). The HOF-based biotuner regulates extra/intracellular cholesterol metabolism, effectively blocking the programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) pathway and reducing 2B4 expression. This metabolically disrupts the immunosuppressive microenvironment of GBM and rejuvenates CD8+ T cells. Moreover, cholesterol metabolism regulation offers additional benefits in treating GBM invasion. Furthermore, tumor microenvironment (TME)-initiated chemiexcited photodynamic therapy (PDT) is enhanced during the regulation of cholesterol metabolism, and the biotuner can effectively trigger immunogenic cell death (ICD) and increase the infiltration of cytotoxic T lymphocytes (CTLs) in GBM. By reversing the immunosuppressive microenvironment and bolstering chemiexcited-PDT, this approach invigorates efficient antibody non-dependent immunotherapy for GBM. This study provides a model for enhancing immunotherapy through cholesterol metabolism regulation and explores the feasibility of a "metabolic checkpoint" strategy in GBM treatment.

Synergistic photothermal conversion and photocatalysis in 2D/2D MXene/Bi2S3 hybrids for efficient solar-driven water purification

Plasmonic hybrids are regarded as promising candidates for water purification due to their structure-dependent photocatalysis and photothermal performance. It remains a challenge to develop materials that possess these two characteristics for efficient water purification. Herein, plasmonic Ti3C2Tx/Bi2S3 two-dimensional (2D)/2D hybrids were prepared for efficient solar-driven water purification via the combination of photothermal conversion and photocatalysis. Benefitting from broad light absorption, large 2D/2D interfaces, and efficient charge transfer, the binary hybrids showed high-efficiency photothermal conversion and photothermal-assisted photocatalytic activity. By depositing these 2D/2D hybrids on a hydrophilic and porous cotton piece, the Ti3C2Tx/Bi2S3 membrane displayed a high water evaporation rate and solar-to-vapor efficiency under one-sun irradiation. The solar-driven evaporation of seawater, heavy metal ion solution, and dye solution jointly indicated that the plasmonic membrane shows great potential for drinkable water generation and industrial wastewater treatment. Most importantly, the synergistic effect of photothermal evaporation and photocatalysis of the Ti3C2Tx/Bi2S3 membrane on water purification was demonstrated. The polluted water can not only be treated by evaporation, but also be degraded via photocatalysis under solar light irradiation. This work provides new insight into designing functional materials for water purification based on the combination of photothermal conversion and photocatalysis.

Sonocatalytic Optimization of Titanium-Based Therapeutic Nanomedicine

Recent considerable technological advances in ultrasound-based treatment modality provides a magnificent prospect for scientific communities to conquer the related diseases, which is featured with remarkable tissue penetration, non-invasive and non-thermal characteristics. As one of the critical elements that influences treatment outcomes, titanium (Ti)-based sonosensitizers with distinct physicochemical properties and exceptional sonodynamic efficiency have been applied extensively in the field of nanomedical applications. To date, a myriad of methodologies has been designed to manipulate the sonodynamic performance of titanium-involved nanomedicine and further enhance the productivity of reactive oxygen species for disease treatments. In this comprehensive review, the sonocatalytic optimization of diversified Ti-based nanoplatforms, including defect engineering, plasmon resonance modulation, heterojunction, modulating tumor microenvironment, as well as the development of synergistic therapeutic modalities is mainly focused. The state-of-the-art Ti-based nanoplatforms ranging from preparation process to the extensive medical applications are summarized and highlighted, with the goal of elaborating on future research prospects and providing a perspective on the bench-to-beside translation of these sonocatalytic optimization tactics. Furthermore, to spur further technological advancements in nanomedicine, the difficulties currently faced and the direction of sonocatalytic optimization of Ti-based therapeutic nanomedicine are proposed and outlooked.

Precise Engineering of a Se/Te Nanochaperone for Reinvigorating Cancer Radio-Immunotherapy

Facilely synthesized nanoradiosensitizers with well-controlled structure and multifunctionality are greatly desired to address the challenges of cancer radiotherapy. In this work, a universal method is developed for synthesizing chalcogen-based TeSe nano-heterojunctions (NHJs) with rod-, spindle-, or dumbbell-like morphologies by engineering the surfactant and added selenite. Interestingly, dumbbell-shaped TeSe NHJs (TeSe NDs) as chaperone exhibit better radio-sensitizing activities than the other two nanostructural shapes. Meanwhile, TeSe NDs can serve as cytotoxic chemodrugs that degrade to highly toxic metabolites in acidic environment and deplete GSH within tumor to facilitate radiotherapy. More importantly, the combination of TeSe NDs with radiotherapy significantly decreases regulatory T cells and M2-phenotype tumor-associated macrophage infiltrations within tumors to reshape the immunosuppressive microenvironment and induce robust T lymphocytes-mediated antitumor immunity, resulting in great abscopal effects on combating distant tumor progression. This study provides a universal method for preparing NHJ with well-controlled structure and developing nanoradiosensitizers to overcome the clinical challenges of cancer radiotherapy.

Spectral computed tomography-guided radiotherapy of osteosarcoma utilizing BiOI nanosheets

As an aggressive malignant bone tumor, osteosarcoma (OS) is usually found in children and adolescents. Computed tomography (CT) is an important tool for the clinical evaluation of osteosarcoma, but limits to low diagnostic specificity due to single parameters of traditional CT and modest signal-to-noise ratio of clinical iodinated contrast agents. As one kind of spectral CT, dual-energy CT (DECT), with the advantage of a provision of multi-parameter information, makes it possible to acquire the best signal-to-noise ratio image, accurate detection, as well as imaging-guided therapy of bone tumors. Hereby, we synthesized BiOI nanosheets (BiOI NSs) as a DECT contrast agent with superior imaging capability compared to iodine agents for clinical detection of OS. Meanwhile, the synthesized BiOI NSs with great biocompatibility is able to achieve effective radiotherapy (RT) by enhancing X-ray dose deposition at the tumor site, leading to DNA damage, which in turn inhibits tumor growth. This study offers a promising new avenue for DECT imaging-guided treatment of OS. STATEMENT OF SIGNIFICANCE: Osteosarcoma (OS) is a common primary malignant bone tumor. Traditional surgical procedures and conventional CT scans are often used for the treatment and monitoring of OS, but the effects are generally unsatisfactory. In this work, BiOI nanosheets (NSs) was reported for dual-energy CT (DECT) imaging-guided OS radiotherapy. The powerful and constant X-ray absorption of BiOI NSs at any energy guarantees excellent enhanced DECT imaging performance, allowing detailed visualization of OS through images with a better signal-to-noise ratio and guiding radiotherapy process. The deposition of X-rays could be greatly enhanced by Bi atoms to induce serious DNA damage in radiotherapy. Taken together, the BiOI NSs for DECT-guided radiotherapy will greatly improve the current treatment status of OS.

Application of nano-radiosensitizers in combination cancer therapy

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

α-Fe2O3@Au-PEG-Ce6-Gd Nanoparticles as Acidic H2O2-Driven Oxygenators for Multimodal Imaging and Synergistic Tumor Therapy

Nanoparticles with visual imaging capabilities and synergistic therapeutics have a bright future in antitumor applications. However, most of the current nanomaterials lack multiple imaging-guided therapeutic capabilities. In this study, a novel enhanced photothermal photodynamic antitumor nanoplatform with photothermal imaging, fluorescence (FL) imaging, and MRI-guided therapeutic capabilities was constructed by grafting gold, dihydroporphyrin Ce6, and Gd onto α-iron trioxide. This antitumor nanoplatform can convert NIR light into local hyperthermia at a temperature of up to 53 °C under NIR light irradiation, while Ce6 can generate singlet oxygen, which further synergizes the tumor-killing effect. At the same time, α-Fe₂O₃@Au-PEG-Ce6-Gd can also have significant photothermal imaging effect under light irradiation, which can guide to see the temperature change near the tumor tissue. It is worth noting that α-Fe₂O₃@Au-PEG-Ce6-Gd can have obvious MRI and FL imaging effects after tail vein injection in mice with blood circulation, realizing imaging-guided synergistic antitumor therapy. α-Fe₂O₃@Au-PEG-Ce6-Gd NPs provide a new solution for tumor imaging and treatment.

NIR-II Light-Activated Gold Nanorods for Synergistic Thermodynamic and Photothermal Therapy of Tumor

There are tricky challenges in tumor therapy due to the hypoxic tumor microenvironment, inevitably inhibiting the treatment efficacy of the traditional photodynamic therapy (PDT), radiation therapy (RT), and sonodynamic therapy (SDT). Herein, to overcome tumor hypoxia limitation, we constructed a near-infrared II (NIR-II) light-triggered thermodynamic therapy (TDT) nanoplatform of Au@mSiO₂-AIPH@PCM/PEG (ASAPP) by integrating the Au nanorods (Au NRs) and thermally activated alkyl free radical-releasing molecules (AIPH). Au NRs@mSiO₂ was used as a photothermally responsive material and AIPH carrier, and the hot-melt phase-change material (PCM) was used as a capping agent to prevent leakage of AIPH during blood circulation. Upon NIR-II light irradiation, heat-triggered free radical release from AIPH was successfully achieved for killing cancer cells in vitro and in vivo without oxygen dependence, leading to synergistically enhanced antitumor therapy.

Recent advances in stimuli-responsive nano-heterojunctions for tumor therapy

Stimuli-responsive catalytic therapy based on nano-catalysts has attracted much attention in the field of biomedicine for tumor therapy, due to its excellent and unique properties. However, the complex tumor microenvironment conditions and the rapid charge recombination in the catalyst limit catalytic therapy's effectiveness and further development. Effective heterojunction nanomaterials are constructed to address these problems to improve catalytic performance. Specifically, on the one hand, the band gap of the material is adjusted through the heterojunction structure to promote the charge separation efficiency under exogenous stimulation and further improve the catalytic capacity. On the other hand, the construction of a heterojunction structure can not only preserve the function of the original catalyst but also achieve significantly enhanced synergistic therapy ability. This review summarized the construction and functions of stimuli-responsive heterojunction nanomaterials under the excitation of X-rays, visible-near infrared light, and ultrasound in recent years, and further introduces their application in cancer therapy. Hopefully, the summary of stimuli-responsive heterojunction nanomaterials' applications will help researchers promote the development of nanomaterials in cancer therapy.

Potential and Progress of 2D Materials in Photomedicine for Cancer Treatment

Over the last decades, photomedicine has made a significant impact and progress in treating superficial cancer. With tremendous efforts many of the technologies have entered clinical trials. Photothermal agents (PTAs) have been considered as emerging candidates for accelerating the outcome from photomedicine based cancer treatment. Besides various inorganic and organic candidates, 2D materials such as graphene, boron nitride, and molybdenum disulfide have shown significant potential for photothermal therapy (PTT). The properties such as high surface area to volume, biocompatibility, stability in physiological media, ease of synthesis and functionalization, and high photothermal conversion efficiency have made 2D nanomaterials wonderful candidates for PTT to treat cancer. The targeting or localized activation could be achieved when PTT is combined with chemotherapies, immunotherapies, or photodynamic therapy (PDT) to provide better outcomes with fewer side effects. Though significant development has been made in the field of phototherapeutic drugs, several challenges have restricted the use of PTT in clinical use and hence they have not yet been tested in large clinical trials. In this review, we attempted to discuss the progress, properties, applications, and challenges of 2D materials in the field of PTT and their application in photomedicine.

Reactive oxygen species-upregulating nanomedicines towards enhanced cancer therapy

Reactive oxygen species (ROS) play a crucial role in physiological and pathological processes, emerging as a therapeutic target in cancer. Owing to the high concentration of ROS in solid tumor tissues, ROS-based treatments, such as photodynamic therapy and chemodynamic therapy, and ROS-responsive drug delivery systems have been widely explored to powerfully and specifically suppress tumors. However, their anticancer efficacy is still hampered by the heterogeneous ROS levels, and thus comprehensively upregulating the ROS levels in tumor tissues can ensure an enhanced therapeutic effect, which can further sensitize and/or synergize with other therapies to inhibit tumor growth and metastasis. Herein, we review the recently emerging drug delivery strategies and technologies for increasing the H₂O₂, ˙OH, ¹O₂, and ˙O₂^- concentrations in cancer cells, including the efficient delivery of natural enzymes, nanozymes, small molecular biological molecules, and nanoscale Fenton-reagents and semiconductors and neutralization of intracellular antioxidant substances and localized input of mechanical and electromagnetic waves (such as ultrasound, near infrared light, microwaves, and X-rays). The applications of these ROS-upregulating nanosystems in enhancing and synergizing cancer therapies including chemotherapy, chemodynamic therapy, phototherapy, and immunotherapy are surveyed. In addition, we discuss the challenges of ROS-upregulating systems and the prospects for future studies.

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

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

Recent Advances in Contrast-Enhanced Photoacoustic Imaging: Overcoming the Physical and Practical Challenges

For decades now, photoacoustic imaging (PAI) has been investigated to realize its potential as a niche biomedical imaging modality. Despite its highly desirable optical contrast and ultrasonic spatiotemporal resolution, PAI is challenged by such physical limitations as a low signal-to-noise ratio (SNR), diminished image contrast due to strong optical attenuation, and a lower-bound on spatial resolution in deep tissue. In addition, contrast-enhanced PAI has faced practical limitations such as insufficient cell-specific targeting due to low delivery efficiency and difficulties in developing clinically translatable agents. Identifying these limitations is essential to the continuing expansion of the field, and substantial advances in developing contrast-enhancing agents, complemented by high-performance image acquisition systems, have synergistically dealt with the challenges of conventional PAI. This review covers the past four years of research on pushing the physical and practical challenges of PAI in terms of SNR/contrast, spatial resolution, targeted delivery, and clinical application. Promising strategies for dealing with each challenge are reviewed in detail, and future research directions for next generation contrast-enhanced PAI are discussed.

Distribution and inflammatory cell response to intracranial delivery of radioluminescent Y2(SiO4)O:Ce particles

Due to increasing advances in their manufacture and functionalization, nanoparticle-based systems have become a popular tool for in vivo drug delivery and biodetection. Recently, scintillating nanoparticles such as yttrium orthosilicate doped with cerium (Y2(SiO4)O:Ce) have come under study for their potential utility in optogenetic applications, as they emit photons upon low levels of stimulation from remote x-ray sources. The utility of such nanoparticles in vivo is hampered by rapid clearance from circulation by the mononuclear phagocytic system, which heavily restricts nanoparticle accumulation at target tissues. Local transcranial injection of nanoparticles may deliver scintillating nanoparticles to highly specific brain regions by circumventing the blood-brain barrier and avoiding phagocytic clearance. Few studies to date have examined the distribution and response to nanoparticles following localized delivery to cerebral cortex, a crucial step in understanding the therapeutic potential of nanoparticle-based biodetection in the brain. Following the synthesis and surface modification of these nanoparticles, two doses (1 and 3 mg/ml) were introduced into mouse secondary motor cortex (M2). This region was chosen as the site for RLP delivery, as it represents a common target for optogenetic manipulations of mouse behavior, and RLPs could eventually serve as an injectable x-ray inducible light delivery system. The spread of particles through the target tissue was assessed 24 hours, 72 hours, and 9 days post-injection. Y2(SiO4)O:Ce nanoparticles were found to be detectable in the brain for up to 9 days, initially diffusing through the tissue until 72 hours before achieving partial clearance by the final endpoint. Small transient increases in the presence of IBA-1+ microglia and GFAP+ astrocytic cell populations were detected near nanoparticle injection sites of both doses tested 24 hours after surgery. Taken together, these data provide evidence that Y2(SiO4)O:Ce nanoparticles coated with BSA can be injected directly into mouse cortex in vivo, where they persist for days and are broadly tolerated, such that they may be potentially utilized for remote x-ray activated stimulation and photon emission for optogenetic experiments in the near future.

Image-Guided Precision Treatments

Chemotherapy, radiotherapy, and surgery are traditional cancer treatments, which usually produce unpredictable side effects and potential risks to normal healthy organs/tissues. Thus, safe and reliable treatment strategies are urgently required for maximized therapeutic efficiency to lesions and minimized risks to healthy regions. To this end, molecular imaging is responsible to undertake a specific targeting therapy. Besides that, the image guidance as a precision visualized approach for real-time in situ evaluations as well as an intraoperational navigation approach has earned attractive attention in the past decade. Along with the rapid development of multifunctional micro-/nanobiomaterials, versatile cutting-edge and advanced therapy strategies (e.g., thermal therapy, dynamic therapy, gas therapy, etc.) have been achieved and greatly contributed to the image-guided precision treatments in every aspect. Therefore, this chapter aims to discuss about both traditional and advanced cancer treatments and especially to elucidate the important roles that visualized medicine has been playing in the image-guided precision treatments.

Synthesis of Z-schemes 0D–3D heterojunction bi-functional photocatalyst with ZnInCuS alloyed QDs supported BiOI MF for H2O2 production and N2 fixation

Photocatalytic H2O2 and NH3 production on Zn–Cu–In–S QDs coupled with BiOI MFs via a Z-scheme charge transfer dynamic.

Improve the cytotoxic effects of megavoltage radiation treatment by Fe3O4@Cus–PEG nanoparticles as a novel radiosensitizer in colorectal cancer cells

Background

To enhance the performance of radiotherapy, emerging nanoparticles that can professionally enhance X-ray irradiation to destruct cancer cells are extremely necessary. Here, we examined the potential of PEG-coated magnetite copper sulfide hetero-nanoparticles (Fe3O4@Cus–PEG) as a radiosensitizer agent.

Methods

Fe3O4@Cus–PEG nanoparticles were synthesized and characterized. The toxicity of nanoparticles on HT-29 colorectal cancer cells was assessed by the MTT assay. The radio-sensitizing effects of Fe3O4@Cus–PEG nanoparticles on HT-29 cancer cells were investigated by the MTT and colony formation assays. Moreover, the underlying mechanisms for Fe3O4@Cus–PEG nanoparticles to improve the radiation sensitivity of cells were evaluated.

Results

The results demonstrated that nanoparticles enhanced the effects of X-ray irradiation in a dose-dependent manner. The effects of combined treatments (nanoparticles and X-ray radiation) were strongly synergistic. The sensitizing enhancement ratio (SER) of nanoparticles was 2.02. Our in vitro assays demonstrated that the nitric oxide production, the intracellular hydrogen peroxide concentration, and the expression level of Bax and Caspase-3 genes significantly increased in the cells treated with the combination of nanoparticles and radiation. Whereas, the Glutathione peroxidase enzyme activity and the expression level of the Bcl-2 gene in the combined treatment significantly decreased compared to the radiation alone.

Conclusions

Our study suggests that Fe3O4@Cus–PEG nanoparticles are the promising nano radio-sensitizing agents for the treatment of cancer cells to enhance the efficacy of radiation therapy through increasing the reactive oxygen species generation, nitric oxide production, and inducing apoptosis.

Graphical Abstract

An overview of the intracellular localization of high-Z nanoradiosensitizers

Radiation therapy (RT) is a method commonly used for cancer treatment worldwide. Commonly, RT utilizes two routes for combating cancers: 1) high-energy radiation to generate toxic reactive oxygen species (ROS) (through the dissociation of water molecules) for damaging the deoxyribonucleic acid (DNA) inside the nucleus 2) direct degradation of the DNA. However, cancer cells have mechanisms to survive under intense RT, which can considerably decrease its therapeutic efficacy. Excessive radiation energy damages healthy tissues, and hence, low doses are applied for cancer treatment. Additionally, different radiosensitizers were used to sensitize cancer cells towards RT through individual mechanisms. Following this route, nanoparticle-based radiosensitizers (herein called nanoradiosensitizers) have recently gained attention owing to their ability to produce massive electrons which leads to the production of a huge amount of ROS. The success of the nanoradiosensitizer effect is closely correlated to its interaction with cells and its localization within the cells. In other words, tumor treatment is affected from the chain of events which is started from cell-nanoparticle interaction followed by the nanoparticles direction and homing inside the cell. Therefore, passive or active targeting of the nanoradiosensitizers in the subcellular level and the cell-nano interaction would determine the efficacy of the radiation therapy. The importance of the nanoradiosensitizer's targeting is increased while the organelles beyond nucleus are recently recognized as the mediators of the cancer cell death or resistance under RT. In this review, the principals of cell-nanomaterial interactions and which dominate nanoradiosensitizer efficiency in cancer therapy, are thoroughly discussed.

Tantalum-carbon-integrated nanozymes as a nano-radiosensitizer for radiotherapy enhancement

Radiotherapy (RT) plays a pivotal role in the comprehensive treatment of multiple malignant tumors, exerting its anti-tumor effects through direct induction of double-strand breaks (DSBs) or indirect induction of reactive oxygen species (ROS) production. However, RT resistance remains a therapeutic obstacle that leads to cancer recurrence and treatment failure. In this study, we synthesised a tantalum-carbon-integrated nanozyme with excellent catalase-like (CAT-like) activity and radiosensitivity by immobilising an ultrasmall tantalum nanozyme into a metal-organic framework (MOF)-derived carbon nanozyme through in situ reduction. The integrated tantalum nanozyme significantly increased the CAT activity of the carbon nanozyme, which promoted the production of more oxygen and increased the ROS levels. By improving hypoxia and increasing the level of ROS, more DNA DSBs occur at the cellular level, which, in turn, improves the sensitivity of RT. Moreover, tantalum-carbon-integrated nanozymes combined with RT have demonstrated notable anti-tumor activity in vivo. Therefore, exploiting the enzymatic activity and the effect of ROS amplification of this nanozyme has the potential to overcome resistance to RT, which may offer new horizons for nanozyme-based remedies for biomedical applications.

Ultrasmall zirconium carbide nanodots for synergistic photothermal-radiotherapy of glioma

Glioma is characterized by highly invasive, progressive, and lethal features. In addition, conventional treatments have been poorly effective in treating glioma. To overcome this challenge, synergistic therapies combining radiotherapy (RT) with photothermal therapy (PTT) have been proposed and extensively explored as a highly feasible cancer treatment strategy. Herein, ultrasmall zirconium carbide (ZrC) nanodots were successfully synthesized with high near-infrared absorption and strong photon attenuation for synergistic PTT-RT of glioma. ZrC-PVP nanodots with an average size of approximately 4.36 nm were prepared by the liquid exfoliation method and modified with the surfactant polyvinylpyrrolidone (PVP), with a satisfactory absorption and photothermal conversion efficiency (53.4%) in the near-infrared region. Furthermore, ZrC-PVP nanodots can also act as radiosensitizers to kill residual tumor cells after mild PTT due to their excellent photon attenuating ability, thus achieving a significant synergistic therapeutic effect by combining RT and PTT. Most importantly, both in vitro and in vivo experimental results further validate the high biosafety of ZrC-PVP NDs at the injected dose. This work systematically evaluates the feasibility of ZrC-PVP NDs for glioma treatment and provides evidence of the application of zirconium-based nanomaterials in photothermal radiotherapy.

Novel Implications of Nanoparticle-Enhanced Radiotherapy and Brachytherapy: Z-Effect and Tumor Hypoxia

Radiotherapy and internal radioisotope therapy (brachytherapy) induce tumor cell death through different molecular signaling pathways. However, these therapies in cancer patients are constrained by dose-related adverse effects and local discomfort due to the prolonged exposure to the surrounding tissues. Technological advancements in nanotechnology have resulted in synthesis of high atomic elements such as nanomaterials, which can be used as radiosensitizers due to their photoelectric characteristics. The aim of this review is to elucidate the effects of novel nanomaterials in the field of radiation oncology to ameliorate dose-related toxicity through the application of ideal nanoparticle-based radiosensitizers such as Au (gold), Bi (bismuth), and Lu (Lutetium-177) for enhancing cytotoxic effects of radiotherapy via the high-Z effect. In addition, we discuss the role of nanoparticle-enhanced radiotherapy in alleviating tumor hypoxia through the nanodelivery of genes/drugs and other functional anticancer molecules. The implications of engineered nanoparticles in preclinical and clinical studies still need to be studied in order to explore potential mechanisms for radiosensitization by minimizing tumor hypoxia, operational/logistic complications and by overcoming tumor heterogeneity in radiotherapy/brachytherapy.

Spectral computed tomography with inorganic nanomaterials: State-of-the-art

Recently, spectral computed tomography (CT) technology has received great interest in the field of radiology. Spectral CT imaging utilizes the distinct, energy-dependent X-ray absorption properties of substances in order to provide additional imaging information. Dual-energy CT and multi-energy CT (Spectral CT) are capable of constructing monochromatic energy images, material separation images, energy spectrum curves, constructing effective atomic number maps, and more. However, poor contrast, due to neighboring X-ray attenuation of organs and tissues, is still a challenge to spectral CT. Hence, contrast agents (CAs) are applied for better differentiation of a given region of interest (ROI). Currently, many different kinds of inorganic nanoparticulate CAs for spectral CT have been developed due to the limitations of clinical iodine (I)-based contrast media, leading to the conclusion that inorganic nanomedicine applied to spectral CT will be a powerful collaboration both in basic research and in clinics. In this review, the underlying principles and types of spectral CT techniques are discussed, and some evolving clinical diagnosis applications of spectral CT techniques are introduced. In particular, recent developments in inorganic CAs used for spectral CT are summarized. Finally, the challenges and future developments of inorganic nanomedicine in spectral CT are briefly discussed.

Magnetite and bismuth sulfide Janus heterostructures as radiosensitizers for in vivo enhanced radiotherapy in breast cancer

Janus heterostructures based on bimetallic nanoparticles have emerged as effective radiosensitizers owing to their radiosensitization capabilities in cancer cells. In this context, this study aims at developing a novel bimetallic nanoradiosensitizer, Bi₂S₃-Fe₃O₄, to enhance tumor accumulation and promote radiation-induced DNA damage while reducing adverse effects. Due to the presence of both iron oxide and bismuth sulfide metallic nanoparticles in these newly developed nanoparticle, strong radiosensitizing capacity is anticipated through the generation of reactive oxygen species (ROS) to induce DNA damage under X-Ray irradiation. To improve blood circulation time, biocompatibility, colloidal stability, and tuning surface functionalization, the surface of Bi₂S₃-Fe₃O₄ bimetallic nanoparticles was coated with bovine serum albumin (BSA). Moreover, to achieve higher cellular uptake and efficient tumor site specificity, folic acid (FA) as a targeting moiety was conjugated onto the bimetallic nanoparticles, termed Bi₂S₃@BSA-Fe₃O₄-FA. Biocompatibility, safety, radiation-induced DNA damage by ROS activation and generation, and radiosensitizing ability were confirmed via in vitro and in vivo assays. The administration of Bi₂S₃@BSA-Fe₃O₄-FA in 4T1 breast cancer murine model upon X-ray radiation revealed highly effective tumor eradication without causing any mortality or severe toxicity in healthy tissues. These findings offer compelling evidence for the potential capability of Bi₂S₃@BSA-Fe₃O₄-FA as an ideal nanoparticle for radiation-induced cancer therapy and open interesting avenues of future research in this area.

Long-term solar water and CO2 splitting with photoelectrochemical BiOI-BiVO4 tandems

Photoelectrochemical (PEC) devices have been developed for direct solar fuel production but the limited stability of submerged light absorbers can hamper their commercial prospects.^1,2 Here, we demonstrate photocathodes with an operational H₂ evolution activity over weeks, by integrating a BiOI light absorber into a robust, oxide-based architecture with a graphite paste conductive encapsulant. In this case, the activity towards proton and CO₂ reduction is mainly limited by catalyst degradation. We also introduce multiple-pixel devices as an innovative design principle for PEC systems, displaying superior photocurrents, onset biases and stability over corresponding conventional single-pixel devices. Accordingly, PEC tandem devices comprising multiple-pixel BiOI photocathodes and BiVO₄ photoanodes can sustain bias-free water splitting for 240 h, while devices with a Cu₉₂In₈ alloy catalyst demonstrate unassisted syngas production from CO₂.

Research Progress of Conjugated Nanomedicine for Cancer Treatment

The conventional cancer therapeutic modalities include surgery, chemotherapy and radiotherapy. Although immunotherapy and targeted therapy are also widely used in cancer treatment, chemotherapy remains the cornerstone of tumor treatment. With the rapid development of nanotechnology, nanomedicine is believed to be an emerging field to further improve the efficacy of chemotherapy. Until now, there are more than 17 kinds of nanomedicine for cancer therapy approved globally. Thereinto, conjugated nanomedicine, as an important type of nanomedicine, can not only possess the targeted delivery of chemotherapeutics with great precision but also achieve controlled drug release to avoid adverse effects. Meanwhile, conjugated nanomedicine provides the platform for combining several different therapeutic approaches (chemotherapy, photothermal therapy, photodynamic therapy, thermodynamic therapy, immunotherapy, etc.) with the purpose of achieving synergistic effects during cancer treatment. Therefore, this review focuses on conjugated nanomedicine and its various applications in synergistic chemotherapy. Additionally, the further perspectives and challenges of the conjugated nanomedicine are also addressed, which clarifies the design direction of a new generation of conjugated nanomedicine and facilitates the translation of them from the bench to the bedside.