The dose threshold for nanoparticle tumour delivery

Enzymatic interlocking aptamer-micelles for enhanced cellular internalization and nucleus-targeted cancer phototherapy

Multifunctional micelles that permit both diagnosis and treatment present enormous advantage and potential for precision medicine. However, the inherent complexities and structural instability of these systems often cause unsatisfactory targeting and therapeutic performances. Herein, by ingenious design of a 2,5-bis(2-thienyl)pyrrole (SNS) modifier to covalently link with AS1411 aptamer and lipid segment, a simple strategy is proposed for one-step enzymatic preparation of interlocked aptamer-micelle (IApM) under bio-friendly conditions. The interlocked poly(SNS) skeleton in IApM can not only stabilize the micelle structure but also enhance near-infrared (NIR) absorption ability, thus further enhancing cellular internalization and photothermal therapy. In addition, the multivalent AS1411 aptamers tethered in the hydrophilic shell can simultaneously increase the specific binding affinity of DNA micelles and induce nucleus-targeted accumulation for DNA damage-triggered apoptosis. This DNA micelle achieves "best of both worlds" with enhanced biostability for cellular internalization and improved NIR photothermal conversion efficiency for nucleus-targeted therapy, which provides a promising formulation strategy for precision cancer treatment.

J-aggregates of strong electron-donating groups linked Aza-BODIPY adjusting by polypeptide for NIR-II phototheranostics

The commonly employed strategies for engineering second near-infrared (NIR-II) organic phototheranostic agents are based on expanding conjugated backbone length, strengthening donor (D)-acceptor (A) effect, or forming J-aggregates. We constructed the D-A-D' structure by incorporating strong electron-donating methoxy and tetraphenylethene (TPE) moieties on the electron-deficient Aza-BODIPY core, and simultaneously expanded the π-conjugation effect by introducing thiophene groups, to obtain a dye BDP-TPE. Next, the nanoparticles P-TPE were prepared via the assembly of BDP-TPE with amphiphilic polypeptides (mPEG2000-P(Asp)10), and successfully constructed the J-aggregates. The obtained P-TPE exhibited strong absorption and fluorescence with maxima at 808 and 1018 nm, respectively, with a conspicuous absolute quantum yield of 0.241 %. Moreover, P-TPE also showed excellent biocompatibility, and high photothermal conversion efficiency of 61.15 %, and excellent resistance to pH, long-term storage, and photobleaching. In vitro and in vivo experiments revealed that P-TPE exhibited good biocompatibility and effectively achieved NIR-II fluorescence imaging-guided PTT with complete tumor ablation under 808 nm laser irradiation. These results provided good evidence for the use of P-TPE as a NIR-II fluorescence imaging-guided PTT therapeutic agent in vivo.

A comparative study of PEO-PBO content on the targeting and anti-glioma activity of annonaceous acetogenins-loaded nanomicelles

Annonaceous acetogenins (ACGs) have great potential in the treatment of gliomas, but are extremely insoluble and difficult for delivery in vivo. Poly(ethylene oxide)-b-poly(butylene oxide) (PEO-PBO) is an amphiphilic polymer and can reduce the clearance of nanoparticles by mononuclear phagocyte system. To explore an efficient and safe nanomedicine for glioma, ACGs-loaded nanomicelles (ACGs/EB-NCs) was constructed using PEO-PBO as a carrier, and the effect of PEO-PBO content on the targeting and anti-glioma activity were also compared. ACGs/EB5-NCs, ACGs/EB10-NCs and ACGs/EB20-NCs, the three nanomicellels prepared with different ACGs/EB feeding ratios, had average particle sizes of 148.8±0.5 nm, 32.7±4.1 nm, and 27.1±0.3 nm, respectively. The three ACGs/EB-NCs were spherical in shape, with drug loading content close to the theoretical drug loading content, encapsulation efficiency greater than 97 %, and good stability in physiological media. The cumulative release rates of ACGs/EB5-NCs, ACGs/EB10-NCs and ACGs/EB20-NCs were 78.2 %, 63.4 %, and 56.3 % within 216 hours, respectively. The inhibitory effects of three ACGs/EB-NCs on U87 MG cells were similar and stronger than free ACGs (P<0.05), with half inhibitory concentration of 0.17, 0.18, and 0.16 ng/mL (P>0.05), respectively. In U87 MG tumor‑bearing mice, ACGs/EB5-NC, ACGs/EB10-NCs and ACGs/EB20-NCs showed a similar tumor inhibition rate of 61.1±5.9 %, 56.2±8.6 % and 64.3±9.4 % (P>0.05), with good safety. Three ACGs/EB-NCs exhibited excellent liver escape ability and tumor targeting ability, with the tumor targeting index greater than 1.5. Three ACGs/EB-NCs were successfully prepared with strong anti-glioma activity and tumor targeting properties, which are expected to provide new options for the clinical treatment of gliomas. The content of PEO-PBO in micelles did not have a significant effect on the tumor targeting and anti-glioma activity of ACGs/EB-NCs.

Impact of formulation parameters and circulation time on PEGylated liposomal doxorubicin related hand-foot syndrome

PEGylated liposomal doxorubicin (PLD) has effectively reduced the cardiac toxicity of free doxorubicin (DOX) due to its unique nanoscale properties. However, an unexpected accumulation of PLD in the skin has led to hand-foot syndrome (HFS), negatively impacting quality of life and psychological well-being. In this study, self-limiting HFS rat models were created to mimic human symptoms through varying dosing schedules and intensities of PLD. The effects of PLD formulation parameters on HFS were also investigated. The results demonstrated that replacing ammonium sulfate with citric buffer, increasing liposome size, or reducing DSPE-mPEG2000 modification density alleviated HFS. Additionally, liposomes without DSPE-mPEG2000 modification completely avoided HFS, suggesting that PEGylated phospholipid was the key formulation parameter contributing to PLD-induced HFS. Furthermore, the correlation between liposome pharmacokinetics and HFS indicated that PEGylation, rather than the extended circulation time of liposomes, may mediated PLD-related HFS. Better understanding of the formulation parameters that trigger HFS can guide reformulation strategies to mitigate or prevent this syndrome.

Optimizing lipid nanoparticles for fetal gene delivery in vitro, ex vivo, and aided with machine learning

There is a clinical need to develop lipid nanoparticles (LNPs) to deliver congenital therapies to the fetus during pregnancy. The aim of these therapies is to restore normal fetal development and prevent irreversible conditions after birth. As a first step, LNPs need to be optimized for transplacental transport, safety on the placental barrier and fetal organs and transfection efficiency. We developed and characterized a library of LNPs of varying compositions and used machine learning (ML) models to delineate the determinants of LNP size and zeta potential. Utilizing different in vitro placental models with the help of a Random Forest algorithm, we could identify the top features driving percentage LNP transport and kinetics at 24 h, out of a total of 18 input features represented by 41 LNP formulations and 48 different transport experiments. We further evaluated the LNPs for safety, placental cell uptake, transfection efficiency in placental trophoblasts and fetal lung fibroblasts. To ensure the integrity of the LNPs following transplacental transport, we screened LNPs for transport and transfection using a high-throughput integrated transport-transfection in vitro model. Finally, we assessed toxicity of the LNPs in a tracheal occlusion fetal lung explant model. LNPs showed little to no toxicity to fetal and placental cells. Immunoglobin G (IgG) orientation on the surface of LNPs, PEGylated lipids, and ionizable lipids had significant effects on placental transport. The Random Forest algorithm identified the top features driving LNPs placental transport percentage and kinetics. Zeta potential emerged in the top driving features. Building on the ML model results, we developed new LNP formulations to further optimize the transport leading to 622 % increase in transport at 24 h versus control LNP formulation. To induce preferential siRNA transfection of fetal lung, we further optimized cationic lipid percentage and the lipid-to-siRNA ratio. Studying LNPs in an integrated placental and fetal lung fibroblasts model showed a strong correlation between zeta potential and fetal lung transfection. Finally, we assessed the toxicity of LNPs in a tracheal occlusion lung explant model. The optimized formulations appeared to be safe on ex vivo fetal lungs as indicated by insignificant changes in apoptosis (Caspase-3) and proliferation (Ki67) markers. In conclusion, we have optimized an LNP formulation that is safe, with high transplacental transport and preferential transfection in fetal lung cells. Our research findings represent an important step toward establishing the safety and effectiveness of LNPs for gene delivery to the fetal organs.

Neutrophil Hitchhiking Enhances Liposomal Dexamethasone Therapy of Sepsis

Sepsis is characterized by a dysregulated immune response and is very difficult to treat. In the cecal ligation and puncture (CLP) mouse model, we show that nanomedicines can effectively alleviate systemic and local septic events by targeting neutrophils. Specifically, by decorating the surface of clinical-stage dexamethasone liposomes with cyclic arginine-glycine-aspartic acid (cRGD) peptides, we promote their engagement with neutrophils in the systemic circulation, leading to their prominent accumulation at primary and secondary sepsis sites. cRGD-targeted dexamethasone liposomes potently reduce immature circulating neutrophils and neutrophil extracellular traps in intestinal sepsis induction sites and the liver. Additionally, they mitigate inflammatory cytokines systemically and locally while preserving systemic IL-10 levels, contributing to lower IFN-γ/IL-10 ratios as compared to control liposomes and free dexamethasone. Our strategy addresses sepsis at the cellular level, illustrating the use of neutrophils both as a therapeutic target and as a chariot for drug delivery.

RVG-peptide-camouflaged iron-coordinated engineered polydopamine nanoenzyme with ROS scavenging and inhibiting inflammatory response for ischemic stroke therapy

Stroke is one of the most common causes of death and disability. In addition, most neuroprotective agents fail to rescue neurons from cerebral ischemic insults due to their poor ability to penetrate the blood-brain barrier (BBB). Here, the tailored engineered nanoenzyme has been successfully synthesized by coordination-driven co-assembly of dopamine (DA) and iron ion (Fe3+), which is subsequently camouflaged by neuron-specific rabies viral glycoprotein (RVG) peptide to scavenge reactive oxygen species (ROS) and inhibit inflammatory response in damaged neuron for the efficient therapy of ischemic stroke. The resulting nanoenzyme with good biocompatibility, core-shell structure, and suitable diameter can nondestructively cross the BBB and then internalize into the damaged neuron through the camouflaging and homologous targeted strategy of neuron-specific RVG peptide. After intravenous injection into transient middle cerebral artery occlusion (tMCAO) mouse models, nanoenzyme exerted a significant neuroprotective effect, resulting in a 50 % reduction in neurological scores and an approximate 33 % decrease in cerebral infarction volume. Interestingly, such nanoenzyme can eliminate free radicals, reduce neuroinflammation, enhance BBB integrity, improve mitochondrial function, and inhibit neuronal ferroptosis. Taken together, this well-designed nanoenzyme with its excellent biocompatibility and well-understood mechanisms holds promise a robust therapy for ischemic stroke.

Enhanced docetaxel therapeutic effect using dual targeted SRL-2 and TA1 aptamer conjugated micelles in inhibition Balb/c mice breast cancer model

Effective targeting and delivery of large amounts of medications into the cancer cells enhance their therapeutic efficacy through saturation of cellular defensive mechanisms, which is the most privilege of nano drug delivery systems (NDDS) compared to traditional approaches. Herein, we designed dual-pH/redox responsive DTX-loaded poly (β-amino ester) (PBAS) micelles decorated with a chimeric peptide and TA1 aptamer. In vitro and in vivo results demonstrated that the designed nanoplatform possessed an undetectable nature in the blood circulation, but after exposure to the tumor microenvironment (TME) of 4T1 breast cancer, it suddenly changed into dual targeting nanoparticles (NPs) (containing two ligands, SRL-2 and TA1 aptamer). The dual targeting NPs destruction in the high GSH and low pH conditions of the cancer cells led to amplified DTX release (around 70% at 24 h). The IC50 value of DTX-loaded MMP-9 sensitive heptapeptide/TA1 aptamer-modified poly (β-amino ester) (MST@PBAS) micelles and free DTX after 48 h of exposure was determined to be 1.5 µg/ml and 7.5 µg/ml, respectively. The nano-formulated DTX exhibited cytotoxicity that was 5-fold stronger than free DTX (Pvalue˂0.001). Cell cycle assay test results showed that following exposure to MST@PBAS micelles, a considerable rise in the sub G1 population (48%) suggested that apoptosis by cell cycle arrest had occurred. DTX-loaded MST@PBAS micelles revealed significantly higher (Pvalue ˂ 0.001) levels of early apoptosis (59.8%) than free DTX (44.7%). Interestingly, in vitro uptake studies showed a significantly higher TME accumulation of dual targeted NPs (6-fold) compared to single targeted NPs (Pvalue < 0.001) which further confirmed by in vivo biodistribution and fluorescent TUNEL assay experiments. NPs treated groups demonstrated notable tumor growth inhibition in 4T1 tumor bearing Balb/c mice by only 1/10th of the DTX therapeutic dose (TD) as a drug model. In conclusion, cleverly designed nanostructures here demonstrated improved anticancer effects by enhancing tumor targeting, delivering chemotherapeutic agents more accurately, promoting drug release, reducing the therapeutic dosage, and lowering side effects of anticancer drugs.

Stable triangle: nanomedicine-based synergistic application of phototherapy and immunotherapy for tumor treatment

In recent decades, cancer has posed a challenging obstacle that humans strive to overcome. While phototherapy and immunotherapy are two emerging therapies compared to traditional methods, they each have their advantages and limitations. These limitations include easy metastasis and recurrence, low response rates, and strong side effects. To address these issues, researchers have increasingly focused on combining these two therapies by utilizing a nano-drug delivery system due to its superior targeting effect and high drug loading rate, yielding remarkable results. The combination therapy demonstrates enhanced response efficiency and effectiveness, leading to a preparation that is highly targeted, responsive, and with low recurrence rates. This paper reviews several main mechanisms of anti-tumor effects observed in combination therapy based on the nano-drug delivery system over the last five years. Furthermore, the challenges and future prospects of this combination therapy are also discussed.

Multivalent supramolecular fluorescent probes for accurate disease imaging

Optical imaging is a powerful tool for early disease detection and effective treatment planning, but its accuracy is often compromised by the uptake of imaging materials by the mononuclear phagocyte system (MPS). Herein, we leverage multivalent host-guest interactions between cyanine dyes and β-cyclodextrin polymers to develop supramolecular probes with enhanced stability, optical, and transport profiles for accurate in vivo imaging. These multivalent interactions not only ensure the stability of the probes but also enhance fluorescence efficiency by minimizing nonradiative decay. Our self-assembly approach effectively modulates probe size and surface properties, enabling evasion of MPS clearance and promoting prolonged bloodstream circulation, thereby improving the signal-to-background ratio for imaging. The effectiveness of our design is demonstrated by substantial advancements in the early diagnosis of acute kidney injury and by providing high-contrast imaging and precise surgical navigation across various tumor models. Our strategy not only advances optical imaging materials toward clinical translation but also establishes a versatile platform applicable to multiple imaging modalities.

Nanomaterial-assisted delivery of CpG oligodeoxynucleotides for boosting cancer immunotherapy

Cancer immunotherapy aims to improve immunity to not only eliminate the primary tumor but also inhibit metastasis and recurrence. It is considered an extremely promising therapeutic approach that breaks free from the traditional paradigm of oncological treatment. As the medical community learns more about the immune system's mechanisms that "turn off the brake" and "step on the throttle", there is increasingly successful research on immunomodulators. However, there are still more restrictions than countermeasures with immunotherapy related to immunomodulators, such as low responsiveness and immune-related adverse events that cause multiple adverse reactions. Therefore, medical experts and materials scientists attempted to the efficacy of immunomodulatory treatments through various methods, especially nanomaterial-assisted strategies. CpG oligodeoxynucleotides (CpG) not only act as an adjuvant to promote immune responses, but also induce autophagy. In this review, the enhancement of immunotherapy using nanomaterial-based CpG formulations is systematically elaborated, with a focus on the delivery, protection, synergistic promotion of CpG efficacy by nanomaterials, and selection of the timing of treatment. In addition, we also discuss and prospect the existing problems and future directions of research on nanomaterials in auxiliary CpG therapy.

STING Agonist Delivered by Neutrophil Membrane-Coated Gold Nanoparticles Exerts Synergistic Tumor Inhibition with Radiotherapy

Radiotherapy (RT) is one of the major treatments for cancers and a promising initiator of immune response. Gold nanoparticles are a promising radiosensitizer. In this study, we sought to optimize the drug delivery efficiency of gold nanoparticles and explore their function in delivering stimulator of interferon genes (STING) agonists with or without RT. Gold nanoparticles covalent to MSA-2 (MSA-Au) were mixed with cRGD-modified neutrophil membranes to obtain M-Au@RGD-NM. We explored the treatment efficiency of M-Au@RGD-NM combined with RT. Immune cell regulation and STING pathway activation were detected. We successfully prepared M-Au@RGD-NM with significant tumor suppression by induction of ROS and the resulting DNA damage. In vivo dynamic imaging showed that M-Au@RGD-NM was mainly targeted to radiated tumors. Tumor-bearing mice showed significant tumor inhibition following a combination therapy. M-Au@RGD-NM significantly activated the STING pathway and regulated the whole-body immune response. Locally radiated tumors showed dendritic cells mature, CD8+ T cells upregulation, and M1 polarization, with systematic immune response demonstrated by CD8+ T cell infiltration in abscopal tumors. In this study, we synthesized M-Au@RGD-NM loading MSA-2. Following characterization, we found that RT-based M-Au@RGD-NM treatment achieved good antitumor effects, tumor RT enhancement, and induction of an immune response via STING activation.

Dual-pore protocells with multitasking capacities for simultaneous delivery of therapeutic enzymes and drugs in macrophage depletion therapy

Macrophages are usually present in solid tumors where they participate in tumor progression, angiogenesis, immunosuppression and metastasis. The design of nanocarriers capable of delivering therapeutic agents to specific cell populations has received considerable attention in the last decades. However, the capacity of many of these nanosystems to deliver multiple therapeutic agents with very different chemical properties is more limited. Herein, a novel multitasking nanoplatform capable of delivering large macromolecules and cytotoxic drugs to macrophages is presented. This novel nanosystem has exhibited excellent skills in performing simultaneous tasks, macrophage depletion and glucose starvation, maintaining the oxygen levels in the tissue. This nanodevice is composed of a dual-pore mesoporous silica core with the capacity to house small cytotoxic drugs, such as doxorubicin or zoledronic acid, and large macromolecules, such as glucose oxidase. The external surface of the silica core was coated with a lipid bilayer to avoid the premature release of the housed drugs. Finally, polymeric nanocapsules loaded with catalase were covalently anchored on the outer lipid bilayer, and carboxy-mannose was attached to the exposed side of the nanocapsules to provide selectivity to the macrophages. These nanoassemblies were able to transport enzymes (Gox and CAT), maintaining their catalytic activity. Therefore, they could induce glucose starvation, keeping the oxygen levels in the tissue, owing to the tandem enzymatic reaction. The capacity of these nanoassemblies to deliver therapeutic agents to macrophages was evaluated both in static and under flow conditions, showing a rapid capture of the nanoparticles by the macrophages. Once there, the nanoassemblies also exhibited excellent capacity to induce potent macrophage depletion. This strategy can be directly adapted for the treatment of different malignancies due to the modular nature of the nanoplatform, which can be loaded with different therapeutic agent combinations and pave the way for the development of personalized nanomedicines for diverse types of tumors.

Developing an erythrocyte‒MHC-I conjugate for cancer treatment

Mature erythrocytes are known to lack major histocompatibility complex (MHC) proteins. However, the presence of MHC molecules on erythrocytes has been occasionally reported, though without a defined function. In this study, we designed erythrocyte conjugated solely with a fusion protein consisting of an antigenic peptide linked to MHC class I (MHC-I) protein, termed MHC-I‒Ery. The modified erythrocyte, decorated with the peptide derived from human papillomavirus (HPV) 16 oncoprotein E6/E7, effectively activated antigen-specific CD8+ T cells in peripheral blood mononuclear cells (PBMCs) from HPV16+ cervical cancer patients. Additionally, MHC-I‒Ery monotherapy was shown to inhibit antigen-positive tumor growth in mice. This treatment immediately activated CD8+ T cells and reduced suppressive myeloid cells in the spleen, leading to systemic anti-tumor activity. Safety and tolerability evaluations of MHC-I‒Ery in non-human primates further supported its clinical potential. Our results first demonstrated that erythrocytes equipped solely with antigen peptide‒MHC-I complexes can robustly stimulate the immune system, suggesting a novel and promising approach for advancing cancer immunotherapy.

Evaluating the breadth of nucleic acid-based payloads delivered in lipid nanoparticles to establish fundamental differences in development

INTRODUCTION

Nucleic acid (NA)-based therapeutics have shown great potential for downregulating or augmenting gene expression, and for promising applications, e.g., protein-replacement therapy and vaccination, a comprehensive understanding of the requirements for their targeted delivery to specific tissues or cells is needed.

AREAS COVERED

In this review, we discuss clinical applications of four representative types of NA-based therapeutics, i.e. antisense oligonucleotides, small interfering RNA, messenger RNA, and circular RNA, with a focus on the lipid nanoparticle (LNP) technology used for intracellular delivery. The in vivo fate of LNPs is discussed to improve the understanding of trafficking of nanomedicines at the systemic and cellular levels. In addition, NA-based vaccines are discussed, focusing on targeting antigen-presenting cells and immune activation.

EXPERT OPINION

Optimization of delivery systems for NA-based therapeutics is mainly focused on the standard requirements of prolonged systemic circulation and enhancing endosomal escape. Depending on the final destination in specific target tissues or cells, strategies should be adjusted to achieve the desired biodistribution of NA-based payloads. More studies relating to the pharmacokinetics of both cargo and carrier are encouraged, because their in vivo fates may differ, considering the possibility of premature cargo release before reaching the target.

Folic acid-conjugated bovine serum albumin-coated selenium-ZIF-8 core/shell nanoparticles for dual target-specific drug delivery in breast cancer

Methotrexate (MTX), a frequently used chemotherapeutic agent, has limited water solubility, leading to rapid clearance even in local injections. In the present study, we developed folic acid-conjugated BSA-stabilized selenium-ZIF-8 core/shell nanoparticles for targeted delivery of MTX to combat breast cancer. FT-IR, XRD, SEM, TEM, and elemental mapping analysis confirmed the successful formation of FA-BSA@MTX@Se@ZIF-8. The developed nano-DDS had a mean diameter, polydispersity index, and zeta potential of 254.8 nm, 0.17, and - 16.5 mV, respectively. The release behavior of MTX from the nanocarriers was pH-dependent, where the cumulative release percentage at pH 5.4 was higher than at pH 7.4. BSA significantly improved the blood compatibility of nanoparticles so that after modifying their surface with BSA, the percentage of hemolysis decreased from 12.67 to 5.12%. The loading of methotrexate in BSA@Se@ZIF-8 nanoparticles reduced its IC50 on 4T1 cells from 40.29 µg/mL to 16.54 µg/mL, and by conjugating folic acid on the surface, this value even decreased to 12.27 µg/mL. In vivo evaluation of the inhibitory effect in tumor-bearing mice showed that FA-BSA@MTX@Se@ZIF-8 caused a 2.8-fold reduction in tumor volume compared to the free MTX, which is due to the anticancer effect of selenium nanoparticles, the pH sensitivity of ZIF-8, and the presence of folic acid on the surface as a targeting agent. More importantly, histological studies and animal body weight monitoring confirmed that developed nano-DDS does not have significant organ toxicity. Taking together, the incorporation of chemotherapeutics in folic acid-conjugated BSA-stabilized selenium-ZIF-8 nanoparticles may hold a significant impact in the field of future tumor management.

Transvascular transport of nanocarriers for tumor delivery

Nanocarriers (NCs) play a crucial role in delivering theranostic agents to tumors, making them a pivotal focus of research. However, the persistently low delivery efficiency of engineered NCs has been a significant challenge in the advancement of nanomedicine, stirring considerable debate. Transvascular transport is a critical pathway for NC delivery from vessels to tumors, yet a comprehensive understanding of the interactions between NCs and vascular systems remains elusive. In recent years, considerable efforts have been invested in elucidating the transvascular transport mechanisms of NCs, leading to promising advancements in tumor delivery and theranostics. In this context, we highlight various delivery mechanisms, including the enhanced permeability and retention effect, cooperative immune-driven effect, active transcytosis, and cell/bacteria-mediated delivery. Furthermore, we explore corresponding strategies aimed at enhancing transvascular transport of NCs for efficient tumor delivery. These approaches offer intriguing solutions spanning physicochemical, biological, and pharmacological domains to improve delivery and therapeutic outcomes. Additionally, we propose a forward-looking delivery framework that relies on advanced tumor/vessel models, high-throughput NC libraries, nano-bio interaction datasets, and artificial intelligence, which aims to guide the design of next-generation carriers and implementation strategies for optimized delivery.

Design and preparation of pH-sensitive cytotoxic liposomal formulations containing antitumor colchicine analogues for target release

Herein, we describe the synthesis of pH-sensitive lipophilic colchicine prodrugs for liposomal bilayer inclusion, as well as preparation and characterization of presumably stealth PEGylated liposomes with above-mentioned prodrugs. These formulations liberate strongly cytotoxic colchicinoid derivatives selectively under slightly acidic tumor-associated conditions, ensuring tumor-targeted delivery of the compounds. The design of the prodrugs is addressed to pH-triggered release of active compounds in the slight acidic media, that corresponds to tumor microenvironment, while keeping sufficient stability of the whole formulation at physiological pH. Correlations between the structure of the conjugates, their hydrolytic stability, colloidal stability, ability of the prodrug retention in the lipid bilayer are described. Several formulations were found promising for further development and in vivo investigations.

Advances in Microfluidic-Based Core@Shell Nanoparticles Fabrication for Cancer Applications

Current research in cancer therapy focuses on personalized therapies, through nanotechnology-based targeted drug delivery systems. Particularly, controlled drug release with nanoparticles (NPs) can be designed to safely transport various active agents, optimizing delivery to specific organs and tumors, minimizing side effects. The use of microfluidics (MFs) in this field has stood out against conventional methods by allowing precise control over parameters like size, structure, composition, and mechanical/biological properties of nanoscale carriers. This review compiles applications of microfluidics in the production of core-shell NPs (CSNPs) for cancer therapy, discussing the versatility inherent in various microchannel and/or micromixer setups and showcasing how these setups can be utilized individually or in combination, as well as how this technology allows the development of new advances in more efficient and controlled fabrication of core-shell nanoformulations. Recent biological studies have achieved an effective, safe, and controlled delivery of otherwise unreliable encapsulants such as small interfering RNA (siRNA), plasmid DNA (pDNA), and cisplatin as a result of precisely tuned fabrication of nanocarriers, showing that this technology is paving the way for innovative strategies in cancer therapy nanofabrication, characterized by continuous production and high reproducibility. Finally, this review analyzes the technical, biological, and technological limitations that currently prevent this technology from becoming the standard.

Advances in Nanomaterials for Immunotherapeutic Improvement of Cancer Chemotherapy

Immuno-stimulative effect of chemotherapy (ISECT) is recognized as a potential alternative to conventional immunotherapies, however, the clinical application is constrained by its inefficiency. Metronomic chemotherapy, though designed to overcome these limitations, offers inconsistent results, with effectiveness varying based on cancer types, stages, and patient-specific factors. In parallel, a wealth of preclinical nanomaterials holds considerable promise for ISECT improvement by modulating the cancer-immunity cycle. In the area of biomedical nanomaterials, current literature reviews mainly concentrate on a specific category of nanomaterials and nanotechnological perspectives, while two essential issues are still lacking, i.e., a comprehensive analysis addressing the causes for ISECT inefficiency and a thorough summary elaborating the nanomaterials for ISECT improvement. This review thus aims to fill these gaps and catalyze further development in this field. For the first time, this review comprehensively discusses the causes of ISECT inefficiency. It then meticulously categorizes six types of nanomaterials for improving ISECT. Subsequently, practical strategies are further proposed for addressing inefficient ISECT, along with a detailed discussion on exemplary nanomedicines. Finally, this review provides insights into the challenges and perspectives for improving chemo-immunotherapy by innovations in nanomaterials.

Glycopolymeric Micellar Nanoparticles for Platelet-Mediated Tumor-Targeted Delivery of Docetaxel for Cancer Therapy

The high level of accumulation of therapeutic agents in tumors is crucial for cancer treatment. Compared to the passive tumor-targeting effect, active tumor-targeting delivery systems, primarily mediated by peptides with high production costs and reduced circulation time, are highly desired. Platelet-driven technologies have opened new avenues for targeted drug delivery prevalently through a membrane coating strategy that involves intricate manufacturing procedures or the fucoidan-mediated hitchhiking method with limited platelet affinity. Here, a novel type of amphiphilic glycopolymer self-assembled micellar nanoparticle has been developed to adhere to naturally activated platelets in the blood. The simultaneous integration of fucose and sialic acid segments into glycopolymers enables closer mimicry of the structure of P-selectin glycoprotein ligand-1 (PSGL-1), thereby increasing the affinity for activated platelets. It results in the formation of glycopolymeric micelle-platelet hybrids, facilitating targeted drug delivery to tumors. The selective platelet-assisted cellular uptake of docetaxel (DTX)-loaded glycopolymeric micelles leads to lower IC50 values against 4T1 cells than that of free DTX. The directed tumor-targeting effect of activated platelets has significantly improved the tumor accumulation capacity of the glycopolymeric nanoparticles, with up to 21.0% found in tumors within the initial 0.2 h. Additionally, with acid-responsive drug release and inherent antimetastasis properties, the glycopolymeric nanoparticles ensured potent therapeutic efficacy, prolonged survival time, and reduced cardiotoxicity, presenting a new and unexplored strategy for platelet-directed drug delivery to tumors, showing promising prospects in treating localized tumors and preventing tumor metastasis.

Marginated Neutrophils in the Lungs Effectively Compete for Nanoparticles Targeted to the Endothelium, Serving as a Part of the Reticuloendothelial System

Nanomedicine has long pursued the goal of targeted delivery to specific organs and cell types but has yet to achieve this goal with the vast majority of targets. One rare example of success in this pursuit has been the 25+ years of studies targeting the lung endothelium using nanoparticles conjugated to antibodies against endothelial surface molecules. However, here we show that such "endothelial-targeted" nanocarriers also effectively target the lungs' numerous marginated neutrophils, which reside in the pulmonary capillaries and patrol for pathogens. We show that marginated neutrophils' uptake of many of these "endothelial-targeted" nanocarriers is on par with endothelial uptake. This generalizes across diverse nanomaterials and targeting moieties and was even found with physicochemical lung tropism (i.e., without targeting moieties). Further, we observed this in ex vivo human lungs and in vivo healthy mice, with an increase in marginated neutrophil uptake of nanoparticles caused by local or distant inflammation. These findings have implications for nanomedicine development for lung diseases. These data also suggest that marginated neutrophils, especially in the lungs, should be considered a major part of the reticuloendothelial system (RES), with a special role in clearing nanoparticles that adhere to the lumenal surfaces of blood vessels.

Recent Review on Biological Barriers and Host-Material Interfaces in Precision Drug Delivery: Advancement in Biomaterial Engineering for Better Treatment Therapies

Preclinical and clinical studies have demonstrated that precision therapy has a broad variety of treatment applications, making it an interesting research topic with exciting potential in numerous sectors. However, major obstacles, such as inefficient and unsafe delivery systems and severe side effects, have impeded the widespread use of precision medicine. The purpose of drug delivery systems (DDSs) is to regulate the time and place of drug release and action. They aid in enhancing the equilibrium between medicinal efficacy on target and hazardous side effects off target. One promising approach is biomaterial-assisted biotherapy, which takes advantage of biomaterials' special capabilities, such as high biocompatibility and bioactive characteristics. When administered via different routes, drug molecules deal with biological barriers; DDSs help them overcome these hurdles. With their adaptable features and ample packing capacity, biomaterial-based delivery systems allow for the targeted, localised, and prolonged release of medications. Additionally, they are being investigated more and more for the purpose of controlling the interface between the host tissue and implanted biomedical materials. This review discusses innovative nanoparticle designs for precision and non-personalised applications to improve precision therapies. We prioritised nanoparticle design trends that address heterogeneous delivery barriers, because we believe intelligent nanoparticle design can improve patient outcomes by enabling precision designs and improving general delivery efficacy. We additionally reviewed the most recent literature on biomaterials used in biotherapy and vaccine development, covering drug delivery, stem cell therapy, gene therapy, and other similar fields; we have also addressed the difficulties and future potential of biomaterial-assisted biotherapies.

Predicting tissue distribution and tumor delivery of nanoparticles in mice using machine learning models

Nanoparticles (NPs) can be designed for targeted delivery in cancer nanomedicine, but the challenge is a low delivery efficiency (DE) to the tumor site. Understanding the impact of NPs' physicochemical properties on target tissue distribution and tumor DE can help improve the design of nanomedicines. Multiple machine learning and artificial intelligence models, including linear regression, support vector machine, random forest, gradient boosting, and deep neural networks (DNN), were trained and validated to predict tissue distribution and tumor delivery based on NPs' physicochemical properties and tumor therapeutic strategies with the dataset from Nano-Tumor Database. Compared to other machine learning models, the DNN model had superior predictions of DE to tumors and major tissues. The determination coefficients (R2) for the test datasets were 0.41, 0.42, 0.45, 0.79, 0.87, and 0.83 for DE in tumor, heart, liver, spleen, lung, and kidney, respectively. All the R2 and root mean squared error (RMSE) results of the test datasets were similar to the 5-fold cross validation results. Feature importance analysis showed that the core material of NPs played an important role in output predictions among all physicochemical properties. Furthermore, multiple NP formulations with greater DE to the tumor were determined by the DNN model. To facilitate model applications, the final model was converted to a web dashboard. This model could serve as a high-throughput pre-screening tool to support the design of new and efficient nanomedicines with greater tumor DE and serve as an alternative tool to reduce, refine, and partially replace animal experimentation in cancer nanomedicine research.

Localized in vivo prodrug activation using radionuclides

Radionuclides used for imaging and therapy can show high molecular specificity in the body with appropriate targeting ligands. We hypothesized that local energy delivered by molecularly targeted radionuclides could chemically activate prodrugs at disease sites while avoiding activation in off-target sites of toxicity. As proof-of-principle, we tested whether this strategy of " RA dionuclide i nduced D rug E ngagement for R elease" ( RAiDER ) could locally deliver combined radiation and chemotherapy to maximize tumor cytotoxicity while minimizing exposure to activated chemotherapy in off-target sites.

Methods

We screened the ability of radionuclides to chemically activate a model radiation-activated prodrug consisting of the microtubule destabilizing monomethyl auristatin E caged by a radiation-responsive phenyl azide ("caged-MMAE") and interpreted experimental results using the radiobiology computational simulation suite TOPAS-nBio. RAiDER was evaluated in syngeneic mouse models of cancer using fibroblast activation protein inhibitor (FAPI) agents 99m Tc-FAPI-34 and 177 Lu-FAPI-04, the prostate-specific membrane antigen (PSMA) agent 177 Lu-PSMA-617, combined with caged-MMAE or caged-exatecan. Biodistribution in mice, combined with clinical dosimetry, estimated the relationship between radiopharmaceutical uptake in patients and anticipated concentrations of activated prodrug using RAiDER.

Results

RAiDER efficiency varied by 250-fold across radionuclides ( 99m Tc> 177 Lu> 64 Cu> 68 Ga> 223 Ra> 18 F), yielding up to 1.22µM prodrug activation per Gy of exposure from 99m Tc. Computational simulations implicated low-energy electron-mediated free radical formation as driving prodrug activation. Clinically relevant radionuclide concentrations chemically activated caged-MMAE restored its ability to destabilize microtubules and increased its cytotoxicity by up to 600-fold compared to non-irradiated prodrug. Mice treated with 99m Tc-FAPI-34 and caged-MMAE accumulated up to 3000× greater concentrations of activated MMAE in tumors compared to other tissues. RAiDER with 99m Tc-FAPI-34 or 177 Lu-FAPI-04 delayed tumor growth, while monotherapies did not ( P <0.03). Clinically-guided dosimetry suggests sufficient radiation doses can be delivered to activate therapeutically meaningful levels of prodrug.

Conclusion

This proof-of-concept study shows that RAiDER is compatible with multiple radionuclides commonly used in nuclear medicine and has the potential to improve the efficacy of radiopharmaceutical therapies to treat cancer safely. RAiDER thus shows promise as an effective strategy to treat disseminated malignancies and broadens the capability of radiopharmaceuticals to trigger diverse biological and therapeutic responses.

Abstract Figure

Natural lignin nanoparticles target tumor by saturating the phagocytic capacity of Kupffer cells in the liver

Ligand-receptor recognition serves as the fundamental driving force for active targeting, yet it is still constrained by off-target effects. Herein, we demonstrate that circumventing or blocking the mononuclear phagocyte system (MPS) are both viable strategies to address off-target effects. Naturally derived lignin nanoparticles (LNPs) show great potential to block MPS due to its good stability, low toxicity, and degradability. We further demonstrate the impact of LNPs dosage on in vivo tumor targeting and antitumor efficacy. Our results show that a high dose of LNPs (300 mg/kg) leads to significant accumulation at the tumor site for a duration of 14 days after intravenous administration. In contrast, the low-dose counterparts (e.g., 50, 150 mg/kg) result in almost all LNPs accumulating in the liver. This discovery indicates that the liver is the primary site of LNP capture, leaving only the surplus LNPs the chance to reach the tumor. In addition, although cell membrane-engineered LNPs can rapidly penetrate tumors, they are still prone to capture by the liver during subsequent circulation in the bloodstream. Excitingly, comparable therapeutic efficacy is obtained for the above two strategies. Our findings may offer valuable insights into the targeted delivery of drugs for disease treatment.

Bioinspired Adaptive Microdrugs Enhance the Chemotherapy of Malignant Glioma: Beyond Their Nanodrugs

Solid nanoparticle-mediated drug delivery systems are usually confined to nanoscale due to the enhanced permeability and retention effect. However, they remain a great challenge for malignant glioma chemotherapy because of poor drug delivery efficiency and insufficient tumor penetration resulting from the blood-brain barrier/blood-brain tumor barrier (BBB/BBTB). Inspired by biological microparticles (e.g., cells) with excellent adaptive deformation, it is demonstrated that the adaptive microdrugs (even up to 3.0 µm in size) are more efficient than their nanodrugs (less than 200 nm in size) to cross BBB/BBTB and penetrate into tumor tissues, achieving highly efficient chemotherapy of malignant glioma. The distinct delivery of the adaptive microdrugs is mainly attributed to the enhanced interfacial binding and endocytosis via adaptive deformation. As expected, the obtained adaptive microdrugs exhibit enhanced accumulation, deep penetration, and cellular internalization into tumor tissues in comparison with nanodrugs, significantly improving the survival rate of glioblastoma mice. It is believed that the bioinspired adaptive microdrugs enable them to efficiently cross physiological barriers and deeply penetrate tumor tissues for drug delivery, providing an avenue for the treatment of solid tumors.

Macrophage-Derived Nanosponges Adsorb Cytokines and Modulate Macrophage Polarization for Renal Cell Carcinoma Immunotherapy

Renal cell carcinoma (RCC) is a hot tumor infiltrated by large numbers of CD8+ T cells and is highly sensitive to immunotherapy. However, tumor-associated macrophages (TAMs), mainly M2 macrophages, tend to undermine the efficacy of immunotherapy and promote the progression of RCC. Here, macrophage-derived nanosponges are fabricated by M2 macrophage membrane-coated poly（lactic-co-glycolic acid）（PLGA）, which could chemotaxis to the CXC and CC chemokine subfamily-enriched RCC microenvironment via corresponding membrane chemokine receptors. Subsequently, the nanosponges act like cytokine decoys to adsorb and neutralize broad-spectrum immunosuppressive cytokines such as colony stimulating factor-1(CSF-1), transforming growth factor-β（TGF-β）, and Lnterleukin-10（IL-10）, thereby reversing the polarization of M2-TAMs toward the pro-inflammatory M1 phenotype, and enhancing the anti-tumor effect of CD8+ T cells. To further enhance the polarization reprogramming efficiency of TAMs, DSPE-PEG-M2pep is conjugated on the surface of macrophage-derived nanosponges for specific recognition of M2-TAMs, and the toll like receptors 7/8（TLR7/8） agonist, R848, is encapsulated in these nanosponges to induce M1 polarization, which result in significant efficacy against RCC. In addition, these nanosponges exhibit undetectable biotoxicity, making them suitable for clinical applications. In summary, a promising and facile strategy is provided for immunomodulatory therapies, which are expected to be used in the treatment of tumors, autoimmune diseases, and inflammatory diseases.

Anticancer and Chemosensitizing Effects of Menadione-Containing Peptide-Targeted Solid Lipid Nanoparticles

Vitamin K derivatives such as menadione (MD) have been recognized as promising redox-modulating and chemosensitizing agents for anticancer therapy, however, their cellular activities in peptide-targeted nanocarriers have not been elucidated to date. This study provides the guidelines for developing MD-loaded solid lipid nanoparticles (SLN) modified with extracellular matrix (ECM)-derived peptides. Relationships between RGD peptide concentration and changes in DLS characteristics as well as accumulation of SLN in cancer cells were revealed to adjust the peptide-lipid ratio. SLN system maintained adequate nanoparticle concentration and low dispersity after introduction of MD and MD/RGD, whereas formulated MD was protected from immediate conjugation with reduced glutathione (GSH). RGD-modified MD-containing SLN showed enhanced prooxidant, GSH-depleting and cytotoxic activities toward PC-3 prostate cancer cells attributed to improved cellular pharmacokinetics of the targeted formulation. Furthermore, this formulation effectively sensitized PC-3 cells and OVCAR-4 ovarian cancer cells to free doxorubicin and cisplatin so that cell growth was inhibited by MD-drug composition at nontoxic concentrations of the ingredients. These results provide an important background for further improving chemotherapeutic methods based on combination of conventional cytostatics with peptide-targeted SLN formulations of MD.

Nanoparticle-Patch System for Localized, Effective, and Sustained miRNA Administration into Infarcted Myocardium to Alleviate Myocardial Ischemia-Reperfusion Injury

Timely blood reperfusion after myocardial infarction (MI) paradoxically triggers ischemia-reperfusion injury (I/RI), which currently has not been conquered by clinical treatments. Among innovative repair strategies for myocardial I/RI, microRNAs (miRNAs) are expected as genetic tools to rescue damaged myocardium. Our previous study identified that miR-30d can provide protection against myocardial apoptosis and fibrosis to alleviate myocardial injury. Although common methods such as liposomes and viral vectors have been used for miRNA transfection, their therapeutic efficiencies have struggled with inefficient in vivo delivery, susceptible inactivation, and immunogenicity. Here, we establish a nanoparticle-patch system for miR-30d delivery in a murine myocardial I/RI model, which contains ZIF-8 nanoparticles and a conductive microneedle patch. Loaded with miR-30d, ZIF-8 nanoparticles leveraging the proton sponge effect enable miR-30d to escape the endocytic pathway, thus avoiding premature degradation in lysosomes. Meanwhile, the conductive microneedle patch offers a distinct advantage by intramyocardial administration for localized, effective, and sustained miR-30d delivery, and it simultaneously releases Au nanoparticles to reconstruct electrical impulses within the infarcted myocardium. Consequently, the nanoparticle-patch system supports the consistent and robust expression of miR-30d in cardiomyocytes. Results from echocardiography and electrocardiogram (ECG) revealed improved heart functions and standard ECG wave patterns in myocardial I/RI mice after implantation of a nanoparticle-patch system for 3 and 6 weeks. In summary, our work incorporated conductive microneedle patch and miR-30d nanodelivery systems to synergistically transcend the limitations of common RNA transfection methods, thus mitigating myocardial I/RI.

Advances in antitumor application of ROS enzyme-mimetic catalysts

The rapid growth of research on enzyme-mimetic catalysts (Enz-Cats) is expected to promote further advances in nanomedicine for biological detection, diagnosis and treatment of disease, especially tumors. ROS-based nanomedicines present fascinating potential in antitumor therapy owing to the rapid development of nanotechnology. In this review, we focus on the applications of Enz-Cats based on ROS in antitumor therapy. Firstly, the definition and category of ROS are introduced, and the key factors enhancing ROS levels are carefully elucidated. Then, the rationally engineered Enz-Cats via different synthetic approaches with high ROS-producing efficiencies are comprehensively discussed. Subsequently, oncotherapy application of Enz-Cats is comprehensively discussed, which integrates diverse synergistic treatment modalities and exhibits high efficiency in ROS generation. Finally, the challenges and future research direction of this field are presented. This review is dedicated to unraveling the enigmas surrounding the interplay of nanomedicine and organisms.

STING agonist-conjugated metal-organic framework induces artificial leukocytoid structures and immune hotspots for systemic antitumor responses

Radiotherapy is widely used for cancer treatment, but its clinical utility is limited by radioresistance and its inability to target metastases. Nanoscale metal-organic frameworks (MOFs) have shown promise as high-Z nanoradiosensitizers to enhance radiotherapy and induce immunostimulatory regulation of the tumor microenvironment. We hypothesized that MOFs could deliver small-molecule therapeutics to synergize with radiotherapy for enhanced antitumor efficacy. Herein, we develop a robust nanoradiosensitizer, GA-MOF, by conjugating a STING agonist, 2',3'-cyclic guanosine monophosphate-adenosine monophosphate (GA), on MOFs for synergistic radiosensitization and STING activation. GA-MOF demonstrated strong anticancer efficacy by forming immune-cell-rich nodules (artificial leukocytoid structures) and transforming them into immunostimulatory hotspots with radiotherapy. Further combination with an immune checkpoint blockade suppressed distant tumors through systemic immune activation. Our work not only demonstrates the potent radiosensitization of GA-MOF, but also provides detailed mechanisms regarding MOF distribution, immune regulatory pathways and long-term immune effects.

Truly Tiny Acoustic Biomolecules for Ultrasound Imaging and Therapy

Nanotechnology offers significant advantages for medical imaging and therapy, including enhanced contrast and precision targeting. However, integrating these benefits into ultrasonography is challenging due to the size and stability constraints of conventional bubble-based agents. Here bicones, truly tiny acoustic contrast agents based on gas vesicles (GVs), a unique class of air-filled protein nanostructures naturally produced in buoyant microbes, are described. It is shown that these sub-80 nm particles can be effectively detected both in vitro and in vivo, infiltrate tumors via leaky vasculature, deliver potent mechanical effects through ultrasound-induced inertial cavitation, and are easily engineered for molecular targeting, prolonged circulation time, and payload conjugation.

Development of a nanoparticle-based tendon-targeting drug delivery system to pharmacologically modulate tendon healing

Satisfactory healing following acute tendon injury is marred by fibrosis. Despite the high frequency of tendon injuries and poor outcomes, there are no pharmacological therapies in use to enhance the healing process. Moreover, systemic treatments demonstrate poor tendon homing, limiting the beneficial effects of potential tendon therapeutics. To address this unmet need, we leveraged our existing tendon healing spatial transcriptomics dataset and identified an area enriched for expression of Acp5 (TRAP) and subsequently demonstrated robust TRAP activity in the healing tendon. This unexpected finding allowed us to refine and apply our existing TRAP binding peptide (TBP) functionalized nanoparticle (NP) drug delivery system (DDS) to facilitate improved delivery of systemic treatments to the healing tendon. To demonstrate the translational potential of this DDS, we delivered niclosamide (NEN), an S100a4 inhibitor. While systemic delivery of free NEN did not alter healing, TBP-NPNEN enhanced both functional and mechanical recovery, demonstrating the translational potential of this approach to enhance the tendon healing process.

Size and Surface Properties of Functionalized Organosilica Particles Impact Cell-Particle Interactions Including Mitochondrial Activity

Understanding of the interactions between macrophages and multifunctional nanoparticles is important for development of novel macrophage-based immunotherapies. Here, we investigated the effects of fluorescent thiol-organosilica particle size and surface properties on cell-particle interactions, including mitochondrial activity, using the mouse macrophage cell line J774A.1. Three different sizes of thiol-organosilica particles (150, 400, and 680 nm in diameter) containing fluorescein (OS/F150, OS/F400, and OS/F680) and particles surface functionalized with polyethylenimine (PEI) (OS/F150PEI, OS/F400PEI, and OS/F680PEI) were prepared. Flow cytometric analysis, time-lapse imaging, and single-cell analysis of particle uptake and mitochondrial activity of J774A.1 cells demonstrated variations in uptake and kinetics depending on the particle size and surface as well as on each individual cell. Cells treated with OS/F150 and OS/F150PEI showed higher uptake and mitochondrial activity than those treated with other particles. The interaction between endosomes and mitochondria was observed using 3D fluorescent imaging and was characterized by the involvement of iron transport into mitochondria by iron-containing proteins adsorbed on the particle surface. Scanning electron microscopy of the cells treated with the particles revealed alterations in cell membrane morphology, depending on particle size and surface. We performed correlative light and electron microscopy combined with time-lapse and 3D imaging to develop an integrated correlation analysis of particle uptake, mitochondrial activity, and cell membrane morphology in single macrophages. These cell-specific characteristics of macrophages against functional particles and their evaluation methods are crucial for understanding the immunological functions of individual macrophages and developing novel immunotherapies.

Synthesis of ionizable lipopolymers using split-Ugi reaction for pulmonary delivery of various size RNAs and gene editing

We present an efficient approach for synthesizing cationic poly(ethylene imine) derivatives using the multicomponent split-Ugi reaction to rapidly create a library of complex functional ionizable lipopolymers. We synthesized a diverse library of 155 polymers, formulated them into polyplexes to establish structure-activity relationships crucial for endosomal escape and efficient transfection. After discovering a lead structure, lipopolymer-lipid hybrid nanoparticles are introduced to preferentially deliver to and elicit effective mRNA transfection in lung endothelium and immune cells, including T cells with low in vivo toxicity. The lipopolymer-lipid hybrid nanoparticles showed 300-fold improvement in systemic mRNA delivery to the lung compared to in vivo -JetPEI ® . Lipopolymer-lipid hybrid nanoparticles demonstrated efficient delivery of mRNA-based therapeutics for treatment of two different disease models. Lewis Lung cancer progression was significantly delayed after treatment with loaded IL-12 mRNA in U155@lipids after repeated i.v. administration. Systemic delivery of human CFTR (hCFTR) mRNA resulted in production of functional form of CFTR protein in the lungs. The functionality of hCFTR protein was confirmed by restoration of CFTR- mediated chloride secretion in conductive airway epithelia in CFTR knockout mice after nasal instillation of hCFTR mRNA loaded U155@lipids. We further showed that, U155@lipids nanoparticles can deliver complex CRISPR-Cas9 based RNA cargo to the lung, achieving 5.6 ± 2.4 % gene editing in lung tissue. Moreover, we demonstrated successful PD-1 gene knockout of T cells in vivo . Our results highlight a versatile delivery platform for systemic delivering of mRNA of various sizes for gene therapy for a variety of therapeutics.

Protein-nanoparticle co-assembly supraparticles for drug delivery: Ultrahigh drug loading and colloidal stability, and instant and complete lysosomal drug release

Two frequent problems hindering clinical translation of nanomedicine are low drug loading and low colloidal stability. Previous efforts to achieve ultrahigh drug loading (>30 %) introduce new hurdles, including lower colloidal stability and others, for clinical translation. Herein, we report a new class of drug nano-carriers based on our recent finding in protein-nanoparticle co-assembly supraparticle (PNCAS), with both ultrahigh drug loading (58 % for doxorubicin, i.e., DOX) and ultrahigh colloidal stability (no significant change in hydrodynamic size after one year). We further show that our PNCAS-based drug nano-carrier possesses a built-in environment-responsive drug release feature: once in lysosomes, the loaded drug molecules are released instantly (<1 min) and completely (∼100 %). Our PNCAS-based drug delivery system is spontaneously formed by simple mixing of hydrophobic nanoparticles, albumin and drugs. Several issues related to industrial production are studied. The ultrahigh drug loading and stability of DOX-loaded PNCAS enabled the delivery of an exceptionally high dose of DOX into a mouse model of breast cancer, yielding high efficacy and no observed toxicity. With further developments, our PNCAS-based delivery systems could serve as a platform technology to meet the multiple requirements of clinical translation of nanomedicines.

Multiple Synergistic Effects of the Microglia Membrane-Bionic Nanoplatform on Mediate Tumor Microenvironment Remodeling to Amplify Glioblastoma Immunotherapy

Glioblastoma (GBM) is a lethal brain tumor with high levels of malignancy. Most chemotherapy agents show serious systemic cytotoxicity and restricted delivery effectiveness due to the impediments of the blood-brain barrier (BBB). Immunotherapy has developed great potential for aggressive tumor treatments. Disappointingly, its efficacy against GBM is hindered by the immunosuppressive tumor microenvironment (TME) and BBB. Herein, a multiple synergistic immunotherapeutic strategy against GBM was developed based on the nanomaterial-biology interaction. We have demonstrated that this BM@MnP-BSA-aPD-1 can transverse the BBB and target the TME, resulting in amplified synergetic effects of metalloimmunotherapy and photothermal immunotherapy (PTT). The journey of this nanoformulation within the TME contributed to the activation of the stimulator of the interferon gene pathway, the initiation of the immunogenic cell death effect, and the inhibition of the programmed cell death-1/programmed cell death ligand 1 (PD-1/PD-L1) signaling axis. This nanomedicine revitalizes the immunosuppressive TME and evokes the cascade effect of antitumor immunity. Therefore, the combination of BM@MnP-BSA-aPD-1 and PTT without chemotherapeutics presents favorable benefits in anti-GBM immunotherapy and exhibits immense potential for clinical translational applications.

Mechanisms and Barriers in Nanomedicine: Progress in the Field and Future Directions

In recent years, steady progress has been made in synthesizing and characterizing engineered nanoparticles, resulting in several approved drugs and multiple promising candidates in clinical trials. Regulatory agencies such as the Food and Drug Administration and the European Medicines Agency released important guidance documents facilitating nanoparticle-based drug product development, particularly in the context of liposomes and lipid-based carriers. Even with the progress achieved, it is clear that many barriers must still be overcome to accelerate translation into the clinic. At the recent conference workshop "Mechanisms and Barriers in Nanomedicine" in May 2023 in Colorado, U.S.A., leading experts discussed the formulation, physiological, immunological, regulatory, clinical, and educational barriers. This position paper invites open, unrestricted, nonproprietary discussion among senior faculty, young investigators, and students to trigger ideas and concepts to move the field forward.

Albumin Nanoparticles Increase the Efficacy of Doxorubicin Hydrochloride Liposome Injection Based on Threshold Theory

One of the most significant reasons hindering the clinical translation of nanomedicines is the rapid clearance of intravenously injected nanoparticles by the mononuclear phagocyte system, particularly by Kupffer cells in the liver, leading to an inefficient delivery of nanomedicines for tumor treatment. The threshold theory suggests that the liver's capacity to clear nanoparticles is limited, and a single high dose of nanoparticles can reduce the hepatic clearance efficiency, allowing more nanomedicines to reach tumor tissues and enhance therapeutic efficacy. Building upon this theory, researchers have conducted numerous validation studies based on the same nanoparticle carrier systems. These studies involve the use of albumin nanoparticles to improve the therapeutic efficacy of albumin nanomedicines as well as polyethylene glycol (PEG)-modified liposomal nanoparticles to enhance the efficacy of PEGylated liposomal nanomedicines. However, there is no research indicating the feasibility of the threshold theory when blank nanoparticles and nanomedicine belong to different nanoparticle carrier systems currently. In this study, we prepared two different sizes of albumin nanoparticles by using bovine serum albumin. We used the marketed nanomedicine liposomal doxorubicin hydrochloride injection (trade name: LIBOD, manufacturer: Shanghai Fudan-zhangjiang Biopharmaceutical Co., Ltd.), as the representative nanomedicine. Through in vivo experiments, we found that using threshold doses of albumin nanoparticles still can reduce the clearance rate of LIBOD, prolong its time in vivo, increase the area under the plasma concentration-time curve (AUC), and also lead to an increased accumulation of the drug at the tumor site. Furthermore, evaluation of in vivo efficacy and safety further indicates that threshold doses of 100 nm albumin nanoparticles can enhance the antitumor effect of LIBOD without causing harm to the animals. During the study, we found that the particle size of albumin nanoparticles influenced the in vivo distribution of the nanomedicine at the same threshold dose. Compared with 200 nm albumin nanoparticles, 100 nm albumin nanoparticles more effectively reduce the clearance efficiency of LIBOD and enhance nanomedicine accumulation at the tumor site, warranting further investigation. This study utilized albumin nanoparticles to reduce hepatic clearance efficiency and enhance the delivery efficiency of nonalbumin nanocarrier liposomal nanomedicine, providing a new avenue to improve the efficacy and clinical translation of nanomedicines with different carrier systems.

Nanomedicine Tumor Targeting

Nanomedicines are extensively explored for cancer therapy. By delivering drug molecules more efficiently to pathological sites and by attenuating their accumulation in healthy organs and tissues, nanomedicine formulations aim to improve the balance between drug efficacy and toxicity. More than 20 cancer nanomedicines are approved for clinical use, and hundreds of formulations are in (pre)clinical development. Over the years, several key pitfalls have been identified as bottlenecks in nanomedicine tumor targeting and translation. These go beyond materials- and production-related issues, and particularly also encompass biological barriers and pathophysiological heterogeneity. In this manuscript, the author describes the most important principles, progress, and products in nanomedicine tumor targeting, delineates key current problems and challenges, and discusses the most promising future prospects to create clinical impact.

Understanding nanoparticle-liver interactions in nanomedicine

INTRODUCTION

Understanding the interactions between administered nanoparticles and the liver is crucial for developing safe and effective nanomedicines. As the liver can sequester up to 99% of these particles due to its major phagocytic role, understanding these interactions is vital for clinical translation.

AREAS COVERED

This review highlights recent studies on nanoparticle-liver interactions, including the influence of nanoparticle physicochemical properties on delivery, strategies to enhance delivery efficiency by modulating liver Kupffer cells, and their potential for treating certain hepatic diseases. Additionally, we discuss how aging impacts the liver's phagocytic functions.

EXPERT OPINION

While liver accumulation can hinder nanomedicine safety and effectiveness, it also presents opportunities for treating certain liver diseases. A thorough understanding of nanoparticle-liver interactions is essential for advancing the clinical application of nanomedicines.

Rediscovery of mononuclear phagocyte system blockade for nanoparticle drug delivery

Rapid uptake of nanoparticles by mononuclear phagocyte system (MPS) significantly hampers their therapeutic efficacy. Temporal MPS blockade is one of the few ways to overcome this barrier - the approach rediscovered many times under different names but never extensively used in clinic. Using meta-analysis of the published data we prove the efficacy of this technique for enhancing particle circulation in blood and their delivery to tumours, describe a century of its evolution and potential combined mechanism behind it. Finally, we discuss future directions of the research focusing on the features essential for successful clinical translation of the method.

Enhancing in vivo cell and tissue targeting by modulation of polymer nanoparticles and macrophage decoys

The in vivo efficacy of polymeric nanoparticles (NPs) is dependent on their pharmacokinetics, including time in circulation and tissue tropism. Here we explore the structure-function relationships guiding physiological fate of a library of poly(amine-co-ester) (PACE) NPs with different compositions and surface properties. We find that circulation half-life as well as tissue and cell-type tropism is dependent on polymer chemistry, vehicle characteristics, dosing, and strategic co-administration of distribution modifiers, suggesting that physiological fate can be optimized by adjusting these parameters. Our high-throughput quantitative microscopy-based platform to measure the concentration of nanomedicines in the blood combined with detailed biodistribution assessments and pharmacokinetic modeling provides valuable insight into the dynamic in vivo behavior of these polymer NPs. Our results suggest that PACE NPs-and perhaps other NPs-can be designed with tunable properties to achieve desired tissue tropism for the in vivo delivery of nucleic acid therapeutics. These findings can guide the rational design of more effective nucleic acid delivery vehicles for in vivo applications.

Tumor versus Tumor Cell Targeting in Metal-Based Nanoparticles for Cancer Theranostics

The application of metal-based nanoparticles (mNPs) in cancer therapy and diagnostics (theranostics) has been a hot research topic since the early days of nanotechnology, becoming even more relevant in recent years. However, the clinical translation of this technology has been notably poor, with one of the main reasons being a lack of understanding of the disease and conceptual errors in the design of mNPs. Strikingly, throughout the reported studies to date on in vivo experiments, the concepts of "tumor targeting" and "tumor cell targeting" are often intertwined, particularly in the context of active targeting. These misconceptions may lead to design flaws, resulting in failed theranostic strategies. In the context of mNPs, tumor targeting can be described as the process by which mNPs reach the tumor mass (as a tissue), while tumor cell targeting refers to the specific interaction of mNPs with tumor cells once they have reached the tumor tissue. In this review, we conduct a critical analysis of key challenges that must be addressed for the successful targeting of either tumor tissue or cancer cells within the tumor tissue. Additionally, we explore essential features necessary for the smart design of theranostic mNPs, where 'smart design' refers to the process involving advanced consideration of the physicochemical features of the mNPs, targeting motifs, and physiological barriers that must be overcome for successful tumor targeting and/or tumor cell targeting.

Critical parameters to standardize the size and concentration determination of nanomaterials by nanoparticle tracking analysis

The size and concentration are critical for the diagnostic and therapeutic applications of nanomaterials but the accurate measurement remains challenging. Nanoparticle tracking analysis (NTA) is widely used for size and concentration determination. However, highly repeatable standard operating procedures (SOPs) are absent. We adopted the "search-evaluate-test" strategy to standardize the measurement by searching the critical parameters. The particles per frame are linearly proportional to the sample concentration and the measured results are more accurate and repeatable when the concentration is 108-109 particles/ml. The optimal detection threshold is around 5. The optimal camera level is such that it allows clear observation of particles without diffractive rings and overexposure. The optimal speed is ≤ 50 in AU and ∼ 10 μl/min in flow rate. We then evaluated the protocol using polydisperse polystyrene particles and we found that NTA could discriminate particles in bimodal mixtures with high size resolution but the performance on multimodal mixtures is not as good as that of resistive pulse sensing (RPS). We further analyzed the polystyrene particles, SiO2 particles, and biological samples by NTA following the SOPs. The size and concentration measured by NTA differentially varies to those determined by RPS and transmission electron microscopy.

Theranostic Bottle-Brush Polymers Tailored for Universal Solid-Tumor Targeting

Designing an efficient nanocarrier to target multiple types of cancer remains a major challenge in the development of cancer nanomedicines. The majority of systemically administered nanoparticles (NPs) are rapidly cleared by the liver, resulting in poor tumor-targeting efficiency and severe side effects. Here, we present a delicately tailored design and synthesis of fluorescent bottle-brush polymers and screen nine derived NPs, each varying in size and surface coatings, for tumor imaging and targeted delivery. Our optimized polymer bearing (oligo(ethylene glycol) methyl ether methacrylate) in the side chains shows reduced macrophage uptake, prolonged blood-circulation time (up to 27 h), and exceptionally high accumulation in the tumor compared to the liver, elucidating an immune-evasion-induced tumor-targeting mechanism. High tumor accumulation significantly improved the antitumor efficacy. The outstanding tumor-targeting ability has been further validated across five distinct tumor models, including orthotopic glioblastoma and pancreatic cancer, which demonstrate the universality of our polymeric nanocarrier for tumor-targeting delivery.

Convergence of nanomedicine and neutrophils for drug delivery

Neutrophils have recently emerged as promising carriers for drug delivery due to their unique properties including rapid response toward inflammation, chemotaxis, and transmigration. When integrated with nanotechnology that has enormous advantages in improving treatment efficacy and reducing side effects, neutrophil-based nano-drug delivery systems have expanded the repertoire of nanoparticles employed in precise therapeutic interventions by either coating nanoparticles with their membranes, loading nanoparticles inside living cells, or engineering chimeric antigen receptor (CAR)-neutrophils. These neutrophil-inspired therapies have shown superior biocompatibility, targeting ability, and therapeutic robustness. In this review, we summarized the benefits of combining neutrophils and nanotechnologies, the design principles and underlying mechanisms, and various applications in disease treatments. The challenges and prospects for neutrophil-based drug delivery systems were also discussed.