Potential-Independent Intracellular Drug Delivery and Mitochondrial Targeting

Crystallization of supersaturated PEG-b-PLA for the production of drug-loaded polymeric micelles

In this study, we propose the "crystallization from supersaturated solution" method for producing drug-loaded polymeric micelles. This method involves the formation of solid drug-encapsulating crystals of a diblock copolymer through isothermal crystallization from a supersaturated solution of the copolymer in low molecular weight PEGs containing the drug, followed by dissolution of the crystals to obtain drug-loaded micelles. We fabricated and characterized micelles loaded with several model drugs (paclitaxel, rapamycin, and docetaxel) and their oligo(lactic acid)8-prodrugs using PEG4kDa-b-PLA2.2kDa as the micelle-forming copolymer and PEGs of varying molecular weights (200, 400, and 600 Da) as solvents. Our findings indicate that the molecular weight of the solvent PEG and the target drug loading significantly influence the physicochemical properties of the resulting micelles, including loading efficiency and particle size distribution. Micelles produced with PEG200 as the solvent exhibited the highest loading efficiency, followed by those made with PEG600 and PEG400 for all the drugs and prodrugs tested. Increasing the target drug loading enhanced both the loading efficiency and average particle size across all formulations. Furthermore, prodrug-loaded micelles showed higher loading efficiency and improved stability in aqueous solutions compared to their parent drug counterparts. Crystals encapsulating both parent drugs and prodrugs could be stored at room temperature for extended periods, producing micelles with no significant differences in loading efficiency and particle size distribution compared to freshly prepared micelles. Additionally, the crystals demonstrated a rapid dissolution rate, forming uniform micelles after just 5 s of hydration and agitation. Cytotoxicity studies against 4 T1 and MDA-MB-231 breast cancer cell lines revealed that the molecular weight of the PEG used as the solvent impacts the cytotoxicity of the resulting micelles, with those produced using PEG200 displaying the highest cytotoxicity, followed by PEG400 and PEG600. Overall, the crystallization from supersaturated solution method proves to be an effective platform for prolonged storage and rapid formation of stable, drug-loaded polymeric micelles. It has the potential to eliminate the need for freeze-drying in the formulation and storage of drug-loaded polymeric micelles. These findings highlight the method's potential for advancing drug delivery systems, particularly for the solubilization of hydrophobic drugs using micellar formulations.

A charge reversal nano-assembly prevents hepatic steatosis by resolving inflammation and improving lipid metabolism

Lipid metabolism imbalance combined with over-activated inflammation are two key factors for hepatic stestosis. However, on-demand anchoring inflammation and lipid metabolism disorder for hepatic stestosis treatment has yet to be realized. Here we propose a charge reversal fullerene based nano-assembly to migrate hepatic steatosis via inhibiting macrophage-mediated inflammation and normalizing hepatocellular lipid metabolism in obesity mice. Our nano-assembly (abbreviated as FPPD) is comprised of electropositive polyetherimide (PEI), charge-shielded dimethylmaleic anhydride (DMA), and poly(lactic-co-glycolic acid) (PLGA), which provides hydrophobic chains for self-assembly with anti-oxidative dicarboxy fullerene poly(ethylene glycol) molecule (FP). The obtained FPPD nano-assembly owns a charge reversal ability that switches to a positive charge in an acidic environment that targets the electronegative mitochondria both in pro-inflammatory macrophages and steatosis hepatocytes. We demonstrate that the anti-oxidative and mitochondria-targeting FPPD notably reduces inflammation in macrophages and lipid accumulation in hepatocytes by quenching excessive reactive oxygen species (ROS) and improving mitochondrial function in vitro. Importantly, FPPD nano-assembly reveals a superior anti-hepatic steatosis effect via migrating inflammation and facilitating lipid transport in obesity mice. Overall, the charge reversal nano-assembly reduces over-activated inflammation and promotes lipid metabolism that provides an effectiveness of a multi-target strategy for hepatic steatosis treatment.

Progress on mitochondria and hair follicle development in androgenetic alopecia: relationships and therapeutic perspectives

Hair loss has long been a significant concern for many individuals. Recent studies have indicated that mitochondria play a more crucial role in hair loss than previously recognized. This review summarizes the connection between mitochondrial dysfunction and hair follicle development, outlines the links between diseases related to mitochondrial disorders and hair issues, and highlights the influence of mitochondrial dysfunction on androgenetic alopecia. We discuss the cellular and signaling mechanisms associated with hair loss and examine how mitochondrial dysfunction, such as insufficient energy supply, signaling irregularities, protein/gene abnormalities, and programmed cell death, can hinder the normal proliferation, differentiation, and growth of hair follicle cells. Furthermore, we discuss current treatment approaches and potential innovative therapies, including mitochondrion-targeting drugs and advanced techniques that directly target hair follicle cells, providing fresh insights into the crucial role of mitochondria in maintaining hair follicle health and managing hair disorders. Furthermore, this review explores future therapeutic strategies and proposes that mitochondrial research could lead to groundbreaking treatments for hair loss, thus providing optimism and new avenues for the treatment of individuals experiencing hair loss. This review not only underscores the central importance of mitochondria in hair health but also emphasizes the importance of advancing research and treatment in this field.

Polyproline-Polyornithine Diblock Copolymers with Inherent Mitochondria Tropism

Mitochondria play critical roles in regulating cell fate, with dysfunction correlating with the development of multiple diseases, emphasizing the need for engineered nanomedicines that cross biological barriers. Said nanomedicines often target fluctuating mitochondrial properties and/or present inefficient/insufficient cytosolic delivery (resulting in poor overall activity), while many require complex synthetic procedures involving targeting residues (hindering clinical translation). The synthesis/characterization of polypeptide-based cell penetrating diblock copolymers of poly-L-ornithine (PLO) and polyproline (PLP) (PLOn-PLPm, n:m ratio 1:3) are described as mitochondria-targeting nanocarriers. Synthesis involves a simple two-step methodology based on N-carboxyanhydride ring-opening polymerization, with the scale-up optimization using a "design of experiments" approach. The molecular mechanisms behind targetability and therapeutic activity are investigated through physical/biological processes for diblock copolymers themselves or as targeting moieties in a poly-L-glutamic (PGA)-based conjugate. Diblock copolymers prompt rapid cell entry via energy-independent mechanisms and recognize mitochondria through the mitochondria-specific phospholipid cardiolipin (CL). Stimuli-driven conditions and mitochondria polarization dynamics, which decrease efficacy depending on disease type/stage, do not compromise diblock copolymer uptake/targetability. Diblock copolymers exhibit inherent concentration-dependent anti-tumorigenic activity at the mitochondrial level. The diblock copolymer conjugate possesses improved safety, significant cell penetration, and mitochondrial accumulation via cardiolipin recognition. These findings may support the development of efficient and safe mitochondrial-targeting nanomedicines.

Dually fluorinated unimolecular micelles for stable oxygen-carrying and enhanced photosensitive efficiency to boost photodynamic therapy against hypoxic tumors

Tumor hypoxia is one of key challenges in deep tumor photodynamic therapy (PDT), and how to fix this issue is attracting ongoing concerns worldwide. This work demonstrates dually fluorinated unimolecular micelles with desirable and stable oxygen-carrying capacity, high cellular penetration, and integrative type I & II PDT for deep hypoxic tumors. Dually fluorinated star copolymers with fluorinated phthalocyanines as the core are prepared through photoinitiated electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization under irradiation with NIR LED light at room temperature, followed by assembly into unimolecular micelles. Perfluorocarbons (PFCs) are also introduced into the star polymers during the polymerization to further enhance and stabilize oxygen-carrying capacity, which is slightly affected by concentration-induced size transformation. PFCs assist unimolecular micelles with repelling mucin adsorption, which results in superior cellular uptake within 1 h and high effective accumulation rates in tumors of CT26 tumor-bearing mice within 24 h after systemic administration, and showing effective anti-tumor effects under the irradiation of NIR LED light. This work provides a new type of nano-photosensitizers for highly efficient hypoxic PDT. STATEMENT OF SIGNIFICANCE: One of the major challenges in improving the efficiency of photodynamic therapy (PDT) for deep tumors is how to address tumor hypoxia, which is receiving continued attention worldwide. However, most of the reported oxygen carriers combine with photosensitizers by physical means and the carriers have the risk of dissociating easily, which is not conducive to long-term and efficient PDT, resulting in poor therapeutic effect. This work demonstrates dually fluorinated unimolecular micelles with desirable and stable oxygen-carrying capacity, high cellular penetration, and integrative type I & II PDT for enhanced deep hypoxic tumors, overcoming the key challenges of tumor hypoxia and low photosensitizer efficiency.

A minimalist multifunctional nano-prodrug for drug resistance reverse and integration with PD-L1 mAb for enhanced immunotherapy of hepatocellular carcinoma

Clinical treatment of hepatocellular carcinoma (HCC) with 5-fluorouracil (5-FU), the primary anticancer agent, remains unsatisfactory due to the glutathione (GSH)-associated drug resistance and immunosuppressive microenvironment of HCC. To develop a facile yet robust strategy to overcome 5-FU resistance for enhanced immunotherapy treatment of HCC via all dimensional GSH exhaustion, we report in this study construction of a minimalist prodrug consisting of 5-FU linked to an indoleamine-(2,3)-dioxygenase (IDO) inhibitor (IND) via a disulfide bridge, FU-SS-IND that can further self-assemble into stabilized nanoparticles, FU-SS-IND NPs. Specifically, besides the disulfide linker-induced GSH exhaustion, IND inhibits GSH biosynthesis and enhances the effector function of T cells for turning a "cold" tumor to a "hot" one, which synergistically achieving a tumor inhibition rate (TIR) of 92.5% in a 5-FU resistant mice model. Most importantly, FU-SS-IND NPs could upregulate programmed death ligand 1 (PD-L1) expression on the surface of tumor cells, which enables facile combination with immune checkpoint blockade (ICB) for a ultimate prolonged survival lifetime of 5-FU-resistant tumors-bearing mice. Overall, the minimalist bioreducible nano-prodrug developed herein demonstrates great translatable potential for efficiently reversing drug resistance and enhancing immunotherapy of HCC.

Myocardial cell mitochondria-targeted mesoporous polydopamine nanoparticles eliminate inflammatory damage in cardiovascular disease

Excess reactive oxide species (ROS) is a direct factor in myocardial injury death, thus anti-oxidant therapy is a necessary measure to prevent rapid death of cardiomyocyte cell. Cysteine (Cys) is a potent antioxidant but easily become instability because of the hyperactivity. Therefore, in order to protect the the stability of Cys, we according to the mitochondria are the main sites of ROS production, utilized the loading and ROS scavenging capacity of mesoporous polydopamine (mPDA) constructed a nanosystem targeting mitochondria with effectively ROS elimination capability by loading cysteine (Cys-mPDA@TPP). The mesoporous structure of mPDA effectively inhibited the advance reaction and hyperactivity of Cys, thus effectively improving its stability that reached the double-collaborative treatment excess ROS. In particular, Cys-mPDA@TPP achieved directly reacting with ROS in mitochondria under the targeting of triphenylphosphine (TPP), not only enhancing the elimination efficiency of ROS, but also preventing mitochondrial dysfunction of monocyte-macrophage. Furthermore, with double-collaborative ROS elimination, Cys-mPDA@TPP effectively prevent the damage of cardiomyocyte cell through inhibiting macrophage inflammatory response. Therefore, this study provides a new therapeutic strategy for myocardial inflammatory injury.

Copper-Consuming Nanoplatform for Alleviating Hypoxia and Overcoming Resistance to Sonodynamic Therapy of Breast Cancer

Sonodynamic therapy (SDT) is a promising treatment modality for breast cancer; however, its effectiveness is often impeded by the hypoxic tumor microenvironment owing to an insufficient oxygen supply in the solid tumors. To overcome this challenge, we elaborately developed a 4T1 tumor-targeted multifunctional nanoagent by integrating both dendrimer-structured copper chelating agents and organic sonosensitizers (IR820) into a biotin-modified nanoliposome via a microfluidic-assisted self-assembly. In particular, the aforementioned copper chelating agent was constructed by introducing multiple xanthate groups into a dendrimer polymer, which showed a significant selectivity for the consumption of the intracellular copper levels. Based on this, the nanoliposome-based therapeutic not only disrupted the activity of the mitochondrial complex IV to directly inhibit the tumor cell proliferation but also suppressed the resistance to the SDT via inhibition of the oxygen consumption for cellular respiration. Both in vitro and in vivo studies confirmed that the designed nanoagents exhibit a synergistic tumor inhibition effect of copper consumption and IR820-mediated SDT. Taken together, this approach establishes a proof-of-concept for the construction of a copper-ion-modulated nanomedicine to significantly enhance the efficiency of oxygen-dependent cancer treatments.

Advancements in mitochondrial-targeted nanotherapeutics: overcoming biological obstacles and optimizing drug delivery

In recent decades, nanotechnology has significantly advanced drug delivery systems, particularly in targeting subcellular organelles, thus opening new avenues for disease treatment. Mitochondria, critical for cellular energy and health, when dysfunctional, contribute to cancer, neurodegenerative diseases, and metabolic disorders. This has propelled the development of nanomedicines aimed at precise mitochondrial targeting to modulate their function, marking a research hotspot. This review delves into the recent advancements in mitochondrial-targeted nanotherapeutics, with a comprehensive focus on targeting strategies, nanocarrier designs, and their therapeutic applications. It emphasizes nanotechnology's role in enhancing drug delivery by overcoming biological barriers and optimizing drug design for specific mitochondrial targeting. Strategies exploiting mitochondrial membrane potential differences and specific targeting ligands improve the delivery and mitochondrial accumulation of nanomedicines. The use of diverse nanocarriers, including liposomes, polymer nanoparticles, and inorganic nanoparticles, tailored for effective mitochondrial targeting, shows promise in anti-tumor and neurodegenerative treatments. The review addresses the challenges and future directions in mitochondrial targeting nanotherapy, highlighting the need for precision, reduced toxicity, and clinical validation. Mitochondrial targeting nanotherapy stands at the forefront of therapeutic strategies, offering innovative treatment perspectives. Ongoing innovation and research are crucial for developing more precise and effective treatment modalities.

Ameliorating Mitochondrial Dysfunction for the Therapy of Parkinson's Disease

Parkinson's disease (PD) is currently the second most incurable central neurodegenerative disease resulting from various pathogenesis. As the "energy factory" of cells, mitochondria play an extremely important role in supporting neuronal signal transmission and other physiological activities. Mitochondrial dysfunction can cause and accelerate the occurrence and progression of PD. How to effectively prevent and suppress mitochondrial disorders is a key strategy for the treatment of PD from the root. Therefore, the emerging mitochondria-targeted therapy has attracted considerable interest. Herein, the relationship between mitochondrial dysfunction and PD, the causes and results of mitochondrial dysfunction, and major strategies for ameliorating mitochondrial dysfunction to treat PD are systematically reviewed. The study also prospects the main challenges for the treatment of PD.

High-Performance Aluminum Fuels Induced by Monolayer Self-Assembly of Nano-Sized Energetic Fluoride Vesicles on the Surface

Surface modification is frequently used to solve the problems of low combustion properties and agglomeration for aluminum-based fuels. However, due to the intrinsic incompatibility between the aluminum powder and the organic modifiers, the surface coating is usually uneven and disordered, which significantly deteriorates the uniformity and performances of the Al-based fuels. Herein, a new approach of monolayer nano-vesicular self-assembly is proposed to prepare high-performance Al fuels. Triblock copolymer G-F-G is produced by glycidyl azide polymer (GAP) and 2,2'-(2,2,3,3,4,5,5-Octafluorohexane-1,6-diyl) bis (oxirane) (fluoride) ring-open addition reaction. By utilizing G-F-G vesicular self-assembly in a special solvent, the nano-sized vesicles are firmly adhered to the surface of Al powder through the long-range attraction between the fluorine segments and Al. Meanwhile, the electrostatic repulsion between vesicles ensures an extremely thin coating thickness (≈15 nm), maintaining the monolayer coating structure. Nice ignition, combustion, anti-agglomeration, and water-proof properties of Al@G-F-G(DMF) are achieved, which are superior among the existing Al-based fuels. The derived Al-based fuel has excellent comprehensive properties, which can not only inspire the development of new-generation energetic materials but also provide facile but exquisite strategies for exquisite surface nanostructure construction via ordered self-assembly for many other applications.

Fluorinated Organic Polymers for Cancer Drug Delivery

In the realm of cancer therapy, the spotlight is on nanoscale pharmaceutical delivery systems, especially polymer-based nanoparticles, for their enhanced drug dissolution, extended presence in the bloodstream, and precision targeting achieved via surface engineering. Leveraging the amplified permeation and retention phenomenon, these systems concentrate therapeutic agents within tumor tissues. Nonetheless, the hurdles of systemic toxicity, biological barriers, and compatibility with living systems persist. Fluorinated polymers, distinguished by their chemical idiosyncrasies, are poised for extensive biomedical applications, notably in stabilizing drug metabolism, augmenting lipophilicity, and optimizing bioavailability. Material science heralds the advent of fluorinated polymers that, by integrating fluorine atoms, unveil a suite of drug delivery merits: the hydrophobic traits of fluorinated alkyl chains ward off lipid or protein disruption, the carbon-fluorine bond's stability extends the drug's lifecycle in the system, and a lower alkalinity coupled with a diminished ionic charge bolsters the drug's ability to traverse cellular membranes. This comprehensive review delves into the utilization of fluorinated polymers for oncological pharmacotherapy, elucidating their molecular architecture, synthetic pathways, and functional attributes, alongside an exploration of their empirical strengths and the quandaries they encounter in both experimental and clinical settings.

A pH-sensitive imidazole grafted polymeric micelles nanoplatform based on ROS amplification for ferroptosis-enhanced chemodynamic therapy

Highly toxic reactive oxygen species (ROS), crucial in inducing apoptosis and ferroptosis, are pivotal for cell death pathways in cancer therapy. However, the effectiveness of ROS-related tumor therapy is impeded by the limited intracellular ROS and substrates, coupled with the presence of abundant ROS scavengers like glutathione (GSH). In this research, we developed acid-responsive, iron-coordinated polymer nanoparticles (PPA/TF) encapsulating a mitochondrial-targeting drug alpha-tocopheryl succinate (α-TOS) for enhanced synergistic tumor treatment. The imidazole grafted micelles exhibit prolonged blood circulation and improve the delivery efficiency of the hydrophobic drug α-TOS. Additionally, PPA's design aids in delivering Fe3+, supplying ample iron ions for chemodynamic therapy (CDT) and ferroptosis through the attachment of imidazole groups to Fe3+. In the tumor's weakly acidic intracellular environment, PPA/TF facilitates pH-responsive drug release. α-TOS specifically targets mitochondria, generating ROS and replenishing those depleted by the Fenton reaction. Moreover, the presence of Fe3+ in PPA/TF amplifies ROS upregulation, promotes GSH depletion, and induces oxidative damage and ferroptosis, effectively inhibiting tumor growth. This research presents an innovative ROS-triggered amplification platform that optimizes CDT and ferroptosis for effective cancer treatment.

Unlocking the Mitochondria for Nanomedicine-based Treatments: Overcoming Biological Barriers, Improving Designs, and Selecting Verification Techniques

Enhanced targeting approaches will support the treatment of diseases associated with dysfunctional mitochondria, which play critical roles in energy generation and cell survival. Obstacles to mitochondria-specific targeting include the presence of distinct biological barriers and the need to pass through (or avoid) various cell internalization mechanisms. A range of studies have reported the design of mitochondrially-targeted nanomedicines that navigate the complex routes required to influence mitochondrial function; nonetheless, a significant journey lies ahead before mitochondrially-targeted nanomedicines become suitable for clinical use. Moving swiftly forward will require safety studies, in vivo assays confirming effectiveness, and methodologies to validate mitochondria-targeted nanomedicines' subcellular location/activity. From a nanomedicine standpoint, we describe the biological routes involved (from administration to arrival within the mitochondria), the features influencing rational design, and the techniques used to identify/validate successful targeting. Overall, rationally-designed mitochondria-targeted-based nanomedicines hold great promise for precise subcellular therapeutic delivery.

Design consideration of phthalocyanines as sensitizers for enhanced sono-photodynamic combinatorial therapy of cancer

Cancer remains one of the diseases with the highest incidence and mortality globally. Conventional treatment modalities have demonstrated threatening drawbacks including invasiveness, non-controllability, and development of resistance for some, including chemotherapy, radiation, and surgery. Sono-photodynamic combinatorial therapy (SPDT) has been developed as an alternative treatment modality which offers a non-invasive and controllable therapeutic approach. SPDT combines the mechanism of action of sonodynamic therapy (SDT), which uses ultrasound, and photodynamic therapy (PDT), which uses light, to activate a sensitizer and initiate cancer eradication. The use of phthalocyanines (Pcs) as sensitizers for SPDT is gaining interest owing to their ability to induce intracellular oxidative stress and initiate toxicity under SDT and PDT. This review discusses some of the structural prerequisites of Pcs which may influence their overall SPDT activities in cancer therapy.

Immunogenic Bifunctional Nanoparticle Suppresses Programmed Cell Death-Ligand 1 in Cancer and Dendritic Cells to Enhance Adaptive Immunity and Chemo-Immunotherapy

Blockade of programmed cell death-1/programmed cell death-ligand 1 (PD-L1) immune checkpoints with monoclonal antibodies has shown great promise for cancer treatment, but these antibodies can cause immune-related adverse events in normal organs. Here we report a dual-cell targeted chemo-immunotherapeutic nanoscale coordination polymer (NCP), OxPt/BP, comprising oxaliplatin (OxPt) and 2-bromopalmitic acid (BP), for effective downregulation of PD-L1 expression in both cancer cells and dendritic cells (DCs) by inhibiting palmitoyl acyltransferase DHHC3. OxPt/BP efficiently promotes DC maturation by increasing intracellular oxidative stress and enhancing OxPt-induced immunostimulatory immunogenic cancer cell death. Systemic administration of OxPt/BP reduces the growth of subcutaneous and orthotopic colorectal carcinoma by facilitating the infiltration and activation of cytotoxic T lymphocytes together with reducing the population of immunosuppressive regulatory T cells. As a result, OxPt/BP significantly extends mouse survival without causing side effects. This work highlights the potential of NCPs in simultaneously reprogramming cancer cells and DCs for potent cancer treatment.

Ligand Phase Separation-Promoted, "Squeezing-Out" Mode Explaining the Mechanism and Implications of Neutral Nanoparticles That Escaped from Lysosomes

Neutral nanomaterials functionalized with PEG or similar molecules have been popularly employed as nanomedicines. Compared to positive counterparts that are capable of harnessing the well-known proton sponge effect to facilitate their escape from lysosomes, it is yet unclear how neutral substances got their entry into the cytosol. In this study, by taking PEGylated, neutral Au nanospheres as an example, we systematically investigated their time-dependent translocation postuptake. Specifically, we harnessed dissipative particle dynamics simulations to uncover how nanospheres bypass lysosomal entrapment, wherein a mechanism termed as "squeezing-out" mode was discovered. We next conducted a comprehensive investigation on how nanomaterials implicate lysosomes in terms of integrity and functionality. By using single-molecule imaging, specific preservation of PEG-terminated with targeting moieties in lysosomes supports the "squeezing-out" mode as the mechanism underlying the lysosomal escape of nanomaterials. All evidence points out that such a process is benign to lysosomes, wherein the escape of nanomaterials proceeds at the expense of targeting moieties loss. Furthermore, we proved that by fine-tuning of the efficacy of nanomaterials escaping from lysosomes, modulation of distinct pathways and metabolic machinery can be achieved readily, thereby offering us a simple and robust tool to implicate cells.

A Self-Assembly Nano-Prodrug for Combination Therapy in Triple-Negative Breast Cancer Stem Cells

Triple-negative breast cancer (TNBC) displays a highly aggressive nature that originates from a small subpopulation of TNBC stem cells (TNBCSCs), and these TNBCSCs give rise to chemoresistance, tumor metastasis, and recurrence. Unfortunately, traditional chemotherapy eradicates normal TNBC cells but fails to kill quiescent TNBCSCs. To explore a new strategy for eradicating TNBCSCs, a disulfide-mediated self-assembly nano-prodrug that can achieve the co-delivery of ferroptosis drug, differentiation-inducing agent, and chemotherapeutics for simultaneous TNBCSCs and TNBC treatment, is reported. In this nano-prodrug, the disulfide bond not only induces self-assembly behavior of different small molecular drug but also serves as a glutathione (GSH)-responsive trigger in controlled drug release. More importantly, the differentiation-inducing agent can transform TNBCSCs into normal TNBC cells, and this differentiation with chemotherapeutics provides an effective approach to indirectly eradicate TNBCSCs. In addition, ferroptosis therapy is essentially different from the apoptosis-induced cell death of differentiation or chemotherapeutic, which causes cell death to both TNBCSCs and normal TNBC cells. In different TNBC mouse models, this nano-prodrug significantly improves anti-tumor efficacy and effectively inhibits the tumor metastasis. This all-in-one strategy enables controlled drug release and reduces stemness-related drug resistance, enhancing the chemotherapeutic sensitivity in TNBC treatment.

Subcellular visualization: Organelle-specific targeted drug delivery and discovery

Organelles perform critical biological functions due to their distinct molecular composition and internal environment. Disorders in organelles or their interacting networks have been linked to the incidence of numerous diseases, and the research of pharmacological actions at the organelle level has sparked pharmacists' interest. Currently, cell imaging has evolved into a critical tool for drug delivery, drug discovery, and pharmacological research. The introduction of advanced imaging techniques in recent years has provided researchers with richer biological information for viewing and studying the ultrastructure of organelles, protein interactions, and gene transcription activities, leading to the design and delivery of precision-targeted drugs. Therefore, this reviews the research on organelles-targeted drugs based upon imaging technologies and development of fluorescent molecules for medicinal purposes. We also give a thorough analysis of a number of subcellular-level elements of drug development, including subcellular research instruments and methods, organelle biological event investigation, subcellular target and drug identification, and design of subcellular delivery systems. This review will make it possible to promote drug research from the individual/cellular level to the subcellular level, as well as give a new focus based on newly found organelle activities.

Cancer cell-mitochondria hybrid membrane coated Gboxin loaded nanomedicines for glioblastoma treatment

Glioblastoma (GBM) remains the most lethal malignant tumours. Gboxin, an oxidative phosphorylation inhibitor, specifically restrains GBM growth by inhibiting the activity of F₀F₁ ATPase complex V. However, its anti-GBM effect is seriously limited by poor blood circulation, the blood brain barrier (BBB) and non-specific GBM tissue/cell uptake, leading to insufficient Gboxin accumulation at GBM sites, which limits its further clinical application. Here we present a biomimetic nanomedicine (HM-NPs@G) by coating cancer cell-mitochondria hybrid membrane (HM) on the surface of Gboxin-loaded nanoparticles. An additional design element uses a reactive oxygen species responsive polymer to facilitate at-site Gboxin release. The HM camouflaging endows HM-NPs@G with unique features including good biocompatibility, improved pharmacokinetic profile, efficient BBB permeability and homotypic dual tumour cell and mitochondria targeting. The results suggest that HM-NPs@G achieve improved blood circulation (4.90 h versus 0.47 h of free Gboxin) and tumour accumulation (7.73% ID/g versus 1.06% ID/g shown by free Gboxin). Effective tumour inhibition in orthotopic U87MG GBM and patient derived X01 GBM stem cell xenografts in female mice with extended survival time and negligible side effects are also noted. We believe that the biomimetic Gboxin nanomedicine represents a promising treatment for brain tumours with clinical potential.

Maintenance of mitochondrial homeostasis for Alzheimer's disease: Strategies and challenges

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases, and its early onset is closely related to mitochondrial energy metabolism. The brain is only 2% of body weight, but consumes 20% of total energy needs. Mitochondria are responsible for providing energy in cells, and maintaining their homeostasis ensures an adequate supply of energy to the brain. Mitochondrial homeostasis is constituted by mitochondrial quantity and quality control, which is dynamically regulated by mitochondrial energy metabolism, mitochondrial dynamics and mitochondrial quality control. Impaired energy metabolism of brain cells occurs early in AD, and maintaining mitochondrial homeostasis is a promising therapeutic target in the future. We summarized the mechanism of mitochondrial homeostasis in AD, its influence on the pathogenesis of early AD, strategies for maintaining mitochondrial homeostasis, and mitochondrial targeting strategies. This review concludes with the authors' opinions on future research and development for mitochondrial homeostasis of early AD.

Quantitative Measurement of Drug Release Dynamics within Targeted Organelles Using Förster Resonance Energy Transfer

Measuring the release dynamics of drug molecules after their delivery to the target organelle is critical to improve therapeutic efficacy and reduce side effects. However, it remains challenging to quantitatively monitor subcellular drug release in real time. To address the knowledge gap, a novel gemini fluorescent surfactant capable of forming mitochondria-targeted and redox-responsive nanocarriers is designed. A quantitative Förster resonance energy transfer (FRET) platform is fabricated using this mitochondria-anchored fluorescent nanocarrier as a FRET donor and fluorescent drugs as a FRET acceptor. The FRET platform enables real-time measurement of drug release from organelle-targeted nanocarriers. Moreover, the obtained drug release dynamics can evaluate the duration of drug release at the subcellular level, which established a new quantitative method for organelle-targeted drug release. This quantitative FRET platform can compensate for the absent assessment of the targeted release performances of nanocarriers, offering in-depth understanding of the drug release behaviors at the subcellular targets.

Mitochondrial-Targeted Delivery of Polyphenol-Mediated Antioxidases Complexes against Pyroptosis and Inflammatory Diseases

Excess accumulation of mitochondrial reactive oxygen species (mtROS) is a key target for inhibiting pyroptosis-induced inflammation and tissue damage. However, targeted delivery of drugs to mitochondria and efficient clearance of mtROS remain challenging. In current study, it is discovered that polyphenols such as tannic acid (TA) can mediate the targeting of polyphenol/antioxidases complexes to mitochondria. This affinity does not depend on mitochondrial membrane potential but stems from the strong binding of TA to mitochondrial outer membrane proteins. Taking advantage of the feasibility of self-assembly between TA and proteins, superoxide dismutase, catalase, and TA are assembled into complexes (referred to as TSC) for efficient enzymatic activity maintenance. In vitro fluorescence confocal imaging shows that TSC not only promoted the uptake of biological enzymes in hepatocytes but also highly overlapped with mitochondria after lysosomal escape. The results from an in vitro model of hepatocyte oxidative stress demonstrate that TSC efficiently scavenges excess mtROS and reverses mitochondrial depolarization, thereby inhibiting inflammasome-mediated pyroptosis. More interestingly, TSC maintain superior efficacy compared with the clinical gold standard drug N-acetylcysteine in both acetaminophen- and D-galactosamine/lipopolysaccharide-induced pyroptosis-related hepatitis mouse models. In conclusion, this study opens a new paradigm for targeting mitochondrial oxidative stress to inhibit pyroptosis and treat inflammatory diseases.

Regulating the Membrane Affinity of Multi-module Probes to Address the Trade-off between Anchoring and Internalization

Cell membrane transport is the first and crucial step for bioprobes to realize the diagnosis, imaging, and therapy in cells. However, during this transport, there is a trade-off between anchoring and internalization steps, which will seriously affect the membrane transport efficiency. In the past, because the interaction between probes and cell membrane is constant, this challenge is hard to solve. Here, we proposed a strategy to regulate the membrane affinity of multi-module probes that enabled probe to have strong affinity during cell membrane anchoring and weak affinity during internalization. Specifically, a multi-module probe defined as LK-M-NA was constructed, which consisted of three main parts, membrane-anchoring α-helix peptide (LK), anchoring regulator (M), and therapeutic module (NA). With the α-helix module, LK-M-NA was able to rapidly anchor on the cell membrane and the binding energy was -1450.90 kcal/mol. However, after pericellular cleavage by the highly active matrix metalloproteinase-2 , LK could be removed due to the breakage of M and the binding energy reduced to -869.95 kcal/mol. Thus, the internalization restriction caused by high affinity was relieved. Owing to the alterable affinity, the membrane transport efficiency of LK-M-NA increased to 14.58%, well addressing the trade-off problem.

Insight into Drug Loading Regulated Micellar Rigidity by Nuclear Magnetic Resonance

The rigidity of polymeric micelles plays an important role in their biological behaviors. However, how drug loading affects the rigidity of polymeric micelles remains elusive. Herein, the indomethacin (IMC)-loaded Pluronic F127 micelle is used as a model system to illustrate the impact of drug loading on the rigidity and biological behaviors of polymeric micelles. Against expectations, micelles with moderate drug loading show higher cellular uptake and more severe cytotoxicity as compared to both high and low drug loading counterparts. Extensive one- and two-dimensional nuclear magnetic resonance (NMR) measurements are employed to reveal that the higher drug loading induces stronger interaction between IMC and hydrophilic block to boost the micellar rigidity; consequently, the moderate drug loading imparts micelles with appropriate rigidity for satisfactory cellular uptake and cytotoxicity. In summary, NMR spectroscopy is an important tool to gain insight into drug loading regulated micellar rigidity, which is helpful to understand their biological behaviors.

Tumor-targeted dual-starvation therapy based on redox-responsive micelle nanosystem with co-loaded LND and BPTES

The starvation therapy mediated by the lonidamine (LND) was limited by the low drug delivery efficiency, off-target effect and compensative glutamine metabolism. Herein, a hyaluronic acid (HA)-modified reduction-responsive micellar nanosystem co-loaded with glycolysis and glutamine metabolism inhibitor (LND and bis-2-(5-phenylacetmido-1,2,4-thiadiazol-2-yl)ethyl sulfide, BPTES) was constructed for tumor-targeted dual-starvation therapy. The in vitro and in vivo results collectively suggested that the fabricated nanosystem could effectively endocytosed by tumor cells via HA receptor-ligand recognition, and rapidly release starvation-inducers LND and BPTES in response to the GSH-rich intratumoral cytoplasm. Furthermore, the released LND and BPTES were capable of inducing glycolysis and glutamine metabolism suppression, and accompanied by significant mitochondrial damage, cell cycle arrest and tumor cells apoptosis, eventually devoting to the blockade of the energy and substance supply and tumor killing with high efficiency. In summary, HPPPH@L@B nanosystem significantly inhibited the compensatory glycolysis and glutamine metabolism via the dual-starvation therapy strategy, blocked the indispensable energy and substance supply of tumors, consequently leading to the desired tumor starvation and effective tumor killing with reliable biosafety.

An Investigation for Skin Tissue Regeneration Enhancement/Augmentation by Curcumin-Loaded Self-Emulsifying Drug Delivery System (SEDDS)

Diabetes, one of the global metabolic disorders, is often associated with delayed wound healing due to the elevated level of free radicals at the wound site, which hampers skin regeneration. This study aimed at developing a curcumin-loaded self-emulsifying drug delivery system (SEDDS) for diabetic wound healing and skin tissue regeneration. For this purpose, various curcumin-loaded SEDDS formulations were prepared and optimized. Then, the SEDDS formulations were characterized by the emulsion droplet size, surface charge, drug content/entrapment efficiency, drug release, and stability. In vitro, the formulations were assessed for the cellular uptake, cytotoxicity, cell migration, and inhibition of the intracellular ROS production in the NIH3T3 fibroblasts. In vivo, the formulations' wound healing and skin regeneration potential were evaluated on the induced diabetic rats. The results indicated that, after being dispersed in the aqueous medium, the optimized SEDDS formulation was readily emulsified and formed a homogenous dispersion with a droplet size of 37.29 ± 3.47 nm, surface charge of -20.75 ± 0.07 mV, and PDI value of less than 0.3. The drug content in the optimized formulation was found to be 70.51% ± 2.31%, with an encapsulation efficiency of 87.36% ± 0.61%. The SEDDS showed a delayed drug release pattern compared to the pure drug solution, and the drug release rate followed the Fickian diffusion kinetically. In the cell culture, the formulations showed lower cytotoxicity, higher cellular uptake, and increased ROS production inhibition, and promoted the cell migration in the scratch assay compared to the pure drug. The in vivo data indicated that the curcumin-loaded SEDDS-treated diabetic rats had significantly faster-wound healing and re-epithelialization compared with the untreated and pure drug-treated groups. Our findings in this work suggest that the curcumin-loaded SEDDS might have great potential in facilitating diabetic wound healing and skin tissue regeneration.

In vivo fate and intracellular trafficking of vaccine delivery systems

With the pandemic of severe acute respiratory syndrome coronavirus 2, vaccine delivery systems emerged as a core technology for global public health. Given that antigen processing takes place inside the cell, the intracellular delivery and trafficking of a vaccine antigen will contribute to vaccine efficiency. Investigations focusing on the in vivo behavior and intracellular transport of vaccines have improved our understanding of the mechanisms relevant to vaccine delivery systems and facilitated the design of novel potent vaccine platforms. In this review, we cover the intracellular trafficking and in vivo fate of vaccines administered via various routes and delivery systems. To improve immune responses, researchers have used various strategies to modulate vaccine platforms and intracellular trafficking. In addition to progress in vaccine trafficking studies, the challenges and future perspectives for designing next-generation vaccines are discussed.