From phosphorus to phosphorene: Applications in disease theranostics

Diethylbenzene and ethyltoluene adsorption studies on novel beta antimonide phosphorus nanosheets-a first-principle study

CONTEXT

In the present work, we examined the sensing behavior of monolayer beta antimonide phosphorus (β-SbP) sheets towards toxic volatile organic compounds (VOCs) namely, 1,2-diethylbenzene and 2-ethyltoluene using density functional theory (DFT) method. At first, using cohesive energy structural stability of the monolayer β-SbP is confirmed. The calculated energy band gap value of monolayer β-SbP is 2.168 eV, which is a semiconductor. Furthermore, the adsorption properties of 1,2-diethylbenzene and 2-ethyltoluene on β-SbP are studied through key factors, such as adsorption energy, Mulliken charge transfer, and relative band gap variation. The adsorption energy clearly shows (- 0.335 to - 0.903 eV) that both 1,2-diethylbenzene and 2-ethyltoluene are physisorbed on β-SbP monolayer. Besides, Mulliken charge transfer falls in the range of - 0.465 to 0.933 e; this information clearly shows that the β-SbP monolayer is a potential candidate for sensing 1,2-diethylbenzene and 2-ethyltoluene molecules.

METHODS

The structural firmness including electronic and adsorption properties of 1,2-diethylbenzene and 2-ethyltoluene on β-SbP monolayer are investigated with the support of the DFT method. Particularly, the hybrid generalized gradient approximation (hybrid GGA) along with Beck's three-parameter + Lee-Yang-Parr (B3LYP) exchange-correlation functional is utilized for relaxing the β-SbP monolayer. In the present work, all calculations are performed using the Quantum Atomistic Tool Kit (ATK) simulation package. In the present work, we utilized β-SbP monolayer as a chief sensing element to detect 1,2-diethylbenzene and 2-ethyltoluene to safeguard humans from toxic environments.

A win-win platform: Stabilized black phosphorous nanosheets loading gallium ions for enhancing the healing of bacterial-infected wounds through synergistic antibacterial approaches

Bacterial infection is the most common complication in wound healing, highlighting an urgent need for the development of innovative antibacterial technologies and treatments to address the growing threats posed by bacterial infections. Black phosphorus nanosheets (BPNSs), as a promising two-dimensional nanomaterial, have been utilized in treating infected wounds. However, BP's limited stability restricts its application. In this study, we enhance BP's stability and its antibacterial properties by anchoring gallium ions (Ga3+) onto BP's surface, creating a novel antibacterial platform. This modification reduces BP's electron density and enhances its antibacterial capabilities through a synergistic effect. Under near-infrared (NIR) irradiation, the BP/Ga3+ combination exerts antibacterial effects via photothermal therapy (PTT) and photodynamic therapy (PDT), while also releasing Ga3+. The Ga3+ employ a 'Trojan horse strategy' to disrupt iron metabolism, significantly boosting the antibacterial efficacy of the complex. This innovative material offers a viable alternative to antibiotics and holds significant promise for treating infected wounds and aiding skin reconstruction.

Ultrasound imaging guided targeted sonodynamic therapy enhanced by magnetophoretically controlled magnetic microbubbles

Sonodynamic therapy (SDT) utilizes ultrasonic excitation of a sensitizer to generate reactive oxygen species (ROS) to destroy tumor. Two dimensional (2D) black phosphorus (BP) is an emerging sonosensitizer that can promote ROS production to be used in SDT but it alone lacks active targeting effect and showed low therapy efficiency. In this study, a stable dispersion of integrated micro-nanoplatform consisting of BP nanosheets loaded and Fe3O4 nanoparticles (NPs) connected microbubbles was introduced for ultrasound imaging guided and magnetic field directed precision SDT of breast cancer. The targeted ultrasound imaging at 18 MHz and efficient SDT effects at 1 MHz were demonstrated both in-vitro and in-vivo on the breast cancer. The magnetic microbubbles targeted deliver BP nanosheets to the tumor site under magnetic navigation and increased the uptake of BP nanosheets by inducing cavitation effect for increased cell membrane permeability via ultrasound targeted microbubble destruction (UTMD). The mechanism of SDT by magnetic black phosphorus microbubbles was proposed to be originated from the ROS triggered mitochondria mediated apoptosis by up-regulating the pro-apoptotic proteins while down-regulating the anti-apoptotic proteins. In conclusion, the ultrasound theranostic was realized via the magnetic black phosphorus microbubbles, which could realize targeting and catalytic sonodynamic therapy.

Regulation of band gap and localized surface plasmon resonance by loading Au nanorods on violet phosphene nanosheets for photodynamic/photothermal synergistic anti-infective therapy

In the face of the serious threat to human health and the economic burden caused by bacterial antibiotic resistance, 2D phosphorus nanomaterials have been widely used as antibacterial agents. Violet phosphorus nanosheets (VPNSs) are an exciting bandgap-adjustable 2D nanomaterial due to their good physicochemical properties, yet the study of VPNS-based antibiotics is still in its infancy. Here, a composite of gold nanorods (AuNRs) loaded onto VPNS platforms (VPNS/AuNR) is constructed to maximize the potential of VPNSs for antimicrobial applications. The loading with AuNRs not only enhances the photothermal performance via a localized surface plasmon resonance (LSPR) effect, but also enhances the light absorption capacity due to the narrowing of the band gap of the VPNSs, thus increasing the ROS generation capacity. The results demonstrate that VPNS/AuNR exhibits outstanding antibacterial properties and good biocompatibility. Attractively, VPNS/AuNR is then extensively tested for treating skin wound infections, suggesting promising in vivo antibacterial and wound-healing features. Our findings may open a novel direction to develop a versatile VPNS-based treatment platform, which can significantly boost the progress of VPNS exploration.

Recent Advances in Phosphorene: Structure, Synthesis, and Properties

Phosphorene is a 2D phosphorus atomic layer arranged in a honeycomb lattice like graphene but with a buckled structure. Since its exfoliation from black phosphorus in 2014, phosphorene has attracted tremendous research interest both in terms of synthesis and fundamental research, as well as in potential applications. Recently, significant attention in phosphorene is motivated not only by research on its fundamental physical properties as a novel 2D semiconductor material, such as tunable bandgap, strong in-plane anisotropy, and high carrier mobility, but also by the study of its wide range of potential applications, such as electronic, optoelectronic, and spintronic devices, energy conversion and storage devices. However, a lot of avenues remain to be explored including the fundamental properties of phosphorene and its device applications. This review recalls the current state of the art of phosphorene and its derivatives, touching upon topics on structure, synthesis, characterization, properties, stability, and applications. The current needs and future opportunities for phosphorene are also discussed.

Innovative Phosphorene Nanoplatform for Light Antimicrobial Therapy

Over the past few years, antibiotic resistance has reached global dimensions as a major threat to public health. Consequently, there is a pressing need to find effective alternative therapies and therapeutic agents to combat drug-resistant pathogens. Photodynamic therapy (PDT), largely employed as a clinical treatment for several malignant pathologies, has also gained importance as a promising antimicrobial approach. Antimicrobial PDT (aPDT) relies on the application of a photosensitizer able to produce singlet oxygen (1O2) or other cytotoxic reactive oxygen species (ROS) upon exposure to appropriate light, which leads to cell death after the induced photodamage. Among different types of 2D nanomaterials with antimicrobial properties, phosphorene, the exfoliated form of black phosphorus (bP), has the unique property intrinsic photoactivity exploitable for photothermal therapy (PTT) as well as for PDT against pathogenic bacteria.

Plasma-Enabled Graphene Quantum Dot Hydrogel-Magnesium Composites as Bioactive Scaffolds for In Vivo Bone Defect Repair

Bioactive and mechanically stable metal-based scaffolds are commonly used for bone defect repair. However, conventional metal-based scaffolds induce nonuniform cell growth, limiting damaged tissue restoration. Here, we develop a plasma nanotechnology-enhanced graphene quantum dot (GQD) hydrogel-magnesium (Mg) composite scaffold for functional bone defect repair by integrating a bioresource-derived nitrogen-doped GQD (NGQD) hydrogel into the Mg ZK60 alloy. Each scaffold component brings major synergistic advantages over the current alloy-based state of the art, including (1) mechanical support of the cortical bone and calcium deposition by the released Mg2+ during degradation; (2) enhanced uptake, migration, and distribution of osteoblasts by the porous hydrogel; and (3) improved osteoblast adhesion and proliferation, osteogenesis, and mineralization by the NGQDs in the hydrogel. Through an in vivo study, the hybrid scaffold with the much enhanced osteogenic ability induced by the above synergy promotes a more rapid, uniform, and directional bone growth across the hydrogel channel, compared with the control Mg-based scaffold. This work provides insights into the design of multifunctional hybrid scaffolds, which can be applied in other areas well beyond the demonstrated bone defect repair.

Magnetic ε-Phosphorene for Sensing Greenhouse Gas Molecules

It is critical for gas sensors that sense greenhouse gas molecules to have both good sensitivity and selectivity for water molecules in the ambient environment. Here, we study the charge transfer, IV curves, and electric field tuning of vanadium-doped monolayer ϵ-phosphorene as a sensor for NO, NO₂, and H₂O gas molecules via first-principle and transport calculations. We find that the paramagnetic toxic molecules of NO and NO₂ have a high adsorption energy on V-ϵ-phosphorene, which originates from a large amount of charge transfer driven by the hybridisation of the localised spin states of the host with the molecular frontier orbital. Using the non-equilibrium Green's function, we investigate the IV responses with respect to the adsorption of different molecules to study the performance of gas molecule sensors. Our IV curves show a larger amount of changes in resistance of the paramagnetic NO and NO₂ than nonmagnetic H₂O gas molecules, suggesting both sensitivity and selectivity. Moreover, our calculations show that an applied external electric field (gate voltage) can effectively tune the amount of charge transfer. More charge transfer makes the sensor more sensitive to the molecule, while less charge transfer can reduce the adsorption energy and remove the adsorbed molecules, allowing for the repeated use of the sensor.

Mitochondria-Targeting Pyroptosis Amplifier of Lonidamine-Modified Black Phosphorus Nanosheets for Glioblastoma Treatments

Pyroptosis is accompanied by immunogenic mediators' release and serves as an innovative strategy to reprogram tumor microenvironments. However, damaged mitochondria, the origin of pyroptosis, are frequently eliminated by mitophagy, which will severely impair pyroptosis-elicited immune activation. Herein, black phosphorus nanosheets (BP) are employed as a pyroptosis inducer delivery and mitophagy flux blocking system since the degradation of BP could impair lysosomal function by altering the pH within lysosomes. The pyroptosis inducer of lonidamine (LND) was precoupled with the mitochondrial target moiety of triphenylphosphonium to facilitate the occurrence of pyroptosis. The mitochondria-targeting LND-modified BP (BP_TLD) were further encapsulated into the macrophage membrane to endow the BP_TLD with blood-brain barrier penetration and tumor-targeting capability. The antitumor activities of membrane-encapsulated BP_TLD (M@BP_TLD) were investigated using a murine orthotopic glioblastoma model. The results demonstrated that the engineered nanosystem of M@BP_TLD could target the mitochondria, and induce as well as reinforce pyroptosis via mitophagy flux blocking, thereby boosting the release of immune-activated factors to promote the maturation of dendritic cells. Furthermore, upon near-infrared (NIR) irradiation, M@BP_TLD induced stronger mitochondrial oxidative stress, which further advanced robust immunogenic pyroptosis in glioblastoma cells. Thus, this study utilized the autophagy flux inhibition and phototherapy performance of BP to amplify LND-mediated pyroptosis, which might greatly contribute to the development of pyroptosis nanomodulators.

Cytotoxicity Induced by Black Phosphorus Nanosheets in Vascular Endothelial Cells via Oxidative Stress and Apoptosis Activation

Black phosphorus (BP), an emerging two-dimensional material with unique optical, thermoelectric, and mechanical properties, has been proposed as bioactive material for tissue engineering. However, its toxic effects on physiological systems remain obscure. The present study investigated the cytotoxicity of BP to vascular endothelial cells. BP nanosheets (BPNSs) with a diameter of 230 nm were fabricated via a classical liquid-phase exfoliation method. Human umbilical vein endothelial cells (HUVECs) were used to determine the cytotoxicity induced by BPNSs (0.31-80 μg/mL). When the concentrations were over 2.5 μg/mL, BPNSs adversely affected the cytoskeleton and cell migration. Furthermore, BPNSs caused mitochondrial dysfunction and generated excessive intercellular reactive oxygen species (ROS) at tested concentrations after 24 h. BPNSs could influence the expression of apoptosis-related genes, including the P53 and BCL-2 family, resulting in the apoptosis of HUVECs. Therefore, the viability and function of HUVECs were adversely influenced by the concentration of BPNSs over 2.5 μg/mL. These findings provide significant information for the potential applications of BP in tissue engineering.

Bifunctional electrospun poly (L-lactic acid) membranes incorporating black phosphorus nanosheets and nano-zinc oxide for enhanced biocompatibility and antibacterial properties in catheter materials

For several decades, urinary tract infections caused by catheter-associated devices have negatively impacted not only medical device utilization, but also patient health. As such, the creation of catheter materials with both superior biocompatibility and antibacterial properties has become necessary. This study aimed to produce electrospun membranes based on polylactic acid (PLA) with the incorporation of black phosphorus nanosheets (BPNS) and nano-zinc oxide (nZnO) particles, as well as a mixture of both, in order to design bifunctional membranes with enhanced bioactivity and antibacterial features. The optimum spinning process was determined through examination of various PLA mass concentrations, spinning solution propelling speeds, and receiving drum rotating speeds, with emphasis on the mechanical properties of PLA membranes. Additionally, the antibacterial properties and cytocompatibility of the ZnO-BP/PLA antibacterial membranes were explored. Results demonstrated that the ZnO-BP/PLA antibacterial membranes displayed a rich porous structure, with uniform distribution of nZnO particles and BPNS. With the increase of polylactic acid concentration and the decrease of spinning solution advancing and drum rotation speeds, the mechanical properties of the fiber membrane were significantly improved. Furthermore, the composite membranes exhibited remarkable photothermal therapy (PTT) capabilities when aided by the synergistic effect of BP nanosheets and ZnO. This was achieved through near-infrared (NIR) irradiation, which not only dissipated the biofilm but also enhanced the release capability of Zn²⁺. Consequently, the composite membrane demonstrated an improved inhibitory effect on both Escherichia coli and Staphylococcus aureus. The results of cytotoxicity and adhesion experiments also indicated good cytocompatibility, with cells growing normally on the surface of the ZnO-BP/PLA antibacterial membrane. Overall, these findings validate the utilization of both BPNS and n-ZnO fillers in the creation of novel bifunctional PLA-based membranes, which possess both biocompatibility and antibacterial properties for interventional catheter materials.

Photodynamic and Photothermal Therapies: Synergy Opportunities for Nanomedicine

Tumoricidal photodynamic (PDT) and photothermal (PTT) therapies harness light to eliminate cancer cells with spatiotemporal precision by either generating reactive oxygen species or increasing temperature. Great strides have been made in understanding biological effects of PDT and PTT at the cellular, vascular and tumor microenvironmental levels, as well as translating both modalities in the clinic. Emerging evidence suggests that PDT and PTT may synergize due to their different mechanisms of action, and their nonoverlapping toxicity profiles make such combination potentially efficacious. Moreover, PDT/PTT combinations have gained momentum in recent years due to the development of multimodal nanoplatforms that simultaneously incorporate photodynamically- and photothermally active agents. In this review, we discuss how combining PDT and PTT can address the limitations of each modality alone and enhance treatment safety and efficacy. We provide an overview of recent literature featuring dual PDT/PTT nanoparticles and analyze the strengths and limitations of various nanoparticle design strategies. We also detail how treatment sequence and dose may affect cellular states, tumor pathophysiology and drug delivery, ultimately shaping the treatment response. Lastly, we analyze common experimental design pitfalls that complicate preclinical assessment of PDT/PTT combinations and propose rational guidelines to elucidate the mechanisms underlying PDT/PTT interactions.

Nanoparticles-mediated ion channels manipulation: From their membrane interactions to bioapplications

Ion channels are transmembrane proteins ubiquitously expressed in all cells that control various ions (e.g. Na⁺, K⁺, Ca²⁺ and Cl^- etc) crossing cellular plasma membrane, which play critical roles in physiological processes including regulating signal transduction, cell proliferation as well as excitatory cell excitation and conduction. Abnormal ion channel function is usually associated with dysfunctions and many diseases, such as neurodegenerative disorders, ophthalmic diseases, pulmonary diseases and even cancers. The precise regulation of ion channels not only helps to decipher physiological and pathological processes, but also is expected to become cutting-edge means for disease treatment. Recently, nanoparticles-mediated ion channel manipulation emerges as a highly promising way to meet the increasing requirements with respect to their simple, efficient, precise, spatiotemporally controllable and non-invasive regulation in biomedicine and other research frontiers. Thanks the advantages of their unique properties, nanoparticles can not only directly block the pore sites or kinetics of ion channels through their tiny size effect, and perturb active voltage-gated ion channel by their charged surface, but they can also act as antennas to conduct or enhance external physical stimuli to achieve spatiotemporal, precise and efficient regulation of various ion channel activities (e.g. light-, mechanical-, and temperature-gated ion channels etc). So far, nanoparticles-mediated ion channel regulation has shown potential prospects in many biomedical fields at the interfaces of neuro- and cardiovascular modulation, physiological function regeneration and tumor therapy et al. Towards such important fields, in this typical review, we specifically outline the latest studies of different types of ion channels and their activities relevant to the diseases. In addition, the different types of stimulation responsive nanoparticles, their interaction modes and targeting strategies towards the plasma membrane ion channels will be systematically summarized. More importantly, the ion channel regulatory methods mediated by functional nanoparticles and their bioapplications associated with physiological modulation and therapeutic development will be discussed. Last but not least, current challenges and future perspectives in this field will be covered as well.

Graphdiyne Oxide-Mediated Photodynamic Therapy Boosts Enhancive T-Cell Immune Responses by Increasing Cellular Stiffness

Purpose

Nanomaterial-based photodynamic therapy (PDT) has been commonly used for the treatment of cancerous tumors. Despite significant achievements made in this field, the intrinsic impact of nanomaterials-based PDT on the mechanical properties of oral squamous cell carcinoma (OSCC) cells is not entirely understood. Here, we used atomic force microscopy (AFM) to measure the stiffness of OSCC cells subjected to PDT in co-culture systems to evaluate the T cell-mediated cancer cell-killing effects.

Methods

In this study, AFM was used to assess the stiffness of PDT-subjected cells. The phototoxicity of graphdiyne oxide (GDYO) was assessed using confocal laser scanning microscopy (CLSM), measurements of membrane cholesterol levels, and assessments of the F-actin cytoskeleton. A co-culture system was used to evaluate the effects of CD8⁺ T cells (cytotoxic T lymphocytes), demonstrating how PDT modulates the mechanical properties of cancer cells and activates T cell responses. The antitumor immunotherapeutic effect of GDYO was further evaluated in a murine xenograft model.

Results

GDYO increased the mechanical stiffness of tumor cells and augmented T-cell cytotoxicity and inflammatory cytokine secretion (IFN-γ and TNF-α) under laser in vitro. Furthermore, GDYO-based PDT exerted inhibitory effects on OSCC models and elicited antitumor immune responses via specific cytotoxic T cells.

Conclusion

These results highlight that GDYO is a promising candidate for OSCC therapy, shifting the mechanical forces of OSCC cells and breaking through the barriers of the immunosuppressive tumor microenvironment. Our study provides a novel perspective on nanomaterial-based antitumor therapies.

Immunoengineered MXene nanosystem for mitigation of alloantigen presentation and prevention of transplant vasculopathy

MXenes are an emerging class of nanomaterials with significant potential for applications in nanomedicine. Amongst MXene technologies, titanium carbide (Ti₃C₂T_x) nanomaterials are the most mature and have received significant attention to tackle longstanding clinical challenges due to its tailored physical and material properties. Cardiac allograft vasculopathy is an aggressive form of atherosclerosis and a major cause of mortality among patients with heart transplants. Blood vessel endothelial cells (ECs) stimulate alloreactive T-lymphocytes to result in sustained inflammation. Herein, we report the first application of Ti₃C₂T_x MXene nanosheets for prevention of allograft vasculopathy. MXene nanosheets interacted with human ECs and downregulated the expression of genes involved in alloantigen presentation, and consequently reduced the activation of allogeneic lymphocytes. RNA-Seq analysis of lymphocytes showed that treatment with MXene downregulated genes responsible for transplant-induced T-cell activation, cell-mediated rejection, and development of allograft vasculopathy. In an in vivo rat model of allograft vasculopathy, treatment with MXene reduced lymphocyte infiltration and preserved medial smooth muscle cell integrity within transplanted aortic allografts. These findings highlight the potential of Ti₃C₂T_x MXene in treatment of allograft vasculopathy and inflammatory diseases.

Boron- and phosphorus-containing molecular/nano platforms: exploiting pathological redox imbalance to fight cancer

Cancer is currently the second leading cause of death globally. Despite multidisciplinary efforts, therapies to fight various types of cancer still remain inefficient. Reducing high recurrence rates and mortality is thus a major challenge to tackle. In this context, redox imbalance is an undervalued characteristic of cancer. However, it may be targeted by boron- and phosphorus-containing materials to selectively or systemically fight cancer. In particular, boron and phosphorus derivatives are attractive building blocks for rational drug discovery due to their unique and wide regioselective chemistry, high degree of tuneability and chemical stability. Thus, they can be meticulously employed to access tunable molecular platforms to selectively exploit the redox imbalance of cancer cells towards necrosis/apoptosis. This field of research holds a remarkable potential; nevertheless, it is still in its infancy. In this mini-review, we underline recent advances in the development of boron- or phosphorus-derivatives as molecular/nano platforms for rational anticancer drug design. Our goal is to provide comprehensive information on different methodologies that bear an outstanding potential to further develop this very promising field of research.

Glioma diagnosis and therapy: Current challenges and nanomaterial-based solutions

Glioma is often referred to as one of the most dreadful central nervous system (CNS)-specific tumors with rapidly-proliferating cancerous glial cells, accounting for nearly half of the brain tumors at an annual incidence rate of 30-80 per a million population. Although glioma treatment remains a significant challenge for researchers and clinicians, the rapid development of nanomedicine provides tremendous opportunities for long-term glioma therapy. However, several obstacles impede the development of novel therapeutics, such as the very tight blood-brain barrier (BBB), undesirable hypoxia, and complex tumor microenvironment (TME). Several efforts have been dedicated to exploring various nanoformulations for improving BBB permeation and precise tumor ablation to address these challenges. Initially, this article briefly introduces glioma classification and various pathogenic factors. Further, currently available therapeutic approaches are illustrated in detail, including traditional chemotherapy, radiotherapy, and surgical practices. Then, different innovative treatment strategies, such as tumor-treating fields, gene therapy, immunotherapy, and phototherapy, are emphasized. In conclusion, we summarize the article with interesting perspectives, providing suggestions for future glioma diagnosis and therapy improvement.

Prediction of highly stable two-dimensional materials of boron and phosphorus: structural and electronic properties

The discovery of two-dimensional (2D) semiconducting materials has attracted broad research interest, owing to their wide applications in spintronics and optoelectronics. Group III-V 2D materials such as hexagonal boron nitride (h-BN) have been demonstrated with remarkable electronic properties. However, the 2D materials consisting of boron and phosphorus have not been comprehensively explored. Using global structural search combined with first-principles calculations, we have hereby theoretically predicted several stable and metastable boron phosphorus (B_mP_n) monolayer 2D compounds that have lower formation enthalpies (ΔH) than black phosphorus and α-bulk boron and could be formed at stoichiometries of m/n ≤ 1. Two of these 2D B_mP_n compounds, i.e., P2₁/m B₁P₃ and Cm B₂P₄, are confirmed to be thermodynamically stable, with bandgaps less than 2 eV. In particular, Cm B₂P₄ features a narrow bandgap of ∼0.609 eV, near the short wavelength infrared ray (SWIR) region, and it possesses anisotropic mechanical properties. Moreover, we have demonstrated that these compounds can be converted into half-metallic spin-polarized states through charge doping, which promises their applications in spintronic devices.

Nanomaterials: A powerful tool for tumor immunotherapy

Cancer represents the leading global driver of death and is recognized as a critical obstacle to increasing life expectancy. In recent years, with the development of precision medicine, significant progress has been made in cancer treatment. Among them, various therapies developed with the help of the immune system have succeeded in clinical treatment, recognizing and killing cancer cells by stimulating or enhancing the body’s intrinsic immune system. However, low response rates and serious adverse effects, among others, have limited the use of immunotherapy. It also poses problems such as drug resistance and hyper-progression. Fortunately, thanks to the rapid development of nanotechnology, engineered multifunctional nanomaterials and biomaterials have brought breakthroughs in cancer immunotherapy. Unlike conventional cancer immunotherapy, nanomaterials can be rationally designed to trigger specific tumor-killing effects. Simultaneously, improved infiltration of immune cells into metastatic lesions enhances the efficiency of antigen submission and induces a sustained immune reaction. Such a strategy directly reverses the immunological condition of the primary tumor, arrests metastasis and inhibits tumor recurrence through postoperative immunotherapy. This paper discusses several types of nanoscale biomaterials for cancer immunotherapy, and they activate the immune system through material-specific advantages to provide novel therapeutic strategies. In summary, this article will review the latest advances in tumor immunotherapy based on self-assembled, mesoporous, cell membrane modified, metallic, and hydrogel nanomaterials to explore diverse tumor therapies.

In(OTf)3-catalyzed N-α phosphonylation of N,O-acetals with triethyl phosphite

A practical approach to α-aminophosphonates has been developed through an In(OTf)₃-catalyzed N-α phosphonylation of N,O-acetals with triethyl phosphite 7. Indoline and isoindoline N,O-acetals 6a-6j and 9a-9j and chain N,O-acetals 11a-11p were subjected to a Lewis acid catalyzed N-α phosphonylation process. As a result, the desired α-aminophosphonates 8a-8j, 10a-10j and 12a-12p were obtained in moderate to good yields.

Ångstrom-scale silver particles potently combat SARS-CoV-2 infection by suppressing the ACE2 expression and inflammatory responses

The SARS-CoV-2 pandemic has become a severe global public health event, and the development of protective and therapeutic strategies is urgently needed. Downregulation of angiotensin converting enzyme 2 (ACE2; one of the important SARS-CoV-2 entry receptors) and aberrant inflammatory responses (cytokine storm) are the main targets to inhibit and control COVID-19 invasion. Silver nanomaterials have well-known pharmaceutical properties, including antiviral, antibacterial, and anticancer properties. Here, based on a self-established metal evaporation-condensation-size graded collection system, smaller silver particles reaching the Ångstrom scale (AgÅPs) were fabricated and coated with fructose to obtain a stabilized AgÅP solution (F-AgÅPs). F-AgÅPs potently inactivated SARS-CoV-2 and prevented viral infection. Considering the application of anti-SARS-CoV-2, a sterilized F-AgÅP solution was produced via spray formulation. In our model, the F-AgÅP spray downregulated ACE2 expression and attenuated proinflammatory factors. Moreover, F-AgÅPs were found to be rapidly eliminated to avoid respiratory and systemic toxicity in this study as well as our previous studies. This work presents a safe and potent anti-SARS-CoV-2 agent using an F-AgÅP spray.

Nanoarchitectured two-dimensional layered double hydroxides-based nanocomposites for biomedical applications

Despite the exceptional physicochemical and morphological characteristics, the pristine layered double hydroxides (LDHs), or two-dimensional (2D) hydrotalcite clays, often suffer from various shortcomings in biomedicine, such as deprived thermal and chemical stabilities, acid-prone degradation, as well as lack of targeting ability, hampering their scale-up and subsequent clinical translation. Accordingly, diverse nanocomposites of LDHs have been fabricated by surface coating of organic species, impregnation of inorganic species, and generation of core-shell architectures, resulting in the complex state-of-the-art architectures. In this article, we initially emphasize various bothering limitations and the chemistry of these pristine LDHs, followed by discussions on the engineering strategies of different LDHs-based nanocomposites. Further, we give a detailed note on diverse LDH nanocomposites and their performance efficacy in various biomedical applications, such as drug delivery, bioimaging, biosensing, tissue engineering and cell patterning, deoxyribonucleic acid (DNA) extraction, as well as photoluminescence, highlighting the influence of various properties of installed supramolecular assemblies on their performance efficacy. In summary, we conclude with interesting perspectives concerning the lessons learned to date and the strategies to be followed to further advance their scale-up processing and applicability in medicine.

Two-Stage Targeted Bismuthene-Based Composite Nanosystem for Multimodal Imaging Guided Enhanced Hyperthermia and Inhibition of Tumor Recurrence

A key challenge for nanomedicines in clinical application is to reduce the dose while achieving excellent efficacy, which has attracted extensive attention in dose toxicity and potential risks. It is thus necessary to reasonably design nanomedicine with high-efficiency targeting and accumulation. Here, we designed and synthesized a tetragonal bismuthene-based "all-in-one" composite nanosystem (TPP-Bi@PDA@CP) with two-stage targeting, multimodal imaging, photothermal therapy, and immune enhancement functions. Through the elaborate design of its structure, the composite nanosystem possesses multiple properties including (i) two-stage targeting function of hepatoma cells and mitochondria [the aggregation at the tumor site is 2.63-fold higher than that of traditional enhanced permeability and retention (EPR) effect]; (ii) computed tomography (CT) contrast-enhancement efficiency as high as ∼51.8 HU mL mg^-1 (3.16-fold that of the clinically available iopromide); (iii) ultrahigh photothermal conversion efficiency (52.3%, 808 nm), promising photothermal therapy (PTT), and high-contrast infrared thermal (IRT)/photoacoustic (PA) imaging of tumor; (iv) benefitting from the two-stage targeting function and excellent photothermal conversion ability, the dose used in this strategy is one of the lowest doses in hyperthermia (the inhibition rate of tumor cells was 50% at a dose of 15 μg mL^-1 and 75% at a dose of 25 μg mL^-1); (v) the compound polysaccharide (CP) shell with hepatoma cell targeting and immune enhancement functions effectively inhibited the recurrence of tumor. Therefore, our work reduces the dose toxicity and potential risk of nanomedicines and highlights the great potential as an all-in-one theranostic nanoplatform for two-stage targeting, integrated diagnostic imaging, photothermal therapy, and inhibition of tumor recurrence.

Gallium(III)-Mediated Dual-Cross-Linked Alginate Hydrogels with Antibacterial Properties for Promoting Infected Wound Healing

The metal gallium has enormous promise in fighting infections by disrupting bacterial iron metabolism via a "Trojan horse" trick. It is well worth trying to study the potential of gallium-mediated hydrogel for treating infected wounds. Herein, on the basis of a conventional gelation strategy of sodium alginate combined with metal ions, Ga³⁺ has been innovatively given a dual role in a dual-cross-linked hydrogel. It acts nor only as a cross-linking agent to form a hydrogel material but also as a therapeutic agent to slow-release and continuously treat infected wounds. Further photo-cross-linking is introduced to improve the mechanical properties of the hydrogel. Thus, a new gallium ionic- and photo-dual-cross-linked alginate hydrogel, with broad-spectrum antimicrobial activity and strengthened mechanical performance, for the treatment of infected wounds is reported. The morphology, degradability, swelling behavior, rheological properties, and gallium release kinetics together indicated the homogeneous and the strengthened mechanical performance of this hydrogel but did not impede the release of gallium ions. Interestingly, in vitro and in vivo results also demonstrated its favorable biocompatibility, reduced bacterial growth, and accelerated infected wound healing, making the gallium-incorporated hydrogel an ideal antimicrobial dressing.

Combining Fruquintinib and Doxorubicin in Size-Converted Nano-Drug Carriers for Tumor Therapy

Single-modality tumor therapy confronts many challenges, such as incomplete tumor ablation, tumor metastasis, and limited tumor tissue penetration. Combination therapy simultaneously achieves deep drug delivery to fully exert synergistic effects and has received increasing attention. Herein, based on the excellent efficacy of anti-angiogenesis therapy combined with chemotherapy and the specific size of the poly-amidoamine dendrimer (PAMAM), we developed a pH-triggered size-converted nano-drug delivery system to co-deliver fruquintinib (FRU) and doxorubicin (DOX). This study used cyclic Arg-Gly-Asp (cRGD) as the target, pH-responsive liposomes (PRLs), and PAMAM as the drug carrier. The FRU and DOX-loaded small-particle-size complex polyamide-amine-doxorubicin (PD) was encapsulated into PRLs with the target to construct a size-converted nano-drug delivery system, PRL-PD/FRU-cRGD. This nanoparticle (∼120 nm) actively targeted tumor tissues and used the acidic microenvironment outside tumor cells to release FRU and small-particle-size complex PD (∼15 nm), enabling the conversion of large-size nanoparticles to small-size nanoparticles and resulting in efficient tumor accumulation. In addition, the released PD could realize the deep delivery of DOX, showing efficient deep tumor penetration and further enhancing the tumor-suppressing effect. The results of in vivo and in vitro experiments showed that PRL-PD/FRU-cRGD exhibited the excellent synergistic effects of anti-angiogenesis therapy combined with chemotherapy and effectively inhibited tumor cell proliferation and metastasis, thereby achieving efficient tumor therapy. Thus, PRL-PD/FRU-cRGD shows great potential for combined tumor therapy.

Heterogeneous Iron Oxide/Dysprosium Oxide Nanoparticles Target Liver for Precise Magnetic Resonance Imaging of Liver Fibrosis

Challenges remain in precisely diagnosing the progress of liver fibrosis in a noninvasive way. We here synthesized small (4 nm) heterogeneous iron oxide/dysprosium oxide nanoparticles (IO-DyO NPs) as a contrast agent (CA) for magnetic resonance imaging (MRI) to precisely diagnose liver fibrosis in vivo at both 7.0 and 9.4 T field strength. Our IO-DyO NPs can target the liver and show an increased T₂ relaxivity along with an increase of magnetic field strength. At a ultrahigh magnetic field, IO-DyO NPs can significantly improve spatial/temporal image resolution and signal-to-noise ratio of the liver and precisely distinguish the early and moderate liver fibrosis stages. Our IO-DyO NP-based MRI diagnosis can exactly match biopsy (a gold standard for liver fibrosis diagnosis in the clinic) but avoid the invasiveness of biopsy. Moreover, our IO-DyO NPs show satisfactory biosafety in vitro and in vivo. This work illustrates an advanced T₂ CA used in ultrahigh-field MRI (UHFMRI) for the precise diagnosis of liver fibrosis via a noninvasive means.

Few-layer Mg-deficient borophene nanosheets: I2 oxidation and ultrasonic delamination from MgB2

By using I₂ as an oxidant and CH₃CN as a reaction medium, few-layer Mg-deficient borophene nanosheets (FBN) with a stoichiometric ratio of Mg_0.22B₂ are prepared by oxidizing MgB₂ in a mixture of CH₃CN and HCl for 14 days under nitrogen protection and followed by ultrasonic delaminating in CH₃CN for 2 h. The prepared FBN possess a two-dimensional flake morphology, and they show a clear interference fringe with a d-spacing of 0.251 nm corresponding to the (208) plane of rhombohedral boron. While maintaining the hexagonal boron networks of MgB₂, the FBN have an average thickness of about 4.14 nm (four monolayer borophene) and a lateral dimension of 500 nm, and the maximum Mg deintercalation rate can reach 78%. The acidity of the reaction system plays an important role; the HCl reaction system not only facilitates the oxidation of MgB₂ by I₂, but also increases the deintercalation ratio of Mg atoms. Etching of the Mg atom layer with HCl, the negative charge decrease of the boron layer by I₂ oxidation, and the Mg chelating effect from CH₃COOH due to the hydrolysis of CH₃CN in an HCl environment led to a high deintercalation rate of the Mg atom. Density functional theory (DFT) calculations further support the result that the maximum deintercalation rate of Mg atoms is about 78% while maintaining the hexagonal layer structure of boron. This research solves the problems of low Mg atom deintercalation rate and hexagonal boron structure destruction when using the precursor MgB₂ to produce borophene nanosheets, which is of great significance for large-scale novel preparation and application of borophene nanosheets.

MXenes: state-of-the-art synthesis, composites and bioapplications

MXenes have proven significant potential in a multitude of scientific domains as they provide substantial benefits over carbon graphene, such as ease of production and functionalization, large surface area, adjustable...

A tailored and red-emissive type I photosensitizer to potentiate photodynamic immunotherapy

Photodynamic immunotherapy (PDIT) emerges and shows great potentials in eradicating malignant tumors for the advantages on simultaneously damaging primary tumors, inhibiting tumors metastasis and recurrence. However, hypoxic microenvironment of tumor...

Chemistry, Functionalization, and Applications of Recent Monoelemental Two-Dimensional Materials and Their Heterostructures

The past decades have witnessed a rapid expansion in investigations of two-dimensional (2D) monoelemental materials (Xenes), which are promising materials in various fields, including applications in optoelectronic devices, biomedicine, catalysis, and energy storage. Apart from graphene and phosphorene, recently emerging 2D Xenes, specifically graphdiyne, borophene, arsenene, antimonene, bismuthene, and tellurene, have attracted considerable interest due to their unique optical, electrical, and catalytic properties, endowing them a broader range of intriguing applications. In this review, the structures and properties of these emerging Xenes are summarized based on theoretical and experimental results. The synthetic approaches for their fabrication, mainly bottom-up and top-down, are presented. Surface modification strategies are also shown. The wide applications of these emerging Xenes in nonlinear optical devices, optoelectronics, catalysis, biomedicine, and energy application are further discussed. Finally, this review concludes with an assessment of the current status, a description of existing scientific and application challenges, and a discussion of possible directions to advance this fertile field.

Dispersion of Few-Layer Black Phosphorus in Binary Polymer Blend and Block Copolymer Matrices

Exfoliated black phosphorus (bP) embedded into a polymer is preserved from oxidation, is stable to air, light, and humidity, and can be further processed into devices without degrading its properties. Most of the examples of exfoliated bP/polymer composites involve a single polymer matrix. Herein, we report the preparation of biphasic polystyrene/poly(methyl methacrylate) (50/50 wt.%) composites containing few-layer black phosphorus (fl-bP) (0.6–1 wt.%) produced by sonicated-assisted liquid-phase exfoliation. Micro-Raman spectroscopy confirmed the integrity of fl-bP, while scanning electron microscopy evidenced the influence of fl-bP into the coalescence of polymeric phases. Furthermore, the topography of thin films analyzed by atomic force microscopy confirmed the effect of fl-bP into the PS dewetting, and the selective PS etching of thin films revealed the presence of fl-bP flakes. Finally, a block copolymer/fl-bP composite (1.2 wt.%) was prepared via in situ reversible addition–fragmentation chain transfer (RAFT) polymerization by sonication-assisted exfoliation of bP into styrene. For this sample, ³¹P solid-state NMR and Raman spectroscopy confirmed an excellent preservation of bP structure.