Black phosphorous nanosheet: A novel immune-potentiating nanoadjuvant for near-infrared-improved immunotherapy

Stable triangle: nanomedicine-based synergistic application of phototherapy and immunotherapy for tumor treatment

In recent decades, cancer has posed a challenging obstacle that humans strive to overcome. While phototherapy and immunotherapy are two emerging therapies compared to traditional methods, they each have their advantages and limitations. These limitations include easy metastasis and recurrence, low response rates, and strong side effects. To address these issues, researchers have increasingly focused on combining these two therapies by utilizing a nano-drug delivery system due to its superior targeting effect and high drug loading rate, yielding remarkable results. The combination therapy demonstrates enhanced response efficiency and effectiveness, leading to a preparation that is highly targeted, responsive, and with low recurrence rates. This paper reviews several main mechanisms of anti-tumor effects observed in combination therapy based on the nano-drug delivery system over the last five years. Furthermore, the challenges and future prospects of this combination therapy are also discussed.

2D nanomaterials-based delivery systems and their potentials in anticancer synergistic photo-immunotherapy

As the field of cancer therapeutics evolves, integrating two-dimensional (2D) nanomaterials with photo-immunotherapy has emerged as a promising approach with significant potential to augment cancer treatment efficacy. These 2D nanomaterials include graphene-based 2D nanomaterials, 2D MXenes, 2D layered double hydroxides, black phosphorus nanosheets, 2D metal-organic frameworks, and 2D transition metal dichalcogenides. They exhibit high load capacities, multiple functionalization pathways, optimal biocompatibility, and physiological stability. Predominantly, they function as anti-tumor delivery systems, amalgamating diverse therapeutic modalities, most notably phototherapy and immunotherapy, and the former is a recognized non-invasive treatment modality, and the latter represents the most promising anti-cancer strategy presently accessible. Thus, integrating phototherapy and immunotherapy founded on 2D nanomaterials unveils a novel paradigm in the war against cancer. This review delineates the latest developments in 2D nanomaterials as delivery systems for synergistic photo-immunotherapy in cancer treatment. We elaborate on the burgeoning realm of photo-immunotherapy, exploring the interplay between phototherapy and enhanced immune cells, immune response modulation, or immunosuppressive tumor microenvironments. Notably, the strategies to augment photo-immunotherapy have also been discussed. Finally, we discuss the challenges and future perspectives of these 2D nanomaterials in photo-immunotherapy.

Mannosylated Fluoropolypeptide Nanovaccines Remodeling Tumor Immunosuppressive Microenvironment to Achieve Highly Potent Cancer Immunotherapy

It is challenging for nanovaccines (NVs) to effectively deliver antigens/neoantigens to prime specifically potent immunities and remodel immunosuppressive tumor microenvironment (TME) for combating immune "cold" cancers. Herein, a novel kind of mannosylated fluoropolypeptide NVs of MFPCOFG (i.e., mannosylated fluoropoly(D,L-cysteine) ovalbumin-loaded Fe2+-gallic acid) is designed that synergistically integrates triple antigen-metal-thermoimmunity to remodel immunosuppressive TME and achieve highly potent immunities. MFPCOFG plus near-infrared irradiation (NIR) effectively facilitated antigen uptake and escape, induced the maturation and antigen cross-presentations of dendritic cells and macrophages, polarized anti-inflammatory macrophage phenotype M2 into tumoricial M1, primed potent CD4+/CD8+T cells responses, proinflammatory cytokines secretion and immune memory effects, showcasing triple antigen-metal-thermoimmunity outperforming combo/mono-immunity. Importantly, both MFPCOFG + NIR and personalized NVs can remarkably enhance the tumor infiltration of CD4+/CD8+T and NK cells to boost potent immunities and long-lasting memory effects, reduce regulatory T (Tregs) and M2 to remodel immunosuppressive TME in B16-OVA and 4T1 models, achieving superior tumor prevention, ablation, and tumor relapse and metastasis inhibition, as further orchestrated with anti-PD-1. Consequently, this work opens up a new avenue to design biocompatible polypeptide nanovaccines with potent immune-priming and TME-remodeling capabilities, holding great potentials to combat immune "cold" cancers with clinic-used anti-PD-1 for cancer immunotherapy and personalized immunotherapy.

Recent Advances in Non-Ti MXenes: Synthesis, Properties, and Novel Applications

One of the most fascinating 2D nanomaterials (NMs) ever found is various members of MXene family. Among them, the titanium-based MXenes, with more than 70% of publication-related investigations, are comparatively well studied, producing fundamental foundation for the 2D MXene family members with flexible properties, familiar with a variety of advanced novel technological applications. Nonetheless, there are still more candidates among transitional metals (TMs) that can function as MXene NMs in ways that go well beyond those that are now recognized. Systematized details of the preparations, characteristics, limitations, significant discoveries, and uses of the novel M-based MXenes (M-MXenes), where M stands for non-Ti TMs (M = Sc, V, Cr, Y, Zr, Nb, Mo, Hf, Ta, W, and Lu), are given. The exceptional qualities of the 2D non-Ti MXene outperform standard Ti-MXene in several applications. There is many advancement in top-down as well as bottom-up production of MXenes family members, which allows for exact control of the M-characteristics MXene NMs to contain cutting-edge applications. This study offers a systematic evaluation of existing research, covering everything in producing complex M-MXenes from primary limitations to the characterization and selection of their applications in accordance with their novel features. The development of double metal combinations, extension of additional metal candidates beyond group-(III-VI)B family, and subsequent development of the 2D TM carbide/TMs nitride/TM carbonitrides to 2D metal boride family are also included in this overview. The possibilities and further recommendations for the way of non-Ti MXene NMs are in the synthesis of NMs will discuss in detail in this critical evaluation.

Effect of Bioactive Black Phosphorus Nanomaterials on Cancer-Associated Fibroblast Heterogeneity in Pancreatic Cancer

Tumor-stromal interactions and stromal heterogeneity in the tumor microenvironment are critical factors that influence the progression, metastasis, and chemoresistance of pancreatic ductal adenocarcinoma (PDAC). Here, we used spatial transcriptome technology to profile the gene expression landscape of primary PDAC and liver metastatic PDAC after bioactive black phosphorus nanomaterial (bioactive BP) treatment using a murine model of PDAC (LSL-KrasG12D/+; LSL-Trp53R172H/+; and Pdx-1-Cre mice). Bioinformatic and biochemical analyses showed that bioactive BP contributes to the tumor-stromal interplay by suppressing cancer-associated fibroblast (CAF) activation. Our results showed that bioactive BP contributes to CAF heterogeneity by decreasing the amount of inflammatory CAFs and myofibroblastic CAFs, two CAF subpopulations. Our study demonstrates the influence of bioactive BP on tumor-stromal interactions and CAF heterogeneity and suggests bioactive BP as a potential PDAC treatment.

Bibliometric and visual analysis in the field of two-dimensions nano black phosphorus in cancer from 2015 to 2023

This study aims to provide a comprehensive summary of the status and trends of Two-Dimensional Nano Black Phosphorus (2D nano BP) in cancer research from 2015 to 2023, offering insights for future studies. To achieve this, articles from the Web of Science database published between 2015 and 2023 were analyzed using R and VOSviewer software. The analysis included 446 articles, revealing a consistent increase in publication rates, especially between 2017 and 2019. China emerged as a leader in both publication volume and international collaborations. Prominent journals in this field included ACS Applied Materials & Interfaces and Advanced Materials, while key researchers were identified as Zhang Han, Tao Wei, and Yu Xuefeng. The analysis highlighted common keywords such as drug delivery, photothermal therapy, photodynamic therapy, and immunotherapy, indicating the major research focuses. The findings suggest that 2D nano BP holds significant promise in cancer treatment research, with a growing global interest. This study thus serves as a valuable reference for future investigations, providing a detailed analysis of the current state and emerging trends in this promising field.

Engineering customized nanovaccines for enhanced cancer immunotherapy

Nanovaccines have gathered significant attention for their potential to elicit tumor-specific immunological responses. Despite notable progress in tumor immunotherapy, nanovaccines still encounter considerable challenges such as low delivery efficiency, limited targeting ability, and suboptimal efficacy. With an aim of addressing these issues, engineering customized nanovaccines through modification or functionalization has emerged as a promising approach. These tailored nanovaccines not only enhance antigen presentation, but also effectively modulate immunosuppression within the tumor microenvironment. Specifically, they are distinguished by their diverse sizes, shapes, charges, structures, and unique physicochemical properties, along with targeting ligands. These features of nanovaccines facilitate lymph node accumulation and activation/regulation of immune cells. This overview of bespoke nanovaccines underscores their potential in both prophylactic and therapeutic applications, offering insights into their future development and role in cancer immunotherapy.

Biomimetic MDSCs membrane coated black phosphorus nanosheets system for photothermal therapy/photodynamic therapy synergized chemotherapy of cancer

Photothermal therapy is favored by cancer researchers due to its advantages such as controllable initiation, direct killing and immune promotion. However, the low enrichment efficiency of photosensitizer in tumor site and the limited effect of single use limits the further development of photothermal therapy. Herein, a photo-responsive multifunctional nanosystem was designed for cancer therapy, in which myeloid-derived suppressor cell (MDSC) membrane vesicle encapsulated decitabine-loaded black phosphorous (BP) nanosheets (BP@ Decitabine @MDSCs, named BDM). The BDM demonstrated excellent biosafety and biochemical characteristics, providing a suitable microenvironment for cancer cell killing. First, the BDM achieves the ability to be highly enriched at tumor sites by inheriting the ability of MDSCs to actively target tumor microenvironment. And then, BP nanosheets achieves hyperthermia and induces mitochondrial damage by its photothermal and photodynamic properties, which enhancing anti-tumor immunity mediated by immunogenic cell death (ICD). Meanwhile, intra-tumoral release of decitabine induced G2/M cell cycle arrest, further promoting tumor cell apoptosis. In vivo, the BMD showed significant inhibition of tumor growth with down-regulation of PCNA expression and increased expression of high mobility group B1 (HMGB1), calreticulin (CRT) and caspase 3. Flow cytometry revealed significantly decreased infiltration of MDSCs and M2-macrophages along with an increased proportion of CD4+, CD8+ T cells as well as CD103+ DCs, suggesting a potentiated anti-tumor immune response. In summary, BDM realizes photothermal therapy/photodynamic therapy synergized chemotherapy for cancer.

Myeloid Cell-Triggered In Situ Cell Engineering for Robust Vaccine-Based Cancer Treatment

Following the success of the dendritic cell (DC) vaccine, the cell-based tumor vaccine shows its promise as a vaccination strategy. Except for DC cells, targeting other immune cells, especially myeloid cells, is expected to address currently unmet clinical needs (e.g., tumor types, safety issues such as cytokine storms, and therapeutic benefits). Here, it is shown that an in situ injected macroporous myeloid cell adoptive scaffold (MAS) not only actively delivers antigens (Ags) that are triggered by scaffold-infiltrating cell surface thiol groups but also releases granulocyte-macrophage colony-stimulating factor and other adjuvant combos. Consequently, this promotes cell differentiation, activation, and migration from the produced monocyte and DC vaccines (MASVax) to stimulate antitumor T-cell immunity. Neoantigen-based MASVax combined with immune checkpoint blockade induces rejection of established tumors and long-term immune protection. The combined depletion of immunosuppressive myeloid cells further enhances the efficacy of MASVax, indicating the potential of myeloid cell-based therapies for immune enhancement and normalization treatment of cancer.

Two-dimensional nanomaterials induced nano-bio interfacial effects and biomedical applications in cancer treatment

Two-dimensional nanomaterials (2D NMs), characterized by a large number of atoms or molecules arranged in one dimension (typically thickness) while having tiny dimensions in the other two dimensions, have emerged as a pivotal class of materials with unique properties. Their flat and sheet-like structure imparts distinctive physical, chemical, and electronic attributes, which offers several advantages in biomedical applications, including enhanced surface area for efficient drug loading, surface-exposed atoms allowing precise chemical modifications, and the ability to form hierarchical multilayer structures for synergistic functionality. Exploring their nano-bio interfacial interactions with biological components holds significant importance in comprehensively and systematically guiding safe applications. However, the current lack of in-depth analysis and comprehensive understanding of interfacial effects on cancer treatment motivates our ongoing efforts in this field. This study provides a comprehensive survey of recent advances in utilizing 2D NMs for cancer treatment. It offers insights into the structural characteristics, synthesis methods, and surface modifications of diverse 2D NMs. The investigation further delves into the formation of nano-bio interfaces during their in vivo utilization. Notably, the study discusses a wide array of biomedical applications in cancer treatment. With their potential to revolutionize therapeutic strategies and outcomes, 2D NMs are poised at the forefront of cancer treatment, holding the promise of transformative advancements.

Black Phosphorus Nanosheets Assist Nanoerythrosomes for Efficient mRNA Vaccine Delivery and Immune Activation

Messenger RNA (mRNA)-based vaccines have enormous potential in infectious disease prevention and tumor neoantigen application. However, developing an advanced delivery system for efficient mRNA delivery and intracellular release for protein translation remains a challenge. Herein, a biocompatible biomimetic system is designed using red blood cell-derived nanoerythrosomes (NER) and black phosphorus nanosheets (BP) for mRNA delivery. BP is covalently modified with polyethyleneimine (PEI), serving as a core to efficiently condense mRNA via electrostatic interactions. To facilitate the spleen targeting of the mRNA-loaded BP (BPmRNA ), NER is co-extruded with BPmRNA to construct a stable "core-shell" nanovaccine (NER@BPmRNA ). The mRNA nanovaccine exhibits efficient protein expression and immune activation via BP-mediated adjuvant effect and enhanced lysosomal escape. In vivo evaluation demonstrates that the system delivery of mRNA encoding coronavirus receptor-binding domain (RBD) significantly increases the antibody titer and pseudovirus neutralization effect compared with that of NER without BP assistance. Furthermore, the mRNA extracted from mouse melanoma tissues is utilized to simulate tumor neoantigen delivered by NER@BPmRNA . In the vaccinated mice, BP-assisted NER for the delivery of melanoma mRNA can induce more antibodies that specifically recognize tumor antigens. Thus, BP-assisted NER can serve as a safe and effective delivery vehicle in mRNA-based therapy.

Four Ounces Can Move a Thousand Pounds: The Enormous Value of Nanomaterials in Tumor Immunotherapy

The application of nanomaterials in healthcare has emerged as a promising strategy due to their unique structural diversity, surface properties, and compositional diversity. In particular, nanomaterials have found a significant role in improving drug delivery and inhibiting the growth and metastasis of tumor cells. Moreover, recent studies have highlighted their potential in modulating the tumor microenvironment (TME) and enhancing the activity of immune cells to improve tumor therapy efficacy. Various types of nanomaterials are currently utilized as drug carriers, immunosuppressants, immune activators, immunoassay reagents, and more for tumor immunotherapy. Necessarily, nanomaterials used for tumor immunotherapy can be grouped into two categories: organic and inorganic nanomaterials. Though both have shown the ability to achieve the purpose of tumor immunotherapy, their composition and structural properties result in differences in their mechanisms and modes of action. Organic nanomaterials can be further divided into organic polymers, cell membranes, nanoemulsion-modified, and hydrogel forms. At the same time, inorganic nanomaterials can be broadly classified as nonmetallic and metallic nanomaterials. The current work aims to explore the mechanisms of action of these different types of nanomaterials and their prospects for promoting tumor immunotherapy.

Identification of a Self-Assembling Small-Molecule Cancer Vaccine Adjuvant with an Improved Toxicity Profile

Protein or peptide cancer vaccines usually include immune potentiators, so-called adjuvants. However, it remains challenging to identify structurally simple, chemically accessible synthetic molecules that are effective and safe as vaccine adjuvant. Here, we present cholicamideβ (6), a self-assembling small-molecule vaccine adjuvant with an improved toxicity profile and proven efficacy in vivo. We demonstrate that cholicamideβ (6), which is less cytotoxic than its parent compound, forms virus-like particles to potently activate dendritic cells with the concomitant secretion of cytokines. When combined with a peptide antigen, cholicamideβ (6) potentiated the antigen presentation on dendritic cells to induce antigen-specific T cells. As a therapeutic cancer vaccine adjuvant in mice, a mixture of cholicamideβ (6) and a peptide antigen protected mice from the challenges of malignant cancer cells without overt toxicity. Cholicamideβ (6) may offer a translational opportunity as an unprecedented class of small-molecule cancer vaccine adjuvants.

Copper-Catalyzed Aerobic Oxidative/Decarboxylative Phosphorylation of Aryl Acrylic Acids with P(III)-Nucleophiles

A copper-catalyzed aerobic oxidative/decarboxylative phosphorylation of aryl acrylic acids with P(III)-nucleophiles via the Michaelis-Arbuzov rearrangement for the synthesis of β-ketophosphine oxides, β-ketophosphinates, and β-ketophosphonates is reported. The present reaction could be conducted effectively without the use of a ligand and a base. Various kinds of aryl acrylic acids and P(III)-nucleophiles are tolerated in the transformation, generating the desired β-keto-organophosphorus compounds as a valuable class of phosphorus-containing intermediates with good to excellent yields. In addition, the possible mechanism and kinetic studies for the reaction have been explored by step-by-step control experiments and competitive experiments, and the results proved that this transformation may follow second-order chemical kinetics as well as involve a radical process.

Nanomaterials for Skin Cancer Photoimmunotherapy

Skin cancer is one of the most common types of cancer, and its incidence continues to increase. It is divided into two main categories, melanoma and non-melanoma. Treatments include surgery, radiation therapy, and chemotherapy. The relatively high mortality in melanoma and the existing recurrence rates, both for melanoma and non-melanoma, create the need for studying and developing new approaches for skin cancer management. Recent studies have focused on immunotherapy, photodynamic therapy, photothermal therapy, and photoimmunotherapy. Photoimmunotherapy has gained much attention due to its excellent potential outcomes. It combines the advantages of photodynamic and/or photothermal therapy with a systemic immune response, making it ideal for metastatic cancer. This review critically discusses different new nanomaterials' properties and mechanisms of action for skin cancer photoimmunotherapy and the main results obtained in the field.

Black phosphorus nanosheets-enabled DNA hydrogel integrating 3D-printed scaffold for promoting vascularized bone regeneration

The classical 3D-printed scaffolds have attracted enormous interests in bone regeneration due to the customized structural and mechanical adaptability to bone defects. However, the pristine scaffolds still suffer from the absence of dynamic and bioactive microenvironment that is analogous to natural extracellular matrix (ECM) to regulate cell behaviour and promote tissue regeneration. To address this challenge, we develop a black phosphorus nanosheets-enabled dynamic DNA hydrogel to integrate with 3D-printed scaffold to build a bioactive gel-scaffold construct to achieve enhanced angiogenesis and bone regeneration. The black phosphorus nanosheets reinforce the mechanical strength of dynamic self-healable hydrogel and endow the gel-scaffold construct with preserved protein binding to achieve sustainable delivery of growth factor. We further explore the effects of this activated construct on both human umbilical vein endothelial cells (HUVECs) and mesenchymal stem cells (MSCs) as well as in a critical-sized rat cranial defect model. The results confirm that the gel-scaffold construct is able to promote the growth of mature blood vessels as well as induce osteogenesis to promote new bone formation, indicating that the strategy of nano-enabled dynamic hydrogel integrated with 3D-printed scaffold holds great promise for bone tissue engineering.

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Therapeutic VEGF-engineered black phosphorus nanosheets are incorporated into DNA hydrogels.

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Nano-enabled DNA hydrogel integrating with 3D-printed scaffold builds gel-scaffold construct.

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Gel-scaffold construct upregulates the expression of genes and proteins related to angiogenesis and osteogenesis.

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Gel-scaffold construct accelerates the formation of early vascular network and new bone tissue.

Biological Effects of Black Phosphorus Nanomaterials on Mammalian Cells and Animals

The remarkable progress of applied black phosphorus nanomaterials (BPNMs) is attributed to BP's outstanding properties. Due to its potential for applications, environmental release and subsequent human exposure are virtually inevitable. Therefore, how BPNMs impact biological systems and human health needs to be considered. In this comprehensive Minireview, the most recent advancements in understanding the mechanisms and regulation factors of BPNMs' endogenous toxicity to mammalian systems are presented. These achievements lay the groundwork for an understanding of its biological effects, aimed towards establishing regulatory principles to minimize the adverse health impacts.

ROS Generative Black Phosphorus-Tamoxifen Nanosheets for Targeted Endocrine-Sonodynamic Synergistic Breast Cancer Therapy

Introduction

Tamoxifen (TAM) has proven to be a therapeutic breakthrough to reduce mortality and recurrence in estrogen receptor-positive (ER+) breast cancer patients. However, the application of TAM exhibits low bioavailability, off-target toxicity, instinct and acquired TAM resistance.

Methods

We utilized black phosphorus (BP) as a drug carrier and sonosensitizer, integrated with TAM and tumor-targeting ligand folic acid (FA) to construct TAM@BP-FA for synergistic endocrine and sonodynamic therapy (SDT) of breast cancer. The exfoliated BP nanosheets were modified through in situ polymerization of dopamine, followed by electrostatic adsorption of TAM and FA. The anticancer effect of TAM@BP-FA was evaluated through in vitro cytotoxicity and in vivo antitumor model. RNA-sequencing (RNA-seq), quantitative real-time PCR, Western blot analysis, flow cytometry analysis and peripheral blood mononuclear cells (PBMCs) analysis were performed for mechanism investigation.

Results

TAM@BP-FA had satisfactory drug loading capacity, the TAM release behavior can be controlled through pH microenvironment and ultrasonic stimulation. An amount of hydroxyl radical (∙OH) and singlet oxygen (¹O₂) were as expected generated under ultrasound stimulation. TAM@BP-FA nanoplatform showed excellent internalization in both TAM-sensitive MCF7 and TAM-resistant (TMR) cells. Using TMR cells, TAM@BP-FA displayed significantly enhanced antitumor ability in comparison with TAM (7.7% vs 69.6% viability at 5μg/mL), the additional SDT further caused 15% more cell death. RNA-seq unraveled the TAM@BP-FA antitumor mechanisms including effects on cell cycle, apoptosis and cell proliferation. Further analysis showed additional SDT successfully triggering reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) reduction. Moreover, PBMCs exposed to TAM@BP-FA induced an antitumor immune response by natural killer (NK) cell upregulation and immunosuppression macrophage reduction.

Conclusion

The novel BP-based strategy not only delivers TAM specifically to tumor cells but also exhibits satisfactory antitumor effects through targeted therapy, SDT, and immune cell modulation. The nanoplatform may provide a superior synergistic strategy for breast cancer therapy.

Design Strategies of Tumor-Targeted Delivery Systems Based on 2D Nanomaterials

Conventional chemotherapy and radiotherapy are nonselective and nonspecific for cell killing, causing serious side effects and threatening the lives of patients. It is of great significance to develop more accurate tumor-targeting therapeutic strategies. Nanotechnology is in a leading position to provide new treatment options for cancer, and it has great potential for selective targeted therapy and controlled drug release. 2D nanomaterials (2D NMs) have broad application prospects in the field of tumor-targeted delivery systems due to their special structure-based functions and excellent optical, electrical, and thermal properties. This review emphasizes the design strategies of tumor-targeted delivery systems based on 2D NMs from three aspects: passive targeting, active targeting, and tumor-microenvironment targeting, in order to promote the rational application of 2D NMs in clinical practice.

Rational Design of T-Cell- and B-Cell-Based Therapeutic Cancer Vaccines

Cancer vaccines provide an efficient strategy to enhance tumor-specific immune responses by redeploying immune systems. Despite the approval of the first cancer vaccine (Sipuleucel-T) by the U.S. Food and Drug Administration in 2010, most therapeutic cancer vaccines fail in clinical trials. Basically, tumor-specific immune responses rely on not only T-cell but also B-cell immunity, which indicates that cancer vaccines should leverage both arms of the adaptive immune system. For example, CD8⁺ T cells activated by antigen-presenting cells (APCs) recognize and directly kill tumor cells via peptide-bound major histocompatibility complex (pMHC). B cells recognize antigen with no need of pMHC and require CD4⁺ T cells for sufficient activation and antibody generation, enabling antibody-mediated nondirect killing on tumor cells. Considering the different mechanisms of T-cell and B-cell activation, the rational design of therapeutic cancer vaccines should consider several factors, including antigen selection and recognition, immune activation, vaccine delivery, and repeatable vaccination, which can be advanced by chemical strategies.In this Account, we summarize our recent contributions to the development of effective T-cell- and B-cell-based therapeutic cancer vaccines. For T-cell-based vaccines, we focus on adjuvants as the key component for controllable APC activation and T-cell priming. Not only synthetic molecular agonists of pattern recognition receptors (PRRs) but also adjuvant nanomaterials were explored to satisfy diversiform vaccine designs. For example, a type of natural cyclic dinucleotide (CDN) that was chemically modified with fluorination and ipsilateral phosphorothioation to activate the stimulator of interferon gene (STING) was found to mediate antitumor responses. It retains structural similarity to the parent CDN scaffold but possesses increased stability, cellular uptake, and immune activation for antitumor treatment. It also facilitates facile conjugation with other agonists, which not only enhances APC-targeting delivery but also balances cellular and humoral antitumor responses. We also explored the intrinsic properties of nanomaterials that allow them to serve as adjuvants. A black phosphorus nanosheet-based nanovaccine was constructed and found to strongly potentiate antigen-specific T-cell antitumor immune responses through multiple immune-potentiating properties, leading to a highly integrated nanomaterial-based adjuvant design. For B-cell-based vaccines, multicomponent and multivalent strategies were applied to improve the immunogenicity. A multicomponent linear vaccine conjugate coordinates helper T (Th) cells and APCs to proliferate and differentiates B cells for enhanced antitumor immunoglobulin G antibody responses. To further improve antigen recognition, clustered designs on a multivalent epitope were applied by generating various structures, including branched lysine-based peptides, natural multivalent scaffold molecules, and self-assembled nanofibers. We also engineered nano- and microvaccine systems to optimize systemic and localized vaccination. A multilayer-assembled nanovaccine successfully integrated antigens and multiple agonists to modulate APC activation. A DNA hydrogel contributed to the control of APC's immune behaviors, including cell recruitment, activation, and migration, and induced robust antitumor responses as an all-in-one designable platform. In this Account, by summarizing strategies for both T-cell- and B-cell-based vaccine design, we not only compare the differences but also address the intrinsic uniformity between such vaccine designs and further discuss the potential of a combined T-cell- and B-cell-based vaccine, which highlights the applicability and feasibility of chemical strategies.

Black Phosphorus-Synergic Nitric Oxide Nanogasholder Spatiotemporally Regulates Tumor Microenvironments for Self-Amplifying Immunotherapy

The lack of tumor immunogenicity coupled with the presence of tumor immunosuppression severely hinders antitumor immunity, especially in the treatment of "immune cold" tumors. Here, we have developed a drug-free and NIR-enabled nitric oxide (NO)-releasing nanogasholder (NO_PS@BP) composed of an outer cloak of nitrate-containing polymeric NO donor and an inner core of black phosphorus (BP) as the energy converter to spatiotemporally regulate NO-mediated tumor microenvironment remodeling and achieve multimodal therapy. Following NIR-irradiation, BP-induced photothermia and its intrinsic reducing property accelerate NO release from the outer cloak, by which the instantaneous NO burst concomitant with mild photothermia, on the one hand, induces immunogenic cell death (ICD), thereby provoking antitumor responses such as the maturation of dendritic cells (DCs) and the infiltration of cytotoxic T lymphocytes (CTLs); on the other hand, it reverses tumor immunosuppression via Treg inhibition, M2 macrophage restraint, and PD-L1 downregulation, further strengthening antitumor immunity. Therefore, this drug-free NO_PS@BP by means of multimodal therapy (NO gas therapy, immune therapy, photothermal therapy) realizes extremely significant curative effects against primary and distant tumors and even metastasis in B16F10 tumor models, providing a new modality to conquer immune cold tumors by NO-potentiated ICD and immunosuppression reversal.

New opportunities for immunomodulation of the tumour microenvironment using chemical tools

Immunotherapy is recognised as an attractive method for the treatment of cancer, and numerous treatment strategies have emerged over recent years. Investigations of the tumour microenvironment (TME) have led to the identification of many potential therapeutic targets and methods. However, many recently applied immunotherapies are based on previously identified strategies, such as boosting the immune response by combining commonly used stimulators, and the release of drugs through changes in pH. Although methodological improvements such as structural optimisation and combining strategies can be undertaken, applying those novel targets and methods in immunotherapy remains an important goal. In this review, we summarise the latest research on the TME, and discuss how small molecules, immune cells, and their interactions with tumour cells can be regulated in the TME. Additionally, the techniques currently employed for delivery of these agents to the TME are also mentioned. Strategies to modulate cell phenotypes and interactions between immune cells and tumours are mainly discussed. We consider both modulatory and targeting methods aiming to bridge the gap between the TME and chemical modulation thereof.

Inorganic nanosheets facilitate humoral immunity against medical implant infections by modulating immune co-stimulatory pathways

Strategies to manipulate immune cell co-inhibitory or co-activating signals have revolutionized immunotherapy. However, certain immunologically cold diseases, such as bacterial biofilm infections of medical implants are hard to target due to the complexity of the immune co-stimulatory pathways involved. Here we show that two-dimensional manganese chalcogenophosphates MnPSe₃ (MPS) nanosheets modified with polyvinylpyrrolidone (PVP) are capable of triggering a strong anti-bacterial biofilm humoral immunity in a mouse model of surgical implant infection via modulating antigen presentation and costimulatory molecule expression in the infectious microenvironment (IME). Mechanistically, the PVP-modified MPS (MPS-PVP) damages the structure of the biofilm which results in antigen exposure by generating reactive oxidative species, while changing the balance of immune-inhibitory (IL4I1 and CD206) and co-activator signals (CD40, CD80 and CD69). This leads to amplified APC priming and antigen presentation, resulting in biofilm-specific humoral immune and memory responses. In our work, we demonstrate that pre-surgical neoadjuvant immunotherapy utilizing MPS-PVP successfully mitigates residual and recurrent infections following removal of the infected implants. This study thus offers an alternative to replace antibiotics against hard-to-treat biofilm infections.

Potential of Black Phosphorus in Immune-Based Therapeutic Strategies

Black phosphorus (BP) consists of phosphorus atoms, an essential element of bone and nucleic acid, which covalently bonds to three adjacent phosphorus atoms to form a puckered bilayer structure. With its anisotropy, band gap, biodegradability, and biocompatibility properties, BP is considered promising for cancer therapy. For example, BP under irradiation can convert near-infrared (NIR) light into heat and reactive oxygen species (ROS) to damage cancer cells, called photothermal therapy (PTT) and photodynamic therapy (PDT). Compared with PTT and PDT, the novel techniques of sonodynamic therapy (SDT) and photoacoustic therapy (PAT) exhibit amplified ROS generation and precise photoacoustic-shockwaves to enhance anticancer effect when BP receives ultrasound or NIR irradiation. Based on the prospective phototherapy, BP with irradiation can cause a “double-kill” to tumor cells, involving tumor-structure damage induced by heat, ROS, and shockwaves and a subsequent anticancer immune response induced by in situ vaccines construction in tumor site, which is referred to as photoimmunotherapy (PIT). In conclusion, BP shows promise in natural antitumor biological activity, biological imaging, drug delivery, PTT/PDT/SDT/PAT/PIT, nanovaccines, nanoadjuvants, and combination immunotherapy regimens.

Understanding the bidirectional interactions between two-dimensional materials, microorganisms, and the immune system

Two-dimensional (2D) materials such as the graphene-based materials, transition metal dichalcogenides, transition metal carbides and nitrides (MXenes), black phosphorus, hexagonal boron nitride, and others have attracted considerable attention due to their unique physicochemical properties. This is true not least in the field of medicine. Understanding the interactions between 2D materials and the immune system is therefore of paramount importance. Furthermore, emerging evidence suggests that 2D materials may interact with microorganisms - pathogens as well as commensal bacteria that dwell in and on our body. We discuss the interplay between 2D materials, the immune system, and the microbial world in order to bring a systems perspective to bear on the biological interactions of 2D materials. The use of 2D materials as vectors for drug delivery and as immune adjuvants in tumor vaccines, and 2D materials to counteract inflammation and promote tissue regeneration, are explored. The bio-corona formation on and biodegradation of 2D materials, and the reciprocal interactions between 2D materials and microorganisms, are also highlighted. Finally, we consider the future challenges pertaining to the biomedical applications of various classes of 2D materials.

Preparation of composite scaffolds composed of gelatin and Au nanostar-deposited black phosphorus nanosheets for the photothermal ablation of cancer cells and adipogenic differentiation of stem cells

Photothermal nanoparticles are important in photothermal therapy. Combining different nanoparticles can achieve a high photothermal capacity. In this study, composite nanoparticles composed of black phosphorus nanosheets (BPNSs) and gold nanostars (BP-AuNSs) were synthesized by using BPNSs as the reductant. AuNSs were deposited on the BPNSs. The BP-AuNSs were further hybridized with porous gelatin scaffolds to prepare gelatin-BP-AuNS composite scaffolds. The gelatin-BP-AuNS composite scaffolds promoted cell migration and distribution. The synergistic effects of the BPNSs and AuNSs endowed the gelatin-BP-AuNS composite scaffolds with excellent photothermal properties. The gelatin-BP-AuNS composite scaffolds eliminated cancer cells after near infrared laser exposure and supported the adipogenic differentiation of human mesenchymal stem cells. Thus, this gelatin-BP-AuNS composite scaffold holds promise for breast cancer therapy.

NIR-II Responsive Molybdenum Dioxide Nanosystem Manipulating Cellular Immunogenicity for Enhanced Tumor Photoimmunotherapy

Photothermal therapy (PTT) in the second near-infrared (NIR-II) window has emerged as a better candidate for deep-tissue tumor elimination. More interestingly, the photothermal ablated tumor cells also manifest somewhat immunostimulation potency to elicit antitumor immunity, although most dying cells are undergoing apoptosis that is commonly considered as immunologically silent. Here, a NIR-II responsive nanosystem is established for tumor photoimmunotherapy using molybdenum dioxide (MoO₂) nanodumbbells as the nanoconverter. Meanwhile, an apoptosis-blocking strategy is proposed to regulate the cell death pattern under NIR-II laser irradiation in order to improve the immunogenic cell death. The nanoformulation can efficiently block caspase 8-dependent apoptotic pathway in photothermal ablated tumor cells and transform into more immunogenic death patterns, thereby activating systemic immunity to inhibit tumor growth and metastasis. In addition, this strategy also helps enhance the body's responses to α-PD-1 immune checkpoint inhibitor, which implies a potential optimal combination for cancer immunotherapy.

Two-dimensional nanomaterials for tumor microenvironment modulation and anticancer therapy

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

Black phosphorus-Au-thiosugar nanosheets mediated photothermal induced anti-tumor effect enhancement by promoting infiltration of NK cells in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a heterogeneous cancer required combination therapy, such as photothermal therapy and chemotherapy. In recent years, cancer immunotherapies are rapidly evolving and are some of the most promising avenues to approach malignancies. Thus, the combination of the traditional therapies and immunotherapy in one platform may improve the efficacy for HCC treatment.

Results

In this work, we have prepared a black phosphorus (BP)-Au-thiosugar nanosheets (BATNS), in which Au-thiosugar coating and functionalization improved the stability of both black phosphorus nanosheets (BPNS) and gold ions in different simulated physiological environments. The compression of the BATNS band gap can convert more photon energy to heat generation compared with BPNS, resulting in higher photothermal conversion efficiency. The in vitro and in vivo results also revealed a stronger reduction on the hepatocellular carcinoma of mice and prolonged survival of disease models compared with BPNS. More importantly, BATNS showed an additional immune effect by increasing local NK cell infiltration but not T cell on the liver cancer treatment, and this immune effect was caused by the thermal effect of BATNS photothermal treatment.

Conclusions

The novel BATNS could improve the stability of BPNS and simultaneously combine the cancer thermotherapy and immunotherapy leaded by local NK cell infiltration, resulting in a better therapeutic efficacy on hepatocellular carcinoma. This work also provided a new path to design BP-based materials for biomedical applications.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01286-z.

Overcoming STING Agonists Barriers: Peptide, Protein, Biomembrane-based Biocompatible Delivery Strategies

After the development for more ten years, stimulator of interferon genes (STING), a representative of pattern recognition receptors (PRRs), is now entering the stage of widespread applications. Along with evolution of STING agonists of cyclic dinucleotides (CDNs) and non-nucleotide molecules, the stability of agonists has been improved. However, their poor performance in clinical trials triggers urgent demands for highly effective delivery strategies to further improve the cellular permeability, tissue targetability and retention. In this review, we summarized the recent progress of STING agonists applications and delivery strategies with a focus on the biocompatible platforms of peptide, protein and biomembrane, providing a novel vision for STING field and future direction.

Zinc-Loaded Black Phosphorus Multifunctional Nanodelivery System Combined With Photothermal Therapy Have the Potential to Treat Prostate Cancer Patients Infected With COVID-19

Since 2019, coronavirus disease 2019 (COVID-19) has swept the world and become a new virus threatening the health of all mankind. The survey found that prostate cancer accounts for one in three male cancer patients infected with COVID-19. This undoubtedly makes prostate cancer patients face a more difficult situation. Prostate cancer is the second most harmful malignant tumor in men because of its insidious onset, easy metastasis, and easy development into castration-resistant prostate cancer even after treatment. Due to its high immunogenicity and a small number of specific infiltrating T cells with tumor-associated antigens in the tissue, it is difficult to obtain a good therapeutic effect with immune checkpoint blocking therapy alone. Therefore, in the current study, we developed a platform carrying Doxorubicin (DOX)-loaded black phosphate nanometer combined with photothermal therapy (PTT) and found this drug combination stimulated the immungentic cell death (ICD) process in PC-3 cells and DC maturation. More importantly, zinc ions have a good immunomodulatory function against infectious diseases, and can improve the killing ability of the nanosystem against prostate cancer cells. The introduction of Aptamer (Apt) enhances the targeting of the entire nanomedicine. We hope that this excellent combination will lead to effective treatment strategies for prostate cancer patients infected with COVID-19.

Amino acid sequence determines the adjuvant potency of a D-Tetra-Peptide hydrogel

The development of novel vaccine adjuvants is essential for the production of modern vaccines against infectious agents and cancer. We recently reported a supramolecular hydrogel of a self-assembling D-tetra-peptide named...

Black Phosphorus, an Emerging Versatile Nanoplatform for Cancer Immunotherapy

Black phosphorus (BP) is one of the emerging versatile nanomaterials with outstanding biocompatibility and biodegradability, exhibiting great potential as a promising inorganic nanomaterial in the biomedical field. BP nanomaterials possess excellent ability for valid bio-conjugation and molecular loading in anticancer therapy. Generally, BP nanomaterials can be classified into BP nanosheets (BPNSs) and BP quantum dots (BPQDs), both of which can be synthesized through various preparation routes. In addition, BP nanomaterials can be applied as photothermal agents (PTA) for the photothermal therapy (PTT) due to their high photothermal conversion efficiency and larger extinction coefficients. The generated local hyperpyrexia leads to thermal elimination of tumor. Besides, BP nanomaterials are capable of producing singlet oxygen, which enable its application as a photosensitizer for photodynamic therapy (PDT). Moreover, BP nanomaterials can be oxidized and degraded to nontoxic phosphonates and phosphate under physiological conditions, improving their safety as a nano drug carrier in cancer therapy. Recently, it has been reported that BP-based PTT is capable of activating immune responses and alleviating the immunosuppressive tumor microenvironment by detection of T lymphocytes and various immunocytokines, indicating that BP-based nanocomposites not only serve as effective PTAs to ablate large solid tumors but also function as an immunomodulation agent to eliminate discrete tumorlets. Therefore, BP-mediated immunotherapy would provide more possibilities for synergistic cancer treatment.