Effect of physicochemical properties on in vivo fate of nanoparticle-based cancer immunotherapies

Recent advances in PD-L1 siRNA nanocarriers for cancer therapy

Tumor immune evasion depends on the programmed death-ligand 1 (PD-L1) mechanism, making it a prominent target in cancer therapy. Small interfering RNA (siRNA) designed to inhibit PD-L1 expression presents an innovative approach for boosting immunity against tumors. However, the therapeutic use of siRNA faces challenges, primarily due to its instability and inefficient cellular delivery. Recent advancements in nanocarrier technologies have shown promise in overcoming these obstacles, improving the delivery and efficacy of PD-L1 siRNA. This review comprehensively explores various nanocarrier systems, including lipid nanoparticles, polymeric carriers, and inorganic nanoparticles, highlighting their design innovations and applications in targeting PD-L1 in diverse cancer models. We discuss the synergistic effects of PD-L1 siRNA delivered via nanocarriers in conjunction with chemotherapy and immunomodulators, showcasing their potential to boost immune responses and reduce tumor growth. Additionally, we address ongoing challenges such as optimizing biodistribution and minimizing off-target effects, which hinder clinical translation. By synthesizing recent research findings, this review aims to illuminate the transformative potential of PD-L1 siRNA nanocarriers in cancer immunotherapy, paving the way for future studies aimed at enhancing therapeutic strategies and improving patient outcomes.

Construction and application of macrophage-based extracellular drug-loaded delivery systems

Given their unique phagocytic function, inflammatory site tropism, and ability to penetrate deep into the lesion sites, macrophages are considered to have promising application potential in the field of living-cell drug delivery. The methods of drug delivery using macrophages primarily include intracellular phagocytic and extracellular drug loading. Comparatively, extracellular drug loading is potential less cytotoxicity and has minimal effects on the motility and orientation of cells. In this review, we provide an overview of the methods of extracellular drug loading, and examine the effects of the different properties of nanoformulations on extracellular drug-loaded delivery systems. In addition, we assess the prospects and challenges of a self-propelled macrophage-based drug delivery system. We hope this research contributes to optimizing the design of these drug delivery systems.

Emerging strategies in lymph node-targeted nano-delivery systems for tumor immunotherapy

The emergence of immunotherapy has led to the clinical approval of several related drugs. However, their efficacy against solid tumors remains limited. As the hub of immune activation, lymph nodes (LNs) play a critical role in tumor immunotherapy by initiating and amplifying immune responses. Nevertheless, the intricate physiological structure and barriers within LNs, combined with the immunosuppressive microenvironment induced by tumor cells, significantly impede the therapeutic efficacy of immunotherapy. Engineered nanoparticles (NPs) have shown great potential in overcoming these challenges by facilitating targeted drug transport to LNs and directly or indirectly activating T cells. This review systematically examines the structural features of LNs, key factors influencing the targeting efficiency of NPs, and current strategies for remodeling the immunosuppressive microenvironment of LNs. Additionally, it discusses future opportunities for optimizing NPs to enhance tumor immunotherapy, addressing challenges in clinical translation and safety evaluation.

Perfluorocarbon-Loaded Poly(lactide-co-glycolide) Nanoparticles from Core to Crust: Multifaceted Impact of Surfactant on Particle Ultrastructure, Stiffness, and Cell Uptake

Poly(lactide-co-glycolide) nanoparticles (PLGA NPs) loaded with Perfluoro-15-crown-5-ether (PFCE) have been developed for imaging applications. A slight modification of the formulation led to the formation of two distinct particle ultrastructures: multicore particles (MCPs) and core-shell particles (CSPs), where poly(vinyl alcohol) (PVA), a nonionic surfactant, and sodium cholate (NaCh), an anionic surfactant, were used, respectively. Despite their similar composition and colloidal characteristics, these particles have previously demonstrated significant differences in their in vivo distribution and clearance. We hypothesize that these differences are collectively driven by variations in their structural, chemical, and mechanical properties, which are investigated in this study. Nanomechanical characterizations of MCPs and CSPs by atomic force microscopy (AFM) revealed elastic modulus values of 54 and 270 MPa in water, respectively, indicating a better permeability and deformability of the multicore ultrastructure. The impact of the surfactant on the NP surface chemistry was evidenced by their protein corona, which was significantly greater in the CSPs. Additionally, an important amount of residual NaCh was found on the surface of CSPs, which formed strong interactions with bovine serum albumin (BSA), accounting for the difference in protein coronas and surface chemistry. Surprisingly, in vitro cell uptake studies showed a higher uptake of MCPs by RAW macrophages but a preference for CSPs by HeLa cells. We conclude that for this specific formulation and in this stiffness range, mechanical differences have a stronger impact in HeLa cells, while surface properties and chemical recognition play a more important role in uptake by macrophages. Overall, the extent to which a physical factor impacts cell uptake is highly dependent on the specific uptake mechanism. With this study, we provide an integrated perspective on the role of different surfactants in the particle formation process, their impact on particle ultrastructure, mechanical properties, and surface chemistry, and the overall effect on cell uptake in vitro.

Modulating active targeting nanoparticle design according to tumor progressions

Targeting drug delivery systems mediated by nanoparticles has shown great potential in the diagnosis and treatment of cancer. However, influences of different tumor progressions on the accumulation of nanoparticles, especially the ligand-modified active targeting nanoparticles are seldom exploited. In this work, the accumulation and penetration of RGD-modified gold nanoparticles (active AuNPs) with different sizes were investigated in orthotopic breast cancer with different tumor progressions. The results showed that the smallest active AuNPs had better accumulation and permeation effects in early tumor tissues with the relatively looser extracellular matrix, larger gaps, lower interstitial fluid pressure, and less receptor expression, which was due to size effects. However, the larger active AuNPs had better accumulation and penetration effects in late tumor tissues with highly expressed target receptors integrin α v β 3 because of the multivalent interactions between larger active nanoparticles and integrin α v β 3. In the midterm, tumor accumulation of active AuNPs was equally influenced by size effects and multivalent interactions. Therefore, RGD-modified nanoparticles with sizes of 7 and 90 nm accumulated more in tumors. This study will guide a rational design of active targeting nanoparticles for enhancing the diagnosis and treatment of tumors based on their progressions.

Hyaluronic acid regulated facile synthesis of size-tunable multifunctional nanomedicine for effective cancer therapy

The complex and heterogeneous nature of cancer necessitates the development of innovative multifunctional nanomedicines (MN). Hyaluronic acid (HA) is a functional carbohydrate polysaccharide that is widely used in various biomedical fields. In this study, we employed HA as a stabilizer and regulator for the synthesis of a size-tunable nanomedicine comprising ferric ions, doxorubicin, and epigallocatechin gallate (EGCG), referred to as HDE-MN, for cancer therapy. A change in the HA ratio can yield HDE-MNs with sizes varying from ~20 nm to over 100 nm. Modified HA can respond to hyaluronidase (HAase) to provide controllable pH/HAase dual-responsive drug release for improved cancer therapy. Moreover, HA can mediate the targeted delivery of HDE-MNs both in vitro and in vivo to cancer cells. In addition, HDE-MNs reversed multidrug resistance owing to the incorporation of EGCG, inducing ferroptosis due to the involvement of ferric ions. More importantly, HDE-MNs have a photothermal conversion effect, enabling photothermal therapy, photothermally enhanced drug release, and ferroptosis, which collectively contribute to significantly improved cancer therapy. Therefore, the HDE-MNs with laser irradiation achieved full ablation of the in vivo tumors. Together with its good biocompatibility, HDE-MNs may be promising for effective cancer therapy.

Impact of nanoparticle properties on immune cell interactions in the lymph node

The lymphatic system plays an important role in health and many diseases, such as cancer, autoimmune, cardiovascular, metabolic, hepatic, viral, and other infectious diseases. The lymphatic system is, therefore, an important treatment target site for a range of diseases. Lymph nodes (LNs), rich in T cells, B cells, dendritic cells, and macrophages, are also primary sites of action for vaccines and immunotherapies. Promoting the delivery of therapeutics and vaccines to LNs can, therefore, enhance treatment efficacy and facilitate avoidance of off-target side effects by enabling a reduction in therapeutic dose. Several nanoparticle (NP) based delivery systems, such as polymeric NPs, lipid NPs, liposomes, micelles, and dendrimers, have been reported to enhance the delivery of therapeutics and/or vaccines to LNs. Specific uptake into the lymph following injection into tissues is highly dependent on particle properties, particularly particle size, as small molecules are more likely to be taken up by blood capillaries due to higher blood flow rates, whereas larger molecules and NPs can be specifically transported via the lymphatic vessels to LNs as the initial lymphatic capillaries are more permeable than blood capillaries. Once NPs enter LNs, particle properties also have an important influence on their disposition within the node and association with immune cells, which has significant implications for the design of vaccines and immunotherapies. This review article focuses on the impact of NP properties, such as size, surface charge and modification, and route of administration, on lymphatic uptake, retention, and interactions with immune cells in LNs. We suggest that optimizing all these factors can enhance the efficacy of vaccines or therapeutics with targets in the lymphatics and also be helpful for the rational design of vaccines. STATEMENT OF SIGNIFICANCE: The lymphatic system plays an essential role in health and is an important treatment target site for a range of diseases. Promoting the delivery of immunotherapies and vaccines to immune cells in lymph nodes can enhance efficacy and facilitate avoidance of off-target side effects by enabling a reduction in therapeutic dose. One of the major approaches used to deliver therapeutics and vaccines to lymph nodes is via injection in nanoparticle delivery systems. This review aims to provide an overview of the impact of nanoparticle properties, such as size, surface charge, modification, and route of administration, on lymphatic uptake, lymph node retention, and interactions with immune cells in lymph nodes. This will inform the design of future improved nanoparticle systems for vaccines and immunotherapies.

In Vivo Delivery Processes and Development Strategies of Lipid Nanoparticles

Lipid nanoparticles (LNPs) represent an advanced and highly efficient delivery system for RNA molecules, demonstrating exceptional biocompatibility and remarkable delivery efficiency. This is evidenced by the clinical authorization of three LNP formulations: Patisiran, BNT162b2, and mRNA-1273. To further maximize the efficacy of RNA-based therapy, it is imperative to develop more potent LNP delivery systems that can effectively protect inherently unstable and negatively charged RNA molecules from degradation by nucleases, while facilitating their cellular uptake into target cells. Therefore, this review presents feasible strategies commonly employed for the development of efficient LNP delivery systems. The strategies encompass combinatorial chemistry for large-scale synthesis of ionizable lipids, rational design strategy of ionizable lipids, functional molecules-derived lipid molecules, the optimization of LNP formulations, and the adjustment of particle size and charge property of LNPs. Prior to introducing these developing strategies, in vivo delivery processes of LNPs, a crucial determinant influencing the clinical translation of LNP formulations, is described to better understand how to develop LNP delivery systems.

Nano-fluorescence imaging: advancing lymphatic disease diagnosis and monitoring

The lymphatic system plays a crucial role in maintaining physiological homeostasis and regulating immune responses. Traditional imaging modalities such as magnetic resonance imaging, computerized tomography, and positron emission tomography have been widely used to diagnose disorders in the lymphatic system, including lymphedema, lymphangioma, lymphatic metastasis, and Castleman disease. Nano-fluorescence technology has distinct advantages-including naked-eye visibility, operational simplicity, portability of the laser, and real-time visibility-and serves as an innovative alternative to traditional imaging techniques. This review explores recent advancements in nano-fluorescence imaging aimed at enhancing the resolution of lymphatic structure, function, and immunity. After delineating the fundamental characteristics of lymphatic systems, it elaborates on the development of various nano-fluorescence systems (including nanoparticles incorporating fluorescent dyes and those with intrinsic fluorescence) while addressing key challenges such as photobleaching, limited tissue penetration, biocompatibility, and signal interference from biomolecules. Furthermore, this review highlights the clinical applications of nano-fluorescence and its potential integration into standard diagnostic protocols. Ongoing advancements in nanoparticle technology underscore the potential of nano-fluorescence to revolutionize the diagnosis and treatment of lymphatic disease.

Effects of nanoparticle size, shape, and zeta potential on drug delivery

Nanotechnology has brought about a significant revolution in drug delivery, and research in this domain is increasingly focusing on understanding the role of nanoparticle (NP) characteristics in drug delivery efficiency. First and foremost, we center our attention on the size of nanoparticles. Studies have indicated that NP size significantly influences factors such as circulation time, targeting capabilities, and cellular uptake. Secondly, we examine the significance of nanoparticle shape. Various studies suggest that NPs of different shapes affect cellular uptake mechanisms and offer potential advantages in directing drug delivery. For instance, cylindrical or needle-like NPs may facilitate better cellular uptake compared to spherical NPs. Lastly, we address the importance of nanoparticle charge. Zeta potential can impact the targeting and cellular uptake of NPs. Positively charged NPs may be better absorbed by negatively charged cells, whereas negatively charged NPs might perform more effectively in positively charged cells. This review provides essential insights into understanding the role of nanoparticles in drug delivery. The properties of nanoparticles, including size, shape, and charge, should be taken into consideration in the rational design of drug delivery systems, as optimizing these characteristics can contribute to more efficient targeting of drugs to the desired tissues. Thus, research into nanoparticle properties will continue to play a crucial role in the future of drug delivery.

Evaluation of PLGA, lipid-PLGA hybrid nanoparticles, and cationic pH-sensitive liposomes as tuberculosis vaccine delivery systems in a Mycobacterium tuberculosis challenge mouse model - A comparison

Tuberculosis (TB) continues to pose a global threat for millennia, currently affecting over 2 billion people and causing 10.6 million new cases and 1.3 million deaths annually. The only existing vaccine, Mycobacterium Bovis Bacillus Calmette-Guérin (BCG), provides highly variable and inadequate protection in adults and adolescents. This study explores newly developed subunit tuberculosis vaccines that use a multistage protein fusion antigen Ag85b-ESAT6-Rv2034 (AER). The protection efficacy, as well as in vivo induced immune responses, were compared for five vaccines: BCG; AER-CpG/MPLA mix; poly(D,L-lactic-co-glycolic acid) (PLGA); lipid-PLGA hybrid nanoparticles (NPs); and cationic pH-sensitive liposomes (the latter three delivering AER together with CpG and MPLA). All vaccines, except the AER-adjuvant mix, induced protection in Mycobacterium tuberculosis (Mtb)-challenged C57/Bl6 mice as indicated by a significant reduction in bacterial burden in lungs and spleens of the animals. Four AER-based vaccines significantly increased the number of circulating multifunctional CD4+ and CD8+ T-cells producing IL-2, IFNγ, and TNFα, exhibiting a central memory phenotype. Furthermore, AER-based vaccines induced an increase in CD69+ B-cell counts as well as high antigen-specific antibody titers. Unexpectedly, none of the observed immune responses were associated with the bacterial burden outcome, such that the mechanism responsible for the observed vaccine-induced protection of these vaccines remains unclear. These findings suggest the existence of non-classical protective mechanisms for Mtb infection, which could, once identified, provide interesting targets for novel vaccines.

Preclinical evaluation of polymer encapsulated carbon-based nano and microparticles for sentinel lymph node tattooing

Selective sentinel lymph node biopsy (SNLB) is the standard method for detecting regional metastases in breast cancer patients. Identifying affected axillary lymph nodes before neoadjuvant treatment is crucial, as such treatment may alter drainage pathways and lymph node morphology, hindering the identification of sentinel lymph nodes. The use of carbon-based tattooing on sentinel lymph nodes (SLN) has been employed as a permanent tattooing method in clinical studies of Targeted Axillary Dissection (TAD), aiding in the SLN identification during surgery. Our study introduces a new method of lymph node tattooing based on poly lactic-co-glycolic (PLGA) particles with encapsulated carbon. This strategy substantially improves tattooing efficiency over single carbon suspensions currently used in clinical studies. We synthesized and characterized carbon-loaded PLGA micro- and nanoparticles, experimentally assessing their biological impact on porcine lymph nodes. The effect of particles' size and concentration was evaluated over time (from 1 to 16 weeks). Light and electron microscopy studies were conducted to characterize the cellular effects induced by the presence of these particles. Our findings reveal that the diverse physicochemical parameters of the particles interact differently with the lymphatic tissue, influencing their biodistribution within the lymph nodes and the intensity of the inflammatory response.

Exemplifying interspecies variation of liposome in vivo fate by the effects of anti-PEG antibodies

The different fate of liposomes among species has been discovered and mentioned in many studies, but the underlying mechanisms have not been explored. In the present work, we concentrated on the in vivo fate of PEGylated liposomes (sLip) in three commonly used species (mice, rats, and dogs). It was exhibited that the accelerated blood clearance (ABC) phenomenon and hypersensitivity in large animals (beagle dogs) were much more significant than that in rodents. We demonstrated that anti-PEG IgM (partially) and complement (mostly) determined the elimination of sLip and linked the distinct interspecies performances with the diverse complement capacity among species. Based on the data from animals and clinical patients, it was revealed that the fate of sLip in large animals was closer to that in humans, for the sufficient complement capacity could expose the potential adverse reactions caused by anti-PEG antibodies. Our results suggested that the distinctive interspecies performances of sLip were highly related to the physiological variabilities among species, which should not be overlooked in the innovation and translation of nanomedicines.

Design and development of dual targeting CAR protein for the development of CAR T-cell therapy against KRAS mutated pancreatic ductal adenocarcinoma using computational approaches

Mutant KRAS promotes the proliferation, metastasis, and aggressiveness of various cancers including pancreatic ductal adenocarcinoma (PDAC), non-small cell lung cancer (NSCLC), and colorectal adenocarcinoma (CRC) respectively. Mutant KRAS therapeutics are limited, while Sotorasib and Adagrasib were the only FDA-approved drugs for the treatment of KRASG12C mutated NSCLC. Chimeric antigen receptor (CAR) T-cell therapy has been emerged as an effective strategy against hematological malignancies and being extended towards solid cancers including PDAC. mesothelin (MSLN) and Carcinoembryonic Antigen (CEA) were reported to be highly overexpressed in KRAS-mutated PDAC. Meanwhile, in clinical trials, several CAR T-cell therapy studies are mainly focused towards these two cancer antigens in PDAC, however, the dual targeting of these two neoantigens is not reported. In the present study, we have designed and developed a novel dual-targeting CAR protein by employing various bioinformatics approaches such as functional analysis (antigenicity, allergenicity, antigen binding sites & signalling cascades), qualitative analysis (physicochemical, prediction, refinement & validation of 2D and 3D structures), molecular docking, and in silico cloning. Our results revealed that the designed CAR protein specifically binds with both MSLN & CEA with significant binding affinities, and was predicted to be stable & non-allergenic. Additionally, the protein-protein interaction network reveals the T-cell mediated antitumor responses of each domain in the designed CAR. Conclusively, we have designed and developed a dual targeting (MSLN & CEA) CAR protein towards KRAS-mutated PDAC using computational approaches. Alongside, we further recommend to engineer this designed CAR in T-cells and evaluating their therapeutic efficiency in in vitro and in vivo studies in the near future.

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.

Modulating Elasticity of Liposome for Enhanced Cancer Immunotherapy

Cancer immunotherapy has emerged as a promising approach to cancer treatment in recent years. The physical and chemical properties of nanocarriers are critical factors that regulate the immune activation of antigen-presenting cells (APCs) in the tumor microenvironment (TME). Herein, we extensively investigated the behavior of liposome nanoparticles (Lipo-NPs) with different elasticities, focusing on their interaction with immune cells and their transport mechanisms from tumors to tumor-draining lymph nodes (tdLNs). Successfully preparing Lipo-NPs with distinct elastic properties, their varied behaviors were observed, concerning immune cell interaction. Soft Lipo-NPs exhibited an affinity to cell membranes, while those with medium elasticity facilitated the cargo delivery to macrophages through membrane fusion. Conversely, hard Lipo-NPs enter macrophages via classical cellular uptake pathways. Additionally, it was noted that softer Lipo-NPs displayed superior transport to tdLNs in vivo, attributed to their deformable nature with lower elasticity. As a result, the medium elastic Lipo-NPs with agonists (cGAMP), by activating the STING pathway and enhancing transport to tdLNs, promoted abundant infiltration of tumor-infiltrating lymphocytes (TILs), leading to notable antitumor effects and extended survival in a melanoma mouse model. Furthermore, this study highlighted the potential synergistic effect of medium elasticity Lipo-NPs with immune checkpoint blockade (ICB) therapy in preventing tumor immune evasion. These findings hold promise for guiding immune-targeted delivery systems in cancer immunotherapy, particularly in vaccine design for tdLNs targeting and eradicating metastasis within tdLNs.

Nanomedicine in Neuroprotection, Neuroregeneration, and Blood-Brain Barrier Modulation: A Narrative Review

Nanomedicine is a newer, promising approach to promote neuroprotection, neuroregeneration, and modulation of the blood-brain barrier. This review includes the integration of various nanomaterials in neurological disorders. In addition, gelatin-based hydrogels, which have huge potential due to biocompatibility, maintenance of porosity, and enhanced neural process outgrowth, are reviewed. Chemical modification of these hydrogels, especially with guanidine moieties, has shown improved neuron viability and underscores tailored biomaterial design in neural applications. This review further discusses strategies to modulate the blood-brain barrier-a factor critically associated with the effective delivery of drugs to the central nervous system. These advances bring supportive solutions to the solving of neurological conditions and innovative therapies for their treatment. Nanomedicine, as applied to neuroscience, presents a significant leap forward in new therapeutic strategies that might help raise the treatment and management of neurological disorders to much better levels. Our aim was to summarize the current state-of-knowledge in this field.

Lipid- and Polymer-Based Nanocarrier Platforms for Cancer Vaccine Delivery

Cancer immunotherapy has gained popularity in recent years in the search for effective treatment modalities for various malignancies, particularly those that are resistant to conventional chemo- and radiation therapy. Cancer vaccines target the cancer-immunity cycle by boosting the patient's own immune system to recognize and kill cancer cells, thus serving as both preventative and curative therapeutic tools. Among the different types of cancer vaccines, those based on nanotechnology have shown great promise in advancing the field of cancer immunotherapy. Lipid-based nanoparticles (NPs) have become the most advanced platforms for cancer vaccine delivery, but polymer-based NPs have also received considerable interest. This Review aims to provide an overview of the nanotechnology-enabled cancer vaccine landscape, focusing on recent advances in lipid- and polymer-based nanovaccines and their hybrid structures and discussing the challenges against the clinical translation of these important nanomedicines.

Harnessing Immunomodulatory Polymers for Treatment of Autoimmunity, Allergy, and Transplant Rejection

Autoimmunity, allergy, and transplant rejection are a collection of chronic diseases that are currently incurable, drastically decrease patient quality of life, and consume considerable health care resources. Underlying each of these diseases is a dysregulated immune system that results in the mounting of an inflammatory response against self or an innocuous antigen. As a consequence, afflicted patients are required to adhere to lifelong regimens of multiple immunomodulatory drugs to control disease and reclaim agency. Unfortunately, current immunomodulatory drugs are associated with a myriad of side effects and adverse events, such as increased risk of cancer and increased risk of serious infection, which negatively impacts patient adherence rates and quality of life. The field of immunoengineering is a new discipline that aims to harness endogenous biological pathways to thwart disease and minimize side effects using novel biomaterial-based strategies. We highlight and discuss polymeric micro/nanoparticles with inherent immunomodulatory properties that are currently under investigation in biomaterial-based therapies for treatment of autoimmunity, allergy, and transplant rejection.

Bridging Smart Nanosystems with Clinically Relevant Models and Advanced Imaging for Precision Drug Delivery

Intracellular delivery of nano-drug-carriers (NDC) to specific cells, diseased regions, or solid tumors has entered the era of precision medicine that requires systematic knowledge of nano-biological interactions from multidisciplinary perspectives. To this end, this review first provides an overview of membrane-disruption methods such as electroporation, sonoporation, photoporation, microfluidic delivery, and microinjection with the merits of high-throughput and enhanced efficiency for in vitro NDC delivery. The impact of NDC characteristics including particle size, shape, charge, hydrophobicity, and elasticity on cellular uptake are elaborated and several types of NDC systems aiming for hierarchical targeting and delivery in vivo are reviewed. Emerging in vitro or ex vivo human/animal-derived pathophysiological models are further explored and highly recommended for use in NDC studies since they might mimic in vivo delivery features and fill the translational gaps from animals to humans. The exploration of modern microscopy techniques for precise nanoparticle (NP) tracking at the cellular, organ, and organismal levels informs the tailored development of NDCs for in vivo application and clinical translation. Overall, the review integrates the latest insights into smart nanosystem engineering, physiological models, imaging-based validation tools, all directed towards enhancing the precise and efficient intracellular delivery of NDCs.

Intranasal administration enhances size-dependent pulmonary phagocytic uptake of poly(lactic-co-glycolic acid) nanoparticles

BACKGROUND

Nanoparticles exhibit distinct behaviours within the body, depending on their physicochemical properties and administration routes. However, in vivo behaviour of poly(lactic-co-glycolic acid) (PLGA) nanoparticles, especially when administered nasally, remains unexplored; furthermore, there is a lack of comparative analysis of uptake efficiency among different administration routes. Therefore, here, we aimed to comprehensively investigate the real-time in vivo behaviour of PLGA nanoparticles across various administration routes. PLGA-NH2 nanoparticles of three sizes were synthesised using an oil-in-water single-emulsion method. We assessed their uptake by murine macrophage RAW264.7 cells using fluorescence microscopy. To enable real-time tracking, we conjugated p-SCN-Bn-deferoxamine to PLGA-NH2 nanoparticles and further radiolabelled them with 89Zr-oxalate before administration to mice via different routes. Nanoparticle internalisation by lung immune cells was monitored using fluorescence-activated cell sorting analysis.

RESULTS

The nanoparticle sizes were 294 ± 2.1 (small), 522.5 ± 5.58 (intermediate), and 850 ± 18.52 nm (large). Fluorescent labelling did not significantly alter the nanoparticle size and charge. The level of uptake of small and large nanoparticles by RAW264.7 cells was similar, with phagocytosis inhibition primarily reducing the internalisation of large particles. Positron emission tomography revealed that intranasal delivery resulted in the highest and most targeted pulmonary uptake, whereas intravenous administration led to accumulation mainly in the liver and spleen. Nasal delivery of large nanoparticles resulted in enhanced uptake by myeloid immune cells relative to lymphoid cells, whereas dendritic cell uptake initially peaked but declined over time.

CONCLUSIONS

Our study provides valuable insights into advancing nanomedicine and drug delivery, with the potential for expanding the clinical applications of nanoparticles.

CD4+ T cell-targeting immunoliposomes for treatment of latent HIV reservoir

Active targeting nano-delivery is a promising approach to enhance therapeutic efficacy and specificity to the target cells. Liposomes (LPs) have been widely studied for the active targeting delivery due to their low toxicity, biodegradability, biocompatibility, and feasibility of surface medication to provide the interactions with cell receptors. One of the strategies is to functionalize the surface of LPs with monoclonal antibodies (mAbs) to obtain immunoliposomes (imLPs) that recognize specific receptors on target cells. Among several target cells, CD4+ T cells are known for playing a pivotal role in controlling the immune system in several diseases, including cancers, inflammatory diseases, and viral infections, particularly HIV-1. Here, we demonstrate two methods for conjugating αCD4 mAb with imLPs for specific targeting of CD4+ T cells that can harbor viral genome and serve as a predominant latent HIV reservoir. LPs conjugated with αCD4 mAb via neutravidin-biotin linkage were used for selectively targeting CD4+ J-Lat 10.6 cells. We demonstrate, via flow cytometry, the importance of the conjugation step, mAb density, and the presence of polyethylene glycol (PEG) for effective drug delivery to CD4+ T cells. The cellular uptake of imLPs is substantially higher if the imLPs are functionalized with the pre-conjugated αCD4 mAb-neutravidin complex. Furthermore, imLPs loaded with HIV-1 latency reversing agent, suberoylanilide hydroxamic acid (SAHA), could reactivate the J-Lat 10.6 cells, suggesting that the αCD4-imLPs could be potentially used as a targeted drug delivery system for HIV-1 latency reactivation or other CD4-targeted immunotherapies.

mRNA vaccine designs for optimal adjuvanticity and delivery

Adjuvanticity and delivery are crucial facets of mRNA vaccine design. In modern mRNA vaccines, adjuvant functions are integrated into mRNA vaccine nanoparticles, allowing the co-delivery of antigen mRNA and adjuvants in a unified, all-in-one formulation. In this formulation, many mRNA vaccines utilize the immunostimulating properties of mRNA and vaccine carrier components, including lipids and polymers, as adjuvants. However, careful design is necessary, as excessive adjuvanticity and activation of improper innate immune signalling can conversely hinder vaccination efficacy and trigger adverse effects. mRNA vaccines also require delivery systems to achieve antigen expression in antigen-presenting cells (APCs) within lymphoid organs. Some vaccines directly target APCs in the lymphoid organs, while others rely on APCs migration to the draining lymph nodes after taking up mRNA vaccines. This review explores the current mechanistic understanding of these processes and the ongoing efforts to improve vaccine safety and efficacy based on this understanding.

Size-Dependent In Vivo Transport of Nanoparticles: Implications for Delivery, Targeting, and Clearance

Understanding the in vivo transport of nanoparticles provides guidelines for designing nanomedicines with higher efficacy and fewer side effects. Among many factors, the size of nanoparticles plays a key role in controlling their in vivo transport behaviors due to the existence of various physiological size thresholds within the body and size-dependent nano-bio interactions. Encouraged by the evolving discoveries of nanoparticle-size-dependent biological effects, we believe that it is necessary to systematically summarize the size-scaling laws of nanoparticle transport in vivo. In this review, we summarized the size effect of nanoparticles on their in vivo transport along their journey in the body: begin with the administration of nanoparticles via different delivery routes, followed by the targeting of nanoparticles to intended tissues including tumors and other organs, and eventually clearance of nanoparticles through the liver or kidneys. We outlined the tools for investigating the in vivo transport of nanoparticles as well. Finally, we discussed how we may leverage the size-dependent transport to tackle some of the key challenges in nanomedicine translation and also raised important size-related questions that remain to be answered in the future.

Current research trends of nanomedicines

Owing to the inherent shortcomings of traditional therapeutic drugs in terms of inadequate therapeutic efficacy and toxicity in clinical treatment, nanomedicine designs have received widespread attention with significantly improved efficacy and reduced non-target side effects. Nanomedicines hold tremendous theranostic potential for treating, monitoring, diagnosing, and controlling various diseases and are attracting an unfathomable amount of input of research resources. Against the backdrop of an exponentially growing number of publications, it is imperative to help the audience get a panorama image of the research activities in the field of nanomedicines. Herein, this review elaborates on the development trends of nanomedicines, emerging nanocarriers, in vivo fate and safety of nanomedicines, and their extensive applications. Moreover, the potential challenges and the obstacles hindering the clinical translation of nanomedicines are also discussed. The elaboration on various aspects of the research trends of nanomedicines may help enlighten the readers and set the route for future endeavors.

Therapeutic potential of nanotechnology in reproduction disorders and possible limitations

One of the prominent peculiarities of nanoparticles (NPs) is their ability to cross biological barriers. Therefore, the development of NPs with different properties has great therapeutic potential in the area of reproduction because the association of drugs, hormones and other compounds with NPs represents an alternative for delivering substances directly at a specific site and for treatment of reproductive problems. Additionally, lipid-based NPs can be taken up by the tissues of patients with ovarian failure, deep endometriosis, testicular dysfunctions, etc., opening up new perspectives for the treatment of these diseases. The development of nanomaterials with specific size, shape, ligand density and charge certainly will contribute to the next generation of therapies to solve fertility problems in humans. Therefore, this review discusses the potential of NPs to treat reproductive disorders, as well as to regulate the levels of the associated hormones. The possible limitations of the clinical use of NPs are also highlighted.

The interplay between PEGylated nanoparticles and blood immune system

During the last two decades, an increasing number of reports have pointed out that the immunogenicity of polyethylene glycol (PEG) may trigger accelerated blood clearance (ABC) and hypersensitivity reaction (HSR) to PEGylated nanoparticles, which could make PEG modification counterproductive. These phenomena would be detrimental to the efficacy of the load and even life-threatening to patients. Consequently, further elucidation of the interplay between PEGylated nanoparticles and the blood immune system will be beneficial to developing and applying related formulations. Many groups have worked to unveil the relevance of structural factors, dosing schedule, and other factors to the ABC phenomenon and hypersensitivity reaction. Interestingly, the results of some reports seem to be difficult to interpret or contradict with other reports. In this review, we summarize the physiological mechanisms of PEG-specific immune response. Moreover, we speculate on the potential relationship between the induction phase and the effectuation phase to explain the divergent results in published reports. In addition, the role of nanoparticle-associated factors is discussed based on the classification of the action phase. This review may help researchers to develop PEGylated nanoparticles to avoid unfavorable immune responses based on the underlying mechanism.

Orchestrating antigen delivery and presentation efficiency in lymph node by nanoparticle shape for immune response

Activating humoral and cellular immunity in lymph nodes (LNs) of nanoparticle-based vaccines is critical to controlling tumors. However, how the physical properties of nanovaccine carriers orchestrate antigen capture, lymphatic delivery, antigen presentation and immune response in LNs is largely unclear. Here, we manufactured gold nanoparticles (AuNPs) with the same size but different shapes (cages, rods, and stars), and loaded tumor antigen as nanovaccines to explore their disparate characters on above four areas. Results revealed that star-shaped AuNPs captured and retained more repetitive antigen epitopes. On lymphatic delivery, both rods and star-shaped nanovaccines mainly drain into the LN follicles region while cage-shaped showed stronger paracortex retention. A surprising finding is that the star-shaped nanovaccines elicited potent humoral immunity, which is mediated by CD4+ T helper cell and follicle B cell cooperation significantly preventing tumor growth in the prophylactic study. Interestingly, cage-shaped nanovaccines preferentially presented peptide-MHC I complexes to evoke robust CD8+ T cell immunity and showed the strongest therapeutic efficacy when combined with the PD-1 checkpoint inhibitor in established tumor study. These results highlight the importance of nanoparticle shape on antigen delivery and presentation for immune response in LNs, and our findings support the notion that different design strategies are required for prophylactic and therapeutic vaccines.

New trends in brain tumor immunity with the opportunities of lymph nodes targeted drug delivery

Lymph nodes targeted drug delivery is an attractive approach to improve cancer immunotherapy outcomes. Currently, the depth of understanding of afferent and efferent arms in brain immunity reveals the potential clinical applications of lymph node targeted drug delivery in brain tumors, e.g., glioblastoma. In this work, we systematically reviewed the microenvironment of glioblastoma and its structure as a basis for potential immunotherapy, including the glial-lymphatic pathway for substance exchange, the lymphatic drainage pathway from meningeal lymphatic vessels to deep cervical lymph nodes that communicate intra- and extracranial immunity, and the interaction between the blood-brain barrier and effector T cells. Furthermore, the carriers designed for lymph nodes targeted drug delivery were comprehensively summarized. The challenges and opportunities in developing a lymph nodes targeted delivery strategy for glioblastoma using nanotechnology are included at the end.

Advanced subunit vaccine delivery technologies: From vaccine cascade obstacles to design strategies

Designing and manufacturing safe and effective vaccines is a crucial challenge for human health worldwide. Research on adjuvant-based subunit vaccines is increasingly being explored to meet clinical needs. Nevertheless, the adaptive immune responses of subunit vaccines are still unfavorable, which may partially be attributed to the immune cascade obstacles and unsatisfactory vaccine design. An extended understanding of the crosstalk between vaccine delivery strategies and immunological mechanisms could provide scientific insight to optimize antigen delivery and improve vaccination efficacy. In this review, we summarized the advanced subunit vaccine delivery technologies from the perspective of vaccine cascade obstacles after administration. The engineered subunit vaccines with lymph node and specific cell targeting ability, antigen cross-presentation, T cell activation properties, and tailorable antigen release patterns may achieve effective immune protection with high precision, efficiency, and stability. We hope this review can provide rational design principles and inspire the exploitation of future subunit vaccines.

Targeting lymph node delivery with nanovaccines for cancer immunotherapy: recent advances and future directions

Although cancer immunotherapy is a compelling approach against cancer, its effectiveness is hindered by the challenge of generating a robust and durable immune response against metastatic cancer cells. Nanovaccines, specifically engineered to transport cancer antigens and immune-stimulating agents to the lymph nodes, hold promise in overcoming these limitations and eliciting a potent and sustained immune response against metastatic cancer cells. This manuscript provides an in-depth exploration of the lymphatic system's background, emphasizing its role in immune surveillance and tumor metastasis. Furthermore, it delves into the design principles of nanovaccines and their unique capability to target lymph node metastasis. The primary objective of this review is to provide a comprehensive overview of the current advancements in nanovaccine design for targeting lymph node metastasis, while also discussing their potential to enhance cancer immunotherapy. By summarizing the state-of-the-art in nanovaccine development, this review aims to shed light on the promising prospects of harnessing nanotechnology to potentiate cancer immunotherapy and ultimately improve patient outcomes.

Polymer Nanoantidotes

Intoxication is one of the most common causes of accidental death globally. Although some antidotes capable of neutralizing the toxicity of certain xenobiotics have become well established, the current reality is that clinicians primarily rely on nonspecific extracorporeal techniques to remove toxins. Nano-intervention strategies in which nanoantidotes neutralize toxicity in situ via physical interaction, chemical bonding, or biomimetic clearance have begun to show clinical potential. However, most nanoantidotes remain in the proof-of-concept stage, and the difficulty of constructing clinical relevance models and the unclear pharmacokinetics of nanoantidotes hinder their translation to clinic. This Concept reviews the detoxification mechanisms of polymer nanoantidotes and predicts the opportunities and challenges associated with their clinical application.

Application of Nano-Delivery Systems in Lymph Nodes for Tumor Immunotherapy

Immunotherapy has become a promising research "hotspot" in cancer treatment. "Soldier" immune cells are not uniform throughout the body; they accumulate mostly in the immune organs such as the spleen and lymph nodes (LNs), etc. The unique structure of LNs provides the microenvironment suitable for the survival, activation, and proliferation of multiple types of immune cells. LNs play an important role in both the initiation of adaptive immunity and the generation of durable anti-tumor responses. Antigens taken up by antigen-presenting cells in peripheral tissues need to migrate with lymphatic fluid to LNs to activate the lymphocytes therein. Meanwhile, the accumulation and retaining of many immune functional compounds in LNs enhance their efficacy significantly. Therefore, LNs have become a key target for tumor immunotherapy. Unfortunately, the nonspecific distribution of the immune drugs in vivo greatly limits the activation and proliferation of immune cells, which leads to unsatisfactory anti-tumor effects. The efficient nano-delivery system to LNs is an effective strategy to maximize the efficacy of immune drugs. Nano-delivery systems have shown beneficial in improving biodistribution and enhancing accumulation in lymphoid tissues, exhibiting powerful and promising prospects for achieving effective delivery to LNs. Herein, the physiological structure and the delivery barriers of LNs were summarized and the factors affecting LNs accumulation were discussed thoroughly. Moreover, developments in nano-delivery systems were reviewed and the transformation prospects of LNs targeting nanocarriers were summarized and discussed.

Recent advancements in design of nucleic acid nanocarriers for controlled drug delivery

Research of nanoscale nucleic acid carriers has garnered attention in recent years due to their distinctive and controllable properties. However, current knowledge is limited in how we can efficiently utilize these systems for clinical applications. Several researchers have pioneered new and innovative nanocarrier drug delivery systems, but understanding physiochemical properties and behavior in vivo is vital to implementing them as clinical drug delivery platforms. In this review, we outline the most significant innovations in the synthesis, physical properties, and utilization of nucleic acid nanocarriers in the past 5 years, addressing the crucial properties which improve nanocarrier characteristics, delivery, and drug release. The challenges of controlling the transport of nucleic acid nanocarriers and therapeutic release for biological applications are outlined. Barriers which inhibit effective transport into tissue are discussed with emphasis on the modifications needed to overcome such obstacles. The novel strategies discussed in this work summarize the pivotal features of modern nucleic nanocarriers and postulate where future developments could revolutionize the translation of these tools into a clinical setting.

Nucleic acid nanostructures for in vivo applications: The influence of morphology on biological fate

The development of programmable biomaterials for use in nanofabrication represents a major advance for the future of biomedicine and diagnostics. Recent advances in structural nanotechnology using nucleic acids have resulted in dramatic progress in our understanding of nucleic acid-based nanostructures (NANs) for use in biological applications. As the NANs become more architecturally and functionally diverse to accommodate introduction into living systems, there is a need to understand how critical design features can be controlled to impart desired performance in vivo. In this review, we survey the range of nucleic acid materials utilized as structural building blocks (DNA, RNA, and xenonucleic acids), the diversity of geometries for nanofabrication, and the strategies to functionalize these complexes. We include an assessment of the available and emerging characterization tools used to evaluate the physical, mechanical, physiochemical, and biological properties of NANs in vitro. Finally, the current understanding of the obstacles encountered along the in vivo journey is contextualized to demonstrate how morphological features of NANs influence their biological fates. We envision that this summary will aid researchers in the designing novel NAN morphologies, guide characterization efforts, and design of experiments and spark interdisciplinary collaborations to fuel advancements in programmable platforms for biological applications.

Surgically Derived Cancer Cell Membrane-Coated R837-Loaded Poly(2-Oxazoline) Nanoparticles for Prostate Cancer Immunotherapy

Cancer cell membranes (CCMs) are widely used as sources of tumor-associated antigens (TAAs) for the development of cancer vaccines. To improve the CCM-associated cancer vaccine efficiency, personalized cancer vaccines and effective delivery systems are required. In this study, we employed surgically harvested cancer tissues to prepare personalized CCMs for use as TAAs. Thioglycolic-acid-grafted poly(2-methyl-2-oxazoline)-block-poly(2-butyl-2-oxazoline-co-2-butenyl-2-oxazoline) (PMBEOx-COOH) was synthesized to load imiquimod (R837) efficiently. The personalized CCMs were then coated onto R837-loaded PMBEOx-COOH nanoparticles (POxTA NPs/R837) to obtain surgically derived CCM-coated POxTA NPs (SCNPs/R837). SCNPs/R837 efficiently travelled to the draining lymph nodes and were taken up and presented by plasmacytoid dendritic cells to elicit enhanced antitumor immune responses. When combined with programmed cell death-1 antibodies, SCNPs/R837 exhibited high efficiency corresponding to antitumor progression. Therefore, SCNP/R837 might represent a promising personalized cancer vaccine with significant potential for cancer immunotherapy.

"Hook&Loop" multivalent interactions based on disk-shaped nanoparticles strengthen active targeting

How to enhance active targeting efficiency remains a challenge. Multivalent interactions play a crucial role in improving the binding ability between ligands and receptors. It is hypothesized that nanoparticles bearing a flat conformation attain simultaneous formation of multiple ligand-receptor bindings, which could be vividly metaphorized by the "Hook&Loop" rationale. In this study, spherical, rod-shaped and disk-shaped folic acid-modified red blood cell membrane-coated biomimetic mesoporous silica nanoparticles (FRMSNs) were prepared to verify the shape-based multivalent interactions. The fundamental concepts of multivalent interactions have been proved by a series of both in vitro and in vivo evaluations. Physical characterization confirmed the morphology, shape and surface features of FRMSNs. Strengthened binding and internalization of disk-shaped FRMSNs by K562 cells stresses the merits of multivalent interactions. Whereas Bio-TEM visually demonstrates the proposed "plane" contact of disk-shaped particles with cells, quantification further confirmed strengthened "plane" binding affinity with folate binding proteins owing to multivalent interactions. In K562 xenograft mice, doxorubicin-loaded disk-shaped FRMSNs effectively slowed down chronic myeloid leukemia progression. It is concluded that disks favor multivalent interactions which leads to enhanced active targeting efficiency.

Nanomedicine embraces cancer radio-immunotherapy: mechanism, design, recent advances, and clinical translation

Cancer radio-immunotherapy, integrating external/internal radiation therapy with immuno-oncology treatments, emerges in the current management of cancer. A growing number of pre-clinical studies and clinical trials have recently validated the synergistic antitumor effect of radio-immunotherapy, far beyond the "abscopal effect", but it suffers from a low response rate and toxicity issues. To this end, nanomedicines with an optimized design have been introduced to improve cancer radio-immunotherapy. Specifically, these nanomedicines are elegantly prepared by incorporating tumor antigens, immuno- or radio-regulators, or biomarker-specific imaging agents into the corresponding optimized nanoformulations. Moreover, they contribute to inducing various biological effects, such as generating in situ vaccination, promoting immunogenic cell death, overcoming radiation resistance, reversing immunosuppression, as well as pre-stratifying patients and assessing therapeutic response or therapy-induced toxicity. Overall, this review aims to provide a comprehensive landscape of nanomedicine-assisted radio-immunotherapy. The underlying working principles and the corresponding design strategies for these nanomedicines are elaborated by following the concept of "from bench to clinic". Their state-of-the-art applications, concerns over their clinical translation, along with perspectives are covered.

Poly (beta-amino ester) as an in vivo nanocarrier for therapeutic nucleic acids

Therapeutic nucleic acids are an emerging class of therapy for treating various diseases through immunomodulation, protein replacement, gene editing, and genetic engineering. However, they need a vector to effectively and safely reach the target cells. Most gene and cell therapies rely on ex vivo gene delivery, which is laborious, time-consuming, and costly; therefore, devising a systematic vector for effective and safe in vivo delivery of therapeutic nucleic acids is required to target the cells of interest in an efficient manner. Synthetic nanoparticle vector poly beta amino ester (PBAE), a class of degradable polymer, is a promising candidate for in vivo gene delivery. PBAE is considered the most potent in vivo vector due to its excellent transfection performance and biodegradability. PBAE nanoparticles showed tunable charge density, diverse structural characteristics, excellent encapsulation capacity, high stability, stimuli-responsive release, site-specific delivery, potent binding to nucleic acids, flexible binding ability to various conjugates, and effective endosomal escape. These unique properties of PBAE are an essential contribution to in vivo gene delivery. The current review discusses each of the components used for PBAE synthesis and the impact of various environmental and physicochemical factors of the body on PBAE nanocarrier.

Targeted nanomedicines remodeling immunosuppressive tumor microenvironment for enhanced cancer immunotherapy

Cancer immunotherapy has significantly flourished and revolutionized the limited conventional tumor therapies, on account of its good safety and long-term memory ability. Discouragingly, low patient response rates and potential immune-related side effects make it rather challenging to literally bring immunotherapy from bench to bedside. However, it has become evident that, although the immunosuppressive tumor microenvironment (TME) plays a pivotal role in facilitating tumor progression and metastasis, it also provides various potential targets for remodeling the immunosuppressive TME, which can consequently bolster the effectiveness of antitumor response and tumor suppression. Additionally, the particular characteristics of TME, in turn, can be exploited as avenues for designing diverse precise targeting nanomedicines. In general, it is of urgent necessity to deliver nanomedicines for remodeling the immunosuppressive TME, thus improving the therapeutic outcomes and clinical translation prospects of immunotherapy. Herein, we will illustrate several formation mechanisms of immunosuppressive TME. More importantly, a variety of strategies concerning remodeling immunosuppressive TME and strengthening patients' immune systems, will be reviewed. Ultimately, we will discuss the existing obstacles and future perspectives in the development of antitumor immunotherapy. Hopefully, the thriving bloom of immunotherapy will bring vibrancy to further exploration of comprehensive cancer treatment.

Liposomes and liposome-like nanoparticles: From anti-fungal infection to the COVID-19 pandemic treatment

The liposome is the first nanomedicine transformed into the market and applied to human patients. Since then, such phospholipid bilayer vesicles have undergone technological advancements in delivering small molecular-weight compounds and biological drugs. Numerous investigations about liposome uses were conducted in different treatment fields, including anti-tumor, anti-fungal, anti-bacterial, and clinical analgesia, owing to liposome's ability to reduce drug cytotoxicity and improve the therapeutic efficacy and combinatorial delivery. In particular, two liposomal vaccines were approved in 2021 to combat COVID-19. Herein, the clinically used liposomes are reviewed by introducing various liposomal preparations in detail that are currently proceeding in the clinic or on the market. Finally, we discuss the challenges of developing liposomes and cutting-edge liposomal delivery for biological drugs and combination therapy.

Immunogenic Cell Death Activates the Tumor Immune Microenvironment to Boost the Immunotherapy Efficiency

Tumor immunotherapy is only effective in a fraction of patients due to a low response rate and severe side effects, and these challenges of immunotherapy in clinics can be addressed through induction of immunogenic cell death (ICD). ICD is elicited from many antitumor therapies to release danger associated molecular patterns (DAMPs) and tumor-associated antigens to facilitate maturation of dendritic cells (DCs) and infiltration of cytotoxic T lymphocytes (CTLs). The process can reverse the tumor immunosuppressive microenvironment to improve the sensitivity of immunotherapy. Nanostructure-based drug delivery systems (NDDSs) are explored to induce ICD by incorporating therapeutic molecules for chemotherapy, photosensitizers (PSs) for photodynamic therapy (PDT), photothermal conversion agents for photothermal therapy (PTT), and radiosensitizers for radiotherapy (RT). These NDDSs can release loaded agents at a right dose in the right place at the right time, resulting in greater effectiveness and lower toxicity. Immunotherapeutic agents can also be combined with these NDDSs to achieve the synergic antitumor effect in a multi-modality therapeutic approach. In this review, NDDSs are harnessed to load multiple agents to induce ICD by chemotherapy, PDT, PTT, and RT in combination of immunotherapy to promote the therapeutic effect and reduce side effects associated with cancer treatment.

Tailoring combinatorial lipid nanoparticles for intracellular delivery of nucleic acids, proteins, and drugs

Lipid nanoparticle (LNP)-based drug delivery systems have become the most clinically advanced non-viral delivery technology. LNPs can encapsulate and deliver a wide variety of bioactive agents, including the small molecule drugs, proteins and peptides, and nucleic acids. However, as the physicochemical properties of small- and macromolecular cargos can vary drastically, every LNP carrier system needs to be carefully tailored in order to deliver the cargo molecules in a safe and efficient manner. Our group applied the combinatorial library synthesis approach and in vitro and in vivo screening strategy for the development of LNP delivery systems for drug delivery. In this Review, we highlight our recent progress in the design, synthesis, characterization, evaluation, and optimization of combinatorial LNPs with novel structures and properties for the delivery of small- and macromolecular therapeutics both in vitro and in vivo. These delivery systems have enormous potentials for cancer therapy, antimicrobial applications, gene silencing, genome editing, and more. We also discuss the key challenges to the mechanistic study and clinical translation of new LNP-enabled therapeutics.

Bispecific prodrug nanoparticles circumventing multiple immune resistance mechanisms for promoting cancer immunotherapy

Cancer immunotherapy is impaired by the intrinsic and adaptive immune resistance. Herein, a bispecific prodrug nanoparticle was engineered for circumventing immune evasion of the tumor cells by targeting multiple immune resistance mechanisms. A disulfide bond-linked bispecific prodrug of NLG919 and JQ1 (namely NJ) was synthesized and self-assembled into a prodrug nanoparticle, which was subsequently coated with a photosensitizer-modified and tumor acidity-activatable diblock copolymer PHP for tumor-specific delivery of NJ. Upon tumor accumulation via passive tumor targeting, the polymeric shell was detached for facilitating intracellular uptake of the bispecific prodrug. NJ was then activated inside the tumor cells for releasing JQ1 and NLG919 via glutathione-mediated cleavage of the disulfide bond. JQ1 is a bromodomain-containing protein 4 inhibitor for abolishing interferon gamma-triggered expression of programmed death ligand 1. In contrast, NLG919 suppresses indoleamine-2,3-dioxygenase 1-mediated tryptophan consumption in the tumor microenvironment, which thus restores robust antitumor immune responses. Photodynamic therapy (PDT) was performed to elicit antitumor immunogenicity by triggering immunogenic cell death of the tumor cells. The combination of PDT and the bispecific prodrug nanoparticle might represent a novel strategy for blockading multiple immune evasion pathways and improving cancer immunotherapy.