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

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.

Protocol and Software for Automated Detection of Lysosome Active "Runs" and "Flights" with Wavelet Transform Approach

Lysosomes are highly dynamic degradation/recycling organelles that harbor sophisticated molecular sensors and signal transduction machinery through which they control cell adaptation to environmental cues and nutrients. The movements of these signaling hubs comprise persistent, directional runs-active, ATP-dependent transport along the microtubule tracks-interspersed by short, passive movements and pauses imposed by cytoplasmic constraints. The trajectories of individual lysosomes are usually obtained by time-lapse imaging of the acidic organelles labeled with LysoTracker dyes or fluorescently-tagged lysosomal-associated membrane proteins LAMP1 and LAMP2. Subsequent particle tracking generates large data sets comprising thousands of lysosome trajectories and hundreds of thousands of data points. Analyzing such data sets requires unbiased, automated methods to handle large data sets while capturing the temporal heterogeneity of lysosome trajectory data. This chapter describes integrated and largely automated workflow from live cell imaging to lysosome trajectories to computing the parameters of lysosome dynamics. We describe an open-source code for implementing the continuous wavelet transform (CWT) to distinguish trajectory segments corresponding to active transport (i.e., "runs" and "flights") versus passive lysosome movements. Complementary cumulative distribution functions (CDFs) of the "runs/flights" are generated, and Akaike weight comparisons with several competing models (lognormal, power law, truncated power law, stretched exponential, exponential) are performed automatically. Such high-throughput analyses yield useful aggregate/ensemble metrics for lysosome active transport.

Nanomedicine-Enabled/Augmented Cell Pyroptosis for Efficient Tumor Nanotherapy

The terrible morbidity and mortality of malignant tumors urgently require innovative therapeutics, especially for apoptosis-resistant tumors. Pyroptosis, a pro-inflammatory form of programmed cell death (PCD), is featured with pore formation in plasma membrane, cell swelling with giant bubbles, and leakage of cytoplasmic pro-inflammatory cytokines, which can remodel the tumor immune microenvironment by stimulating a "cold" tumor microenvironment to be an immunogenic "hot" tumor microenvironment, and consequently augment the therapeutic efficiency of malignant tumors. Benefiting from current advances in nanotechnology, nanomedicine is extensively applied to potentiate, enable, and augment pyroptosis for enhancing cancer-therapeutic efficacy and specificity. This review provides a concentrated summary and discussion of the most recent progress achieved in this emerging field, highlighting the nanomedicine-enabled/augmented specific pyroptosis strategy for favoring the construction of next-generation nanomedicines to efficiently induce PCD. It is highly expected that the further clinical translation of nanomedicine can be accelerated by inducing pyroptotic cell death based on bioactive nanomedicines.

Response Surface Methodology (RSM) Powered Formulation Development, Optimization and Evaluation of Thiolated Based Mucoadhesive Nanocrystals for Local Delivery of Simvastatin

In oral administration systems, mucoadhesive polymers are crucial for drug localization and target-specific activities. The current work focuses on the application of thiolated xanthan gum (TXG) to develop and characterize a novel mucoadhesive nanocrystal (NC) system of simvastatin (SIM). Preparation of SIM-NC was optimized using response surface methodology (RSM) coupled with statistical applications. The concentration of Pluronic F-127 and vacuum pressure were optimized by central composite design. Based on this desirable approach, the prerequisites of the optimum formulation can be achieved by a formulation having 92.568 mg of F-127 and 77.85 mbar vacuum pressure to result in EE of 88.8747% and PS of 0.137.835 nm. An optimized formulation was prepared with the above conditions along with xanthan gum (XG) and TXG and various parameters were evaluated. A formulation containing TXG showed 98.25% of SIM at the end of 96 h. Regarding the mucoadhesion potential evaluated by measuring zeta potential, TXG-SIM-NC shoed the maximum zeta potential of 16,455.8 ± 869 mV at the end of 6 h. The cell viability percentage of TXG-SIM-NC (52.54 ± 3.4% with concentration of 50 µg/mL) was less than the plain SIM, with XG-SIM-NC showing the highest cytotoxicity on HSC-3 cells. In vivo pharmacokinetic studies confirm the enhanced bioavailability of formulated mucoadhesive systems of SIM-NC, with TXG-SIM-NC exhibiting the maximum.

Organelle-targeted therapies: a comprehensive review on system design for enabling precision oncology

Cancer is a major threat to human health. Among various treatment methods, precision therapy has received significant attention since the inception, due to its ability to efficiently inhibit tumor growth, while curtailing common shortcomings from conventional cancer treatment, leading towards enhanced survival rates. Particularly, organelle-targeted strategies enable precise accumulation of therapeutic agents in organelles, locally triggering organelle-mediated cell death signals which can greatly reduce the therapeutic threshold dosage and minimize side-effects. In this review, we comprehensively discuss history and recent advances in targeted therapies on organelles, specifically including nucleus, mitochondria, lysosomes and endoplasmic reticulum, while focusing on organelle structures, organelle-mediated cell death signal pathways, and design guidelines of organelle-targeted nanomedicines based on intervention mechanisms. Furthermore, a perspective on future research and clinical opportunities and potential challenges in precision oncology is presented. Through demonstrating recent developments in organelle-targeted therapies, we believe this article can further stimulate broader interests in multidisciplinary research and technology development for enabling advanced organelle-targeted nanomedicines and their corresponding clinic translations.

Dual tumor- and subcellular-targeted photodynamic therapy using glucose-functionalized MoS2 nanoflakes for multidrug-resistant tumor ablation

Photodynamic therapy (PDT) is emerging as an efficient strategy to combat multidrug-resistant (MDR) cancer. However, the short half-life and limited diffusion of reactive oxygen species (ROS) undermine the therapeutic outcomes of this therapy. To address this issue, a tumor-targeting nanoplatform was developed to precisely deliver mitochondria- and endoplasmic reticulum (ER)-targeting PDT agents to desired sites for dual organelle-targeted PDT. The nanoplatform is constructed by functionalizing molybdenum disulfide (MoS₂) nanoflakes with glucose-modified hyperbranched polyglycerol (hPG), and then loading the organelle-targeting PDT agents. The resultant nanoplatform Cy7.5-TG@GPM is demonstrated to mediate both greatly enhanced internalization within MDR cells and precise subcellular localization of PDT agents, facilitating in situ near-infrared (NIR)-triggered ROS generation for augmented PDT and reversal of MDR, causing impressive tumor shrinkage in a HeLa multidrug-resistant tumor mouse model. As revealed by mechanistic studies of the synergistic mitochondria- and ER-targeted PDT, ROS-induced ER stress not only activates the cytosine-cytosine-adenosine-adenosine thymidine/enhancer-binding protein homologous protein (CHOP) pro-apoptotic signaling pathway, but also cooperates with ROS-induced mitochondrial dysfunction to trigger cytochrome C release from the mitochondria and induce subsequent cell death. Furthermore, the mitochondrial dysfunction reduces ATP production and thereby contributes to the reversal of MDR. This nanoplatform, with its NIR-responsive properties and ability to target tumors and subcellular organelles, offers a promising strategy for effective MDR cancer therapy.

Transformable nanoparticles to bypass biological barriers in cancer treatment

Nanomedicine based drug delivery platforms provide an interesting avenue to explore for the future of cancer treatment. Here we discuss the barriers for drug delivery in cancer therapeutics and how nanomaterials have been designed to bypass these blockades through stimuli responsive transformation in the most recent update. Nanomaterials that address the challenges of each step provide a promising solution for new cancer therapeutics.

A Peritumorally Injected Immunomodulating Adjuvant Elicits Robust and Safe Metalloimmunotherapy against Solid Tumors

Clinical immunotherapy of solid tumors elicits durable responses only in a minority of patients, largely due to the highly immunosuppressive tumor microenvironment (TME). Although rational combinations of vaccine adjuvants with inflammatory cytokines or immune agonists that relieve immunosuppression represent an appealing therapeutic strategy against solid tumors, there are unavoidable nonspecific toxicities due to the pleiotropy of cytokines and undesired activation of off-target cells. Herein, a Zn²⁺ doped layered double hydroxide (Zn-LDH) based immunomodulating adjuvant, which not only relieves immunosuppression but also elicits robust antitumor immunity, is reported. Peritumorally injected Zn-LDH sustainably neutralizes acidic TME and releases abundant Zn²⁺ , promoting a pro-inflammatory network composed of M1-tumor-associated macrophages, cytotoxic T cells, and natural-killer cells. Moreover, the Zn-LDH internalized by tumor cells effectively disrupts endo-/lysosomes to block autophagy and induces mitochondrial damage, and the released Zn²⁺ activates the cGas-STING signaling pathway to induce immunogenic cell death, which further promotes the release of tumor-associated antigens to induce antigen-specific cytotoxic T lymphocytes. Unprecedentedly, merely injection of Zn-LDH adjuvant, without using any cytotoxic inflammatory cytokines or immune agonists, significantly inhibits the growth, recurrence, and metastasis of solid tumors in mice. This study provides a rational bottom-up design of potent adjuvant for cancer metalloimmunotherapy against solid tumors.

A supramolecular self-assembled nanomaterial for synergistic therapy of immunosuppressive tumor

Triple negative breast cancer (TNBC) is an immunosuppressive "cold" tumor that lacks immune cell infiltration and activation, resulting in a poor response to immune checkpoint blockade (ICB) therapies. In addition, TNBC is poorly responsive to targeted therapies due to the absence of efficient molecular targets. A strategy that can block molecular signal transduction, stimulate immunogenicity, and activate the immune response is a promising approach to achieve ideal clinical benefit. Herein, we designed and synthesized an aggregation-induced emission luminogen (AIEgen)-conjugated self-assembling peptide that targets epidermal growth factor receptor (EGFR), named TPA-FFG-LA. TPA-FFG-LA peptides form nanoassemblies on the surface of EGFR-positive TNBC cells and are internalized into cells through endocytosis, which inhibit EGFR signaling transduction and provoke lysosomal membrane permeabilization (LMP). Upon light irradiation, the aggregated AIEgens produce massive reactive oxygen species (ROS) to exacerbate LMP and trigger immunogenic cell death (ICD), resulting in elimination of residual EGFR-negative tumor cells and exerting long-term antitumor effects. The in vitro and in vivo experiments verified that TPA-FFG-LA nanoassemblies suppress tumor growth, provoke immune cell activation and infiltration, and cause EGFR degradation and LMP. These results suggest that the combination of supramolecular assembly induced molecular targeting effects and lysosome dysfunction with ICD-stimulated immune activation is a plausible strategy for the efficient therapy of immunosuppressive TNBC.

Stimuli-Responsive Aggregation-Induced Emission (AIE)-Active Polymers for Biomedical Applications

At high concentration or in the aggregated state, most of the traditional luminophores suffer from the general aggregation-caused quenching (ACQ) effect, which significantly limits their biomedical applications. On the contrary, a few fluorophores exhibit an aggregation-induced emission (AIE) feature which is just the opposite of ACQ. The luminophores with aggregation-induced emission (AIEgens) have exhibited noteworthy advantages to get tunable emission, excellent photostability, and biocompatibility. Incorporating AIEgens into polymer design has yielded diversified polymer systems with fascinating photophysical characteristics. Again, stimuli-responsive polymers are capable of undergoing chemical and/or physical property changes on receiving signals from single or multiple stimuli. The combination of the AIE property and stimuli responses in a single polymer platform provides a feasible and effective strategy for the development of smart polymers with promising biomedical applications. Herein, the advancements in stimuli-responsive polymers with AIE characteristics for biomedical applications are summarized. AIE-active polymers are first categorized into conventional π-π conjugated and nonconventional fluorophore systems and then subdivided based on various stimuli, such as pH, redox, enzyme, reactive oxygen species (ROS), and temperature. In each section, the design strategies of the smart polymers and their biomedical applications, including bioimaging, cancer theranostics, gene delivery, and antimicrobial examples, are introduced. The current challenges and future perspectives of this field are also stated at the end of this review article.

How can we use the endocytosis pathways to design nanoparticle drug-delivery vehicles to target cancer cells over healthy cells?

Targeted drug delivery in cancer typically focuses on maximising the endocytosis of drugs into the diseased cells. However, there has been less focus on exploiting the differences in the endocytosis pathways of cancer cells versus non-cancer cells. An understanding of the endocytosis pathways in both cancer and non-cancer cells allows for the design of nanoparticles to deliver drugs to cancer cells whilst restricting healthy cells from taking up anticancer drugs, thus efficiently killing the cancer cells. Herein we compare the differences in the endocytosis pathways of cancer and healthy cells. Second, we highlight the importance of the physicochemical properties of nanoparticles (size, shape, stiffness, and surface chemistry) on cellular uptake and how they can be adjusted to selectively target the dominated endocytosis pathway of cancer cells over healthy cells and to deliver anticancer drug to the target cells. The review generates new thought in the design of cancer-selective nanoparticles based on the endocytosis pathways.

A pH-Driven Small-Molecule Nanotransformer Hijacks Lysosomes and Overcomes Autophagy-Induced Resistance in Cancer

Smart conversion of supramolecular structures in vivo is an attractive strategy in cancer nanomedicine, which is usually achieved via specific peptide sequences. Here we developed a lysosomal targeting small-molecule conjugate, PBC, which self-assembles into nanoparticles at physiological pH and smartly converts to nanofibrils in lysosomes of tumor cells. Such a transformation mechanically leads to lysosomal dysfunction, autophagy inhibition, and unusual cytoplasmic vacuolation, thus granting PBC a unique anticancer activity as a monotherapy. Importantly, the photo-activated PBC elicits significant phototoxicity to lysosomes and shows enormous advantages in overcoming autophagy-caused treatment resistance frequently occurring in conventional phototherapy. This improved phototherapy achieves a complete cure of oral cancer xenografts upon limited administration. Our work provides a new paradigm for the construction of nonpeptide nanotransformers with biomedical activities.

Efficient Immunotherapy of Drug-Free Layered Double Hydroxide Nanoparticles via Neutralizing Excess Acid and Blocking Tumor Cell Autophagy

Cancer immunotherapy efficacy is largely limited by the suppressive tumor immune microenvironment (TIME) where antitumor immune cells are inhibited and tumor antigens continue to mutate or be lost. To remodel the TIME, we here applied weakly alkaline layered double hydroxide nanoparticles (LDH NPs) to neutralize the excess acid and block autophagy of tumor cells for neoadjuvant cancer immunotherapy. Peritumoral injection of LDH NPs provided a long-term and efficient acid-neutralization in the TIME, blocked the lysosome-mediated autophagy pathway in tumor cells, and increased the levels of antitumor tumor-associated macrophages and T cells. These LDH NPs captured tumor antigens released in the tumor tissues and effectively inhibited the growth of both melanoma and colon tumors in vivo. These findings indicate that LDH NPs, as an immunomodulator and adjuvant, successfully "awaken" and promote the host innate and adaptive immune systems, showing promising potential for solid tumor immunotherapy.

Nanoparticle-Driven Controllable Mitochondrial Regulation through Lysosome-Mitochondria Interactome

Precise subcellular manipulation remains challenging in quantitative biological studies. After target modification and hierarchical assembly, nanoparticles can be functionalized for intracellular investigation. However, it remains unclear whether nanoparticles themselves can progressively manipulate subcellular processes, especially organellar networks. Mitochondria act as the energetic supply, whose fission dynamics are often modulated by molecular reagents. Here, using different-sized gold nanoparticles (AuNPs) as a model, we demonstrated the nanoparticle-driven controllable regulation on mitochondria. Compared with molecular reagents, AuNPs could induce size-dependent mitochondrial fission without detectable cell injury, and this process was reversible along with intracellular AuNPs' clearance. Mechanistically, it was attributed to the AuNPs-induced enhanced organelle interactome between lysosomes and mitochondria. Lysosomal accumulation of AuNPs induced lysosomal swelling and lysosomal motility alterations, promoting mitochondrial fission through the increased "kiss" events during the "kiss-and-run" moving of the lysosome-mitochondria interactome. This study highlights the fundamental understanding to fully explore the intrinsic capability of nanoparticles by engineering their basic properties. Also, it provides practical guidance to investigate the delicate nanolevel regulation on biological processes.

Size- and shape-dependent cytotoxicity of nano-sized Zr-based porphyrinic metal-organic frameworks to macrophages

The wide utilization of nano-sized metal-organic frameworks (NMOFs) leads to inevitable health risks to humans. Previous studies on health risks of NMOFs mainly focus on the cytotoxic tests of typical NMOFs，but lack sufficient studies on the effects of physiochemical characteristics of NMOFs on the cytotoxicity and the related mechanisms. Here, four kinds of Zr-based porphyrinic NMOFs (PCNs), including spherical 30, 90, and 180 nm PCN-224 and rod-like 90 nm PCN-222, were taken as a proof of the concept to investigate the effects of the size and shape of NMOFs on the cytotoxicity and related mechanisms to macrophages. The 30 nm spherical PCN-224 induced significant rupture of cell membrane and dissolved in lysosome, leading to the most significant cell necrosis among the studied other nano-sized PCNs. However, other studied PCNs showed insignificant membrane rupture and their dissolution in lysosome. Furthermore, the 90 nm-sized PCN-224 led to much more significant cell necrosis by inducing lysosome damage and inhibiting of autophagy flux than the rod-like 90 nm PCN-222. These findings reveal the size- and shape-dependent cytotoxicity of PCNs and the related mechanisms and are helpful to the assessment of the potential health risks of NMOFs and the safe application of NMOFs.

Microplastics exposure affects neural development of human pluripotent stem cell-derived cortical spheroids

Plastics have been part of our ecosystem for about a century and their degradation by different environmental factors produce secondary microplastics (MPs). To date, the impact of MPs on human health has not been well investigated. To understand the possible effects of polystyrene-MPs (PS-MPs) on the human brain, a 3D model of human forebrain cortical spheroids has been derived, which mimics early development of human cerebral cortex. The spheroids were exposed to 100, 50, and 5 µg/mL of 1 µm and 10 µm PS-MPs during day 4-10 and day 4-30. The short-term MP exposure showed the promoted proliferation and high gene expression of Nestin, PAX6, ATF4, HOXB4 and SOD2. For long-term exposure, reduced cell viability was observed. Moreover, changes in size and concentration of PS-MPs altered the gene expression of DNA damage and neural tissue patterning. In particular, β-tubulin III, Nestin, and TBR1/TBR2 gene expression decreased in PS-MP treated conditions compare to the untreated control. The results of this study suggest that the size- and concentration-dependent exposure to PS-MPs can adversely affect embryonic brain-like tissue development in forebrain cerebral spheroids. This study has significance in assessing environmental factors in neurotoxicity and degeneration in human.

Nanolab in a Cell: Crystallization-Induced In Situ Self-Assembly for Cancer Theranostic Amplification

Conducting crystallization-assisted self-assembly in living biosystems to obtain large-size nanoparticles and achieve a specific physiological purpose remains an appealing yet significantly challenging task. In this study, we designed Au(I)-disulfide nanosheets containing an aggregation-induced emission photosensitizer, namely, NSs@TTVP, which exhibited pH-responsive crystallization-driven self-assembly capability in lysosomes of cancer cells and tumor tissues of mice. The crystallization process endowed NSs@TTVP with a microscale morphology, stronger fluorescence output, and highly enhanced reactive oxygen species production efficiency. The in vivo results demonstrated that NSs@TTVP shows both long-term retention in tumors and extensive destruction to cancer cells, making it supremely powerful for fluorescence imaging-guided tumor tracking and inhibition.

Nano-bio interactions: A major principle in the dynamic biological processes of nano-assemblies

Controllable nano-assembly with stimuli-responsive groups is emerging as a powerful strategy to generate theranostic nanosystems that meet unique requirements in modern medicine. However, this prospective field is still in a proof-of-concept stage due to the gaps in our understanding of complex-(nano-assemblies)-complex-(biosystems) interactions. Indeed, stimuli-responsive assembly-disassembly is, in and of itself, a process of nano-bio interactions, the key steps for biological fate and functional activity of nano-assemblies. To provide a comprehensive understanding of these interactions in this review, we first propose a 4W1H principle (Where, When, What, Which and How) to delineate the relevant dynamic biological processes, behaviour and fate of nano-assemblies. We further summarize several key parameters that govern effective nano-bio interactions. The effects of these kinetic parameters on ADMET processes (absorption, distribution, metabolism, excretion and transformation) are then discussed. Furthermore, we provide an overview of the challenges facing the evaluation of nano-bio interactions of assembled nanodrugs. We finally conclude with future perspectives on safe-by-design and application-driven-design of nano-assemblies. This review will highlight the dynamic biological and physicochemical parameters of nano-bio interactions and bridge discrete concepts to build a full spectrum understanding of the biological outcomes of nano-assemblies. These principles are expected to pave the way for future development and clinical translation of precise, safe and effective nanomedicines with intelligent theranostic features.

A pyroptosis nanotuner for cancer therapy

Pyroptosis is a gasdermin-mediated programmed necrosis that occurs via membrane perforation and that can be exploited for biomedical applications in cancer therapy. However, inducing specific pyroptotic cancer cell death while sparing normal cells is challenging. Here, we report an acid-activatable nanophotosensitizer library that can be used to spatiotemporally target distinct stages of endosomal maturation, enabling tunable cellular pyroptosis. Specific activation of phospholipase C signalling transduction in early endosomes triggers gasdermin-E-mediated pyroptosis, which is dramatically reduced when acid-activatable nanophotosensitizers are transported into late endosomes/lysosomes. This nanotuner platform induces pyroptotic cell death with up to 40-fold tunability in various gasdermin-E-positive human cancers, resulting in enhanced anti-tumour efficacy and minimized systemic side effects. This study offers new insights into how to engineer nanomedicines with tunable pyroptosis activity through specific targeting of distinct endocytic signalling for biomedical applications.

Proving Cooperativity of a Catalytic Reaction by Means of Nanoscale Geometry: The Case of Click Reaction

Establishing whether a reaction is catalyzed by a single-metal catalytic center or cooperatively by a fleeting complex encompassing two such centers may be an arduous pursuit requiring detailed kinetic, isotopic, and other types of studies─as illustrated, for instance, by over a decade-long work on single-copper versus di-copper mechanisms of the popular "click" reaction. This paper describes a method to interrogate such cooperative mechanisms by a nanoparticle-based platform in which the probabilities of catalytic units being proximal can be varied systematically and, more importantly, independently of their volume concentration. The method relies on geometrical considerations rather than a detailed knowledge of kinetic equations, yet the scaling trends it yield can distinguish between cooperative and non-cooperative mechanisms.

Construction Of High Loading Natural Active Substances Nanoplatform and Application in Synergistic Tumor Therapy

Background

Natural bioactive substances have been widely studied for their superior anti-tumor activity and low toxicity. However, natural bioactive substances suffer from poor water-solubility and poor stability in the physiological environment. Therefore, to overcome the drawbacks of natural bioactive substances in tumor therapy, there is an urgent need for an ideal nanocarrier to achieve high bioactive substance loading with low toxicity.

Materials and Methods

Face-centered cubic hollow mesoporous Prussian Blue (HMPB) NPs were prepared by stepwise hydrothermal method. Among them, PVP served as a protective agent and HCl served as an etching agent. Firstly, MPB NPs were obtained by 0.01 M HCl etching. Then, the highly uniform dispersed HMPB NPs were obtained by further etching with 1 M HCl.

Results

In this work, we report a pH-responsive therapeutic nanoplatform based on HMPB NPs. Surprisingly, as-prepared HMPB NPs with ultra-high bioactive substances loading capacity of 329 μg mg⁻¹ owing to the large surface area (131.67 m² g⁻¹) and wide internal pore size distribution (1.8–96.2 nm). Moreover, with the outstanding photothermal conversion efficiency of HMPB NPs (30.13%), natural bioactive substances were released in the tumor microenvironment (TME). HMPB@PC B2 achieved excellent synergistic therapeutic effects of photothermal therapy (PTT) and chemotherapy (CT) in vivo and in vitro without causing any extraneous side effects.

Conclusion

A biocompatible HMPB@PC B2 nanoplatform was constructed by simple physical adsorption. The in vitro and in vivo experiment results demonstrated that the synergy of PTT/CT provided excellent therapeutic efficiency for cervical cancer without toxicity. Altogether, as-designed nanomedicines based on natural bioactive substances may be provide a promising strategy for cancer therapy.

Aggregation-Induced Emission Luminogens for Cell Death Research

Cell death is closely related to various diseases, and monitoring and controlling cell death is a promising strategy to develop efficient therapy. Aggregation-induced emission luminogens (AIEgens) are ideal candidates for developing novel theranostic agents because of their intriguing properties in the aggregate state. The rational application of AIE materials in cell death-related research is still in its infancy but has shown great clinical potential. This review discussed the research frontier and our understanding of AIE materials in various subroutines of cell death, including apoptosis, necrosis, immunogenic cell death, pyroptosis, autophagy, lysosome-dependent cell death, and ferroptosis. We hope that the new insights can be offered to this growing field and attract more researchers to provide valuable contributions.

Recent Progress of Rare Earth Doped Hydroxyapatite Nanoparticles: Luminescence Properties, Synthesis and Biomedical Applications

Hydroxyapatite nanoparticles (HAP NPs) are host materials and can be modified with various substrates and dopants. Among them, rare earth (RE) ions doped HAP NPs have gathered attention due to their unique physicochemical and imaging properties. Compared to other fluorescence probes, RE-doped HAP NPs display advantages in high brightness, high contrast, photostability, nonblinking, and narrow emission bands. Meanwhile, their intrinsic features (composition, morphology, size, crystallinity, and luminescence intensity) can be adjusted by changing the dopant ratio, synthesizing temperature, reaction time, and techniques. And they have been used in various biomedical applications, including imaging probe, drug delivery, bone tissue engineering, and antibacterial studies. This review surveys the luminescent properties, fluorescence enhancement, synthetic methods, and biocompatibility of various RE-doped HAP NPs consolidated from different research works, for their employments in biomedical applications. For this literature review, an electronic search was conducted in the Pubmed, Web of Science, Google Scholar, Scopus and SciFinder databases, using the keywords: hydroxyapatite, rare earth, lanthanide, fluorescence, and imaging. Literature searches of English-language publications from 1979 with updates through April, 2022, and a total of 472 potential papers were identified. In addition, a few references were located by noting their citation in other studies reviewed. STATEMENT OF SIGNIFICANCE: Hydroxyapatite nanoparticles (HAP NPs) have a broad range of promising biological applications. Although prospective biomedical applications are not limited to rare earth-doped hydroxyapatite nanoparticles (RE-doped HAP NPs), some cases do make use of the distinctive features of RE-elements to achieve the expected functions for HAP families. This review surveys the luminescent properties, synthetic methods, and biocompatibility of various RE-doped HAP NPs consolidated from different research works, for their employments in biomedical applications, including imaging probe, drug delivery, bone tissue repair and tracking, and anti-bacteria. Overall, we expect to shed some light on broadening the research and application of RE-doped HAP NPs in biomedical field.

Nanodrugs Detonate Lysosome Bombs

Cancer cell lysosomes contain various hydrolases and non-degraded substrates that are corrosive enough to destroy cancer cells. However, many traditional small molecule drugs targeting lysosomes have strong side effects because they cannot effectively differentiate between normal and cancer cells. Most lysosome-based research has focused on inducing mild lysosomal membrane permeabilization (LMP) to release anticancer drugs from lysosomal traps into the cancer cell cytoplasm. In fact, lysosomes are particularly powerful "bombs". Achieving cancer cell-selective LMP induction may yield high-efficiency anticancer effects and extremely low side effects. Nanodrugs have diverse and combinable properties and can be specifically designed to selectively induce LMP in cancer cells by taking advantage of the differences between cancer cells and normal cells. Although nanodrugs-induced LMP has made great progress recently, related reviews remain rare. Herein, we first comprehensively summarize the advances in nanodrugs-induced LMP. Next, we describe the different nanodrugs-induced LMP strategies, namely nanoparticles aggregation-induced LMP, chemodynamic therapy (CDT)-induced LMP, and magnetic field-induced LMP. Finally, we analyze the prospect of nanodrugs-induced LMP and the challenges to overcome. We believe this review provides a unique perspective and inspiration for designing lysosome-targeting drugs.

Penetrating Micelle for Reversing Immunosuppression and Drug Resistance in Pancreatic Cancer Treatment

Pancreatic ductal adenocarcinoma (PDAC) is on of the most lethal malignant tumors with relatively poor prognosis, characterized with insufficient drug penetration, low immune response and obvious drug resistances. The therapeutic inefficiency is multifactorially related to its specific tumor microenvironment (TME), which is representatively featured as rich stroma and immunosuppression. In this work, a versatile drug delivery system is developed that can coencapsulate two prodrugs modified from gemcitabine (GEM) and a signal transducer and activator of transcription 3 (STAT3) inhibitor (HJC0152), and the gradient pH variation is further sensed in the TME of PDAC to achieve a higher penetration by reversing its surficial charges. The escorted prodrugs can release GEM intracellularly, and respond to the hypoxic condition to yield the parental STAT3 inhibitor HJC0152, respectively. By inhibiting STAT3, the tumor immunosuppression microenvironment can be re-educated through the reversion of M2-like tumor associated macrophages (M2-TAMs), recruitment of cytotoxic T lymphocytes and downregulation of regulatory T cells (Treg s). Furthermore, cytidine deaminase (CDA) and α-smooth muscle actin (α-SMA) expression can be downregulated, plus the lipid modification of GEM, the drug resistance of GEM can be greatly relieved. Based on the above design, a synergetic therapeutic efficacy in PDAC treatment can be achieved to provide more opportunity for clinical applications.

Tumor acidity-activatable photothermal/Fenton nanoagent for synergistic therapy

Intracellular formation of therapeutic agents has become one of the effective ways for cancer-specific treatment. Herein, a tumor acidity-activatable photothermal/Fenton nanoagent (denoted as CoPy) was constructed based on oxidized zeolitic imidazolate framework-67 (oxZIF-67) nanosheet and pyrrole (Py) monomer for synergistic therapy. The CoPy showed negligible toxicity to normal cell models RAW264.7 and 3T3 cell lines, and could be degraded by ascorbic acid in normal physiological conditions. However, once uptaken by 4T1 cells, the acidic pH led to the release of Co³⁺, which served as a strong oxidant to induce the polymerization of Py to form polypyrrole (PPy) for site-specific photothermal therapy (PTT). Most appealingly, the PPy could chelate the generated Co²⁺ in the polymerization process to initiate the Fenton-like reaction, which was more capable to produce highly toxic hydroxyl radical (•OH) for chemodynamic therapy (CDT) compared to the free Co²⁺ ones. In vitro and in vivo experiments demonstrated that all functionalities on CoPy worked collaboratively, and 78% of tumors were inhibited through cooperative PTT/CDT. Such a novel therapeutic nanoagent with tumor selectivity opens new opportunities for combinational treatment paradigms.

Non-apoptotic cell death-based cancer therapy: Molecular mechanism, pharmacological modulators, and nanomedicine

As an emerging cancer therapeutic target, non-apoptotic cell death such as ferroptosis, necroptosis and pyroptosis, etc., has revealed significant potential in cancer treatment for bypassing apoptosis to enhance the undermined therapeutic efficacy triggered by apoptosis resistance. A variety of anticancer drugs, synthesized compounds and natural products have been proven recently to induce non-apoptotic cell death and exhibit excellent anti-tumor effects. Moreover, the convergence of nanotechnology with functional materials and biomedicine science has provided tremendous opportunities to construct non-apoptotic cell death-based nanomedicine for innovative cancer therapy. Nanocarriers are not only employed in targeted delivery of non-apoptotic inducers, but also used as therapeutic components to induce non-apoptotic cell death to achieve efficient tumor treatment. This review first introduces the main characteristics, the mechanism and various pharmacological modulators of different non-apoptotic cell death forms, including ferroptosis, necroptosis, pyroptosis, autophagy, paraptosis, lysosomal-dependent cell death, and oncosis. Second, we comprehensively review the latest progresses of nanomedicine that induces various forms of non-apoptotic cell death and focus on the nanomedicine targeting different pathways and components. Furthermore, the combination therapies of non-apoptotic cell death with photothermal therapy, photodynamic therapy, immunotherapy and other modalities are summarized. Finally, the challenges and future perspectives in this regard are also discussed.

DNA origami nanocalipers for pH sensing at the nanoscale

A DNA origami nanocaliper is employed as a shape-resolved nanomechanical device, with pH-responsive triplex DNA integrated into the two arms. The shape transition of the nanocaliper results in a subtle difference depending on the local pH that is visible via TEM imaging, demonstrating the potential of these nanocalipers to act as a universal platform for pH sensing at the nanoscale.

Chlorine disinfection elevates the toxicity of polystyrene microplastics to human cells by inducing mitochondria-dependent apoptosis

Microplastics (MPs) are ubiquitous in drinking water and pose potential threats to human health. Despite increasingly attentions on the toxicity of MPs, the deleterious effects of MPs after chlorine disinfection, which might be a more accessible form of MPs, has rarely been considered. Here, we first treated pristine polystyrene microplastics (PS-MPs) with chlorine to simulate the reactions that occur during drinking water treatment, and investigated and compared the cytotoxicity of chlorinated PS-MPs to those of pristine PS-MPs. Chlorine disinfection did not change the size of pristine PS-MPs, but increased the surface roughness. In addition, abundant carbon-chlorine bonds and persistent free radicals were generated on the surface of chlorinated PS-MPs. Compared with pristine PS-MPs, chlorinated PS-MPs markedly inhibited the cell proliferation, changed cellular morphology, destroyed cell membrane integrity, induced cell inflammatory response and apoptosis. Proteomics confirmed the difference in interactions with intracellular proteins between these particles. Furthermore, we found that the regulation of PI3K/AKT and Bcl-2/Bax pathways, oxidative stress-triggered mitochondrial depolarization, and the activation of caspase cascade were identified as the underlying mechanisms for the enhanced apoptosis ratio in GES-1 cells when exposed to chlorinated PS-MPs. This exacerbated cytotoxicity could be explained by the enhanced surface roughness and changed surface chemistry of these PS-MPs after chlorine disinfection. This work discloses the impacts of chlorine disinfection on the cytotoxicity of PS-MPs, which provides new insights for a more systematic risk assessment of MPs.

Core-shell lipoplexes inducing active macropinocytosis promote intranasal delivery of c-Myc siRNA for treatment of glioblastoma

Glioblastoma is the most common and aggressive primary brain tumor, whose malignancy is closely correlated with elevated proto-oncogene c-myc. Intranasal administration emerges as a potential approach to deliver gene into the brain and interfere c-Myc expression. However, powerful permeability in nasal mucosa, selective delivery to glioma and avoidance of premature release during remote transport are imperative to ensure the therapeutic effectiveness. To address the above concerns, herein we constructed a lipoplex based on pre-compression of c-Myc-targeting siRNA (sic-Myc) by octaarginine and subsequent encapsulation by liposome modified with a selected peptide derived from penetratin, named 89WP. It was found that the lipoplex exhibited a stable core-shell structure and could be preferentially internalized along with cell debris by glioma cells via active macropinocytosis. Through this cellular uptake pathway, the lipoplex avoided being entrapped by lysosome and released siRNA in cytoplasm within 4 h, inducing substantial downregulation of c-Myc mRNA and protein expression of glioma cells. Furthermore, due to significantly enhanced permeability in tumor spheroids and nasal mucosa, the lipoplex was competent to deliver more siRNA to orthotopic glioma after intranasal administration, and therefore prolonged the survival time of glioma-bearing mice by inducing apoptosis. STATEMENT OF SIGNIFICANCE: In the present work, a lipoplex was designed to address the unmet demands on intranasal siRNA delivery to the brain for treatment of glioma. First, a powerful peptide was selected to enable the lipoplex to penetrate nasal mucosa. Second, we found the lipoplex could be selectively internalized along with cell debris by glioma cells via active macropinocytosis, and recorded the entire process. This cellular uptake pathway not only prevented the lipoplex being entrapped by lysosome, but also increased distribution of the lipoplex in orthotopic glioma. Third, this lipoplex provided additional protection for siRNA to avoid premature release during transport from nasal to brain. Overall, this lipoplex improved the gene delivery efficiency of intranasal administration and was promising in the perspective of selectively silencing disease-related genes in intracranial tumor.

Large-Scale, Wavelet-Based Analysis of Lysosomal Trajectories and Co-Movements of Lysosomes with Nanoparticle Cargos

Lysosomes—that is, acidic organelles known for degradation/recycling—move through the cytoplasm alternating between bursts of active transport and short, diffusive motions or even pauses. While their mobility is essential for lysosomes’ fusogenic and non-fusogenic interactions with target organelles, their movements have not been characterized in adequate detail. Here, large-scale statistical analysis of lysosomal movement trajectories reveals that lysosome trajectories in all examined cell types—both cancer and noncancerous ones—are superdiffusive and characterized by heavy-tailed distributions of run and flight lengths. Consideration of Akaike weights for various potential models (lognormal, power law, truncated power law, stretched exponential, and exponential) indicates that the experimental data are best described by the lognormal distribution, which, in turn, can be related to one of the space-search strategies particularly effective when “thorough” search needs to balance search for rare target(s) (organelles). In addition, automated, wavelet-based analysis allows for co-tracking the motions of lysosomes and the cargos they carry—particularly the nanoparticle aggregates known to cause selective lysosome disruption in cancerous cells. The methods we describe here could help study nanoparticle assemblies, viruses, and other objects transported inside various vesicle types, as well as coordinated movements of organelles/particles in the cytoplasm. Custom-written code that includes integrated workflow for our analyses is made available for academic use.

A benzimidazole-based ratiometric fluorescent probe for the accurate and rapid monitoring of lysosomal pH in cell autophagy and anticounterfeiting

The lysosomal targeted ratiometric fluorescent BD probe reveals excellent application performance in the fields of selective monitoring of the lysosome pH of living cells, real-time dynamic monitoring of autophagy, and document anti-counterfeiting.

Self-Complementary Zwitterionic Peptides Direct Nanoparticle Assembly and Enable Enzymatic Selection of Endocytic Pathways

Supramolecular self-assembly in biological systems holds promise to convert and amplify disease-specific signals to physical or mechanical signals that can direct cell fate. However, it remains challenging to design physiologically stable self-assembling systems that demonstrate tunable and predictable behavior. Here, the use of zwitterionic tetrapeptide modalities to direct nanoparticle assembly under physiological conditions is reported. The self-assembly of gold nanoparticles can be activated by enzymatic unveiling of surface-bound zwitterionic tetrapeptides through matrix metalloprotease-9 (MMP-9), which is overexpressed by cancer cells. This robust nanoparticle assembly is achieved by multivalent, self-complementary interactions of the zwitterionic tetrapeptides. In cancer cells that overexpress MMP-9, the nanoparticle assembly process occurs near the cell membrane and causes size-induced selection of cellular uptake mechanism, resulting in diminished cell growth. The enzyme responsiveness, and therefore, indirectly, the uptake route of the system can be programmed by customizing the peptide sequence: a simple inversion of the two amino acids at the cleavage site completely inactivates the enzyme responsiveness, self-assembly, and consequently changes the endocytic pathway. This robust self-complementary, zwitterionic peptide design demonstrates the use of enzyme-activated electrostatic side-chain patterns as powerful and customizable peptide modalities to program nanoparticle self-assembly and alter cellular response in biological context.

Multifunctional Nanosystems with Enhanced Cellular Uptake for Tumor Therapy

Rapid development of nanotechnology provides promising strategies in biomedicine, especially in tumor therapy. In particular, the cellular uptake of nanosystems is not only a basic premise to realize various biomedical applications, but also a fatal factor for determining the final therapeutic effect. Thus, a systematic and comprehensive summary is necessary to overview the recent research progress on the improvement of nanosystem cellular uptake for cancer treatment. According to the process of nanosystems entering the body, they can be classified into three categories. The first segment is to enhance the accumulation and permeation of nanosystems to tumor cells through extracellular microenvironment stimulation. The second segment is to improve cellular internalization from extracellular to intracellular via active targeting. The third segment is to enhance the intracellular retention of therapeutics by subcellular localization. The major factors in the delivery can be utilized to develop multifunctional nanosystems for strengthening the tumor therapy. Ultimately, the key challenges and prospective in the emerging research frontier are thoroughly outlined. This review is expected to provide inspiring ideas, promising strategies and potential pathways for developing advanced anticancer nanosystems in clinical practice.

AIE-active macromolecules: designs, performances, and applications

Aggregation-induced emission (AIE) macromolecules as emerging luminescent materials gained increasing attention owing to their good processability, high brightness, wide functionality, and smart responsiveness, with great potential in many fields.

Cu-based nanoparticle toxicity to zebrafish cells regulated by cellular discharges

Cellular transport of metal nanoparticles (NPs) is critical in determining their potential toxicity, but the transformation of metal ions released from the internalized NPs is largely unknown. Cu-based NPs are the only metallic-based NPs that are reported to induce higher toxicity compared with their corresponding ions, likely due to their unique cellular turnover. In the present study, we developed a novel gold core to differentiate the particulate and ionic Cu in the Cu₂O microparticles (MPs), and the kinetics of bioaccumulation, exocytosis, and cytotoxicity of Au@Cu₂O MPs to zebrafish embryonic cells were subsequently studied. We demonstrated that the internalized MPs were rapidly dissolved to Cu ions, which then undergo lysosome-mediated exocytosis. The uptake rate of smaller MPs (130 nm) was lower than that of larger ones (200 nm), but smaller MPs were dissolved much quickly in cells and therefore activated the exocytosis more quickly. The rapid release of Cu ions resulted in an immediate toxic action of Cu₂O MPs, while the cell deaths mainly occurred by necrosis. During this process, the buffering ability of glutathione greatly alleviated the Cu toxicity. Therefore, although the turnover of intracellular Cu at a sublethal exposure level was hundred times faster than the basal values, labile Cu(I) concentration increased by only 2 times at most. Overall, this work provided new insights into the toxicity of copper NPs, suggesting that tolerance to Cu-based NPs depended on their ability to discharge the released Cu ions.

Lysosome-Targeted and Fluorescence-Turned "On" Cytotoxicity Induced by Alkaline Phosphatase-Triggered Self-Assembly

Selectively inducing lysosomal membrane permeabilization (LMP) is a promising strategy for cancer therapy. But integrating alkaline phosphatase (ALP)-instructed self-assembly and lysosome-targeting to induce LMP for selective killing of cancer cells was not reported. Herein, a pyrene-peptide conjugate Py-Phe-Phe-Glu-Tyr(H₂ PO₃ )-Gly-lyso (Py-Yp-Lyso) is rationally designed and demonstrated for its lysosome-targeting cytotoxicity on cancer cells, together with its pyrene (Py) excimer fluorescence turning "on" at 480 nm. In vitro results showed that, Py-Yp-Lyso is efficiently dephosphorylated by ALP to yield Py-Phe-Phe-Glu-Tyr-Gly-lyso (Py-Y-Lyso) which self-assembles into nanofibers. Cell experiments verified that, after being taken up by HeLa cells, the excimer fluorescence of Py-Yp-Lyso assemblies has turned "on" and the assemblies specifically target the lysosomes, inducing LMP and ultimate cancer cell death. In vivo experiments indicated that Py-Yp-Lyso has the highest inhibition effect on HeLa tumors among the four compounds studied. This is anticipated for applying Py-Yp-Lyso to treat cancers in the clinic in the future.

Mixed-charge modification as a robust method to realize the antiviral ability of gold nanoparticles in a high protein environment

Pandemics caused by viruses have resulted in incalculable losses to human beings, which are exacerbated due to the lack of antiviral drugs. Sulfonic group modified nanomedicine has been proved to possess a broad-spectrum antiviral ability. However, it is very challenging to maintain the antiviral activity in a high protein environment in vivo. To improve the tolerance to the complex biological environment, sulfonic mixed-charge modified gold nanoparticles (MC_AuNPs) were prepared in this research by introducing positively charged ligands into sulfonic ligand modified gold nanoparticles. The MC_AuNPs showed excellent non-fouling ability while retaining comparable antiviral ability to single sulfonic ligand modified gold nanoparticles (MDS_AuNPs). The MC_AuNPs maintained their antiviral ability in 10 mg mL^-1 protein solutions, but the MDS_AuNPs completely lost their antiviral capability in 1 mg mL^-1 protein medium. The mixed-charge modification strategy provides a practical avenue to maintain the antiviral capability of HSPG mimicking nanoparticles in high protein environments.

Precise Subcellular Organelle Targeting for Boosting Endogenous-Stimuli-Mediated Tumor Therapy

Though numerous external-stimuli-triggered tumor therapies, including phototherapy, radiotherapy, and sonodynamic therapy have made great progress in cancer therapy, the low penetration depth of the laser, safety concerns of radiation, the therapeutic resistance, and the spatio-temporal constraints of the specific equipment restrict their convenient clinical applications. What is more, the inherent physiological barriers of the tumor microenvironment (TME), including hypoxia, heterogeneity, and high expression of antioxidant molecules also restrict the efficiency of tumor therapy. As a result, the development of nanoplatforms responsive to endogenous stimuli (such as glucose, acidic pH, cellular redox events, and etc.) has attracted great attention for starvation therapy, ion therapy, prodrug-mediated chemotherapy, or enzyme-catalyzed therapy. In addition, nanomedicines can be modified by some targeted units for precisely locating in subcellular organelles and boosting the destroying of tumor tissue, decreasing the dosage of nanoagents, reducing side effects, and enhancing the therapeutic efficiency. Herein, the properties of the TME, the advantages of endogenous stimuli, and the principles of subcellular-organelle-targeted strategies will be emphasized. Some necessary considerations for the exploitation of precision medicine and clinical translation of multifunctional nanomedicines in the future are also pointed out.

How to exploit different endocytosis pathways to allow selective delivery of anticancer drugs to cancer cells over healthy cells

It was recently shown that it is possible to exploit the nanoparticle shape to selectively target endocytosis pathways found in cancer and not healthy cells. It is important to understand and compare the endocytosis pathways of nanoparticles in both cancer and healthy cells to restrict the healthy cells from taking up anticancer drugs to help reduce the side effects for patients. Here, the clathrin-mediated endocytosis inhibitor, hydroxychloroquine, and the anticancer drug, doxorubicin, are loaded into the same mesoporous silica nanorods. The use of nanorods was found to restrict the uptake by healthy cells but allowed cancer cells to take up the nanorods via the macropinocytosis pathway. Furthermore, it is shown that the nanorods can selectively deliver doxorubicin to the nucleus of breast cancer cells and to the cytoplasm of pancreatic cancer cells. The dual-drug-loaded nanorods were able to selectively kill the breast cancer cells in the presence of healthy breast cells. This study opens exciting possibilities of targeting cancer cells based on the material shape rather than targeting antibodies.

It was recently shown that it is possible to exploit the nanoparticle shape to selectively target endocytosis pathways found in cancer and not healthy cells.

Multistage targeted "Photoactive neutrophil" for enhancing synergistic photo-chemotherapy

Cell-based drug delivery system holds a great promise in anticancer treatment, due to its potential of maximizing therapeutic efficacy while minimizing adverse effects. However, current cell system can only deliver drugs in tumor lesions, but lack an ability to target subcellular locus of therapeutic actions, thereby compromising anticancer efficacy. Herein, we bioengineered living neutrophils as a novel type of "Photoactive neutrophil" (PAN) with capabilities of self-amplified multistage targeting and inflammation response for enhancing mitochondria-specific photo-chemotherapy. PAN encapsulated multifunctional nanocomplex (RA/Ce6) of RGD-apoptotic peptide conjugate (RA) decorated liposomal photosensitizer Ce6, and could overcome tumor barriers to selectively release RA/Ce6 within tumor. Consequently, RA/Ce6 actively entered cancer cells and accumulated in mitochondria to trigger combined photodynamic therapy (PDT) and RA-induced mitochondrial membrane disruption, resulting in enhanced therapeutic effects. Importantly, PAN exhibited inflammation amplified tumor targeting after PDT, and initiated combined photo-chemotherapy to suppress tumor growth without adverse effects, leading to prolonged mice survival. Therefore, PAN represents the first multistage targeted cell therapy, and brings new insights into cancer treatment.

Targeted Enrichment of Enzyme-Instructed Assemblies in Cancer Cell Lysosomes Turns Immunologically Cold Tumors Hot

Lysosome-relevant cell death induced by lysosomal membrane permeabilization (LMP) has recently attracted increasing attention. However, nearly no studies show that currently available LMP inducers can evoke immunogenic cell death (ICD) or convert immunologically cold tumors to hot. Herein, we report a LMP inducer named TPE-Py-pYK(TPP)pY, which can respond to alkaline phosphatase (ALP), leading to formation of nanoassembies along with fluorescence and singlet oxygen turn-on. TPE-Py-pYK(TPP)pY tends to accumulate in ALP-overexpressed cancer cell lysosomes as well as induce LMP and rupture of lysosomal membranes to massively evoke ICD. Such LMP-induced ICD effectively converts immunologically cold tumors to hot as evidenced by abundant CD8⁺ and CD4⁺ T cells infiltration into the cold tumors. Exposure of ALP-catalyzed nanoassemblies in cancer cell lysosomes to light further intensifies the processes of LMP, ICD and cold-to-hot tumor conversion. This work thus builds a new bridge between lysosome-relevant cell death and cancer immunotherapy.

Supramolecular Tropism Driven Aggregation of Nanoparticles In Situ for Tumor-Specific Bioimaging and Photothermal Therapy

Inorganic nanomedicine has attracted increasing attentions in biomedical sciences due to their excellent biocompatibility and tunable, versatile functionality. However, the relatively poor accumulation and retention of these nanomedicines in targeted tissues have often hindered their clinical translation. Herein, highly efficient, targeted delivery, and in situ aggregation of ferrocene (Fc)-capped Au nanoparticles (NPs) are reported to cucurbit[7]uril (CB[7])-capped Fe₃ O₄ NPs (as an artificial target) that are magnetically deposited into the tumor, driven by strong, multipoint CB[7]-Fc host-guest interactions (here defined as "supramolecular tropism" for the first time), leading to high tumor accumulation and retention of these NPs. The in vitro and in vivo studies demonstrate the precisely controlled, specific accumulation, and retention of Au NPs in the tumor cells and tissue via supramolecular tropism and in situ aggregation, which afford locally enhanced CT imaging of cancer and enable tumor-specific photothermal therapy attributed to the plasmonic coupling effects between adjacent Au NPs within the supramolecular aggregations. This work provides a novel concept of supramolecular tropism, which may drive targeted delivery and enable specific accumulation, retention, and activation of nanomedicine for improved bioimaging and therapy of cancer.