Targeted crystallization of mixed-charge nanoparticles in lysosomes induces selective death of cancer cells

Lysosome-Targeted and pH-Activatable Phototheranostics for NIR-II Fluorescence Imaging-Guided Nasopharyngeal Carcinoma Phototherapy

Currently, clinical therapeutic strategies for nasopharyngeal carcinoma (NPC) confront insurmountable dilemmas in which surgical resection is incomplete and chemotherapy/radiotherapy has significant side effects. Phototherapy offers a maneuverable, effective, and noninvasive pattern for NPC therapy. Herein, we developed a lysosome-targeted and pH-responsive nanophototheranostic for near-infrared II (NIR-II) fluorescence imaging-guided photodynamic therapy (PDT) and photothermal therapy (PTT) of NPC. A lysosome-targeted S-D-A-D-S-type NIR-II phototheranostic molecule (IRFEM) is encapsulated within the acid-sensitive amphiphilic DSPE-Hyd-PEG2k to form IRFEM@DHP nanoparticles (NPs). The prepared IRFEM@DHP exhibits a good accumulation in the acidic lysosomes for facilitating the release of IRFEM, which could disrupt lysosomal function by generating an amount of heat and ROS under laser irradiation. Moreover, the guidelines of NIR-II fluorescence enhance the accuracy of PTT/PDT for NPC and avoid damage to normal tissues. Remarkably, IRFEM@DHP enable efficient antitumor effects both in vitro and in vivo, opening up a new avenue for precise NPC theranostics.

Lysosomal Peptide Self-Assembly to Control Cell Behavior

Lysosomes are membrane-enclosed organelles that play key roles in degrading and recycling cellular debris, cellular signaling, and energy metabolism processes. Confinement of amphiphilic peptides in the lysosome to construct functional nanostructures through noncovalent interactions is an emerging approach to tune the homeostasis of lysosome. After briefly introducing the importance of lysosome and its functions, we discuss the advantages of lysosomal nanostructure formation for disease therapy. We next discuss the strategy for triggering the self-assembly of peptides in the lysosome, followed by a concise outlook of the future perspective about this emerging research direction.

Increased endocytosis rate and enhanced lysosomal pathway of silica-coated superparamagnetic nanoparticles into M-HeLa cells compared with cultured primary motor neurons

The unique properties of superparamagnetic iron oxide nanoparticles (SPIONs) enable their use as magnetic biosensors, targeted drug delivery, magnetothermia, magnetic resonance imaging, etc. Today, SPIONs are the only type of metal oxide nanoparticles approved for biomedical application. In this work, we analyzed the cellular response to the previously reported luminescent silica coated SPIONs of the two cell types: M-HeLa cells and primary motor neuron culture. Both internalization pathways and intracellular fate of SPIONs have been compared for these cell lines using fluorescence and transmission electron microscopy. We also applied a pharmacological approach to analyze the endocytosis pathways of SPIONs into the investigated cell lines. The penetration of SPIONs into M-HeLa cells is already noticeable within 30 s of incubation through both caveolin-dependent endocytosis and micropinocytosis. However, incubation for a longer time (1 h at least) is required for the internalization of SPIONs into motor neuron culture cells provided by dynamin-dependent endocytosis and macropinocytosis. The intracellular colocalization assay reveals that the lysosomal internalization pathway of SPIONs is also dependent on the cell type. The lysosomal pathway is much more pronounced for M-HeLa cells compared with motor neurons. The emphasized differences in cellular responses of the two cell lines open up new opportunities in the application of SPIONs in the diagnostics and therapy of cancer cells.

Self-Assembly of 2D Polyphthalocyanine in Lysosome Enables Multienzyme Activity Enhancement to Induce Tumor Ferroptosis

Nanozymes show great potential in facilitating tumor ferroptosis by upregulation of reactive oxygen species (ROS) and downregulation of glutathione (GSH). However, mild acidity (pH 6.5-6.9) of tumor microenvironment severely restricts the activity of nanozymes. Although lysosomes as acidic organelles (pH = 3.5-5.5) are hopeful for improving enzyme-like activity, most reported nanozymes are not capable of effectively accumulating in the lysosomes. Herein, an acid-responsive self-assembly strategy based on iron phthalocyanine-rich covalent organic framework nanosheets (COFFePc NSs) is developed, which enables lysosomal targeting aggregation of COFFePc NSs due to the existence of abundant negative hydroxyl groups and rigid structure. Meanwhile, COFFePc NSs display exceptional multienzyme-mimic performance at lower pH to efficiently generate ROS to cause lysosome damage and apoptosis by synergistic photothermal effect. Subsequently, the released COFFePc with GSH oxidase-mimicking activity can consume GSH to promote ferroptosis. This is the first report of a 2D COF using its own properties to achieve lysosomal self-assembly. Overall, the work provides a new paradigm for the development of lysosome-targeted nanosystems.

The interactions of subcellular organelles in pulmonary fibrosis induced by carbon black nanoparticles: a comprehensive review

Owing to the widespread use and improper emissions of carbon black nanoparticles (CBNPs), the adverse effects of CBNPs on human health have attracted much attention. In toxicological research, carbon black is frequently utilized as a negative control because of its low toxicity and poor solubility. However, recent studies have indicated that inhalation exposure to CBNPs could be a risk factor for severe and prolonged pulmonary inflammation and fibrosis. At present, the pathogenesis of pulmonary fibrosis induced by CBNPs is still not fully elucidated, but it is known that with small particle size and large surface area, CBNPs are more easily ingested by cells, leading to organelle damage and abnormal interactions between organelles. Damaged organelle and abnormal organelles interactions lead to cell structure and function disorders, which is one of the important factors in the development and occurrence of various diseases, including pulmonary fibrosis. This review offers a comprehensive analysis of organelle structure, function, and interaction mechanisms, while also summarizing the research advancements in organelles and organelle interactions in CBNPs-induced pulmonary fibrosis.

pH-Responsive, Self-Assembled Ruthenium Nanodrug: Dual Impact on Lysosomes and DNA for Synergistic Chemotherapy and Immunogenic Cell Death

Several DNA-damaging antitumor agents, including ruthenium complexes, induce immunogenic cell death (ICD). In this study, an arginyl-glycyl-aspartic acid (RGD) peptide-modified carboline ruthenium complex (KS-Ru) is synthesized as a chemotherapeutic nanodrug and an ICD inducer. The RGD peptide, an integrin ligand, provides tumor-specific targeting and promotes self-assembly of the KS-Ru complex. The pH-responsive self-assembly is assessed through transmission and scanning electron microscopy. Additionally, in vitro cytotoxic activity and anti-metastasis ability are evaluated using MTT and Transwell assays, respectively, along with cellular immunofluorescence staining and imaging flow cytometry. The ability of the complex to inhibit primary tumor formation and lung metastasis in vivo is evaluated using Lewis lung cancer and A549 xenograft models. Furthermore, the tumor immune microenvironment is evaluated using single-cell flow mass cytometry. KS-Ru translocates to the nucleus, causing DNA damage and inducing ICD. Within the lysosomes, KS-Ru self-assembled into nanoflowers, leading to lysosomal swelling and apoptosis. Notably, the as-synthesized pH-dependent ruthenium nanomedicine achieves dual functionality-chemotherapy and immunotherapy. Moreover, the pH-responsive self-assembly of KS-Ru enables simultaneous mechanisms in the lysosome and nucleus, thereby lowering the likelihood of drug resistance. This study provides valuable insight for the design of novel ruthenium-based nanoantitumor drugs.

Tracking the Cellular Degradation of Silver Nanoparticles: Development of a Generic Kinetic Model

Understanding the degradation of nanoparticles (NPs) after crossing the cell plasma membrane is crucial in drug delivery designs and cytotoxicity assessment. However, the key factors controlling the degradable kinetics remain unclear due to the absence of a quantification model. In this study, subcellular imaging of silver nanoparticles (AgNPs) was used to determine the intracellular transfer of AgNPs, and single particle ICP-MS was utilized to track the degradation process. A cellular kinetic model was subsequently developed to describe the uptake, transfer, and degradation behaviors of AgNPs. Our model demonstrated that the intracellular degradation efficiency of AgNPs was much higher than that determined by mimicking testing, and the degradation of NPs was highly influenced by cellular factors. Specifically, deficiencies in Ca or Zn primarily decreased the kinetic dissolution of NPs, while a Ca deficiency also resulted in the retardation of NP transfer. The biological significance of these kinetic parameters was strongly revealed. Our model indicated that the majority of internalized AgNPs dissolved, with the resulting ions being rapidly depurated. The release of Ag ions was largely dependent on the microvesicle-mediated route. By changing the coating and size of AgNPs, the model results suggested that size influenced the transfer of NPs into the degradation process, whereas coating affected the degradation kinetics. Overall, our developed model provides a valuable tool for understanding and predicting the impacts of the physicochemical properties of NPs and the ambient environment on nanotoxicity and therapeutic efficacy.

Acid-assisted self-assembly of pyrene-capped tyrosine ruptures lysosomes to induce cancer cell apoptosis

Induced lysosomal membrane permeabilization (LMP) by peptide self-assembly has emerged as an effective platform for lysosome-targeted cancer therapy. In this study, we shift this strategical paradigm and present an innovative approach to LMP induction through amino acid-based self-assembly. Pyrene-capped tyrosine (Py-Tyr), as a proof-of-concept molecule, is designed with acidity-responsive self-assembly. Under acidic conditions (pH 4), Py-Tyr is protonated with reduced charge repulsion, and self-assembles into micrometer-scaled aggregates, which exceed the biological size of lysosomes. Cell experiments showed that Py-Tyr specifically accumulates in lysosomes and induces lysosome rupture, leading to the release of cathepsin B into the cytoplasm for subsequent apoptosis activation in cancer cells. This study capitalizes on the concept of amino acid assembly for efficient LMP induction, providing a simple and versatile platform for precise and effective therapeutic interventions in cancer therapy.

Developing a Selection Framework for Zinc Ion-Based Biomaterial Design: Guided by the Biosafety Assessment of ZIF-8 and ZnO

In recent years, nanomaterials have gained widespread use in the biomedical field, with ZIF-8 and ZnO emerging as promising candidates due to their remarkable performance in osteogenesis, angiogenesis, and antimicrobial therapy. However, before advancing these nanomaterials for clinical applications, it is imperative to evaluate their biocompatibility. In particular, comparing nanomaterials with similar biomedical functions is crucial for identifying the most suitable nanomaterials for further development and market entry. Our study aimed to compare the biocompatibility of nano-ZIF-8 and nano-ZnO under the same conditions. We found that nano-ZIF-8 exhibited lower toxicity both in vitro and in vivo compared to nano-ZnO. To gain insights into the underlying mechanisms responsible for this difference, we conducted further experiments to investigate lysosome damage, mitochondrial change, and the occurrence of ferroptosis. Additionally, we performed transcriptome sequencing to analyze the expression of relevant genes, thereby providing robust validation for our findings. In summary, our study highlighted the importance of evaluating nanomaterials with similar biomedical effects. Through this comparative study, we have not only shed light on the superior biocompatibility of nano-ZIF-8 over nano-ZnO, but also contributed valuable insights and methodological references for future material screening endeavors. Ultimately, our study served as a stepping stone toward the development of safer and more effective nanomaterials for various biomedical applications.

Lysosome passivation triggered by silver nanoparticles enhances subcellular-targeted drug therapy

Frequently, subcellular-targeted drugs tend to accumulate in lysosomes after cellular absorption, a process termed the lysosomal trap. This accumulation often interferes with the drug's ability to bind to its target, resulting in decreased efficiency. Existing methods for addressing lysosome-induced drug resistance mainly involve improving the structures of small molecules or enveloping drugs in nanomaterials. Nonetheless, these approaches can lead to changes in the drug structure or potentially trigger unexpected reactions within organisms. To address these issues, we introduced a strategy that involves inactivating the lysosome with the use of Ag nanoparticles (Cy3.5@Ag NPs). In this method, the Cy3.5@Ag NPs gradually accumulate inside lysosomes, leading to permeation of the lysosomal membrane and subsequent lysosomal inactivation. In addition, Cy3.5@Ag NPs also significantly affected the motility of lysosomes and induced the occurrence of lysosome passivation. Importantly, coincubating Cy3.5@Ag NPs with various subcellular-targeted drugs was found to significantly increase the efficiency of these treatments. Our strategy illustrates the potential of using lysosomal inactivation to enhance drug efficacy, providing a promising therapeutic strategy for cancer.

Opportunities and challenges for plastic depolymerization by biomimetic catalysis

Plastic waste has imposed significant burdens on the environment. Chemical recycling allows for repeated regeneration of plastics without deterioration in quality, but often requires harsh reaction conditions, thus being environmentally unfriendly. Enzymatic catalysis offers a promising solution for recycling under mild conditions, but it faces inherent limitations such as poor stability, high cost, and narrow substrate applicability. Biomimetic catalysis may provide a new avenue by combining high enzyme-like activity with the stability of inorganic materials. Biomimetic catalysis has demonstrated great potential in biomass conversion and has recently shown promising progress in plastic degradation. This perspective discusses biomimetic catalysis for plastic degradation from two perspectives: the imitation of the active centers and the imitation of the substrate-binding clefts. Given the chemical similarity between biomass and plastics, relevant work is also included in the discussion to draw inspiration. We conclude this perspective by highlighting the challenges and opportunities in achieving sustainable plastic recycling via a biomimetic approach.

Nanocarriers address intracellular barriers for efficient drug delivery, overcoming drug resistance, subcellular targeting and controlled release

The cellular barriers are major bottlenecks for bioactive compounds entering into cells to accomplish their biological functions, which limits their biomedical applications. Nanocarriers have demonstrated high potential and benefits for encapsulating bioactive compounds and efficiently delivering them into target cells by overcoming a cascade of intracellular barriers to achieve desirable therapeutic and diagnostic effects. In this review, we introduce the cellular barriers ahead of drug delivery and nanocarriers, as well as summarize recent advances and strategies of nanocarriers for increasing internalization with cells, promoting intracellular trafficking, overcoming drug resistance, targeting subcellular locations and controlled drug release. Lastly, the future perspectives of nanocarriers for intracellular drug delivery are discussed, which mainly focus on potential challenges and future directions. Our review presents an overview of intracellular drug delivery by nanocarriers, which may encourage the future development of nanocarriers for efficient and precision drug delivery into a wide range of cells and subcellular targets.

Bioorthogonal In Situ Polymerization of Dendritic Agents for Hijacking Lysosomes and Enhancing Antigen Presentation in Cancer Cells

A low-generation lysine dendrimer, SPr-G2, responds to intracellular glutathione to initiate bioorthogonal in situ polymerization, resulting in the formation of large assemblies in mouse breast cancer cells. The intracellular large assemblies of SPr-G2 can interact with lysosomes to induce lysosome expansion and enhance lysosomal membrane permeabilization, leading to major histocompatibility complex class I upregulation on tumor cell surfaces and ultimately tumor cell death. Moreover, the use of the SPr-G2 dendrimer to conjugate the chemotherapeutic drug, camptothecin (CPT), can boost the therapeutic potency of CPT. Excellent antitumor effects in vitro and in vivo are obtained from the combinational treatment of the SPr-G2 dendrimer and CPT. This combinational effect also enhances antitumor immunity through promoting activation of cytotoxic T cells in tumor tissues and maturation of dendritic cells. This study can shed new light on the development of peptide dendritic agents for cancer therapy.

The application of nanoparticles-based ferroptosis, pyroptosis and autophagy in cancer immunotherapy

Immune checkpoint blockers (ICBs) have been applied for cancer therapy and achieved great success in the field of cancer immunotherapy. Nevertheless, the broad application of ICBs is limited by the low response rate. To address this issue, increasing studies have found that the induction of immunogenic cell death (ICD) in tumor cells is becoming an emerging therapeutic strategy in cancer treatment, not only straightly killing tumor cells but also enhancing dying cells immunogenicity and activating antitumor immunity. ICD is a generic term representing different cell death modes containing ferroptosis, pyroptosis, autophagy and apoptosis. Traditional chemotherapeutic agents usually inhibit tumor growth based on the apoptotic ICD, but most tumor cells are resistant to the apoptosis. Thus, the induction of non-apoptotic ICD is considered to be a more efficient approach for cancer therapy. In addition, due to the ineffective localization of ICD inducers, various types of nanomaterials have been being developed to achieve targeted delivery of therapeutic agents and improved immunotherapeutic efficiency. In this review, we briefly outline molecular mechanisms of ferroptosis, pyroptosis and autophagy, as well as their reciprocal interactions with antitumor immunity, and then summarize the current progress of ICD-induced nanoparticles based on different strategies and illustrate their applications in the cancer therapy.

Apoptosis and Paraptosis Induced by Disulfiram-Loaded Ca2+/Cu2+ Dual-Ions Nano Trap for Breast Cancer Treatment

Regarded as one of the hallmarks of tumorigenesis and tumor progression, the evasion of apoptotic cell death would also account for treatment resistance or failure during cancer therapy. In this study, a Ca2+/Cu2+ dual-ion "nano trap" to effectively avoid cell apoptosis evasion by synchronously inducing paraptosis together with apoptosis was successfully designed and fabricated for breast cancer treatment. In brief, disulfiram (DSF)-loaded amorphous calcium carbonate nanoparticles (NPs) were fabricated via a gas diffusion method. Further on, the Cu2+-tannic acid metal phenolic network was embedded onto the NPs surface by self-assembling, followed by mDSPE-PEG/lipid capping to form the DSF-loaded Ca2+/Cu2+ dual-ions "nano trap". The as-prepared nanotrap would undergo acid-triggered biodegradation upon being endocytosed by tumor cells within the lysosome for Ca2+, Cu2+, and DSF releasing simultaneously. The released Ca2+ could cause mitochondrial calcium overload and lead to hydrogen peroxide (H2O2) overexpression. Meanwhile, Ca2+/reactive oxygen species-associated mitochondrial dysfunction would lead to paraptosis cell death. Most importantly, cell paraptosis could be further induced and strengthened by the toxic dithiocarbamate (DTC)-copper complexes formed by the Cu2+ combined with the DTC, the metabolic products of DSF. Additionally, the released Cu2+ will be reduced by intracellular glutathione to generate Cu+, which can catalyze the H2O2 to produce a toxic hydroxyl radical by a Cu+-mediated Fenton-like reaction for inducing cell apoptosis. Both in vitro cellular assays and in vivo antitumor evaluations confirmed the cancer therapeutic efficiency by the dual ion nano trap. This study can broaden the cognition scope of dual-ion-mediated paraptosis together with apoptosis via a multifunctional nanoplatform.

Visualizing the intracellular aggregation behavior of gold nanoclusters via structured illumination microscopy and scanning transmission electron microscopy

Given the growing concerns about nanotoxicity, numerous studies have focused on providing mechanistic insights into nanotoxicity by imaging the intracellular fate of nanoparticles. A suitable imaging strategy is necessary to uncover the intracellular behavior of nanoparticles. Although each conventional technique has its own limitations, scanning transmission electron microscopy (STEM) and three-dimensional structured illumination microscopy (3D-SIM) combine the advantages of chemical element mapping, ultrastructural analysis, and cell dynamic tracking. Gold nanoclusters (AuNCs), synthesized using 6-aza-2 thiothymine (ATT) and L-arginine (Arg) as reducing and protecting ligands, referred to as Arg@ATT-AuNCs, have been widely used in biological sensing and imaging, medicine, and catalyst yield. Based on their intrinsic fluorescence and high electron density, Arg@ATT-AuNCs were selected as a model. STEM imaging showed that both the single-particle and aggregated states of Arg@ATT-AuNCs were compartmentally distributed within a single cell. Real-time 3D-SIM imaging showed that the fluorescent Arg@ATT-AuNCs gradually aggregated after being located in the lysosomes of living cells, causing lysosomal damage. The aggregate formation of Arg@ATT-AuNCs was triggered by the low-pH medium, particularly in the lysosomal acidic environment. The proposed dual imaging strategy was verified using other types of AuNCs, which is valuable for studying nano-cell interactions and any associated cytotoxicity, and has the potential to be a useful approach for exploring the interaction of cells with various nanoparticles.

Fabrication of Yolk-Shell Structure with Multifarious Nanoparticles via Double-Layered Encapsulation Strategy

The post-encapsulation method (such as single-layered encapsulation) is a promising strategy to synthesize yolk-shell structures that protect functional nanoparticles by the molecular sieving effect. However, this method exhibited limited loading capacity and nonuniform encapsulation during the co-encapsulation of various nanoparticles owing to the insufficient surface area for nanoparticle attachment. To address these limitations, we proposed a double-layered encapsulation method comprising an increased number of silica template layers and separate attachment of multifarious nanoparticles to different layers. Compared with conventional methods, this strategy can precisely adjust the ratio of encapsulated nanoparticles and increase the loading amount, which improves the functionality of yolk-shell structures, such as the photothermal properties of gold nanoparticle-encapsulated yolk-shell structures (∼69%). We describe, for the first time, the precise control of the ratio of encapsulated nanoparticles and the loading of numerous nanoparticles. Consequently, this strategy has significant potential for various applications of yolk-shell structures.

Enhancing drug penetration in solid tumors via nanomedicine: Evaluation models, strategies and perspectives

Effective tumor treatment depends on optimizing drug penetration and accumulation in tumor tissue while minimizing systemic toxicity. Nanomedicine has emerged as a key solution that addresses the rapid clearance of free drugs, but achieving deep drug penetration into solid tumors remains elusive. This review discusses various strategies to enhance drug penetration, including manipulation of the tumor microenvironment, exploitation of both external and internal stimuli, pioneering nanocarrier surface engineering, and development of innovative tactics for active tumor penetration. One outstanding strategy is organelle-affinitive transfer, which exploits the unique properties of specific tumor cell organelles and heralds a potentially transformative approach to active transcellular transfer for deep tumor penetration. Rigorous models are essential to evaluate the efficacy of these strategies. The patient-derived xenograft (PDX) model is gaining traction as a bridge between laboratory discovery and clinical application. However, the journey from bench to bedside for nanomedicines is fraught with challenges. Future efforts should prioritize deepening our understanding of nanoparticle-tumor interactions, re-evaluating the EPR effect, and exploring novel nanoparticle transport mechanisms.

Surface-Charge-Driven Ferroptosis and Mitochondrial Dysfunction Is Involved in Toxicity Diversity in the Marine Bivalve Exposed to Nanoplastics

Nanoplastics (NPs) pervade daily life, posing serious threats to marine ecosystems. Despite the crucial role that surface charge plays in NP effects, there is a substantial gap in our understanding of how surface charge influences NP toxicity. Herein, by exposing Ruditapes philippinarum (R. philippinarum) to both positively charged NPs (p-NPs) and negatively charged NPs (n-NPs) at environmentally relevant particle number levels for a duration of 35 days, we unequivocally demonstrate that both types of NPs had discernible impacts on the clams depending on their surface charge. Through transcriptomic and proteomic analyses, we unveiled the primary mechanisms behind p-NP toxicity, which stem from induced mitochondrial dysfunction and ferroptosis. In contrast, n-NPs predominantly stimulated innate immune responses, influencing salivary secretion and modulating the complement and coagulation cascades. Furthermore, in vitro tests on clam immune cells confirmed that internalized p-NPs triggered alterations in mitochondrial morphology, a decrease in membrane potential, and the initiation of ferroptosis. Conversely, n-NPs, to a certain extent, moderated the expression of genes related to immune responses, thus mitigating their adverse effects. Taken together, these findings indicate that the differential surface-charge-driven ferroptosis and mitochondrial dysfunction in clams play a critical role in the toxicity profile of NPs, providing an insightful reference for assessing the ecological toxicity associated with NPs.

Immunogenic antitumor potential of Prakasine nanoparticles in zebrafish by gene expression stimulation

In this study, non-toxic mercury nanoparticle was synthesized as per "Prakash theory of metal drugs" and nanoparticle's characters has been demonstrated by employing several nanotechnological tools including XPS, XRD, EDAX. The size of the Prakasine nanoparticles (PRK-NP) ranged from 90-100 nm, confirmed using TEM, SEM, DLS and along with zeta potential of -29.5 mV before storage and -8.5 mV after storage. The FTIR provided information regarding the nanoparticle capping and functional groups. The study was further elaborated for determining PRK-NPs toxicity, genotoxicity, in-vivo toxicity, immunological anti-tumour activity, immunogenicity potential, gene expression profiling and confirmed by MTT and apoptosis assays, cancer zebrafish model studies and WBC proliferation assay. PRK-NPs revealed no cytotoxicity where cell viability was observed 99% in L6 mouse fibroblasts and 99% in MCF-7 cell lines. Also, the cell viability was to be 89.47% at a very high concentration of 320 µg/ml in HEK 293 cells. The PRK-NPs significantly reduced the tumour in zebrafish at dose of 90 μg/g by up regulating IL-1α, IL-1β, IL-2-ITK, IL-6, IL-8, IL-12, TNF-α and IFN-γ, and down regulating IL-4, IL-5, IL-10 and TGF-β compared to untreated controls without any adverse effects and toxicity. Thus, the current study beholds anticipation PRK-NPs may play a vital role in therapeutic.

Nanoparticles and Mesenchymal Stem Cell (MSC) Therapy for Cancer Treatment: Focus on Nanocarriers and a si-RNA CXCR4 Chemokine Blocker as Strategies for Tumor Eradication In Vitro and In Vivo

Mesenchymal stem cells (MSCs) have a high tropism for the hypoxic microenvironment of tumors. The combination of nanoparticles in MSCs decreases tumor growth in vitro as well as in rodent models of cancers in vivo. Covalent conjugation of nanoparticles with the surface of MSCs can significantly increase the drug load delivery in tumor sites. Nanoparticle-based anti-angiogenic systems (gold, silica and silicates, diamond, silver, and copper) prevented tumor growth in vitro. For example, glycolic acid polyconjugates enhance nanoparticle drug delivery and have been reported in human MSCs. Labeling with fluorescent particles (coumarin-6 dye) identified tumor cells using fluorescence emission in tissues; the conjugation of different types of nanoparticles in MSCs ensured success and feasibility by tracking the migration and its intratumor detection using non-invasive imaging techniques. However, the biosafety and efficacy; long-term stability of nanoparticles, and the capacity for drug release must be improved for clinical implementation. In fact, MSCs are vehicles for drug delivery with nanoparticles and also show low toxicity but inefficient accumulation in tumor sites by clearance of reticuloendothelial organs. To solve these problems, the internalization or conjugation of drug-loaded nanoparticles should be improved in MSCs. Finally, CXCR4 may prove to be a promising target for immunotherapy and cancer treatment since the delivery of siRNA to knock down this alpha chemokine receptor or CXCR4 antagonism has been shown to disrupt tumor-stromal interactions.

Schiff Base Reaction in a Living Cell: In Situ Synthesis of a Hollow Covalent Organic Polymer To Regulate Biological Functions

Artificially performing chemical reactions in living biosystems to attain various physiological aims remains an intriguing but very challenging task. In this study, the Schiff base reaction was conducted in cells using Sc(OTf)3 as a catalyst, enabling the in situ synthesis of a hollow covalent organic polymer (HCOP) without external stimuli. The reversible Schiff base reaction mediated intracellular Oswald ripening endows the HCOP with a spherical, hollow porous structure and a large specific surface area. The intracellularly generated HCOP reduced cellular motility by restraining actin polymerization, which consequently induced mitochondrial deactivation, apoptosis, and necroptosis. The presented intracellular synthesis system inspired by the Schiff base reaction has strong potential to regulate cell fate and biological functions, opening up a new strategic possibility for intervening in cellular behavior.

Ultrasound-Induced Gold Nanoparticle United with Acoustic Reprogramming of Macrophages for Enhanced Cancer Therapy

Sonodynamic therapy (SDT) has considerable potential in cancer treatment and exhibits high tissue penetration with minimal damage to healthy tissues. The efficiency of SDT is constrained by the complex immunological environment and tumor treatment resistance. Herein, a specific acoustic-actuated tumor-targeted nanomachine is proposed to generate mechanical damage to lysosomes for cancer SDT. The hybrid nanomachine was assembled with gold nanoparticles (GNPs) as the core and encapsulated with macrophage exosomes modified by AS1411 aptamers (GNP@EXO-APs) to optimize the pharmacokinetics and tumor aggregation. GNP@EXO-APs could be specifically transferred to the lysosomes of tumor cells. After induction with ultrasound, GNP@EXO-APs generated strong mechanical stress to produce lysosomal-dependent cell death in cancer cells. Notably, tumor-associated macrophages were reprogrammed in the ultrasound environment to an antitumor phenotype. Enhanced mechanical destruction via GNP@EXO-APs and immunotherapy of cancer cells were verified both in vitro and in vivo under SDT. This study provides a new direction for inside-out killing effects on tumor cells for cancer treatment.

Enhancing Efficacy of Albumin-Bound Paclitaxel for Human Lung and Colorectal Cancers through Autophagy Receptor Sequestosome 1 (SQSTM1)/p62-Mediated Nanodrug Delivery and Cancer therapy

Selective autophagy is a defense mechanism by which foreign pathogens and abnormal substances are processed to maintain cellular homeostasis. Sequestosome 1 (SQSTM1)/p62, a vital selective autophagy receptor, recruits ubiquitinated cargo to form autophagosomes for lysosomal degradation. Nab-PTX is an albumin-bound paclitaxel nanoparticle used in clinical cancer therapy. However, the role of SQSTM1 in regulating the delivery and efficacy of nanodrugs remains unclear. Here we showed that SQSTM1 plays a crucial role in Nab-PTX drug delivery and efficacy in human lung and colorectal cancers. Nab-PTX induces SQSTM1 phosphorylation at Ser403, which facilitates its incorporation into the selective autophagy of nanoparticles, known as nanoparticulophagy. Nab-PTX increased LC3-II protein expression, which triggered autophagosome formation. SQSTM1 enhanced Nab-PTX recognition to form autophagosomes, which were delivered to lysosomes for albumin degradation, thereby releasing PTX to induce mitotic catastrophe and apoptosis. Knockout of SQSTM1 downregulated Nab-PTX-induced mitotic catastrophe, apoptosis, and tumor inhibition in vitro and in vivo and inhibited Nab-PTX-induced caspase 3 activation via a p53-independent pathway. Ectopic expression of SQSTM1 by transfection of an SQSTM1-GFP vector restored the drug efficacy of Nab-PTX. Importantly, SQSTM1 is highly expressed in advanced lung and colorectal tumors and is associated with poor overall survival in clinical patients. Targeting SQSTM1 may provide an important strategy to improve nanodrug efficacy in clinical cancer therapy. This study demonstrates the enhanced efficacy of Nab-PTX for human lung and colorectal cancers via SQSTM1-mediated nanodrug delivery.

Tumor Abnormality-Oriented Nanomedicine Design

Anticancer nanomedicines have been proven effective in mitigating the side effects of chemotherapeutic drugs. However, challenges remain in augmenting their therapeutic efficacy. Nanomedicines responsive to the pathological abnormalities in the tumor microenvironment (TME) are expected to overcome the biological limitations of conventional nanomedicines, enhance the therapeutic efficacies, and further reduce the side effects. This Review aims to quantitate the various pathological abnormalities in the TME, which may serve as unique endogenous stimuli for the design of stimuli-responsive nanomedicines, and to provide a broad and objective perspective on the current understanding of stimuli-responsive nanomedicines for cancer treatment. We dissect the typical transport process and barriers of cancer drug delivery, highlight the key design principles of stimuli-responsive nanomedicines designed to tackle the series of barriers in the typical drug delivery process, and discuss the "all-into-one" and "one-for-all" strategies for integrating the needed properties for nanomedicines. Ultimately, we provide insight into the challenges and future perspectives toward the clinical translation of stimuli-responsive nanomedicines.

Supramolecular Biomaterials for Cancer Immunotherapy

Cancer immunotherapy has achieved tremendous successful clinical results and obtained historic victories in tumor treatments. However, great limitations associated with feeble immune responses and serious adverse effects still cannot be neglected due to the complicated multifactorial etiology and pathologic microenvironment in tumors. The rapid development of nanomedical science and material science has facilitated the advanced progress of engineering biomaterials to tackle critical issues. The supramolecular biomaterials with flexible and modular structures have exhibited unparalleled advantages of high cargo-loading efficiency, excellent biocompatibility, and diversiform immunomodulatory activity, thereby providing a powerful weapon for cancer immunotherapy. In past decades, supramolecular biomaterials were extensively explored as versatile delivery platforms for immunotherapeutic agents or designed to interact with the key moleculars in immune system in a precise and controllable manner. In this review, we focused on the crucial role of supramolecular biomaterials in the modulation of pivotal steps during tumor immunotherapy, including antigen delivery and presentation, T lymphocyte activation, tumor-associated macrophage elimination and repolarization, and myeloid-derived suppressor cell depletion. Based on extensive research, we explored the current limitations and development prospects of supramolecular biomaterials in cancer immunotherapy.

Intra-Lysosomal Peptide Assembly for the High Selectivity Index against Cancer

Lysosomes remain powerful organelles and important targets for cancer therapy because cancer cell proliferation is greatly dependent on effective lysosomal function. Recent studies have shown that lysosomal membrane permeabilization induces cell death and is an effective way to treat cancer by bypassing the classical caspase-dependent apoptotic pathway. However, most lysosome-targeted anticancer drugs have very low selectivity for cancer cells. Here, we show intra-lysosomal self-assembly of a peptide amphiphile as a powerful technique to overcome this problem. We designed a peptide amphiphile that localizes in the cancer lysosome and undergoes cathepsin B enzyme-instructed supramolecular assembly. This localized assembly induces lysosomal swelling, membrane permeabilization, and damage to the lysosome, which eventually causes caspase-independent apoptotic death of cancer cells without conventional chemotherapeutic drugs. It has specific anticancer effects and is effective against drug-resistant cancers. Moreover, this peptide amphiphile exhibits high tumor targeting when attached to a tumor-targeting ligand and causes significant inhibition of tumor growth both in cancer and drug-resistant cancer xenograft models.

Gold nanoparticles combat enveloped RNA virus by affecting organelle dynamics

Enveloped RNA viruses are a group of viruses with an outer membrane derived from a host cell and a genome consisting of ribonucleic acid (RNA). These viruses rely on host cell machinery and organelles to replicate and assemble new virus particles. However, the interaction between viruses and host organelles may be disrupted by nanomaterials, such as gold nanoparticles (AuNPs) with unique physical and chemical properties. In this study, we investigated the effects of AuNPs with different surface charge properties on the subcellular structure and function of mammalian cells, and their effects on two representative enveloped RNA viruses: lentivirus and human coronavirus OC43 (HCoV- OC43) antiviral potential. By comparing the subcellular effects of AuNPs with different surface charge properties, we found that treatment with AuNPs with positive surface charges induced more significant disruption of subcellular structures than neutrally charged AuNPs and negatively charged AuNPs, mainly manifested in lysosomes and Cytoskeletal disorders. The antiviral effect of the surface positively charged AuNPs was further evaluated using lentivirus and HCoV-OC43. The results showed that AuNPs had a significant inhibitory effect on both lentivirus and HCoV-OC43 without obvious side effects. In conclusion, our study provides insights into the mechanism of action and biocompatibility of AuNP in biological systems, while supporting the potential of targeting organelle dynamics against enveloped RNA viruses.

Exocytosis of Nanoparticles: A Comprehensive Review

Both biomedical applications and safety assessments of manufactured nanomaterials require a thorough understanding of the interaction between nanomaterials and cells, including how nanomaterials enter cells, transport within cells, and leave cells. However, compared to the extensively studied uptake and trafficking of nanoparticles (NPs) in cells, less attention has been paid to the exocytosis of NPs. Yet exocytosis is an indispensable process of regulating the content of NPs in cells, which in turn influences, even decides, the toxicity of NPs to cells. A comprehensive understanding of the mechanisms and influencing factors of the exocytosis of NPs is not only essential for the safety assessment of NPs but also helpful for guiding the design of safe and highly effective NP-based materials for various purposes. Herein, we review the current status and progress of studies on the exocytosis of NPs. Firstly, we introduce experimental procedures and considerations. Then, exocytosis mechanisms/pathways are summarized with a detailed introduction of the main pathways (lysosomal and endoplasmic reticulum/Golgi pathway) and the role of microtubules; the patterns of exocytosis kinetics are presented and discussed. Subsequently, the influencing factors (initial content and location of intracellular NPs, physiochemical properties of NPs, cell type, and extracellular conditions) are fully discussed. Although there are inconsistent results, some rules are obtained, like smaller and charged NPs are more easily excreted. Finally, the challenges and future directions in the field have been discussed.

Dual-Targeting Biomimetic Nanomaterials for Photo-/Chemo-/Antiangiogenic Synergistic Therapy

Avoiding the low specificity of phototheranostic reagents at the tumor site is a major challenge in cancer phototherapy. Meanwhile, angiogenesis in the tumor is not only the premise of tumor occurrence but also the basis of tumor growth, invasion, and metastasis, making it an ideal strategy for tumor therapy. Herein, biomimetic cancer cell membrane-coated nanodrugs (mBPP NPs) have been prepared by integrating (i) homotypic cancer cell membranes for evading immune cell phagocytosis to increase drug accumulation, (ii) protocatechuic acid for tumor vascular targeting along with chemotherapy effect, and (iii) near-infrared phototherapeutic agent diketopyrrolopyrrole derivative for photodynamic/photothermal synergetic therapy. The mBPP NPs exhibit high biocompatibility, superb phototoxicity, excellent antiangiogenic ability, and double-trigging cancer cell apoptosis in vitro. More significantly, mBPP NPs could specifically bind to tumor cells and vasculature after intravenous injection, inducing fluorescence and photothermal imaging-guided tumor ablation without recurrence and side effects in vivo. The biomimetic mBPP NPs could cause drug accumulation at the tumor site, inhibit tumor neovascularization, and improve phototherapy efficiency, providing a novel avenue for cancer treatment.

Mitochondria-Anchoring Self-assembled Nanoparticles for Multi-Path Energy Depletion: A "Nano Bomb" in Chemo-co-Starvation Therapy

As the main systemic treatment for triple-negative breast cancer (TNBC), the bleak medical prognosis of chemotherapy resulted in impaired life quality by tumor recurrence and metastasis. The feasible cancer starvation therapy could inhibit tumor progression by blocking energy supplements, however, the mono-therapeutic modality showed limited curing efficacy due to heterogeneity and abnormal energy metabolism of TNBC. Thus, the development of a synergistic nano-therapeutic modality involving different anti-tumor mechanisms to simultaneously transport medicines to the organelle where metabolism took place, might remarkably improve curing efficacy, targeting ability, and bio-safety. Herein, the hybrid BLG@TPGS NPs were prepared by doping multi-path energy inhibitors Berberine (BBR) and Lonidamine (LND) as well as the chemotherapeutic agent Gambogic acid (GA). Our research indicated that Nanobomb\mathord{-} BLG@TPGS NPs inherited the mitochondria targeting ability from BBR to accumulate precisely at the "energy factory" mitochondria, and then induce starvation therapy to efficiently eradicated cancer cells by coordinately powered off tumor cells via a "three-prone strategy" to cut off mitochondrial respiration, glycolysis, and glutamine metabolism. The inhibition of tumor proliferation and migration was enlarged by the synergistic combination with chemotherapy. Besides, apoptosis via mitochondria pathway and mitochondria fragmentation supported the hypothesis that NPs eliminated MDA-MB-231 cells by violently attacking MDA-MB-231 cells and especially the mitochondria. In summary, this synergistic chemo-co-starvation nanomedicine proposed an innovative site-specific targeting strategy for improved tumor treatment and decreased toxicity to normal tissues, which provided an option for clinical TNBC-sensitive treatment.

Multifunctional nanostructures: Intelligent design to overcome biological barriers

Over the past three decades, nanoscience has offered a unique solution for reducing the systemic toxicity of chemotherapy drugs and for increasing drug therapeutic efficiency. However, the poor accumulation and pharmacokinetics of nanoparticles are some of the key reasons for their slow translation into the clinic. The is intimately linked to the non-biological nature of nanoparticles and the aberrant features of solid cancer, which together significantly compromise nanoparticle delivery. New findings on the unique properties of tumors and their interactions with nanoparticles and the human body suggest that, contrary to what was long-believed, tumor features may be more mirage than miracle, as the enhanced permeability and retention based efficacy is estimated to be as low as 1%. In this review, we highlight the current barriers and available solutions to pave the way for approved nanoformulations. Furthermore, we aim to discuss the main solutions to solve inefficient drug delivery with the use of nanobioengineering of nanocarriers and the tumor environment. Finally, we will discuss the suggested strategies to overcome two or more biological barriers with one nanocarrier. The variety of design formats, applications and implications of each of these methods will also be evaluated.

Three-dimensional label-free visualization of the interactions of PM2.5 with macrophages and epithelial cells using optical diffraction tomography

Particulate matter ≤ 2.5 µm (PM2.5) poses health risks related to various diseases and infections. However, the interactions between PM2.5 and cells such as uptake and cell responses have not been fully investigated despite advances in bioimaging techniques, because the heterogeneous morphology and composition of PM2.5 make it challenging to employ labeling techniques, such as fluorescence. In this work, we visualized the interaction between PM2.5 and cells using optical diffraction tomography (ODT), which provides quantitative phase images by refractive index distribution. Through ODT analysis, the interactions of PM2.5 with macrophages and epithelial cells, such as intracellular dynamics, uptake, and cellular behavior, were successfully visualized without labeling techniques. ODT analysis clearly shows the behavior of phagocytic macrophages and nonphagocytic epithelial cells for PM2.5. Moreover, ODT analysis could quantitatively compare the accumulation of PM2.5 inside the cells. PM2.5 uptake by macrophages increased substantially over time, but uptake by epithelial cells increased only marginally. Our findings indicate that ODT analysis is a promising alternative approach to visually and quantitatively understanding the interaction of PM2.5 with cells. Therefore, we expect ODT analysis to be employed to investigate the interactions of materials and cells that are difficult to label.

Long-term retention of gold nanoparticles in the liver is not affected by their physicochemical characteristics

Gold nanoparticles (GNPs) are considered promising candidates for healthcare applications, however, their toxicity after long-term exposure to the material remains uncertain. Since the liver is the main filter organ for nanomaterials, this work was aimed at evaluating hepatic accumulation, internalisation and overall safety of well-characterised and endotoxin-free GNPs in healthy mice from 15 minutes to 7 weeks after a single administration. Our data demonstrate that GNPs were rapidly segregated into lysosomes of endothelial cells (LSEC) or Kupffer cells regardless of coating or shape but with different kinetics. Despite the long-lasting accumulation in tissues, the safety of GNPs was confirmed by liver enzymatic levels, as they were rapidly eliminated from the blood circulation and accumulated in the liver without inducing hepatic toxicity. Our results demonstrate that GNPs have a safe and biocompatibile profile despite their long-term accumulation.

Transformable nanodrugs for overcoming the biological barriers in the tumor environment during drug delivery

Drug delivery systems have been studied massively with explosive growth in the last few decades. However, challenges such as biological barriers are still obstructing the delivery efficiency of nanomedicines. Reports have shown that the physicochemical properties, such as the morphologies of nanodrugs, could highly affect their biodistribution and bioavailability. Therefore, transformable nanodrugs that take advantage of different sizes and shapes allow for overcoming multiple biological barriers, providing promising prospects for drug delivery. This review aims to present an overview of the most recent developments of transformable nanodrugs in this emerging field. First, the design principles and transformation mechanisms which serve as guidelines for smart nanodrugs are summarized. Afterward, their applications in overcoming biological barriers, including the bloodstream, intratumoral pressure, cellular membrane, endosomal wrapping, and nuclear membrane, are highlighted. Finally, discussions on the current developments and future perspectives of transformable nanodrugs are given.

Advances in tumor nanotechnology: theragnostic implications in tumors via targeting regulated cell death

Cell death constitutes an indispensable part of the organismal balance in the human body. Generally, cell death includes regulated cell death (RCD) and accidental cell death (ACD), reflecting the intricately molecule-dependent process and the uncontrolled response, respectively. Furthermore, diverse RCD pathways correlate with multiple diseases, such as tumors and neurodegenerative diseases. Meanwhile, with the development of precision medicine, novel nano-based materials have gradually been applied in the clinical diagnosis and treatment of tumor patients. As the carrier, organic, inorganic, and biomimetic nanomaterials could facilitate the distribution, improve solubility and bioavailability, enhance biocompatibility and decrease the toxicity of drugs in the body, therefore, benefiting tumor patients with better survival outcomes and quality of life. In terms of the most studied cell death pathways, such as apoptosis, necroptosis, and pyroptosis, plenty of studies have explored specific types of nanomaterials targeting the molecules and signals in these pathways. However, no attempt was made to display diverse nanomaterials targeting different RCD pathways comprehensively. In this review, we elaborate on the potential mechanisms of RCD, including intrinsic and extrinsic apoptosis, necroptosis, ferroptosis, pyroptosis, autophagy-dependent cell death, and other cell death pathways together with corresponding nanomaterials. The thorough presentation of RCD pathways and diverse nano-based materials may provide a wider cellular and molecular landscape of tumor diagnosis and treatments.

Multi-Targeted Peptide-Modified Gold Nanoclusters for Treating Solid Tumors in the Liver

Apoptosis and autophagy determine the fate of cancer cells. However, simply promoting apoptosis of tumor cells is limited in the treatment of unresectable solid liver tumors. Generally, autophagy is considered the anti-apoptotic "guardian". But the pro-apoptotic effects of autophagy can be activated by excessive endoplasmic reticulum (ER) stress. Here, amphiphilic peptide-modified glutathione (GSH)-gold nanocluster aggregates (AP₁ P₂ -PEG NCs) were designed with the enrichment of solid liver tumors and the prolonged stress in the ER, which can achieve the mutual promotion of autophagy and apoptosis in liver tumor cells. In this study, orthotopic and subcutaneous liver tumor models show the anti-tumor effectiveness of AP₁ P₂ -PEG NCs, with a better antitumor effect than sorafenib, biosafety (Lethal Dose, 50% (LD₅₀ ) of 827.3 mg kg^-1 ), wide therapeutic window (non-toxic in 20 times of therapeutic concentration) and high stability (blood half-life of 4 h). These findings identify an effective strategy to develop peptide-modified gold nanocluster aggregates with low toxicity, high potency, and selectivity for solid liver tumors treatment.

Lysosomal nanotoxicity: Impact of nanomedicines on lysosomal function

Although several nanomedicines got clinical approval over the past two decades, the clinical translation rate is relatively small so far. There are many post-surveillance withdrawals of nanomedicines caused by various safety issues. For successful clinical advancement of nanotechnology, it is of unmet need to realize cellular and molecular foundation of nanotoxicity. Current data suggest that lysosomal dysfunction caused by nanoparticles is emerging as the most common intracellular trigger of nanotoxicity. This review analyzes prospect mechanisms of lysosomal dysfunction-mediated toxicity induced by nanoparticles. We summarized and critically assessed adverse drug reactions of current clinically approved nanomedicines. Importantly, we show that physicochemical properties have great impact on nanoparticles interaction with cells, excretion route and kinetics, and subsequently on toxicity. We analyzed literature on adverse reactions of current nanomedicines and hypothesized that adverse reactions might be linked with lysosomal dysfunction caused by nanomedicines. Finally, from our analysis it becomes clear that it is unjustifiable to generalize safety and toxicity of nanoparticles, since different particles possess distinct toxicological properties. We propose that the biological mechanism of the disease progression and treatment should be central in the optimization of nanoparticle design.

Nanoplastics induces oxidative stress and triggers lysosome-associated immune-defensive cell death in the earthworm Eisenia fetida

Nanoplastics (NPs) are increasingly perceived as an emerging threat to terrestrial environments, but the adverse impacts of NPs on soil fauna and the mechanisms behind these negative outcomes remain elusive. Here, a risk assessment of NPs was conducted on model organism (earthworm) from tissue to cell. Using palladium-doped polystyrene NPs, we quantitatively measured nanoplastic accumulation in earthworm and investigated its toxic effects by combining physiological assessment with RNA-Seq transcriptomic analyses. After a 42-day exposure, earthworm accumulated up to 15.9 and 143.3 mg kg-1 of NPs for the low (0.3 mg kg-1) and high (3 mg kg-1) dose groups, respectively. NPs retention led to the decrease of antioxidant enzyme activity and the accumulation of reactive oxygen species (O2- and H2O2), which reduced growth rate by 21.3 %-50.8 % and caused pathological abnormalities. These adverse effects were enhanced by the positively charged NPs. Furthermore, we observed that irrespective of surface charge, after 2 h of exposure, NPs were gradually internalized by earthworm coelomocytes (∼0.12 μg per cell) and mainly amassed at lysosomes. Those agglomerations stimulated lysosomal membranes to lose stability and even rupture, resulting in impeded autophagy process and cellular clearance, and eventually coelomocyte death. In comparison with negatively charged nanoplastics, the positively charged NPs exerted 83 % higher cytotoxicity. Our findings provide a better understanding of how NPs posed harmful effects on soil fauna and have important implications for evaluating the ecological risk of NPs.

Facile Generation of Surface Diversity in Gold Nanoparticles

Surface chemistry is a key determinant of the physico-chemical and biological properties of gold nanoparticles (AuNPs). The introduction of chemical diversity in the surface of AuNPs is usually accomplished by place-exchange reactions using incoming ligands containing the desired terminal functional groups. As an alternative approach, we present here a simple, practical methodology to modify the surface of gold nanoparticles that allows the preparation of AuNPs stabilized with polyethyleneglycol (PEG) ligands with different surface chemistries using AuNPs stabilized with thiol-PEG-amino ligands as starting material. The surface modification reaction involves the acylation of the terminal amino groups in the ligand with an organic acid anhydride in an aqueous buffer. In addition to a full surface modification, this method also allows the synthesis of AuNPs with tailored mixed surfaces, containing two or more different functional groups, each of them at the desired extent. The ease of the experimental conditions for the reaction, purification, and for determining the level of surface modification makes this strategy an attractive alternative to current methods for the preparation of AuNPs with diverse surface chemistry.

Tumor microenvironment (TME)-modulating nanoreactor for multiply enhanced chemodynamic therapy synergized with chemotherapy, starvation, and photothermal therapy

The combination of chemotherapy (CT) and chemodynamic therapy (CDT) via nanoscale drug delivery systems has great potential for tumor therapy. Nevertheless, the low intracellular H₂O₂ and high reductive glutathione (GSH) levels, as well as the mildly acidic conditions (pH 5.8-6.8) of the tumor microenvironment (TME) still limit their further applications. To tackle these problems, a TME-modulating nanoreactor (denoted as Fe₃O₄-DOX@PDA-GOx@HA, FDPGH) was developed through a simple and practicable method to achieve multiply enhanced CDT synergized with CT, starvation therapy (ST), and photothermal therapy (PTT). Upon cellular uptake, the hyaluronic acid (HA) and PDA shells rapidly collapsed to release Fe₃O₄, glucose oxidase (GOx) and doxorubicin (DOX), and the overexpressed GSH could promote the reduction of Fe³⁺ to Fe²⁺, resulting in CDT activation. GOx-driven oxidation reaction not only produced H₂O₂ for enhanced CDT, but also killed tumor cells by initiating ST. In addition, the acid amplification caused by gluconic acid production in turn accelerated the degradation of FDPGH, promoting the Fenton reaction to enhance CDT. Most importantly, the nanoreactor had excellent photothermal performance to achieve PTT and PTT-enhanced CDT with the release of DOX into tumor tissue to achieve enhanced CT. This novel cascade nanoreactor with TME-modulating capability is intended to provide further inspiration for multimodal treatment paradigms.

An in situ protonation-activated supramolecular self-assembly for selective suppression of tumor growth

An in situ supramolecular self-assembly in the subcellular organelles could provide a new strategy to treat diseases. Herein, we report a protonation-activated in situ supramolecular self-assembly system in the lysosomes, which could destabilize the lysosome membrane, resulting in the selective suppression of cancer cells. In this system, pyridyl-functionalized tetraphenylethylene (TPE-Py) was protonated in the lysosomes of A549 lung cancer cells to form octahedron-like structures with cucurbit[8]uril (CB[8]), which impaired the integrity of the lysosome membrane, resulting in selective suppression of cancer cells. Moreover, its anticancer efficiency was also systematically evaluated in vivo, triggering the apoptosis of tumor tissues with ignorable effects on normal organs. Overall, the protonation-activated self-assembly in the lysosomes based on the host-guest complexation would provide a method for novel anti-cancer systems.

Die hard: cell death mechanisms and their implications in nanotoxicology

Cell death is a fundamental biological process, and its fine-tuned regulation is required for life. However, the complexity of regulated cell death is often reduced to a matter of live-dead discrimination. Here, we provide a perspective on programmed or regulated cell death, focusing on apoptosis, pyroptosis, necroptosis, and ferroptosis (the latter three cell death modalities are examples of regulated necrosis). We also touch on other, recently described manifestations of (pathological) cell death including cuproptosis. Furthermore, we address how engineered nanomaterials impact on regulated cell death. We posit that an improved understanding of nanomaterial-induced perturbations of cell death may allow for a better prediction of the consequences of human exposure and could also yield novel approaches by which to mitigate these effects. Finally, we provide examples of the harnessing of nanomaterials to achieve cancer cell killing through the induction of regulated cell death.

Three near-infrared and lysosome-targeting probes for photodynamic therapy (PDT)

Lysosome, an organelle which contains a number of hydrolases and hydrogen ions, plays a crucial role in cellular survival and apoptosis. If selectively destroy lysosomes membrane, inner hydrolases and hydrogen ions will leak and induce cell death. In this work, three lysosome-targeting fluorescent probes (HCL 1-3, heptamethine cyanine lysosomal-targeting probe) were designed, synthesized and developed for photodynamic therapy. Piperazine and N, N-dimethyl structures made HCL 1-3 have good lysosome targeting ability while Pearson's correlation coefficients reached 0.85, 0.87 and 0.78. It can be concluded from MTT test, HCL 1-3 have high photo cytotoxicity and low dark cytotoxicity from MTT test. Calcein/PI staining assays also supported cytotoxicity of HCL 1-3 under light conditions. In vivo experiments, HCL 2 accumulated in tumor and a strong fluorescence signal was observed at 12 h post injection. All results showed that our experiments provide help and new ideas for cyanine dyes in cancer treatment.

Rationally Constructed De Novo Fluorescent Nanosensor for Nitric Oxide Detection and Imaging in Living Cells and Inflammatory Mice Models

For the early diagnosis and effective evaluation of treatment effects of inflammation, a de novo bioanalytical method is urgently needed to monitor the metabolite nitric oxide (NO) associated with inflammatory diseases. However, developing a reliable detection method with excellent water solubility, biocompatibility, long retention time, and blood circulation is still challenging. In this work, we reported for the first time a de novo host-guest self-assembled nanosensor CTA for the quantitative detection and visualization of NO levels in inflammatory models. CTA mainly consists of two parts: (i) an adamantyl-labeled guest small-molecule RN-adH containing a classical response moiety o-phenylenediamine for a chemical-specific response toward NO and fluorophore rhodamine B with excellent optical properties as an internal reference for self-calibration and (ii) a remarkable water-soluble and biocompatible supramolecular β-cyclodextrin polymer (Poly-β-CD) host. In the presence of NO, the o-phenylenediamine unit was reacted with NO at a low pH value of ∼7.0, accompanied by changes in the intensity of the two emission peaks corrected for each other and the change in fluorescence color of the CTA solution from fuchsia to pink. Furthermore, CTA was an effective tool for NO detection with a fast response time (∼60 s), high selectivity, and sensitivity (LOD: 22.3 nM). Impressively, the CTA nanosensor has successfully achieved the targeted imaging of NO in living inflammatory RAW 264.7 cells and mice models with satisfactory results, which can provide a powerful molecular tool for the visualization and assessment of the occurrence and development of NO-related inflammatory diseases in complex biosystems.

Functional bioinspired nanocomposites for anticancer activity with generation of reactive oxygen species

Cancer is a debilitating and deadly disease caused by the uncontrolled growth of aberrant cell populations. This disease cannot always be controlled with traditional therapies and medicines. Different medicines are being used for this purpose, however these medicines have their side effects and are harmful to healthy cells. A better way to cure cancer disease is by limiting the agglomeration of cancer cells, minimizing their growth and their population by destroying these harmful cells. This could be achieved by controlling the function of mitochondria and DNA in cancer cells with the use of biocompatible materials with tuneable physical properties. Accordingly, research is ongoing as to the use of nanomaterials and nanotechnology in medicine. Zinc oxide semiconductor nanoparticles have displayed good anticancer behaviour. They have unique properties such as biocompatibility, good stability, and are environmentally friendly. Owing to these characteristics, they are focused on biological applications such as drug delivery and cancer therapy. In the present research work, zinc oxide, titanium dioxide nanoparticles and titanium oxide-zinc oxide nanocomposites were successfully trailed for anti-cancer activity. Pure zinc oxide nanoparticles (ZnO NPs), titanium dioxide nanoparticles (TiO₂ NPs) and their nanocomposites (TiO₂+ZnO NPs) were prepared by the co-precipitation technique. The structural properties were investigated by X-ray diffraction, which confirmed the Wurtzite structure of pure ZnO NPs. The morphology of the NPs was checked by scanning electron microscopy. For incident light having a higher energy band gap of nanomaterials, the electrons are excited to the conduction band and these electrons generate reactive oxygen species (ROS). The efficacy of these nanomaterials was checked by exposing the NPs to the human liver cancer cell HepG2. The MTT assay describes anticancer activity via cell viability. The cell viability of composites was observed to be greater than pure ZnO NPs. Their results showed that the structure of ZnO NPs remains the same with composites of TiO₂ NPs, but the band gap of the composite was intermediate for individual samples. It also showed that the anticancer activity of composites was also less than pure ZnO NPs which is due to the reduction of ROS generation. This is observed that nanocomposites of ZnO and TiO₂ could be effective in the development of a treatment of human liver cancer cells.

Boosting ROS-Mediated Lysosomal Membrane Permeabilization for Cancer Ferroptosis Therapy

Due to the deficient catalase, abundant reduced iron and low acidic environment in lysosomes, inducing lysosomal membrane permeabilization (LMP) through Fenton reaction-based reactive oxygen species (ROS) generation recently attracts increasing attention in cancer therapy. However, the lysosomal membranes are protected by highly glycosylated membrane proteins and several endolysosomal damage-response mechanisms can rapidly repair the injured lysosomes. To produce sufficient ROS and cause complete lysosomal membranes rupture, a lysosome-targeted ROS inducer, N-(3-Aminopropyl) morpholine grafted cross-linked lipoic acid vesicles with vitamin C-loading (VC@^N3AM cLAVs), is developed. VC@^N3AM cLAVs efficiently accumulate in lysosomes and convert into two redox couples LA/DHLA (dihydrolipoic acid, reduced form of LA) and VC/DHA (dehydroascorbic acid, oxidized form of VC) by the lysosomal glutathione, which can not only produce a large amount of H₂ O₂ by pro-oxidant action but also accelerate iron transformation through the cyclic redox reactions between each other and cause the efficient conversion of the generated H₂ O₂ into highly toxic •OH. Both in vitro and in vivo experiments demonstrate that VC@^N3AM cLAVs can effectively enhance ROS production and boost LMP, finally initiation irreversible death of tumor cells via ferroptosis pathway, thus representing a potential anticancer drug for cancer therapy.