Stable black phosphorus/Bi2O3 heterostructures for synergistic cancer radiotherapy

Peptide-Functionalized Inorganic Oxide Nanomaterials for Solid Cancer Imaging and Therapy

The diagnosis and treatment of solid tumors have undergone significant advancements marked by a trend toward increased specificity and integration of imaging and therapeutic functions. The multifaceted nature of inorganic oxide nanomaterials (IONs), which boast optical, magnetic, ultrasonic, and biochemical modulatory properties, makes them ideal building blocks for developing multifunctional nanoplatforms. A promising class of materials that have emerged in this context are peptide-functionalized inorganic oxide nanomaterials (PFIONs), which have demonstrated excellent performance in multifunctional imaging and therapy, making them potential candidates for advancing solid tumor diagnosis and treatment. Owing to the functionalities of peptides in tumor targeting, penetration, responsiveness, and therapy, well-designed PFIONs can specifically accumulate and release therapeutic or imaging agents at the solid tumor sites, enabling precise imaging and effective treatment. This review provides an overview of the recent advances in the use of PFIONs for the imaging and treatment of solid tumors, highlighting the superiority of imaging and therapeutic integration as well as synergistic treatment. Moreover, the review discusses the challenges and prospects of PFIONs in depth, aiming to promote the intersection of the interdisciplinary to facilitate their clinical translation and the development of personalized diagnostic and therapeutic systems by optimizing the material systems.

Nanomaterials-Induced Redox Imbalance: Challenged and Opportunities for Nanomaterials in Cancer Therapy

Cancer cells typically display redox imbalance compared with normal cells due to increased metabolic rate, accumulated mitochondrial dysfunction, elevated cell signaling, and accelerated peroxisomal activities. This redox imbalance may regulate gene expression, alter protein stability, and modulate existing cellular programs, resulting in inefficient treatment modalities. Therapeutic strategies targeting intra- or extracellular redox states of cancer cells at varying state of progression may trigger programmed cell death if exceeded a certain threshold, enabling therapeutic selectivity and overcoming cancer resistance to radiotherapy and chemotherapy. Nanotechnology provides new opportunities for modulating redox state in cancer cells due to their excellent designability and high reactivity. Various nanomaterials are widely researched to enhance highly reactive substances (free radicals) production, disrupt the endogenous antioxidant defense systems, or both. Here, the physiological features of redox imbalance in cancer cells are described and the challenges in modulating redox state in cancer cells are illustrated. Then, nanomaterials that regulate redox imbalance are classified and elaborated upon based on their ability to target redox regulations. Finally, the future perspectives in this field are proposed. It is hoped this review provides guidance for the design of nanomaterials-based approaches involving modulating intra- or extracellular redox states for cancer therapy, especially for cancers resistant to radiotherapy or chemotherapy, etc.

Black Phosphorus-based Photocatalysts: Synthesis, Properties, and Applications

Photocatalysis is considered as an eco-friendly and sustainable strategy, since it uses abundant light for the advancement of the reaction, which is freely accessible and is devoid of environmental pollution. During the last decades, (nano)photocatalysts have gained broad industrial applications in terms of purification and detoxification of water as well as production of green fuels and hydrogen gas due to their special attributes. The degradation or remediation of toxic and hazardous compounds from the environment or changing them into non-toxic entities is a significant endeavor and necessary for the safety of humans, animals, and the environment. Black phosphorus (BP), a two-dimensional single-element material, has a marvelous structure, tunable bandgap, changeable morphology from bulk to nanosheet/quantum dot, and unique physicochemical properties, which makes it attractive material for photocatalytic applications, especially for sustainable development purposes. Since it can serve as a photocatalyst with or without coupling with other semiconductors, various aspects for multidimensional exploitation of BP are deliberated including their preparation via solvothermal, ball milling, calcination, and sonication methods to obtain BP from red phosphorus. The techniques for improving the photocatalytic and stability of BP-based composites are discussed along with their multifaceted applications for environmental remediation, pollution degradation, water splitting, N2 fixation, CO2 reduction, bacterial disinfection, H2 generation, and photodynamic therapy. Herein, most recent advancements pertaining to the photocatalytic applications of BP-based photocatalyst are cogitated, with a focus on their synthesis and properties as well as crucial challenges and future perspectives.

Interfacial Engineering Enables Perovskite Heteroepitaxial Growth on Black Phosphorus for Flexible X-ray Detectors

2D materials with atomic-scale thickness and mechanical robustness are required for flexible devices. The superior optoelectronic properties and high-Z atoms in metal halide perovskites render them desirable for X-ray detection, but the intrinsic brittleness is an obstacle hampering the applications in flexible detectors. Herein, an interfacial engineering strategy is demonstrated for the epitaxial growth of methylammonium lead bromide (MAPbBr3 ) on black phosphorus (BP) for flexible X-ray detectors. The mechanically robust, high-quality heterostructure consisting of a Pb transition layer is synthesized for the two-way bridging of BP and MAPbBr3 . Excellent optoelectronic properties such as a high X-ray sensitivity of 1,609 ± 122 µC Gy-1  cm-2 (80 times higher than that of the commercial amorphous Se), a fast response time of 40 ± 5 ms, as well as a low detection limit of 3 µGys-1 (about a fifteenth of the medical chest X-ray dose rate) are achieved from the simple and planar direct X-ray detector fabricated on an organic filter membrane. More importantly, these flat and simple devices are bendable and mechanically durable by exhibiting only 10% photocurrent degradation after 200 bending cycles. The novel heterostructure has great potential in large-area, flexible, and sensitive X-ray detection applications.

Multifunctional chondroitin sulfate based hydrogels for promoting infected diabetic wounds healing by chemo-photothermal antibacterial and cytokine modulation

Diabetic foot (DF) is difficult to heal due to the formation of drug-resistant bacterial biofilms and dysregulation of the wound microenvironment. To solve this problem, multifunctional hydrogels were prepared by in situ or spraying with 3-aminophenylboronic acid modified oxidized chondroitin sulfate (APBA-g-OCS), polyvinyl alcohol (PVA) and black phosphorus/bismuth oxide/ε-polylysine (BP/Bi₂O₃/ε-PL) as precursors for promoting infected diabetic wounds healing. The hydrogels display multiple stimulus responsiveness, strong adhesion and rapid self-healing ability owing to the dynamic borate ester bonds, hydrogen bonds and π-π conjugation cross-link points, remain synergistic chemo-photothermal antibacterial effect and anti-biofilm formation ability due to the doping of BP/ Bi₂O₃/ε-PL into the hydrogel by dynamic imine bonds crosslinking and possess anti-oxidation and inflammatory chemokine adsorption ability attributing to the presence of APBA-g-OCS. Most importantly, as a result of the above functions, the hydrogels can not only respond to the wound microenvironment to conduct combined PTT and chemotherapy for efficient anti-inflammation, but also improve the wound microenvironment by scavenging ROS and regulating the expression of cytokines, thus further accelerating collagen deposition, promoting granulation tissue formation and angiogenesis, finally promoting the healing of infected wounds in diabetic rats.

Multifunctional bismuth oxide (Bi2 O3 ) particles: Evidence for selective melanoma therapy

The current study investigates the therapeutic and optical properties of bismuth oxide (Bi2 O3 ) particles for selective melanoma therapy and prevention. The Bi2 O3 particles were prepared using a standard precipitation method. The Bi2 O3 particles induced apoptosis in human A375 melanoma cells but not human HaCaT keratinocytes or CCD-1090Sk fibroblast cells. This selective apoptosis appears to be associated with a combination of factors: increased particle internalization (2.29 ± 0.41, 1.16 ± 0.08 and 1.66 ± 0.22-fold of control) and enhanced production of reactive oxygen species (ROS) (3.4 ± 0.1, 1.1 ± 0.1 and 2.05 ± 0.17-fold of control) in A375 cells compared to HaCaT and CCD-1090SK cells, respectively. As a high-Z element, bismuth is also an excellent contrast agent for computer tomography, which renders Bi2 O3 a theranostic material. Moreover, Bi2 O3 displays high UV absorption and low photocatalytic activity compared to other semiconducting metal oxides, which opens further potential fields of application as a pigment or as an active ingredient in sunscreens. Overall, this study demonstrates the multifunctional properties of Bi2 O3 particles surrounding the treatment and prevention of melanoma.

3-Bromopyruvate-loaded bismuth sulfide nanospheres improve cancer treatment by synergizing radiotherapy with modulation of tumor metabolism

BACKGROUND

Radiotherapy (RT) is one of the most mainstream cancer therapeutic modalities. However, due to the lack of specificity of the radiation adopted, both normal and cancerous cells are destroyed indiscriminately. This highlights the crucial need to improve radiosensitization. This study aims to address this issue by constructing a multifunctional nanospheres that can sensitize multiple aspects of radiotherapy.

RESULTS

Nanospheres containing high atomic element Bi can effectively absorb ionizing radiation and can be used as radiosensitizers. Cell viability after Bi₂S₃ + X-ray treatment was half that of X-ray treatment alone. On the other hand, exposed 3-bromopyruvate (3BP) could reduce the overactive oxygen (O₂) metabolism of tumor cells and alleviate tumor hypoxia, thereby promoting radiation-induced DNA damage. The combination index (CI) of 3BP and Bi₂S₃-based RT in Bi₂S₃-3BP + X-ray was determined to be 0.46 with the fraction affected (f_a) was 0.5 via Chou-Talalay's isobolographic method, which indicated synergistic effect of 3BP and Bi₂S₃-based RT after integration into Bi₂S₃-3BP + X-ray. Under the combined effect of 3BP and RT, autophagy was over-activated through starvation-induced and redox homeostasis dysregulation pathways, which in turn exhibited pro-death effects. In addition, the prepared nanospheres possess strong X-ray attenuation and high near-infrared (NIR) optical absorption, thus eliminating the need for additional functional components and could serve as bimodal contrast agents for computed tomography/photoacoustic (CT/PA) imaging.

CONCLUSIONS

The rational design of multifunctional nanospheres with the unique properties provided a novel strategy to achieving high therapeutic efficacy in RT. This was accomplished through simultaneous activation of multiple sensitization pathways by increasing ionizing radiation, reducing tumor oxygen consumption, inducing pro-death autophagy, and providing multiple-imaging guidance/monitoring.

A review of bismuth-based nanoparticles and their applications in radiosensitising and dose enhancement for cancer radiation therapy

About 50% of cancer patients receive radiation therapy. Despite the therapeutic benefits of this method, the toxicity of radiation in the normal tissues is unavoidable To improve the quality of radiation therapy, in addition to other methods such as IMRT, IGRT, and high radiation dose, nanoparticles have shown excellent potential when ionising radiation is applied to the target volume. Recently, bismuth-based nanoparticles (BiNPs) have become particularly popular in radiation therapy due to their high atomic numbers (Z), high X-ray attenuation coefficient, low toxicity, and low cost. Moreover, it is easy to synthesise in a variety of sizes and shapes. This study aimed to review the effects of the bismuth-based NP and its combination with other compounds, and their potential synergies in radiotherapy, discussed based on their physical, chemical, and biological interactions. Targeted and non-targeted bismuth-based NPs used in radiotherapy as radiosensitizers and dose enhancement effects are described. The results reported in the literature were categorised into various groups. Also, this review has highlighted the importance of bismuth-based NPs in different forms of cancer treatment to find the highest efficiency for applying them as a suitable candidate for various cancer therapy and future clinical applications.

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.

Metabolic Reprogramming of NK Cells by Black Phosphorus Quantum Dots Potentiates Cancer Immunotherapy

Low persistence, metabolic dysfunction in microenvironment, and tumor-derived immunosuppression of Natural killer (NK) cells in patients are greatly limited the successful clinical application of NK cell-based cancer immunotherapy. Interestingly, herein that human serum albumin-encapsulated black phosphorus quantum dots (BPQDs@HSA) can effectively augment antitumor efficacy of clinical patients-derived NK cell immunotherapy is found. As the donor of phosphate group, BPQDs@HSA binds with the protein of phosphatidylinositol 4-phosphate 5-kinase type-1 gamma (PIP5K1A) and activates the downstream PI3K-Akt and mTOR signaling pathways to reprogram cell metabolism of glycolysis and further promote the oxidative phosphorylation, sequentially maintains the cell viability and immunity of NK cells. And multiomics analysis is therefore conducted to reveal the underlying immunoregulation mechanisms, and that BPQDs@HSA can interact with the Toll-like receptor (TLR) on the NK cell surface and increase the expression level of mTOR, and thus activate downstream NF-κB signalling pathways to regulate cytokine secretion and enhance immune tumoricidal is found. BPQDs@HSA can also enhance immune surveillance, relieve immune suppression, and inhibit tumor immune escape. Collectively, this study not only demonstrates a successful strategy for nanomedicine-potentiated immune-cancer therapy, but also sheds light on the understanding of interface between nanomedicine and immune cells activation.

Biosafe Bi2O2Se ultrathin nanosheet for water disinfection via solar-induced photothermal synergistic effect

Solar-induced sterilization via photothermal synergy has attracted enormous attention due to its zero-energy consumption and the elimination of hazardous chemical disinfectant. Herein, we successfully synthesized a super biosafety Bi₂O₂Se with crossed nanosheet structure (Bi₂O₂Se-CN) for the sterilization of Escherichia coli (E. coli) via solar-induced photothermal synergistic effect. In comparison to bulk Bi₂O₂Se, the lower light reflection and more efficient photogenerated charge carrier separation under visible-infrared light irradiation resulted in the excellent sterilization effect of Bi₂O₂Se-CN, with a sterilization efficiency of 99.9% under the synergistic effect of light and heat. The crossed ultrathin nanosheet structure and suitable band gap width of Bi₂O₂Se-CN are fundamental reasons for its enhanced light absorption and charge carrier separation efficiency. Mechanistic studies showed that Bi₂O₂Se-CN can completely inactivate bacteria via generating a large amount of reactive oxygen species (•O₂^-, •OH, and ¹O₂) to attack the cell membrane, which further resulted in the reduced activity of intracellular enzymes and the leakage of intracellular contents. The biosafety property of Bi₂O₂Se-CN was confirmed by in vivo toxicological evaluation on the mice model. This work provided new ideas for the design of more efficient, energy-saving, biocompatible and environmental friendly solar water purification projects.

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.

Functionalization of TiO2 for Better Performance as Orthopedic Implants

This review mainly focuses on the surface functionalization approaches of titanium dioxide (TiO₂) to prevent bacterial infections and facilitate osteointegration simultaneously for titanium (Ti)-based orthopedic implants. Infection is one of the major causes of implant failure. Meanwhile, it is also critical for the bone-forming cells to integrate with the implant surface. TiO₂ is the native oxide layer of Ti which has good biocompatibility as well as enriched physical, chemical, electronic, and photocatalytic properties. The formed nanostructures during fabrication and the enriched properties of TiO₂ have enabled various functionalization methods to combat the micro-organisms and enhance the osteogenesis of Ti implants. This review encompasses the various modifications of TiO₂ in aspects of topology, drug loading, and element incorporation, as well as the most recently developed electron transfer and electrical tuning approaches. Taken together, these approaches can endow Ti implants with better bactericidal and osteogenic abilities via the functionalization of TiO₂.

Biodistribution, degradability and clearance of 2D materials for their biomedical applications

Two-dimensional (2D) materials have evolved to be a class of rapidly advancing chemical entities in the biomedical field. Nevertheless, potential side effects and safety concerns severely limit their clinical translation. After administration, 2D materials cross multiple biological barriers and are distributed throughout the body. Only the portion that accumulates at the diseased sites exerts a therapeutic effect, whereas those distributed elsewhere may cause damage to healthy tissues and interference to normal physiological function of various organs. To achieve maximum therapeutic efficacy and minimum adverse effects simultaneously, the delivery of 2D materials must be targeted at diseased sites to reach therapeutic concentrations, and the materials must possess sufficient degradation and clearance rates to avoid long-term toxicity. Therefore, it is essential to understand the biodistribution and destiny of 2D materials in vivo. In this review, first, we provide a comprehensive picture of the strategies that are currently adopted for regulating the in vivo fate of 2D materials, including modulations of their size, surface properties, composition, and external stimuli. Second, we systematically review the biodistribution, degradation, and metabolism of several newly emerged 2D materials. Finally, we also discuss the development opportunities of 2D materials in the biomedical field and the challenges to be addressed.

Engineering cancer cell membrane-camouflaged metal complex for efficient targeting therapy of breast cancer

Background

Cancer cell membrane-camouflaged nanotechnology for metal complex can enhance its biocompatibility and extend the effective circulation time in body. The ruthenium polypyridyl complex (RuPOP) has extensive antitumor activity, but it still has disadvantages such as poor biocompatibility, lack of targeting, and being easily metabolized by the organism. Cancer cell membranes retain a large number of surface antigens and tumor adhesion molecules CD47, which can be used to camouflage the metal complex and give it tumor homing ability and high biocompatibility.

Results

Therefore, this study provides an electrostatic adsorption method, which uses the electrostatic interaction of positive and negative charges between RuPOP and cell membranes to construct a cancer cell membrane-camouflaged nano-platform (RuPOP@CM). Interestingly, RuPOP@CM maintains the expression of surface antigens and tumor adhesion molecules, which can inhibit the phagocytosis of macrophage, reduce the clearance rate of RuPOP, and increase effective circulation time, thus enhancing the accumulation in tumor sites. Besides, RuPOP@CM can enhance the activity of cellular immune response and promote the production of inflammatory cytokines including TNF-α, IL-12 and IL-6, which is of great significance in treatment of tumor. On the other hand, RuPOP@MCM can produce intracellular ROS overproduction, thereby accelerating the apoptosis and cell cycle arrest of tumor cells to play an excellent antitumor effect in vitro and in vivo.

Conclusion

In brief, engineering cancer cell membrane-camouflaged metal complex is a potential strategy to improve its biocompatibility, biological safety and antitumor effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01593-5.

Catalytic radiosensitization: Insights from materials physicochemistry

Radiotherapy is indispensable in clinical cancer treatment, but because both tumor and normal tissues have similar sensitivity to X-rays, their clinical curative effect is intrinsically limited. Advanced nanomaterials and nanotechnologies have been developed for radiotherapy sensitization, typically employing high atomic number (high-Z) materials to enhance the energy deposition of X-rays in tumor tissues, but the efficiency is largely limited by the toxicity of heavy metals. A new and promising approach for radiosensitization is catalytic radiosensitization, which takes advantage of the catalytic activity of nanomaterials triggered by radiation. The efficiency of catalytic radiosensitization can be greatly enhanced by electron modulation and energy conversion of nanocatalysts upon X-ray irradiation, further enhancing the clinical curative effect. In this review, we highlight the challenges and opportunities in cancer radiosensitization, discuss novel approaches to catalytic radiosensitization, and finally describe the development of catalytic radiosensitization based on an in-depth understanding of radio-nano interactions and catalysis-biological interactions.

Oxygen-deficient titanium dioxide-loaded black phosphorus nanosheets for synergistic photothermal and sonodynamic cancer therapy

Malignant tumors, particularly those located in deep tissues, have always been a grievous threat to human health. Sonodynamic therapy (SDT) has recently attracted great attention due to deep tissue penetration. However, the lack of effective sonosensitizers and the poor therapeutic efficacy severely limit their wider use. Herein, dual-functionalized black phosphorus nanosheets (BP@PEI-PEG, i.e., PPBP) integrating black oxygen-deficient titanium dioxide particles (B-TiO₂) were successfully constructed (PPBP-B-TiO₂) for synergistic photothermal (PTT)/sonodynamic therapy. In these nanocomposites, black titanium dioxide can enhance the separation of electrons (e^-) and holes (h⁺) due to the oxygen-deficient structure and significantly improves the production of reactive oxygen species (ROS) for SDT, while the BP nanosheets endow the nanocomposites with a higher photothermal conversion capability for photothermal therapy (η = 44.1%) which can prolong the blood circulation and improve the O₂ supply. In vivo experiments prove that PPBP-B-TiO₂ nanocomposites exhibited outstanding tumor inhibition efficacy and excellent biocompatibility. This work provides a prospective platform for combined photothermal/sonodynamic cancer therapy.

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

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

Virus-Inspired Hollow Mesoporous Gadolinium-Bismuth Nanotheranostics for Magnetic Resonance Imaging-Guided Synergistic Photodynamic-Radiotherapy

The anti-tumor efficacy of single photodynamic therapy (PDT) and radiotherapy (RT) has been greatly affected by inadequate tumor uptake of photo/radiation sensitizers, limited laser penetration depth, and radiation sickness caused by high doses of X-rays. Here, the authors report a biomimetic coronavirus-inspired hollow mesoporous gadolinium/bismuth nanocarrier loaded with a new NIR photosensitizer HB (termed as HB@VHMBi-Gd) for magnetic resonance imaging (MRI)-guided synergistic photodynamic-RT. HB@VHMBi-Gd displayed a faster cellular uptake rate than the conventional spherical HMBi-Gd loaded with HB (HB@SHMBi-Gd) because of rough surface-enhanced adhesion. After intravenous injection, HB@VHMBi-Gd is efficiently delivered to the tumor and rapidly invades the tumor cells by surface spikes. Interestingly, lysosomal acidity can trigger the degradation of VHMBi-Gd to produce ultrasmall nanoparticles to amplify the X-ray attenuation ability and enhance MRI contrast and radiosensitization. Under laser and X-ray irradiation, HB@VHMBi-Gd significantly enhances ¹ O₂ generation from HB to induce activation of caspase 9/3 and inhibition of C-myc, while enhancing hydroxyl radical generation from Bi₂ O₃ to induce intense DNA breakage. By synergistically inducing cell apoptosis by distinct reactive oxygen species (ROS), HB@VHMBi-Gd exhibits superior anticancer efficacy with ≈90% tumor inhibition. They envision that biomimetic virus-inspired hollow hybrid metal nanoparticles can provide a promising strategy for imaging-guided synergistic photodynamic-RT.

Z-Scheme heterostructures for glucose oxidase-sensitized radiocatalysis and starvation therapy of tumors

Although many semiconductor heterojunctions have been prepared to promote radiation-generated exciton separation for radiocatalysis therapy (RCT), most of them inevitably sacrifice the redox ability of radiation-generated electrons and holes. Herein, we design and construct BiOI/Bi₂S₃@polydopamine nanosheets modified by amine-polyethylene glycol-folic acid and glucose oxidase for glucose oxidase-sensitized RCT and starvation therapy (ST) synergistic therapy of tumors. The unique Z-scheme energy level arrangement between BiOI and Bi₂S₃ can elevate the charge separation efficiency, as well as maximize the redox ability of radiation-generated electrons and holes, leading to the enhancement of the therapeutic efficacy of RCT. Since glucose oxidase can supply excess H₂O₂ for RCT to produce ˙OH on one hand, but efficiently cut off the energy supply of tumor cells via ST, on the other hand, our nanosheets exhibit superior tumor therapeutic efficacy to any single treatment benefiting from the cascade and synergy effects between RCT and ST.

Neodymium (3+)-Coordinated Black Phosphorus Quantum Dots with Retrievable NIR/X-Ray Optoelectronic Switching Effect for Anti-Glioblastoma

Heteroatom interaction of atomically thin nanomaterials enables the improvement of electronic transfer, band structure, and optical properties. Black phosphorus quantum dots (BP QDs) are considered to be candidate diagnostic and/or therapeutic agents due to their innate biocompatibility and exceptional photochemical effects. However, BP QDs are not competitive regarding second near-infrared (NIR-II) window medical diagnosis and X-ray induced phototherapy. Here, an Nd³⁺ ion coordinated BP QD (BPNd) is synthesized with the aim to sufficiently improve its performances in NIR-II fluorescence imaging and X-ray induced photodynamic therapy, benefitting from the retrievable NIR/X-ray optoelectronic switching effects between BP QD and Nd³⁺ ion. Given its ultrasmall size and efficient cargo loading capacity, BPNd can easily cross the blood-brain barrier to precisely monitor the growth of glioblastoma through intracranial NIR-II fluorescence imaging and impede its progression by specific X-ray induced, synergistic photodynamic chemotherapy.

Strategies to Improve Photodynamic Therapy Efficacy of Metal-Free Semiconducting Conjugated Polymers

Photodynamic therapy (PDT) is a noninvasive therapy for cancer and bacterial infection. Metal-free semiconducting conjugated polymers (SCPS) with good stability and optical and electrical properties are promising photosensitizers (PSs) for PDT compared with traditional small-molecule PSs. This review analyzes the latest progress of strategies to improve PDT effect of linear, planar, and three-dimensional SCPS, including improving solubility, adjusting conjugated structure, enhancing PS-doped SCPs, and combining therapies. Moreover, the current issues, such as hypoxia, low penetration, targeting and biosafety of SCPS, and corresponding strategies, are discussed. Furthermore, the challenges and potential opportunities on further improvement of PDT for SCPs are presented.

Advances in FePt-involved nano-system design and application for bioeffect and biosafety

The rapid development and wide application of nanomaterial-involved theranostic agents have drawn surging attention for improving the living standard of humankind and healthcare conditions. In this review, recent developments in the design, synthesis, biocompatibility evaluation and potential nanomedicine applications of FePt-involved nano-systems are summarized, especially for cancer theranostic and biological molecule detection. The in vivo multi-model imaging capability is discussed in detail, including magnetic resonance imaging and computed tomography. Furthermore, we highlight the significant achievements of various FePt-involved nanotherapeutics for cancer treatment, such as drug delivery, chemodynamic therapy, photodynamic therapy, radiotherapy and immunotherapy. In addition, a series of FePt-involved nanocomposites are also applied for biological molecule detection, such as H₂O₂, glucose and naked-eye detection of cancer cells. Ultimately, we also summarize the challenges and prospects of FePt-involved nano-systems in nanocatalytic medicine. This review is expected to give a general pattern for the development of FePt-involved nano-systems in the field of nanocatalytic medicine and analytical determination.

Near-infrared light-triggered nano-prodrug for cancer gas therapy

Gas therapy (GT) has attracted increasing attention in recent years as a new cancer treatment method with favorable therapeutic efficacy and reduced side effects. Several gas molecules, such as nitric oxide (NO), carbon monoxide (CO), hydrogen (H2), hydrogen sulfide (H2S) and sulfur dioxide (SO2), have been employed to treat cancers by directly killing tumor cells, enhancing drug accumulation in tumors or sensitizing tumor cells to chemotherapy, photodynamic therapy or radiotherapy. Despite the great progress of gas therapy, most gas molecules are prone to nonspecific distribution when administered systemically, resulting in strong toxicity to normal tissues. Therefore, how to deliver and release gas molecules to targeted tissues on demand is the main issue to be considered before clinical applications of gas therapy. As a specific and noninvasive stimulus with deep penetration, near-infrared (NIR) light has been widely used to trigger the cleavage and release of gas from nano-prodrugs via photothermal or photodynamic effects, achieving the on-demand release of gas molecules with high controllability. In this review, we will summarize the recent progress in cancer gas therapy triggered by NIR light. Furthermore, the prospects and challenges in this field are presented, with the hope for ongoing development.

Platelet Membranes Coated Gold Nanocages for Tumor Targeted Drug Delivery and Amplificated Low-Dose Radiotherapy

Continuous high doses of radiation can cause irreversible side effects and radiation resistance; thus, advanced radiosensitizers are urgently needed. To overcome this problem, we developed a nano platelet radiosensitization system (PCA) by coating the chemotherapeutic drug cisplatin (CDDP) loaded gold nanocages (AuNs) within the platelet membrane. The developed PCA system may enable AuNs to have immune escape and targeting capabilities. After administration, PCA will actively target tumor cells and avoid being cleared by the immune system. Subsequently, CDDP, which destroys tumor cell DNA, can not only kill tumor cells directly but also combine with AuNs, which deposit radiation energy into tumor tissues, reducing RT resistance. In vivo and in vitro studies revealed that the combination of PCA with RT (2Gy) efficiently inhibits tumor proliferation without causing side effects such as inflammation. To conclude, this is the first attempt to use platelet membranes to correctly transport AuNs while also accomplishing low-dose RT, which could help AuNs-based tumor RT become more effective.

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

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

Bi/Se-Based Nanotherapeutics Sensitize CT Image-Guided Stereotactic Body Radiotherapy through Reprogramming the Microenvironment of Hepatocellular Carcinoma

The particular characteristics of hypoxia, immune suppression in the tumor microenvironment, and the lack of accurate imaging guidance lead to the limited effects of stereotactic body radiotherapy (SBRT) in reducing the recurrence rate and mortality of hepatocellular carcinoma (HCC). This research developed a novel theranostic agent based on Bi/Se nanoparticles (NPs), synthesized by a simple reduction reaction method for in vivo CT image-guided SBRT sensitization in mice. After loading Lenvatinib (Len), the obtained Bi/Se-Len NPs had excellent performance in reversing hypoxia and the immune suppression status of HCC. In vivo CT imaging results uncovered that the radiotherapy (RT) area could be accurately labeled after the injection of Bi/Se-Len NPs. Under Len's unique and robust properties, in vivo treatment was then carried out upon injection of Bi/Se-Len NPs, achieving excellent RT sensitization effects in a mouse HCC model. Comprehensive tests and histological stains revealed that Bi/Se-Len NPs could reshape and normalize tumor blood vessels, reduce the hypoxic situation of the tumor, and upregulate tumor-infiltrating CD4+ and CD8+ T lymphocytes around the tumors. Our work highlights an excellent proposal of Bi/Se-Len NPs as theranostic nanoparticles for image-guided HCC radiotherapy.

The Use of Bionic Prodrugs for the Enhancement of Low Dose Radiotherapy

Radiotherapy (RT) is a standard treatment strategy for many cancer types, but the need to frequently apply high doses of ionizing radiation in order to achieve therapeutic efficacy can cause severe harm to healthy tissues, leading to adverse patient outcomes. In an effort to minimize these toxic side effects, we herein sought to design a novel approach to the low-dose RT treatment of hypoxic tumors using a Tirapazamine (TPZ)-loaded exosome (EXO) nanoplatform (MT). This MT platform was synthesized via loading EXOs with TPZ, which is a prodrug that is activated when exposed to hypoxic conditions. MT application was able to achieve effective tumor inhibition at a relatively low RT dose (2 Gy) that was superior to standard high-dose (6 Gy) RT treatment with specific targeting to the hypoxic region of tumor. RT-mediated oxygen consumption further aggravated hypoxic conditions to improve TPZ activation and treatment efficacy. Together, our findings demonstrate the clinical promise of this MT platform as a novel tool for the efficient radiosensitization and treatment of cancer patients.

Designing highly stable ferrous selenide-black phosphorus nanosheets heteronanostructure via P-Se bond for MRI-guided photothermal therapy

Background

The design of stable and biocompatible black phosphorus-based theranostic agents with high photothermal conversion efficiency and clear mechanism to realize MRI-guided precision photothermal therapy (PTT) is imminent.

Results

Herein, black phosphorus nanosheets (BPs) covalently with mono-dispersed and superparamagnetic ferrous selenide (FeSe₂) to construct heteronanostructure nanoparticles modified with methoxy poly (Ethylene Glycol) (mPEG-NH₂) to obtain good water solubility for MRI-guided photothermal tumor therapy is successfully designed. The mechanism reveals that the enhanced photothermal conversion achieved by BPs-FeSe₂-PEG heteronanostructure is attributed to the effective separation of photoinduced carriers. Besides, through the formation of the P-Se bond, the oxidation degree of FeSe₂ is weakened. The lone pair electrons on the surface of BPs are occupied, which reduces the exposure of lone pair electrons in air, leading to excellent stability of BPs-FeSe₂-PEG. Furthermore, the BPs-FeSe₂-PEG heteronanostructure could realize enhanced T₂-weighted imaging due to the aggregation of FeSe₂ on BPs and the formation of hydrogen bonds, thus providing accurate PTT guidance and generating hyperthermia to inhabit tumor growth under NIR laser with negligible toxicity in vivo.

Conclusions

Collectively, this work offers an opportunity for fabricating BPs-based heteronanostructure nanomaterials that could simultaneously enhance photothermal conversion efficiency and photostability to realize MRI-guided cancer therapy.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00905-5.

Gold-iron selenide nanocomposites for amplified tumor oxidative stress-augmented photo-radiotherapy

The radio-resistance of tumor tissues has been considered a great challenge for cancer radiotherapy (RT).The development of nanoparticle (NP)-based radio-sensitizers can enhance the radio-sensitization of tumor tissues while reducing the side effects to surrounding tissues. However, most of the nano-radiosensitizers show increased radiation deposition with a high-Z element but achieve limited enhancement. Herein, we investigated polyethylene glycol (PEG)-modified gold-iron selenide nanocomposites (Au-FeSe2 NCs) for simultaneously enhancing therapeutic effects in multiple ways. In this study, the high-Z element Au (Z = 79) endows Au-FeSe2 NCs with enhanced X-ray deposition and thus causes more DNA damage. On the other hand, Au-FeSe2 exhibits the ability to produce reactive oxygen species (ROS) by catalyzing endogenous hydrogen peroxide in tumor sites as well as improve the hydrogen peroxide level during ionizing irradiation. Finally, combined with photothermal therapy (PTT), Au-FeSe2 NCs could exhibit a remarkable RT/PTT synergistic effect on tumor treatment.

Nano-enabled coordination platform of bismuth nitrate and cisplatin prodrug potentiates cancer chemoradiotherapy via DNA damage enhancement

The combination of chemotherapy and radiotherapy (chemoradiotherapy) is a promising strategy, extensively studied and applied clinically. Meanwhile, radiosensitizers play an important role in improving clinical radiotherapy therapeutic efficacy. There are still some disadvantages in practical applications, because radiosensitizers and drugs are difficult to deliver spatio-temporally to tumor sites and work simultaneously with low efficiency for DNA damage and repair inhibition, leading to an inferior synergistic effect. Herein, a suitable radiosensitizer of nano-enabled coordination platform (NP@PVP) with bismuth nitrate and cisplatin prodrug is developed by a simple synthetic route to improve the effectiveness of chemo-radiation synergistic therapy. When NP@PVP is internalized by a tumor cell, the bismuth in NP@PVP can sensitize radiation therapy (RT) by increasing the amount of reactive oxygen species generation to enhance DNA damage after X-ray radiation; meanwhile, the cisplatin in NP@PVP can inhibit DNA damage repair with spatio-temporal synchronization. NP@PVP is demonstrated to exhibit higher sensitization enhancement ratio (SER) of 2.29 and excellent tumor ablation capability upon irradiation in vivo in comparison with cisplatin (SER of 1.78). Our strategy demonstrates that the RT sensitization effect of bismuth and cisplatin based NP@PVP has great anticancer potential in chemo-radiation synergistic therapy, which is promising for clinical application.

Progress in the therapeutic applications of polymer-decorated black phosphorus and black phosphorus analog nanomaterials in biomedicine

Wonderful black phosphorus (BP) and some BP analogs (BPAs) have been increasingly studied for their biomedical applications owing to their fascinating properties and biodegradability, but opportunities and challenges have always coexisted in their study. Poor stability upon exposure to the natural environment is the major obstacle hampering their in vivo applications. BP/polymer and BPAs/polymer nanocomposites can not only efficiently prevent their oxidation and aggregation but also exhibit "biological activity" due to synergistic effects. In this review, we briefly describe the synthesis methods and stability strategies of BP/polymer and BPAs/polymer. Then, advances pertaining to their exciting therapeutic applications in various fields are systematically introduced, such as cancer therapy (phototherapy, drug delivery, and synergistic immunotherapy), bone regeneration, and neurogenesis. Some challenges for future clinical trials and possible directions for further study are finally discussed.

Bi2O3 boosts brightness, biocompatibility and stability of Mn-doped Ba3(VO4)2 as NIR-II contrast agent

Deep-tissue fluorescence imaging remains a major challenge as there is limited availability of bright biocompatible materials with high photo- and chemical stability. Contrast agents with emission wavelengths above 1000 nm are most favorable for deep tissue imaging, offering deeper penetration and less scattering than those operating at shorter wavelengths. Organic fluorophores suffer from low stability while inorganic nanomaterials (e.g. quantum dots) are based typically on heavy metals raising toxicity concerns. Here, we report scalable flame aerosol synthesis of water-dispersible Ba₃(VO₄)₂ nanoparticles doped with Mn⁵⁺ which exhibit a narrow emission band at 1180 nm upon near-infrared excitation. Their co-synthesis with Bi₂O₃ results in even higher absorption and ten-fold increased emission intensity. The addition of Bi₂O₃ also improved both chemical stability and cytocompatibility by an order of magnitude enabling imaging deep within tissue. Taken together, these bright particles offer excellent photo-, chemical and colloidal stability in various media with cytocompatibility to HeLa cells superior to existing commercial contrast agents.

Coordination-Driven Enhancement of Radiosensitization by Black Phosphorus via Regulating Tumor Metabolism

Coordination-driven surface modification is an effective strategy to achieve nanosystem functionalization and improved physicochemical performance. Black phosphorus (BP)-based nanomaterials demonstrate great potential in cancer therapy, but their poor stability, low X-ray mass attenuation coefficient, and nonselectivity limit the application in radiotherapy. Herein, we used unsaturated iridium complex to coordinate with BP nanosheets to synthesize a two-dimensional layered nanosystem (RGD-Ir@BP) with higher biostability. Ir complex improves the photoelectric properties and photoinduced charge carrier dynamics of BP, hence Ir@BP generated more singlet oxygen after X-ray irradiation. In in vivo experiments, with X-ray irradiation, RGD-Ir@BP effectively inhibited nasopharyngeal carcinoma tumor growth but with minor side effects. Additionally, based on untargeted metabolomics analysis, the combined treatment specifically down-regulated the tumor proliferative mark of prostaglandin E2 in cancer cells. In general, this study provides a design strategy of high-performance coordination-driven BP-based nanosensitizer in cancer radiotherapy.

Pnictogen Semimetal (Sb, Bi)-Based Nanomaterials for Cancer Imaging and Therapy: A Materials Perspective

Innovative multifunctional nanomaterials have attracted tremendous interest in current research by facilitating simultaneous cancer imaging and therapy. Among them, antimony (Sb)- and bismuth (Bi)-based nanoparticles are important species with multifunction to boost cancer theranostic efficacy. Despite the rapid development, the extensive previous work treated Sb- and Bi-based nanoparticles as mutually independent species, and therefore a thorough understanding of their relationship in cancer theranostics was lacking. We propose here that the identical chemical nature of Sb and Bi, being semimetals, provides their derived nanoparticles with inherent multifunction for near-infrared laser-driven and/or X-ray-based cancer imaging and therapy as well as some other imparted functions. An overview of recent progress on Sb- and Bi-based nanoparticles for cancer theranostics is provided to highlight the relationship between chemical nature and multifunction. The understanding of Sb- and Bi-based nanoparticles in this way might shed light on the further design of smart multifunctional nanoparticles for cancer theranostics.

Cytotoxicity of black phosphorus quantum dots on lung-derived cells and the underlying mechanisms

Black phosphorus quantum dots (BP-QDs) are a new type of zero-dimensional (0D) nanomaterial that has been widely used due of their superior properties in many biomedical fields, but limited studies have focused on the biocompatibility of BP-QDs, particularly in the respiratory system. In this study, we investigated the potential lung cell toxicity of BP-QDs in vitro. Two human lung-derived cells, A549 and Beas-2B, were treated with 5∼20 μg/mL BP-QDs for 24 h. The results showed that BP-QDs triggered significant lung cell toxicity, including a dose-dependent decrease in cell viability, lactate dehydrogenase (LDH) leakage, cell shape changes, cellular oxidative stress and cell cycle arrest. In addition, pretreatment with the classical phagocytosis inhibitor cytochalasin D (Cyto D) alleviated the decrease in cell viability and LDH leakage induced by BP-QDs. In contrast, BP-QDs induced the production of cellular reactive oxygen species (ROS) and decreases in the glutathione level, whereas the ROS scavenger N-acetyl-L-cysteine (NAC) could protect A549 and Beas-2B cells from BP-QD-induced cellular oxidative stress. Taken together, the results from this study indicate that the potential toxic effects and mechanisms of BP-QDs in two different human lung cells should be considered to evaluate the lung cell safety of BP-QDs.

The Art of Constructing Black Phosphorus Nanosheet Based Heterostructures: From 2D to 3D

Assembling different kinds of 2D nanosheets into heterostructures presents a promising way of designing novel artificial materials with new and improved functionalities by combining the unique properties of each component. In the past few years, black phosphorus nanosheets (BPNSs) have been recognized as a highly feasible 2D material with outstanding electronic properties, a tunable bandgap, and strong in-plane anisotropy, highlighting their suitability as a material for constructing heterostructures. In this study, recent progress in the construction of BPNS-based heterostructures ranging from 2D hybrid structures to 3D networks is discussed, emphasizing the different types of interactions (covalent or noncovalent) between individual layers. The preparation methods, optical and electronic properties, and various applications of these heterostructures-including electronic and optoelectronic devices, energy storage devices, photocatalysis and electrocatalysis, and biological applications-are discussed. Finally, critical challenges and prospective research aspects in BPNS-based heterostructures are also highlighted.

A targeting black phosphorus nanoparticle based immune cells nano-regulator for photodynamic/photothermal and photo-immunotherapy

Photo-immunotherapy is a novel therapeutic approach against malignant tumors with minimal invasiveness. Herein, a targeting multifunctional black phosphorus (BP) nanoparticle, modified by PEGylated hyaluronic acid (HA), was designed for photothermal/photodynamic/photo-immunotherapy. In vitro and in vivo assays indicated that HA-BP nanoparticles possess excellent biocompatibility, stability, and sufficient therapeutic efficacy in the combined therapy of photothermal therapy (PTT) and photodynamic therapy (PDT) for cancer therapy. Moreover, the results of in vitro showed that HA-BP down-regulated the expression of CD206 (M2 macrophage marker) by 42.3% and up-regulated the ratio of CD86（M1 macrophage marker）by 59.6%, indicating that HA-BP nanoparticles have functions in remodeling tumor associated macrophages (TAMs) phenotype (from pro-tumor M2 TAMs to anti-tumor M1 macrophages). Fluorescence (FL) and photoacoustic (PA) multimodal imaging confirmed the selective accumulation of HA-BP in tumor site via both CD44⁺ mediated active targeting and passive EPR effect. In vitro and in vivo studies suggested that the combined therapy of PDT, PTT and immunotherapy using HA-BP could not only significantly inhibit original tumor but also induce immunogenic cell death (ICD) and release Damage-associated molecular patterns (DAMPs), which could induce maturation of dendritic cells (DCs) and activate effector cells that robustly evoke the antitumor immune responses for cancer treatment. This study expands the biomedical application of BP nanoparticles and displays the potential of modified BP as a multifunctional therapeutic platform for the future cancer therapy.

•

Novel HA-BP NPs were synthesized for photothermal/photodynamic/photo-immunotherapy.

•

HA-BP NPs with size around 50 nm possess remarkable enhancement of tumor targeting and accumulation ability.

•

HA-BP NPs could promote M2 to M1 macrophage polarization and further enhance invasion of activated CD4⁺ and CD8⁺ T cells.

Degradation-by-design: how chemical functionalization enhances the biodegradability and safety of 2D materials

A large number of graphene and other 2D materials are currently used for the development of new technologies, increasingly entering different industrial sectors. Interrogating the impact of such 2D materials on health and environment is crucial for both modulating their potential toxicity in living organisms and eliminating them from the environment. In this context, understanding if 2D materials are bio-persistent is mandatory. In this review we describe the importance of biodegradability and decomposition of 2D materials. We initially cover the biodegradation of graphene family materials, followed by other emerging classes of 2D materials including transition metal dichalcogenides and oxides, Xenes, Mxenes and other non-metallic 2D materials. We explain the role of defects and functional groups, introduced onto the surface of the materials during their preparation, and the consequences of chemical functionalization on biodegradability. In strong relation to the chemistry on 2D materials, we describe the concept of "degradation-by-design" that we contributed to develop, and which concerns the covalent modification with appropriate molecules to enhance the biodegradability of 2D materials. Finally, we cover the importance of designing new biodegradable 2D conjugates and devices for biomedical applications as drug delivery carriers, in bioelectronics, and tissue engineering. We would like to highlight that the biodegradation of 2D materials mainly depends on the type of material, the chemical functionalization, the aqueous dispersibility and the redox potentials of the different oxidative environments. Biodegradation is one of the necessary conditions for the safe application of 2D materials. Therefore, we hope that this review will help to better understand their biodegradation processes, and will stimulate the chemists to explore new chemical strategies to design safer products, composites and devices containing 2D materials.

Lentinan-functionalized selenium nanosystems with high permeability infiltrate solid tumors by enhancing transcellular transport

The delivery of nanomedicines into internal areas of solid tumors is a great challenge for the design of chemotherapeutic drugs and the realization of their successful application. Herein, we synthesized stable and efficient selenium nanoparticles (SeNPs) with an ideal size and a transcellular transport capability for the penetration and treatment of a solid tumor, utilizing Tw-80 as a dispersing agent and mushroom polysaccharide lentinan (LET) as a decorator. In vitro cellular experiments demonstrated that this nanosystem, LET-Tw-SeNPs, renders significant cellular uptake of HepG2 by receptor-mediated endocytosis and exhibits predominant transcellular transport and penetration capacity towards HepG2 tumor spheroids. Moreover, this therapeutic agent simultaneously inhibits the proliferation and migration of HepG2 cells via a cell cycle arrest pathway. Internalized LET-Tw-SeNPs give rise to the overproduction of intracellular reactive oxygen species (ROS), thus inducing mitochondrial rupture. Meanwhile, pharmacokinetic analysis showed that LET-Tw-SeNPs displayed a long half-life in blood. Altogether, this study demonstrates an inventive strategy for designing nanosystems with high permeability and low blood clearance, in order to achieve efficient in-depth tumor drug delivery and future clinical treatment of solid tumors.

Interplay between Cellular Uptake, Intracellular Localization and the Cell Death Mechanism in Triphenylamine-Mediated Photoinduced Cell Death

Triphenylamines (TPAs) were previously shown to trigger cell death under prolonged one- or two-photon illumination. Their initial subcellular localization, before prolonged illumination, is exclusively cytoplasmic and they translocate to the nucleus upon photoactivation. However, depending on their structure, they display significant differences in terms of precise initial localization and subsequent photoinduced cell death mechanism. Here, we investigated the structural features of TPAs that influence cell death by studying a series of molecules differing by the number and chemical nature of vinyl branches. All compounds triggered cell death upon one-photon excitation, however to different extents, the nature of the electron acceptor group being determinant for the overall cell death efficiency. Photobleaching susceptibility was also an important parameter for discriminating efficient/inefficient compounds in two-photon experiments. Furthermore, the number of branches, but not their chemical nature, was crucial for determining the cellular uptake mechanism of TPAs and their intracellular fate. The uptake of all TPAs is an active endocytic process but two- and three-branch compounds are taken up via distinct endocytosis pathways, clathrin-dependent or -independent (predominantly caveolae-dependent), respectively. Two-branch TPAs preferentially target mitochondria and photoinduce both apoptosis and a proper necrotic process, whereas three-branch TPAs preferentially target late endosomes and photoinduce apoptosis only.

Graphene and other 2D materials: a multidisciplinary analysis to uncover the hidden potential as cancer theranostics

Cancer represents one of the main causes of death in the world; hence the development of more specific approaches for its diagnosis and treatment is urgently needed in clinical practice. Here we aim at providing a comprehensive review on the use of 2-dimensional materials (2DMs) in cancer theranostics. In particular, we focus on graphene-related materials (GRMs), graphene hybrids, and graphdiyne (GDY), as well as other emerging 2DMs, such as MXene, tungsten disulfide (WS2), molybdenum disulfide (MoS2), hexagonal boron nitride (h-BN), black phosphorus (BP), silicene, antimonene (AM), germanene, biotite (black mica), metal organic frameworks (MOFs), and others. The results reported in the scientific literature in the last ten years (>200 papers) are dissected here with respect to the wide variety of combinations of imaging methodologies and therapeutic approaches, including drug/gene delivery, photothermal/photodynamic therapy, sonodynamic therapy, and immunotherapy. We provide a unique multidisciplinary approach in discussing the literature, which also includes a detailed section on the characterization methods used to analyze the material properties, highlighting the merits and limitations of the different approaches. The aim of this review is to show the strong potential of 2DMs for use as cancer theranostics, as well as to highlight issues that prevent the clinical translation of these materials. Overall, we hope to shed light on the hidden potential of the vast panorama of new and emerging 2DMs as clinical cancer theranostics.

The Rational Design and Biological Mechanisms of Nanoradiosensitizers

Radiotherapy (RT) has been widely used for cancer treatment. However, the intrinsic drawbacks of RT, such as radiotoxicity in normal tissues and tumor radioresistance, promoted the development of radiosensitizers. To date, various kinds of nanoparticles have been found to act as radiosensitizers in cancer radiotherapy. This review focuses on the current state of nanoradiosensitizers, especially the related biological mechanisms, and the key design strategies for generating nanoradiosensitizers. The regulation of oxidative stress, DNA damage, the cell cycle, autophagy and apoptosis by nanoradiosensitizers in vitro and in vivo is highlighted, which may guide the rational design of therapeutics for tumor radiosensitization.

Property-Activity Relationship of Black Phosphorus at the Nano-Bio Interface: From Molecules to Organisms

As a novel member of the two-dimensional nanomaterial family, mono- or few-layer black phosphorus (BP) with direct bandgap and high charge carrier mobility is promising in many applications such as microelectronic devices, photoelectronic devices, energy technologies, and catalysis agents. Due to its benign elemental composition (phosphorus), large surface area, electronic/photonic performances, and chemical/biological activities, BP has also demonstrated a great potential in biomedical applications including biosensing, photothermal/photodynamic therapies, controlled drug releases, and antibacterial uses. The nature of the BP-bio interface is comprised of dynamic contacts between nanomaterials (NMs) and biological systems, where BP and the biological system interact. The physicochemical interactions at the nano-bio interface play a critical role in the biological effects of NMs. In this review, we discuss the interface in the context of BP as a nanomaterial and its unique physicochemical properties that may affect its biological effects. Herein, we comprehensively reviewed the recent studies on the interactions between BP and biomolecules, cells, and animals and summarized various cellular responses, inflammatory/immunological effects, as well as other biological outcomes of BP depending on its own physical properties, exposure routes, and biodistribution. In addition, we also discussed the environmental behaviors and potential risks on environmental organisms of BP. Based on accumulating knowledge on the BP-bio interfaces, this review also summarizes various safer-by-design strategies to change the physicochemical properties including chemical stability and nano-bio interactions, which are critical in tuning the biological behaviors of BP. The better understanding of the biological activity of BP at BP-bio interfaces and corresponding methods to overcome the challenges would promote its future exploration in terms of bringing this new nanomaterial to practical applications.