Unveiling the Power of Cloaking Metal-Organic Framework Platforms via Supramolecular Antibody Conjugation.

Targeted drug delivery systems based on metal-organic frameworks (MOFs) have progressed tremendously since inception and are now widely applicable in diverse scientific fields. However, translating MOF agents directly to targeted drug delivery systems remains a challenge due to the biomolecular corona phenomenon. Here, we observed that supramolecular conjugation of antibodies to the surface of MOF particles (MOF-808) via electrostatic interactions and coordination bonding can reduce protein adhesion in biological environments and show stealth shields. Once antibodies are stably conjugated to particles, they were neither easily exchanged with nor covered by biomolecule proteins, which is indicative of the stealth effect. Moreover, upon conjugation of the MOF particle with specific targeted antibodies, namely, anti-CD44, human epidermal growth factor receptor 2 (HER2), and epidermal growth factor receptor (EGFR), the resulting hybrid exhibits an augmented targeting efficacy toward cancer cells overexpressing these receptors, such as HeLa, SK-BR-3, and 4T1, as evidenced by flow cytometry. The therapeutic effectiveness of the antibody-conjugated MOF (anti-M808) was further evaluated through in vivo imaging and the assessment of tumor inhibition effects using IR-780-loaded EGFR-M808 in a 4T1 tumor xenograft model employing nude mice. This study therefore provides insight into the use of supramolecular antibody conjugation as a promising method for developing MOF-based drug delivery systems.

Drug-Loaded Nanogel for Efficient Orchestration of Cell Death Pathways by Intramitochondrial Disulfide Polymerization.

Chemotherapy using a nanoscaled drug delivery system is an effective cancer therapy, but its high drug concentration often causes drug resistance in cancer cells and normal cell damage. Combination therapy involving two or more different cell signaling pathways can be a powerful tool to overcome the limitations of chemotherapy. Herein, this article presents nanogel (NG)-mediated co-delivery of a chemodrug camptothecin (CPT) and mitochondria-targeting monomer (MT monomer) for efficient activation of two modes of the programmed cell death pathway (apoptosis and necroptosis) and synergistic enhancement of cancer therapy. CPT and the monomer are incorporated together into the redox-degradable polymeric NGs for release in response to the intracellular glutathione. The MT monomer is shown to undergo reactive oxygen species (ROS)-triggered disulfide polymerization inside the cancerous mitochondria in cooperation with the chemotherapeutic CPT elevating the intracellular ROS level. The CPT/monomer interconnection in cell death mechanisms for mitochondrial dysfunction and enhanced cell death is evidenced by a series of cell analyses showing ROS generation, mitochondria damage, impacts on (non)cancerous or drug-resistant cells, and cell death modes. The presented work provides beneficial insights for utilizing combination therapy to facilitate a desired cell death mechanism and developing a novel nanosystem for more efficacious cancer treatment.

Metal-Organic Framework-Supported Catalase Delivery for Enhanced Photodynamic Therapy via Hypoxia Mitigation.

Tumor hypoxia poses a significant challenge in photodynamic therapy (PDT), which uses molecular oxygen to produce reactive oxygen species upon light excitation of a photosensitizer. For hypoxia mitigation, an enzyme catalase (CAT) can be beneficially used to convert intracellular hydrogen peroxide to molecular oxygen, but its utility is significantly limited due to the intrinsic membrane impermeability. Herein, we present direct integration of CAT into the outer surface of unmodified metal-organic framework (MOF) nanoparticles (NPs) via supramolecular interactions for effective cellular entry of CAT and consequent enhancement of PDT. The results demonstrated that CAT-loaded MOF NPs could successfully enter hypoxic cancer cells, after which the intracellularly delivered CAT molecules became dissociated from the MOF surface to efficiently initiate the oxygen generation and PDT process along with a co-delivered photosensitizer IR780. This achievement suggests that our protein-MOF integration strategy holds great potential in biomedical studies to overcome tumor hypoxia as well as to efficiently deliver biomolecular cargos.

Supramolecular Senolytics via Intracellular Oligomerization of Peptides in Response to Elevated Reactive Oxygen Species Levels in Aging Cells.

Senolytics, which eliminate senescent cells from tissues, represent an emerging therapeutic strategy for various age-related diseases. Most senolytics target antiapoptotic proteins, which are overexpressed in senescent cells, limiting specificity and inducing severe side effects. To overcome these limitations, we constructed self-assembling senolytics targeting senescent cells with an intracellular oligomerization system. Intracellular aryl-dithiol-containing peptide oligomerization occurred only inside the mitochondria of senescent cells due to selective localization of the peptides by RGD-mediated cellular uptake into integrin αvß3-overexpressed senescent cells and elevated levels of reactive oxygen species, which can be used as a chemical fuel for disulfide formation. This oligomerization results in an artificial protein-like nanoassembly with a stable α-helix secondary structure, which can disrupt the mitochondrial membrane via multivalent interactions because the mitochondrial membrane of senescent cells has weaker integrity than that of normal cells. These three specificities (integrin αvß3, high ROS, and weak mitochondrial membrane integrity) of senescent cells work in combination; therefore, this intramitochondrial oligomerization system can selectively induce apoptosis of senescent cells without side effects on normal cells. Significant reductions in key senescence markers and amelioration of retinal degeneration were observed after elimination of the senescent retinal pigment epithelium by this peptide senolytic in an age-related macular degeneration mouse model and in aged mice, and this effect was accompanied by improved visual function. This system provides a strategy for the treatment of age-related diseases using supramolecular senolytics.

Azacyclic Anchor-Enabled Cohesive Graphite Electrodes for Sustainable Anion Storage.

Advanced energy-storage devices are indispensable for expanding electric mobility applications. While anion intercalation-type redox chemistry in graphite cathodes has opened the path to high-energy-density batteries, surpassing the limited energy density of conventional lithium-ion batteries , a significant challenge remains: the large volume expansion of graphite upon anion intercalation. In this study, a novel polymeric binder and cohesive graphite cathode design for dual-ion batteries (DIBs) is presented, which exhibits remarkable stability even under high voltage conditions (>5 V). The innovative binder incorporates an acrylate moiety ensuring superior oxidative stability and self-healing features, along with an azide moiety, which allows for azacyclic covalent bonding with graphite and interchain crosslinking. A simple 1-h ultraviolet treatment is sufficient for binder fixation within the electrode, leading to the covalent bond formation with graphite and the creation of a robust three-dimensional network. This modification facilitates deeper and more reversible anion intercalation, leading to improved capacity, extended lifespan, and sustainable anion storage. The binder design, exhibiting exceptional adhesive properties and effective stress mitigation, enables the construction of ultrathick graphite cathodes. These findings provide valuable insights for the development of advanced binders, paving the way for high-performance DIBs.

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.

Surface protein-retractive and redox-degradable mesoporous organosilica nanoparticles for enhanced cancer therapy.

Targeted delivery along with controlled drug release is considered crucial in development of a drug delivery system (DDS) for efficient cancer treatment. In this paper, we present a strategy to obtain such a DDS by utilizing disulfide-incorporated mesoporous organosilica nanoparticles (MONs), which were engineered to minimize the surface interactions with proteins for better targeting and therapeutic performance. That is, after MONs were loaded with a chemodrug doxorubicin (DOX) through the inner pores, their outer surface was treated for conjugation to the glutathione-S-transferase (GST)-fused cell-specific affibody (Afb) (GST-Afb). These particles exhibited prompt responsivity to the SS bond-dissociating glutathione (GSH), which resulted in considerable degradation of the initial particle morphology and DOX release. As the protein adsorption to the MON surface appeared largely reduced, their targeting ability with GSH-stimulated therapeutic activities was demonstrated in vitro by employing two kinds of the GST-Afb protein, which target human cancer cells with the surface membrane receptor, HER2 or EGFR. Compared with unmodified control particles, the presented results show that our system can significantly enhance cancer-therapeutic outcomes of the loaded drug, offering a promising way of designing a more efficacious DDS.

Protein-Precoated Surface of Metal-Organic Framework Nanoparticles for Targeted Delivery.

Metal-organic framework (MOF) nanoparticles have recently emerged as a promising vehicle for drug delivery with high porosity and feasibility. However, employing a MOF-based drug delivery system remains a challenge due to the difficulty in controlling interfaces of particles in a biological environment. In this paper, protein corona-blocked Zr6 -based MOF (PCN-224) nanoparticles are presented for targeted cancer therapy with high efficiency. The unmodified PCN-224 surface is precoated with glutathione transferase (GST)-fused targetable affibody (GST-Afb) proteins via simple mixing conjugations instead of chemical modifications that can induce the impairment of proteins. GST-Afb proteins are shown to stably protect the surface of PCN-224 particles in a specific orientation with GST adsorbed onto the porous surface and the GST-linked Afb posed outward, minimizing the unwanted interfacial interactions of particles with external biological proteins. The Afb-directed cell-specific targeting ability of particles and consequent induction of cell death is demonstrated both in vitro and in vivo by using two kinds of Afb, which targets the surface membrane receptor, human epidermal growth factor receptor 2 (HER2) or epidermal growth factor receptor (EGFR). This study provides insight into the way of regulating the protein-adhesive surface of MOF nanoparticles and designing a more effective MOF-hosted targeted delivery system.

Spatiotemporal Self-Assembly of Peptide Amphiphiles by Carbonic Anhydrase IX-Targeting Induces Cancer-Lysosomal Membrane Disruption.

To achieve spatiotemporal control, an enzyme-instructed self-assembly system is widely used, but this approach typically has a small effect on cellular fate. In this study, we show that the intralysosomal assembly by a carbonic anhydrase IX (CAIX)-targeting peptide amphiphile (Pep-AT) can control cellular fate with a low therapeutic dose by tuning the surface charge based on pH change. Pep-AT self-assembles into a fibrous aggregate with a negative surface charge in an extracellular environment near CAIX. During endocytosis, it changes into a nanofiber with a positive surface charge at the lysosome. Then, it can disrupt the lysosomal membrane and induce cellular apoptosis. This study demonstrates that a spatiotemporal assembly induced by a cancer enzyme and specific organelle can control the cellular fate of cancer.

Enzyme-instructed morphology transformation of mitochondria-targeting peptide for the selective eradication of osteosarcoma.

The treatment of osteosarcoma involves an adjuvant therapy that combines surgery and chemotherapy. However, considering that children are the main victims of osteosarcoma, replacing such a harsh treatment with a soft but powerful method that ensures a complete cure while having no adverse effects is highly desirable. To achieve this aim, we have developed a supramolecular therapeutic strategy based on morphology-transformable mitochondria-targeting peptides for the eradication of osteosarcoma with enhanced selectivity and reduced side effects. A newly designed micelle-forming amphiphilic peptide, l-Mito-FFYp, consisting of a phosphate substrate for the biomarker enzyme of osteosarcoma alkaline phosphatase (ALP), disassembles in response to the ALP enzyme in the cell membrane to generate positively charged l-Mito-FFY molecules, which diffuse inside the targeted cell and self-assemble to form nanostructures specifically inside the mitochondria to induce cell apoptosis.

Ion slippage through Li+-centered G-quadruplex.

Single-ion conductors have garnered attention in energy storage systems as a promising alternative to currently widespread electrolytes that allow migration of cations and anions. However, ion transport phenomena of most single-ion conductors are affected by strong ion (e.g., Li+)-ion (immobilized anionic domains) interactions and tortuous paths, which pose an obstacle to achieving performance breakthroughs. Here, we present a Li+-centered G-quadruplex (LiGQ) as a class of single-ion conductor based on directional Li+ slippage at the microscopic level. A guanine derivative with liquid crystalline moieties is self-assembled to form a hexagonal ordered columnar structure in the LiGQ, thereby yielding one-dimensional central channels that provide weak ion-dipole interaction and straightforward ionic pathways. The LiGQ exhibits weak Li+ binding energy and low activation energy for ion conduction, verifying its viability as a new electrolyte design.

Single-cell transcriptome of the mouse retinal pigment epithelium in response to a low-dose of doxorubicin.

Cellular senescence of the retinal pigment epithelium (RPE) is thought to play an important role in vision-threatening retinal degenerative diseases, such as age-related macular degeneration (AMD). However, the single-cell RNA profiles of control RPE tissue and RPE tissue exhibiting cellular senescence are not well known. We have analyzed the single-cell transcriptomes of control mice and mice with low-dose doxorubicin (Dox)-induced RPE senescence (Dox-RPE). Our results have identified 4 main subpopulations in the control RPE that exhibit heterogeneous biological activities and play roles in ATP synthesis, cell mobility/differentiation, mRNA processing, and catalytic activity. In Dox-RPE mice, cellular senescence mainly occurs in the specific cluster, which has been characterized by catalytic activity in the control RPE. Furthermore, in the Dox-RPE mice, 6 genes that have not previously been associated with senescence also show altered expression in 4 clusters. Our results might serve as a useful reference for the study of control and senescent RPE.

Intramitochondrial co-assembly between ATP and nucleopeptides induces cancer cell apoptosis.

Mitochondria are essential intracellular organelles involved in many cellular processes, especially adenosine triphosphate (ATP) production. Since cancer cells require high ATP levels for proliferation, ATP elimination can be a unique target for cancer growth inhibition. We describe a newly developed mitochondria-targeting nucleopeptide (MNP) that sequesters ATP by self-assembling with ATP inside mitochondria. MNP interacts strongly with ATP through electrostatic and hydrogen bonding interactions. MNP exhibits higher binding affinity for ATP (-637.5 kJ mol-1) than for adenosine diphosphate (ADP) (-578.2 kJ mol-1). To improve anticancer efficacy, the small-sized MNP/ADP complex formed large assemblies with ATP inside cancer cell mitochondria. ATP sequestration and formation of large assemblies of the MNP/ADP-ATP complex inside mitochondria caused physical stress by large structures and metabolic disorders in cancer cells, leading to apoptosis. This work illustrates a facile approach to developing cancer therapeutics that relies on molecular assemblies.

Mesoporous silica nanoparticle-supported nanocarriers with enhanced drug loading, encapsulation stability, and targeting efficiency.

For efficient drug delivery, stable encapsulation of a large amount of anticancer drugs is crucial, not to mention cell-specific delivery. Among many possible nanocarriers, mesoporous silica nanoparticles are versatile frameworks that satisfy those requirements owing to their characteristic internal pores with a large surface area and a tunable surface composition. By using a noncovalent post-modification strategy, MSN-based drug delivery systems with enhanced therapeutic efficiency can be prepared in a simple one-pot process by loading small anticancer drugs in the unmodified mesopores and by subsequently blocking the drug-loaded pores with a stimuli-responsive polymer gatekeeper. For targeted delivery, drug-loaded MSNs can be functionalized with suitable targeting components such as targeting ligands or artificial protein corona. This mini-review highlights the recent research in which MSN-supported nanocarriers are designed, synthesized, and characterized to possess a high drug loading capacity and encapsulation stability along with targeting capability for more efficient cancer treatment.

Stimuli-Responsive Adaptive Nanotoxin to Directly Penetrate the Cellular Membrane by Molecular Folding and Unfolding.

Biological nanomachines, including proteins and nucleic acids whose function is activated by conformational changes, are involved in every biological process, in which their dynamic and responsive behaviors are controlled by supramolecular recognition. The development of artificial nanomachines that mimic the biological functions for potential application as therapeutics is emerging; however, it is still limited to the lower hierarchical level of the molecular components. In this work, we report a synthetic machinery nanostructure in which actuatable molecular components are integrated into a hierarchical nanomaterial in response to external stimuli to regulate biological functions. Two nanometers core-sized gold nanoparticles are covered with ligand layers as actuatable components, whose folding/unfolding motional response to the cellular environment enables the direct penetration of the nanoparticles across the cellular membrane to disrupt intracellular organelles. Furthermore, the pH-responsive conformational movements of the molecular components can induce the apoptosis of cancer cells. This strategy based on the mechanical motion of molecular components on a hierarchical nanocluster would be useful to design biomimetic nanotoxins.

Comparison of the immune activation capacities of fucoidan and laminarin extracted from Laminaria japonica.

Laminaria japonica is a brown alga and is composed primarily of polysaccharides. Fucoidan and laminarin are the major polysaccharides of L. japonica and exhibit biological activities, including immune modulation and anti-coagulant and antioxidant effects in animals and humans. In this study, we evaluated the ability of fucoidan and laminarin from L. japonica to induce immune cell activation and anti-cancer immunity, which has not yet been studied. The injection of fucoidan to mice promoted the upregulation of major histocompatibility complex and surface activation molecules in splenic dendritic cell subsets, whereas laminarin showed a weaker immune activation ability. In addition, fucoidan treatment elicited inflammatory cytokine production; however, laminarin did not induce the production of these cytokines. Regarding cytotoxic cell activities, fucoidan induced the activation of lymphocytes, including natural killer and T cells, whereas laminarin did not induce cell activation. Finally, fucoidan enhanced the anticancer efficacy of anti-programmed Death-Ligand 1 (PD-L1) antibody against Lewis lung carcinoma, whereas laminarin did not promote the cancer inhibition effect of anti-PD-L1 antibody. Thus, these data suggest that fucoidan from L. japonica can be used as an immune stimulatory molecule to enhance the anticancer activities of immune checkpoint inhibitors.

Creating Tunable Mesoporosity by Temperature-Driven Localized Crystallite Agglomeration.

A new synthetic approach for tunable mesoporous metal-organic frameworks (MeMs) is developed. In this approach, mesopores are created in the process of heat conversion of highly mosaic metal-organic framework (MOF) crystals with non-interpenetrated low-density nanocrystallites into MOF crystals with two-fold interpenetrated high-density nanocrystallites. The two-fold interpenetration reduces the volume of the nanocrystallites in the mosaic crystal, and the accompanying localized agglomeration of the nanocrystallites results in the formation of mesopores among the localized crystallite agglomerates. The pore size can be easily modulated from 7 to 90 nm by controlling the heat treatment conditions, that is, the aging temperature and aging time. Various proteins can be encapsulated in the MeM, and immobilized enzymes show catalyst activity comparable to that of the free native enzymes. Immobilized ß-galactosidase is recyclable and the enzyme activity of the immobilized catalase is maintained after exposure to high temperatures and various organic solvents.

Targeting senescent retinal pigment epithelial cells facilitates retinal regeneration in mouse models of age-related macular degeneration.

Although age-related macular degeneration (AMD) is a multifactorial disorder with angiogenic, immune, and inflammatory components, the most common clinical treatment strategies are antiangiogenic therapies. However, these strategies are only applicable to neovascular AMD, which accounts for less than 20% of all AMD cases, and there are no FDA-approved drugs for the treatment of dry AMD, which accounts for ~ 80% of AMD cases. Here, we report that the elimination of senescent cells is a potential novel therapeutic approach for the treatment of all types of AMD. We identified senescent retinal pigment epithelium (RPE) cells in animal models of AMD and determined their contributions to retinal degeneration. We further confirmed that the clearance of senescent RPE cells with the MDM2-p53 inhibitor Nutlin-3a ameliorated retinal degeneration. These findings provide new insights into the use of senescent cells as a therapeutic target for the treatment of AMD.

Mitochondrial Membrane Disrupting Molecules for Selective Killing of Senescent Cells.

Cellular senescence, a stable form of cell cycle arrest, facilitates protection from tumorigenesis and aids in tissue repair as they accumulate in the body at an early age. However, long-term retention of senescent cells causes inflammation, aging of the tissue, and progression of deadly diseases such as obesity, diabetes, and atherosclerosis. Various attempts have been made to achieve selective elimination of senescent cells from the body, yet little has been explored in designing the mitochondria-targeted senolytic agent. Many characteristics of senescence are associated with mitochondria. Here we have designed a library of alkyl-monoquaternary ammonium-triphenyl phosphine (TPP) and alkyl-diquaternary ammonium-TPP of varying alkyl chain lengths, which target the mitochondria; we also studied their senolytic properties. It was observed that the alkyl-diquaternary ammonium-TPP with the longest chain length induced apoptosis in senescent cells selectively via an increase of reactive oxygen species (ROS) and mitochondrial membrane disruption. This study demonstrates that mitochondria could be a potential target for designing new small molecules as senolytic agents for the treatment of a variety of dysfunctions associated with pathological aging.