How successful is nuclear targeting by nanocarriers?

Optical controlled and nuclear targeted CECR2 competitor to downregulate CSF-1 for metastatic breast cancer immunotherapy

The crosstalk between breast cancer cells and tumor associated macrophages (TAMs) greatly contributes to tumor progression and immunosuppression. In this work, cat eye syndrome chromosome region candidate 2 (CECR2) is identified to overexpress in breast cancer patients, which can recognize v-rel avian reticuloendotheliosis viral oncogene homolog A (RelA) and activate nuclear factor κB (NF-κB) to release colony stimulating factor-1 (CSF-1). Pharmacological inhibition of CECR2 by the bromodomain competitor (Bromosporine, Bro) can downregulate CSF-1 to inhibit M2 type TAMs. To amplify the immunotherapeutic effect, a chimeric peptide-based and optical controlled CECR2 competitor (designated as N-PB) is constructed to enhance the nuclear targeted delivery of Bro and initiate an immunogenic cell death (ICD). In vivo results indicate a favorable breast cancer targeting ability and primary tumor suppression effect of N-PB under optical irradiation. Importantly, N-PB downregulates CSF-1 by competitive inhibition of CECR2 and NF-κB(RelA) interactions, thus inhibiting immunosuppressive M2-like TAMs while improving the antitumorigenic M1-like phenotype. Ultimately, the systemic anti-tumor immunity is activated to suppress the metastatic breast cancer in an optical controlled manner. This study provides a promising therapeutic target and reliable strategy for metastatic breast cancer treatment by interrupting immunosuppressive crosstalk between tumor cells and macrophages.

Semiconducting polymer dots for multifunctional integrated nanomedicine carriers

The expansion applications of semiconducting polymer dots (Pdots) among optical nanomaterial field have long posed a challenge for researchers, promoting their intelligent application in multifunctional nano-imaging systems and integrated nanomedicine carriers for diagnosis and treatment. Despite notable progress, several inadequacies still persist in the field of Pdots, including the development of simplified near-infrared (NIR) optical nanoprobes, elucidation of their inherent biological behavior, and integration of information processing and nanotechnology into biomedical applications. This review aims to comprehensively elucidate the current status of Pdots as a classical nanophotonic material by discussing its advantages and limitations in terms of biocompatibility, adaptability to microenvironments in vivo, etc. Multifunctional integration and surface chemistry play crucial roles in realizing the intelligent application of Pdots. Information visualization based on their optical and physicochemical properties is pivotal for achieving detection, sensing, and labeling probes. Therefore, we have refined the underlying mechanisms and constructed multiple comprehensive original mechanism summaries to establish a benchmark. Additionally, we have explored the cross-linking interactions between Pdots and nanomedicine, potential yet complete biological metabolic pathways, future research directions, and innovative solutions for integrating diagnosis and treatment strategies. This review presents the possible expectations and valuable insights for advancing Pdots, specifically from chemical, medical, and photophysical practitioners' standpoints.

Chemical Reactions in Living Systems

The term "in vivo ("in the living") chemistry" refers to chemical reactions that take place in a complex living system such as cells, tissue, body liquids, or even in an entire organism. In contrast, reactions that occur generally outside living organisms in an artificial environment (e.g., in a test tube) are referred to as in vitro. Over the past decades, significant contributions have been made in this rapidly growing field of in vivo chemistry, but it is still not fully understood, which transformations proceed efficiently without the formation of by-products or how product formation in such complex environments can be characterized. Potential applications can be imagined that synthesize drug molecules directly within the cell or confer new cellular functions through controlled chemical transformations that will improve the understanding of living systems and develop new therapeutic strategies. The guiding principles of this contribution are twofold: 1) Which chemical reactions can be translated from the laboratory to the living system? 2) Which characterization methods are suitable for studying reactions and structure formation in complex living environments?

Gene-editing technology, from macromolecule therapeutics to organ transplantation: Applications, limitations, and prospective uses

Gene editing technologies (GETs) could induce gene knockdown or gene knockout for biomedical applications. The clinical success of gene silence by RNAi therapies pays attention to other GETs as therapeutic approaches. This review aims to highlight GETs, categories, mechanisms, challenges, current use, and prospective applications. The different academic search engines, electronic databases, and bibliographies of selected articles were used in the preparation of this review with a focus on the fundamental considerations. The present results revealed that, among GETs, CRISPR/Cas9 has higher editing efficiency and targeting specificity compared to other GETs to insert, delete, modify, or replace the gene at a specific location in the host genome. Therefore, CRISPR/Cas9 is talented in the production of molecular, tissue, cell, and organ therapies. Consequently, GETs could be used in the discovery of innovative therapeutics for genetic diseases, pandemics, cancer, hopeless diseases, and organ failure. Specifically, GETs have been used to produce gene-modified animals to spare human organ failure. Genetically modified pigs are used in clinical trials as a source of heart, liver, kidneys, and lungs for xenotransplantation (XT) in humans. Viral, non-viral, and hybrid vectors have been utilized for the delivery of GETs with some limitations. Therefore, extracellular vesicles (EVs) are proposed as intelligent and future cargoes for GETs delivery in clinical applications. This study concluded that GETs are promising for the production of molecular, cellular, and organ therapies. The use of GETs as XT is still in the early stage as well and they have ethical and biosafety issues.

Research progress in nucleus-targeted tumor therapy

The nucleus is considered the most important organelle in the cell as it plays a central role in controlling cell reproduction, metabolism, and the cell cycle. The successful delivery of drugs into the nucleus can achieve excellent therapeutic effects, which reveals the potential of nucleus-targeted therapy in precision medicine. However, the transportation of therapeutics into the nucleus remains a significant challenge due to various biological barriers. Herein, we summarize the recent progress in the nucleus-targeted drug delivery system (NDDS). The structures of the nucleus and nuclear envelope are first described in order to understand the mechanisms by which drugs cross the nuclear envelope. Then, various drug delivery strategies based on the mechanisms and their applications are discussed. Finally, the challenges and solutions in the field of nucleus-targeted drug delivery are raised for developing a more efficient NDDS and promoting its clinical transformation.

Functional Materials for Subcellular Targeting Strategies in Cancer Therapy: Progress and Prospects

Neoadjuvant and adjuvant therapies have made significant progress in cancer treatment. However, tumor adjuvant therapy still faces challenges due to the intrinsic heterogeneity of cancer, genomic instability, and the formation of an immunosuppressive tumor microenvironment. Functional materials possess unique biological properties such as long circulation times, tumor-specific targeting, and immunomodulation. The combination of functional materials with natural substances and nanotechnology has led to the development of smart biomaterials with multiple functions, high biocompatibilities, and negligible immunogenicities, which can be used for precise cancer treatment. Recently, subcellular structure-targeting functional materials have received particular attention in various biomedical applications including the diagnosis, sensing, and imaging of tumors and drug delivery. Subcellular organelle-targeting materials can precisely accumulate therapeutic agents in organelles, considerably reduce the threshold dosages of therapeutic agents, and minimize drug-related side effects. This review provides a systematic and comprehensive overview of the research progress in subcellular organelle-targeted cancer therapy based on functional nanomaterials. Moreover, it explains the challenges and prospects of subcellular organelle-targeting functional materials in precision oncology. The review will serve as an excellent cutting-edge guide for researchers in the field of subcellular organelle-targeted cancer therapy.

Tracking intracellular nuclear targeted-chemotherapy of chidamide-loaded Prussian blue nanocarriers by SERS mapping

The novel histone deacetylase drug chidamide (CHI) has been proven to regulate gene expression associated with oncogenesis via epigenetic mechanisms. However, huge side effects such as non-targeting, poor intracellular accumulation and low nuclear entry efficiency severely restrict its therapeutic efficacy. Dual-targeted nanodrug delivery systems have been proposed as the solution. Herein, we developed a CHI-loaded drug delivery nanosystem based on Prussian blue (PB) nanocarrier, which combines surface-enhanced Raman scattering (SERS) tracking function with cancer cell/nuclear-targeted chemotherapy capability. With the property of background-free SERS mapping, PB nanocarriers can serve as tracking agents to localize intracellular CHI. The incorporation of targeted molecules specifically enhances the cancer cell/nuclear internalization and chemotherapeutic effects of CHI-loaded PB nanocarriers. In vitro cytotoxicity assay clearly shows that the constructed CHI-loaded PB nanocarriers have significant inhibitory on Jurkat cell proliferation. Furthermore, SERS spectral analysis of Jurkat cells incubated with the CHI-loaded PB nanocarriers reveals obvious features of cellular apoptosis: DNA skeleton fragmentation, chromatin depolymerization, histone acetylation, and nucleosome conformation change. Importantly, this CHI-loaded PB nanocarrier will provide a new insight for lymphoblastic leukemia targeted chemotherapy.

Hyaluronan-estradiol nanogels as potential drug carriers to target ER+ breast cancer cell line

An innovative hyaluronan-based nano-delivery system is proposed for the active targeting towards ER+ breast cancer. Hyaluronic acid (HA), an endogenous and bioactive anionic polysaccharide, is functionalized with estradiol (ES), a sexual hormone involved in the development of some hormone-dependent tumors, to give an amphiphilic derivative (HA-ES) able to spontaneously self-assemble in water to form soft nanoparticles or nanogels (NHs). The synthetic strategy used to obtain the polymer derivatives and the physico-chemical properties of the obtained nanogels (ES-NHs) are reported. ES-NHs ability to entrap hydrophobic molecules has also been investigated, by loading curcumin (CUR) and docetaxel (DTX), both able to inhibit the growth of ER+ breast cancer. The formulations are studied for their capability to inhibit the growth of the MCF-7 cell line, thus evaluating their efficacy and potential as a selective drug delivery systems. Our results demonstrate that ES-NHs have not toxic effects on the cell line, and that both ES-NHs/CUR and ES-NHs/DTX treatments inhibit MCF-7 cell growth, with ES-NHs/DTX effect higher than that of free DTX. Our findings support the use of ES-NHs to deliver drugs to ER+ breast cancer cells, assuming a receptor-dependent targeting.

Coding Therapeutic Nucleic Acids from Recombinant Proteins to Next-Generation Vaccines: Current Uses, Limitations, and Future Horizons

This study aims to highlight the potential use of cTNAs in therapeutic applications. The COVID-19 pandemic has led to significant use of coding therapeutic nucleic acids (cTNAs) in terms of DNA and mRNA in the development of vaccines. The use of cTNAs resulted in a paradigm shift in the therapeutic field. However, the injection of DNA or mRNA into the human body transforms cells into biological factories to produce the necessary proteins. Despite the success of cTNAs in the production of corona vaccines, they have several limitations such as instability, inability to cross biomembranes, immunogenicity, and the possibility of integration into the human genome. The chemical modification and utilization of smart drug delivery cargoes resolve cTNAs therapeutic problems. The success of cTNAs in corona vaccine production provides perspective for the eradication of influenza viruses, Zika virus, HIV, respiratory syncytial virus, Ebola virus, malaria, and future pandemics by quick vaccine design. Moreover, the progress cTNAs technology is promising for the development of therapy for genetic disease, cancer therapy, and currently incurable diseases.

Nuclear Delivery of Nanoparticle-Based Drug Delivery Systems by Nuclear Localization Signals

Nanomedicine 2.0 refers to the next generation of nanotechnology-based medical therapies and diagnostic tools. This field focuses on the development of more sophisticated and precise nanoparticles (NPs) for targeted drug delivery, imaging, and sensing. It has been established that the nuclear delivery of NP-loaded drugs can increase their therapeutic efficacy. To effectively direct the NPs to the nucleus, the attachment of nuclear localization signals (NLSs) to NPs has been employed in many applications. In this review, we will provide an overview of the structure of nuclear pore complexes (NPCs) and the classic nuclear import mechanism. Additionally, we will explore various nanoparticles, including their synthesis, functionalization, drug loading and release mechanisms, nuclear targeting strategies, and potential applications. Finally, we will highlight the challenges associated with developing nucleus-targeted nanoparticle-based drug delivery systems (NDDSs) and provide insights into the future of NDDSs.

Recent progress in nanomedicine-mediated cytosolic delivery

Cytosolic delivery of bioactive agents has exhibited great potential to cure undruggable targets and diseases. Because biological cell membranes are a natural barrier for living cells, efficient delivery methods are required to transfer bioactive and therapeutic agents into the cytosol. Various strategies that do not require cell invasive and harmful processes, such as endosomal escape, cell-penetrating peptides, stimuli-sensitive delivery, and fusogenic liposomes, have been developed for cytosolic delivery. Nanoparticles can easily display functionalization ligands on their surfaces, enabling many bio-applications for cytosolic delivery of various cargo, including genes, proteins, and small-molecule drugs. Cytosolic delivery uses nanoparticle-based delivery systems to avoid degradation of proteins and keep the functionality of other bioactive molecules, and functionalization of nanoparticle-based delivery vehicles imparts a specific targeting ability. With these advantages, nanomedicines have been used for organelle-specific tagging, vaccine delivery for enhanced immunotherapy, and intracellular delivery of proteins and genes. Optimization of the size, surface charges, specific targeting ability, and composition of nanoparticles is needed for various cargos and target cells. Toxicity issues with the nanoparticle material must be managed to enable clinical use.

Advances in nuclei targeted delivery of nanoparticles for the management of cancer

A carrier is inserted into the appropriate organelles (nucleus) in successful medication transport, crucial to achieving very effective illness treatment. Cell-membrane targeting is the major focus of using nuclei to localize delivery. It has been demonstrated that high quantities of anticancer drugs can be injected directly into the nuclei of cancer cells, causing the cancer cells to die and increasing the effectiveness of chemotherapy. There are several effective ways to functionalize Nanoparticles (NPs), including changing their chemical makeup or attaching functional groups to their surface to increase their ability to target organelles. To cause tumor cells to apoptosis, released medicines must engage with molecular targets on particular organelles when their concentration is high enough. Targeted medication delivery studies will increasingly focus on organelle-specific delivery.

Applications and challenges of ultra-small particle size nanoparticles in tumor therapy

With the development of nanotechnology, nanomedicines are widely used in tumor therapy. However, biological barriers in the delivery of nanoparticles still limit their application in tumor therapy. As one of the most fundamental properties of nanoparticles, particle size plays a crucial role in the process of the nanoparticles delivery process. It is difficult for large size nanoparticles with fixed size to achieve satisfactory outcomes in every process. In order to overcome the poor penetration of larger size, nanoparticles with ultra-small particle size are proposed, which are more conducive to deep tumor penetration and uniform drug distribution. In this review, the latest progresses and advantages of ultra-small nanoparticles are systematically summarized, the perspectives and challenges of ultra-small nanoparticles strategy for cancer treatment are also discussed.

Diaminobenzidine Photooxidation to Visualize Fluorescent Nanoparticles in Adhering Cultured Cells at Transmission Electron Microscopy

Visualizing nanoparticles made of organic material (e.g., polysaccharides, proteins, non-osmiophilic lipids) inside cells and tissues at transmission electron microscopy is a difficult task due to the intrinsic weak electron density of these nanoconstructs, which makes them hardly distinguishable in the biological environment. We describe here a simple protocol to apply photooxidation to fluorescently labeled nanoparticles administered to cultured cells in vitro. The conversion of the fluorescent signal into a granular electron-dense reaction product through light irradiation in the presence of diaminobenzidine makes the nanoparticles clearly visible at the ultrastructural level. Our procedure proved to be reliable with various fluorophores and may be applied to any cell type.

Magnetically Induced Brownian Motion of Iron Oxide Nanocages in Alternating Magnetic Fields and Their Application for Efficient siRNA Delivery

Hyperthermia of superparamagnetic nanoparticles driven by Néel relaxation in an alternating magnetic field (AMF) has been studied in biomedical areas; however, Brownian motion, induced by another magnetic relaxation mechanism, has not been explored extensively despite its potential in intracellular mechanoresponsive applications. We investigated whether superparamagnetic cage-shaped iron oxide nanoparticles (IO-nanocages), previously demonstrated to carry payloads inside their cavities for drug delivery, can generate Brownian motion by tuning the nanoparticle size at 335 kHz AMF frequency. The motivation of this work is to examine the magnetically driven Brownian motion for the delivery of nanoparticles allowing escape from endosomes before digestion in lysosomes and efficient delivery of siRNA cargoes to the cytoplasm. Superconducting quantum interference device (SQUID) measurements reveal the nanocage size dependence of Brownian relaxation, and a magnetic Brownian motion of 20 nm IO-nanocages improved the efficiency of siRNA delivery while endosomal membranes were observed to be compromised to release IO-nanocages in AMFs during the delivery process.

A simple, robust and scalable route to prepare sub-50 nm soft PDMS nanoparticles for intracellular delivery of anticancer drugs

Soft nanoparticles (NPs) have recently emerged as a promising material for intracellular drug delivery. In this regard, NPs derived from polydimethylsiloxane (PDMS), an FDA approved polymer can be a suitable alternative to conventional soft NPs due to their intrinsic organelle targeting ability. However, the available synthesis methods of PDMS NPs are complicated or require inorganic fillers, forming composite NPs and compromising their native softness. Herein, for the first time, we present a simple, robust and scalable strategy for preparation of virgin sub-50 nm PDMS NPs at room temperature. The NPs are soft in nature, hydrophobic and about 30 nm in size. They are stable in physiological medium for two months and biocompatible. The NPs have been successful in delivering anticancer drug doxorubicin to mitochondria and nucleus of cervical and breast cancer cells with more than four-fold decrease in IC50 value of doxorubicin as compared to its free form. Furthermore, evaluation of cytotoxicity in reactive oxygen species detection, DNA fragmentation, apoptosis-associated gene expression and tumor spheroid growth inhibition demonstrate the PDMS NPs to be an excellent candidate for delivery of anticancer drugs in mitochondria and nucleus of cancer cells.

AIEgen-Peptide Bioprobes for the Imaging of Organelles

Organelles are important subsystems of cells. The damage and inactivation of organelles are closely related to the occurrence of diseases. Organelles’ functional activity can be observed by fluorescence molecular tools. Nowadays, a series of aggregation-induced emission (AIE) bioprobes with organelles-targeting ability have emerged, showing great potential in visualizing the interactions between probes and different organelles. Among them, AIE luminogen (AIEgen)-based peptide bioprobes have attracted more and more attention from researchers due to their good biocompatibility and photostability and abundant diversity. In this review, we summarize the progress of AIEgen-peptide bioprobes in targeting organelles, including the cell membrane, nucleus, mitochondria, lysosomes and endoplasmic reticulum, in recent years. The structural characteristics and biological applications of these bioprobes are discussed, and the development prospect of this field is forecasted. It is hoped that this review will provide guidance for the development of AIEgen-peptide bioprobes at the organelles level and provide a reference for related biomedical research.

Placental cell translocation of folate-conjugated pullulan acetate non-spherical nanoparticles

Due to the adverse effects of free drugs on the fetus, placental-mediated pregnancy complications still lack effective pharmacotherapy. This study aims to construct a non-spherical drug delivery system based on folate-conjugated pullulan acetate (FPA) for placental targeting and translocation. By adjusting the initial solvent system, FPA nanoparticles with different morphologies were prepared using dialysis method without a surfactant. Cytotoxicity and lactate dehydrogenase release assays indicated the good biocompatibility of FPA nanoparticles in BeWo b30 cells. Cellular uptake and in vitro placental barrier transportation studies showed that FPA nanoparticles entered the cells and transported across the cell monolayer, benefiting from the active target effect mediated by the folate receptor. Moreover, non-spherical FPA nanoparticles showed nuclear translocation due to their shape effect. These findings provide a novel aspect in placental-mediated pregnancy treatment and applications in the obstetrics field of drug use during pregnancy.

Silver nanoclusters show advantages in macrophage tracing in vivo and modulation of anti-tumor immuno-microenvironment

Macrophage-based nanomedicine represents an emerging powerful strategy for cancer therapy. Unfortunately, some obstacles and challenges limit the translational applications of macrophage-mediated nanodrug delivery system. For instance, tracking and effective cell delivery for targeted tumor sites remain to be overcome, and controlling the states of macrophages is still rather difficult due to their plastic nature in response to external stimuli. To address these critical issues, here, we reported a novel type of silver nanoclusters (AgNCs) with excellent fluorescent intensity, especially long-lasting cell labeling stability after endocytosis by macrophages, indicating promising applications in tracking macrophage-based nanomedicine delivery. Our mechanistic investigations uncovered that these merits originate from the escape of AgNCs from lysosomal degradation within macrophages. In addition, the AgNCs would prime the M1-like polarization of macrophages (at least in part) through the toll-like receptor 4 signaling pathway. The engineered macrophages laden with AgNCs could be employed for lung metastasis breast cancer treatment, showing the effective targeting propensity to metastatic tumors, remarkable regulation of tumor immune microenvironment and inhibition of tumor growth. Collectively, AgNC-trained macrophages appear to be a promising strategy for tumor immune-microenvironment regulation, which might be generalized to a wider spectrum of cancer therapeutics.

Mineralized vectors for gene therapy

There is an intense interest in developing materials for safe and effective delivery of polynucleotides using non-viral vectors. Mineralization of organic templates has long been used to produce complex materials with outstanding biocompatibility. However, a lack of control over mineral growth has limited the applicability of mineralized materials to a few in vitro applications. With better control over mineral growth and surface functionalization, mineralized vectors have advanced significantly in recent years. Here, we review the recent progress in chemical synthesis, physicochemical properties, and applications of mineralized materials in gene therapy, focusing on structure-function relationships. We contrast the classical understanding of the mineralization mechanism with recent ideas of mineralization. A brief introduction to gene delivery is summarized, followed by a detailed survey of current mineralized vectors. The vectors derived from calcium phosphate are articulated and compared to other minerals with unique features. Advanced mineral vectors derived from templated mineralization and specialty coatings are critically analyzed. Mineral systems beyond the co-precipitation are explored as more complex multicomponent systems. Finally, we conclude with a perspective on the future of mineralized vectors by carefully demarcating the boundaries of our knowledge and highlighting ambiguous areas in mineralized vectors. STATEMENT OF SIGNIFICANCE: Therapy by gene-based medicines is increasingly utilized to cure diseases that are not alleviated by conventional drug therapy. Gene medicines, however, rely on macromolecular nucleic acids that are too large and too hydrophilic for cellular uptake. Without tailored materials, they are not functional for therapy. One emerging class of nucleic acid delivery system is mineral-based materials. The fact that they can undergo controlled dissolution with minimal footprint in biological systems are making them attractive for clinical use, where safety is utmost importance. In this submission, we will review the emerging synthesis technology and the range of new generation minerals for use in gene medicines.

Different Serum, Different Protein Corona! The Impact of the Serum Source on Cellular Targeting of Folic Acid-Modified Chitosan-Based Nanoparticles

The nanoparticle (NP) protein corona represents an interface between biological components and NPs, dictating their cellular interaction and biological fate. To assess the success of cellular targeting, NPs modified with targeting ligands are incubated with target cells in serum-free culture medium or in the presence of fetal bovine serum (FBS). In the former, the role of the corona is overlooked, and in the latter, the effects of a corona that does not represent the one forming in humans nor the respective disease state are considered. Via proteomic analysis, we demonstrate how the difference in the composition of FBS, sera from healthy human volunteers, and breast cancer patients (BrCr Pt) results in the formation of completely different protein coronas around the same NP. Successful in vitro targeting of breast cancer cells was only observed when NPs were incubated with target cells in the presence of BrCr Pt sera only. In such cases, the success of targeting was not attributed to the targeting ligand itself, but to the adsorption of specific serum proteins that facilitate NP uptake by cancer cells in the presence of BrCr Pt sera. This work therefore demonstrates how the serum source affects the reliability of in vitro experiments assessing NP-cell interactions and the consequent success or failure of active targeting and may in fact indicate an additional reason for the limited clinical success of drug targeting by NPs in cancer.

Design and Synthesis of Shikimoylated-Polypeptides for Nuclear Specific Internalization

Targeted delivery of therapeutics such as small molecule drugs or nucleic acids exclusively to the nucleus of diseased mammalian cells poses a significant challenge. The development of targeting ligands that can specifically enter certain cancer cells via a specific receptor-mediated endocytosis and then traffic exclusively to the nucleus to deliver the cargo inside it can achieve this goal. We have developed an end-functionalized shikimoylated-polypeptide with pendant shikimoyl moieties that can enter mammalian cells via the mannose receptors and are then exclusively trafficked into the nucleus. The presence of the shikimoyl group in the polypeptide, which traffics it exclusively to the nucleus, contrasts with the mannosylated or galactosylated glycopolypeptides that are distributed all over the cytoplasm or the mannose-6-phosphate containing polypeptide that is exclusively trafficked to the lysosome. Using challenge experiments, we demonstrate that these polypeptides can enter both dendritic and cancer cells through mannose-receptors and subsequently enter the cell nucleus via the interaction with a nuclear pore complex (NPC) protein importin-α/β1. To the best of our knowledge, this represents the first example of a synthetic polyvalent glycopolypeptide mimic that performs the dual function of entering mammalian cells through specific receptors and subsequently traffics into the nucleus. The conjugation of these end-functionalized shikimoylated-polypeptides to other biological entities, such as recombinant anticancer drugs, DNA, RNA, and CRISPR-Cas9, may be a suitable alternative for delivery of these biological entities into cells affected by cancer and other genetic diseases.

A Unique Core–Shell Structured, Glycol Chitosan-Based Nanoparticle Achieves Cancer-Selective Gene Delivery with Reduced Off-Target Effects

The inherent instability of nucleic acids within serum and the tumor microenvironment necessitates a suitable vehicle for non-viral gene delivery to malignant lesions. A specificity-conferring mechanism is also often needed to mitigate off-target toxicity. In the present study, we report a stable and efficient redox-sensitive nanoparticle system with a unique core–shell structure as a DNA carrier for cancer theranostics. Thiolated polyethylenimine (PEI-SH) is complexed with DNA through electrostatic interactions to form the core, and glycol chitosan-modified with succinimidyl 3-(2-pyridyldithio)propionate (GCS-PDP) is grafted on the surface through a thiolate-disulfide interchange reaction to form the shell. The resulting nanoparticles, GCS-PDP/PEI-SH/DNA nanoparticles (GNPs), exhibit high colloid stability in a simulated physiological environment and redox-responsive DNA release. GNPs not only show a high and redox-responsive cellular uptake, high transfection efficiency, and low cytotoxicity in vitro, but also exhibit selective tumor targeting, with minimal toxicity, in vivo, upon systemic administration. Such a performance positions GNPs as viable candidates for molecular-genetic imaging and theranostic applications.

Recent advances in targeted nanotherapeutic approaches for breast cancer management

Breast cancer is the most commonly occurring tumor disease worldwide. Breast cancer is currently managed by conventional chemotherapy, which is inadequate in curbing this heterogeneous disease and results in off-site toxic effects, suggesting effective treatment approaches with better therapeutic profiles are needed. This review, therefore, focuses on the recent advancements in delivering therapeutics to the target site using passive and/or active targeted nanodrug-delivery systems to ameliorate endolysosomal escape. In addition, recent strategies in targeting breast cancer stem cells are discussed. The role of naturally cell-secreted nanovesicles (exosomes) in the management of triple-negative breast cancer is also discussed.

Chitosan Nanoparticles at the Biological Interface: Implications for Drug Delivery

The unique properties of chitosan make it a useful choice for various nanoparticulate drug delivery applications. Although chitosan is biocompatible and enables cellular uptake, its interactions at cellular and systemic levels need to be studied in more depth. This review focuses on the various physical and chemical properties of chitosan that affect its performance in biological systems. We aim to analyze recent research studying interactions of chitosan nanoparticles (NPs) upon their cellular uptake and their journey through the various compartments of the cell. The positive charge of chitosan enables it to efficiently attach to cells, increasing the probability of cellular uptake. Chitosan NPs are taken up by cells via different pathways and escape endosomal degradation due to the proton sponge effect. Furthermore, we have reviewed the interaction of chitosan NPs upon in vivo administration. Chitosan NPs are immediately surrounded by a serum protein corona in systemic circulation upon intravenous administration, and their biodistribution is mainly to the liver and spleen indicating RES uptake. However, the evasion of RES system as well as the targeting ability and bioavailability of chitosan NPs can be improved by utilizing specific routes of administration and covalent modifications of surface properties. Ongoing clinical trials of chitosan formulations for therapeutic applications are paving the way for the introduction of chitosan into the pharmaceutical market and for their toxicological evaluation. Chitosan provides specific biophysical properties for effective and tunable cellular uptake and systemic delivery for a wide range of applications.

Asymmetric polymersomes, from the formation of asymmetric membranes to the application on drug delivery

Nano drug delivery systems have attracted researchers' growing attention and are gradually emerging into the public views. More and more nano-formulations are being approved for marketing or clinical use, representing the field's booming development. Copolymer self-assembly systems such as micelles, nanoparticles, polymersomes occupy a prominent position in the field of nano-drug delivery carriers. Among them, polymersomes, unlike micelles or nanoparticles, resemble liposomes' structure and possess large internal hollow hydrophilic reservoirs, allowing them to carry hydrophilic drugs. Nevertheless, their insufficient drug loading efficiency and unruly self-assembly morphology have somewhat constrained their applications. Especially for the delivery of biomacromolecule such as peptides, the encapsulation efficiency is always considered to be a formidable obstacle, even if the enormous hydrophilic core would render the polymersomes to have considerable potential in this regard. Reassuringly, the emergence of asymmetric polymersomes holds the prospect of solving this problem. With the development of synthetic technology and a deeper understanding of the self-assembly process, the asymmetric polymersomes which are with different inner and outer shell composition have been gradually recognized by researchers. It has made possible elevated drug loading, more controllable assembly processes and release performance. The internal hydrophilic blocks different from the outer shell could be engineered to have a more remarkable affinity to the cargos or could contain a non-watery aqueous phase to enable the thermodynamically preferred encapsulation of cargos, which would allow for a substantial improvement in drug encapsulation efficiency compared to the conventional approach. In this paper, we aim to deepen the understanding to asymmetric polymersomes and lay the foundation for the development of this field by describing four main elements: the mechanism of their preparation and asymmetric membrane formation process, the characterization of asymmetric membranes, the efficient drug loading, and the special stimulus-responsive release mechanism.

Repurpose but also (nano)-reformulate! The potential role of nanomedicine in the battle against SARS-CoV2

The coronavirus disease-19 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) has taken the world by surprise. To date, a worldwide approved treatment remains lacking and hence in the context of rapid viral spread and the growing need for rapid action, drug repurposing has emerged as one of the frontline strategies in the battle against SARS-CoV2. Repurposed drugs currently being evaluated against COVID-19 either tackle the replication and spread of SARS-CoV2 or they aim at controlling hyper-inflammation and the rampaged immune response in severe disease. In both cases, the target for such drugs resides in the lungs, at least during the period where treatment could still provide substantial clinical benefit to the patient. Yet, most of these drugs are administered systemically, questioning the percentage of administered drug that actually reaches the lung and as a consequence, the distribution of the remainder of the dose to off target sites. Inhalation therapy should allow higher concentrations of the drug in the lungs and lower concentrations systemically, hence providing a stronger, more localized action, with reduced adverse effects. Therefore, the nano-reformulation of the repurposed drugs for inhalation is a promising approach for targeted drug delivery to lungs. In this review, we critically analyze, what nanomedicine could and ought to do in the battle against SARS-CoV2. We start by a brief description of SARS-CoV2 structure and pathogenicity and move on to discuss the current limitations of repurposed antiviral and immune-modulating drugs that are being clinically investigated against COVID-19. This account focuses on how nanomedicine could address limitations of current therapeutics, enhancing the efficacy, specificity and safety of such drugs. With the appearance of new variants of SARS-CoV2 and the potential implication on the efficacy of vaccines and diagnostics, the presence of an effective therapeutic solution is inevitable and could be potentially achieved via nano-reformulation. The presence of an inhaled nano-platform capable of delivering antiviral or immunomodulatory drugs should be available as part of the repertoire in the fight against current and future outbreaks.

Gene therapy strategies for rare monogenic disorders with nuclear or mitochondrial gene mutations

Rare monogenic disorders are a group of single-gene-mutated diseases that have a low incidence rate (less than 0.5‰) and eventually lead to patient disability and even death. Due to the relatively low number of people affected, these diseases typically fail to attract a great deal of commercial investment and research interest, and the affected patients thus have unmet medical needs. Advances in genomics biology, gene editing, and gene delivery can now offer potentially effective options for treating rare monogenic diseases. Herein, we review the application of gene therapy strategies (traditional gene therapy and gene editing) against various rare monogenic diseases with nuclear or mitochondrial gene mutations, including eye, central nervous system, pulmonary, systemic, and blood cell diseases. We summarize their pathologic features, address the barriers to gene delivery for these diseases, discuss available therapies in the clinic and in clinical trials, and sum up in-development gene delivery systems for various rare monogenic disorders. Finally, we elaborate the possible directions and outlook of gene therapy for rare monogenic disorders.

Delivery of trans-membrane proteins by liposomes; the effect of liposome size and formulation technique on the efficiency of protein delivery

Channelopathies are disorders caused by reduced expression or impaired function of ion channels. Most current therapies rely on symptomatic treatment without addressing the underlying cause. We have recently established proof of principle for delivery of functional ion channel protein into the membrane of target cells using fusogenic liposomes incorporating glycine receptor (GlyR)-containing cell membrane fragments (CMF) that were formulated by thin film hydration. Here, the effect of liposome size and the formulation technique on the performance of the delivery vehicle was assessed. Three types of liposomes were prepared using lecithin and cholesterol, (i) small (SL), and (ii) large (LL) liposomes made by thin film hydration, and (iii) small liposomes prepared by vortex agitation (V-SL). All liposomes were evaluated for their ability to (i) incorporate GlyR-rich CMF, (ii) fuse with the cell membrane of target cells and (iii) deliver functional GlyR, as assessed by patch-clamp electrophysiology. SL prepared by thin film hydration offered the most effective delivery of glycine receptors that gave clear glycine-mediated currents in target cells. LL showed higher incorporation of CMF, but did not effectively fuse with the target cell membrane, while V-SL did not incorporate sufficient amounts of CMF. Additionally, SL showed minimalin vivotoxicity upon intrathecal injection in mice. Thus, liposome-mediated delivery of membrane proteins may be a promising therapeutic approach for the treatment of channelopathies.

Design of acid-activated cell-penetrating peptides with nuclear localization capacity for anticancer drug delivery

Camptothecin (CPT), a DNA-toxin drug, exerts anticancer activity by inhibiting topoisomerase I. Targeted delivery of CPT into the cancer cell nucleus is important for enhancing its therapeutic efficiency. In this study, a new type of acid-activated cell-penetrating peptide (CPP) with nuclear localization capacity was constructed by conjugating six histidine residues and a hydrophobic peptide sequence, PFVYLI, to the nuclear localization sequence (NLS). Our results indicated that HNLS-3 displayed significant pH-dependent cellular uptake efficiency, endosomal escape ability, and nuclear localization activity. More importantly, the HNLS-3-CPT conjugate showed obviously enhanced cytotoxicity and selectivity compared with CPT. Taken together, our findings provide an effective approach to develop efficient CPPs with both cancer- and nucleus-targeting properties.

The reversal of chemotherapy-induced multidrug resistance by nanomedicine for cancer therapy

Multidrug resistance (MDR) of cancer is a persistent problem in chemotherapy. Scientists have considered the overexpressed efflux transporters responsible for MDR and chemotherapy failure. MDR extremely limits the therapeutic effect of chemotherapy in cancer treatment. Many strategies have been applied to solve this problem. Multifunctional nanoparticles may be one of the most promising approaches to reverse MDR of tumor. These nanoparticles can keep stability in the blood circulation and selectively accumulated in the tumor microenvironment (TME) either by passive or active targeting. The stimuli-sensitive or organelle-targeting nanoparticles can release the drug at the targeted-site without exposure to normal tissues. In order to better understand reversal of MDR, three main strategies are concluded in this review. First strategy is the synergistic effect of chemotherapeutic drugs and ABC transporter inhibitors. Through directly inhibiting overexpressed ABC transporters, chemotherapeutic drugs can enter into resistant cells without being efflux. Second strategy is based on nanoparticles circumventing over-expressed efflux transporters and directly targeting resistance-related organelles. Third approach is the combination of multiple therapy modes overcoming cancer resistance. At last, numerous researches demonstrated cancer stem-like cells (CSCs) had a deep relation with drug resistance. Here, we discuss two different drug delivery approaches of nanomedicine based on CSC therapy.

Bacterium-mimicking sequentially targeted therapeutic nanocomplexes based on O-carboxymethyl chitosan and their cooperative therapy by dual-modality light manipulation

An integrated gene nanovector capable of overcoming complicated physiological barriers in one vector is desirable to circumvent the challenges imposed by the intricate tumor microenvironment. Herein, a nuclear localization signals (NLS)-decorated element and an iRGD-functionalized element based on O-carboxymethyl chitosan were synthesized, mixed, and coated onto PEI/DNA to fabricate bacterium-mimicking sequentially targeted therapeutic nanocomplexes (STNPs) which were internalized through receptor-mediated endocytosis and other pathways and achieved nuclear translocation of DNA. The endo/lysosomal membrane disruption triggered by reactive oxygen species (ROS) after short-time illumination, together with the DNA nuclear translocation, evoked an enhanced gene expression. Alternatively, the excessive ROS from long-time irradiation induced apoptosis in tumor cells, bringing about greater anti-tumor efficacy owing to the integration of gene and photodynamic therapy. Overall, these results demonstrated bacterium-mimicking STNPs could be a potential candidate for tumor treatments.

Unravelling the Network of Nuclear Matrix Metalloproteinases for Targeted Drug Design

Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that are responsible for the degradation of a wide range of extracellular matrix proteins, which are involved in many cellular processes to ensure the normal development of tissues and organs. Overexpression of MMPs has been observed to facilitate cellular growth, migration, and metastasis of tumor cells during cancer progression. A growing number of these proteins are being found to exist in the nuclei of both healthy and tumor cells, thus highlighting their localization as having a genuine purpose in cellular homeostasis. The mechanism underlying nuclear transport and the effects of MMP nuclear translocation have not yet been fully elucidated. To date, nuclear MMPs appear to have a unique impact on cellular apoptosis and gene regulation, which can have effects on immune response and tumor progression, and thus present themselves as potential therapeutic targets in certain types of cancer or disease. Herein, we highlight and evaluate what progress has been made in this area of research, which clearly has some value as a specific and unique way of targeting the activity of nuclear matrix metalloproteinases within various cell types.

Mechanistic Approaches of Internalization, Subcellular Trafficking, and Cytotoxicity of Nanoparticles for Targeting the Small Intestine

Targeting the small intestine employing nanotechnology has proved to be a more effective way for site-specific drug delivery. The drug targeting to the small intestine can be achieved via nanoparticles for its optimum bioavailability within the systemic circulation. The small intestine is a remarkable candidate for localized drug delivery. The intestine has its unique properties. It has a less harsh environment than the stomach, provides comparatively more retention time, and possesses a greater surface area than other parts of the gastrointestinal tract. This review focuses on elaborating the intestinal barriers and approaches to overcome these barriers for internalizing nanoparticles and adopting different cellular trafficking pathways. We have discussed various factors that contribute to nanocarriers' cellular uptake, including their surface chemistry, surface morphology, and functionalization of nanoparticles. Furthermore, the fate of nanoparticles after their uptake at cellular and subcellular levels is also briefly explained. Finally, we have delineated the strategies that are adopted to determine the cytotoxicity of nanoparticles.

Nuclear-targeted gold nanoparticles enhance cancer cell radiosensitization

Radiation therapy aims to kill or inhibit proliferation of cancer cells while sparing normal cells. To enhance radiosensitization, we developed 40 nm-sized gold nanoparticles targeting the nucleus. We exploited a strategy that combined RGD and NLS peptides respectively targeting cancer cell and the nucleus to initiate cell-death activated by x-ray irradiation. We observed that the modified gold nanoparticles were either translocated in the nuclei or accumulated in the vicinity of the nuclei. We demonstrated that x-ray irradiation at 225 kVp energy reduced cell proliferation by 3.8-fold when the nuclear targeted gold nanoparticles were used. We determined that the radiation dose to have a 10% survival fraction was reduced from 11.0 Gy to 7.1 Gy when 10.0 µg ml^-1 of the NLS/RGD/PEG-AuNP was incubated with A549 cancer cells. We conclude that the peptide-modified gold nanoparticles targeting the nucleus significantly enhance radiosensitization.

Targeting Nanodiamonds to the Nucleus in Yeast Cells

Nanodiamonds are widely used for drug delivery, labelling or nanoscale sensing. For all these applications it is highly beneficial to have control over the intracellular location of the particles. For the first time, we have achieved targeting the nucleus of yeast cells. In terms of particle uptake, these cells are challenging due to their rigid cell wall. Thus, we used a spheroplasting protocol to remove the cell wall prior to uptake. To achieve nuclear targeting we used nanodiamonds, which were attached to antibodies. When using non-targeted particles, only 20% end up at the nucleus. In comparison, by using diamonds linked to antibodies, 70% of the diamond particles reach the nucleus.

Photosensitizer-Doped and Plasma Membrane-Responsive Liposomes for Nuclear Drug Delivery and Multidrug Resistance Reversal

Clinically approved doxorubicin (Dox)-loaded liposomes (e.g., Doxil) guarantee good biosafety, but their insufficient nuclear delivery of Dox (<0.4%) after cellular uptake significantly hampers their final anticancer efficacy. Here, we report that simply doping protoporphyrin IX (PpIX, a commonly used hydrophobic photosensitizer) into the lipid bilayers of Dox-loaded liposomes (the resultant product is termed PpIX/Dox liposomes) is a feasible way to promote the nuclear delivery of Dox. This facile strategy relies on a unique property of PpIX-it presents considerably higher affinity for the real plasma membrane over its liposomal carrier, which drives the doped PpIX molecules to detach from the liposomes when encountering cancer cells. We demonstrate that this process can trigger the efficient release of the loaded Dox molecules and allow them to enter the nuclei of MCF-7 breast cancer cells without being trapped by lysosomes. Regarding the drug-resistant MCF-7/ADR cells, the aberrant activation of the efflux pumps in the plasma membranes expels the internalized Dox. However, we strikingly find that the robust drug resistance can be reversed upon mild laser irradiation because the photodynamic effect of PpIX disrupts the drug efflux system (e.g., P-glycoprotein) and facilitates the nuclear entry of Dox. As a proof-of-concept, this PpIX doping strategy is also applicable for enhancing the effectiveness of cisplatin-loaded liposomes against both A549 and A549/DDP lung cancer cells. In vivo experimental results prove that a single injection of PpIX/Dox liposomes completely impedes the growth of MCF-7 tumors in nude mice within 2 weeks and, in combination with laser irradiation, can synergistically ablate MCF-7/ADR tumors. Biosafety assessments reveal no significant systemic toxicity caused by PpIX/Dox liposomes. This work exemplifies a facile method to modulate the subcellular fate of liposomal drugs and may inspire the optimization of nanopharmaceuticals in the near future.

Targeting Activated Hepatic Stellate Cells Using Collagen-Binding Chitosan Nanoparticles for siRNA Delivery to Fibrotic Livers

Activated hepatic stellate cells (aHSCs) are the main orchestrators of the fibrotic cascade in inflamed livers, with transforming growth factor-beta (TGF-β) being the most potent pro-fibrotic cytokine. Hence, aHSCs serve as interesting therapeutic targets. However, drug delivery to aHSCs is hindered by excessive collagen deposition in the extracellular matrix (ECM) and capillarization of liver sinusoids. Chitosan-nanoparticles (CS-NPs) show intrinsic affinity for collagen, holding potential for drug delivery to fibrotic livers. Here, we employed CS-NPs for anti-TGF-β siRNA delivery, promoting delivery into aHSCs via modification with platelet-derived growth factor receptor-beta binding peptides. In-vitro experiments using aHSCs demonstrated the association of unmodified CS-NPs to the collagen-rich ECM, with reduced intracellular accumulation. Peptide-modified CS-NPs showed a higher propensity to localize intracellularly; however, this was only the case upon ECM-collagen reduction via collagenase treatment. Peptide-modified CS-NPs were more potent than unmodified CS-NPs in reducing TGF-β expression, implying that while collagen binding promotes liver accumulation, it hinders cell-specific siRNA delivery. In-vivo, CS-NPs successfully accumulated in fibrotic livers via collagen binding. Similar to in-vitro findings, when mice were pretreated with collagenase-loaded CS-NPs, the accumulation of peptide-modified NPs increased. Our findings demonstrate the usefulness of NPs modification with targeting ligands and collagenase treatment for aHSCs targeting and highlight the importance of chitosan-collagen binding in drug delivery to fibrotic diseases.

Bioinspired Cell Nuclear Nanotransporters Generated by Self-Assembly of Amphiphilic Polysaccharide-Amino Acid Derivatives Conjugates

Development of nanomaterials that surely transport functional biomacromolecules and bioactive synthetic compounds into the cell nucleus must be promising for the generation of nuclear-targeting new technologies. However, the development of nuclear transporting nanomaterials thus still remains a significant challenge, because molecular transport between the cytoplasm and the nucleus of a eukaryotic cell is strictly regulated by the sole gateway through the nuclear envelope, the nuclear pore complexes (NPCs). Here, the rational design of novel artificial nuclear nanotransporters (NucPorters), inspired by importin, naturally occurring nuclear transporters is shown. The NucPorter is generated by simple molecular design: self-assembly of amphiphilic polymers, where a few numbers of hydrophobic amino-acid derivatives with phenyl groups are conjugated to negatively charged hydrophilic heparin. The NucPorter can mimic essential structural and chemical features of importin machinery to pass through the NPCs. Importantly, the NucPorter demonstrates remarkable rapid and high efficient nuclear transport in cultured cells, tissue/organ, and living mice. Moreover, the NucPorter successfully imports both enzymes and synthetic anticancer drugs into the nucleus while maintaining their bioactivity. Thus, the NucPorter provides a promising new route to generate innovative nuclear-targeting medicines, diagnostics, cell imaging and engineering techniques, and drug delivery systems.

Enhanced nuclear delivery of H1-S6A, F8A peptide by NrTP6-modified polymeric platform

Nucleus is the central regulator of cell metabolism, growth and differentiation, which is considered as an effective target for the treatment of many diseases. To efficiently deliver drugs into nucleus, delivery systems have to bypass a number of barriers especially crossing the cell membrane and nuclear envelope. Here we report a nucleolar targeting peptide (NrTP6) modified polymeric conjugate platform based on N-(2-hydroxypropyl)-methacrylamide (HPMA) copolymers for enhanced nuclear delivery of H1-S6A, F8A peptide to hinder c-Myc from binding to DNA. On one hand, the modification of NrTP6 would promote cellular uptake and nuclear accumulation of the conjugates, and on the other hand, the conjugates can release smaller molecular weight subunits (H1-NrTP6) via cleavage of lysosomally enzyme-sensitive spacer for facilitating nucleus transport. It was found that NrTP6 modified HPMA copolymer-H1 peptide conjugates could improve internalization and nuclear accumulation of H1 peptide by 2.2 and 37.1-fold, respectively, compared to the non-NrTP6 modified ones, in HeLa cells. Moreover, the same trend was found in MDA-MB-231 cells and 4T1 cells. In addition, we found that the nuclear targeting mechanism of NrTP6 peptide mediation may be associated with the importin α/β pathway. Furthermore, the in vivo investigation revealed that NrTP6-modified polymeric platform exhibited the best therapeutic efficacy with a tumor growth inhibition rate of 77.0%. These results indicated that NrTP6 modification was a promising strategy for simultaneously realizing cellular internalization and nuclear targeting, which might provide a new path for intranuclear drug delivery.

Hyperthermia and smart drug delivery systems for solid tumor therapy

Chemotherapy is a cornerstone of cancer therapy. Irrespective of the administered drug, it is crucial that adequate drug amounts reach all cancer cells. To achieve this, drugs first need to be absorbed, then enter the blood circulation, diffuse into the tumor interstitial space and finally reach the tumor cells. Next to chemoresistance, one of the most important factors for effective chemotherapy is adequate tumor drug uptake and penetration. Unfortunately, most chemotherapeutic agents do not have favorable properties. These compounds are cleared rapidly, distribute throughout all tissues in the body, with only low tumor drug uptake that is heterogeneously distributed within the tumor. Moreover, the typical microenvironment of solid cancers provides additional hurdles for drug delivery, such as heterogeneous vascular density and perfusion, high interstitial fluid pressure, and abundant stroma. The hope was that nanotechnology will solve most, if not all, of these drug delivery barriers. However, in spite of advances and decades of nanoparticle development, results are unsatisfactory. One promising recent development are nanoparticles which can be steered, and release content triggered by internal or external signals. Here we discuss these so-called smart drug delivery systems in cancer therapy with emphasis on mild hyperthermia as a trigger signal for drug delivery.

Cancer-Cell-Membrane-Coated Nanoparticles with a Yolk-Shell Structure Augment Cancer Chemotherapy

Despite rapid advancements in antitumor drug delivery, insufficient intracellular transport and subcellular drug accumulation are still issues to be addressed. Cancer cell membrane (CCM)-camouflaged nanoparticles (NPs) have shown promising potential in tumor therapy due to their immune escape and homotypic binding capacities. However, their efficacy is still limited due to inefficient tumor penetration and compromised intracellular transportation. Herein, a yolk-shell NP with a mesoporous silica nanoparticle (MSN)-supported PEGylated liposome yolk and CCM coating, CCM@LM, was developed for chemotherapy and exhibited a homologous tumor-targeting effect. The yolk-shell structure endowed CCM@LM with moderate rigidity, which might contribute to the frequent transformation into an ellipsoidal shape during infiltration, leading to facilitated penetration throughout multicellular spheroids in vitro (up to a 23.3-fold increase compared to the penetration of membrane vesicles). CCM@LM also exhibited a cellular invasion profile mimicking an enveloped virus invasion profile. CCM@LM was directly internalized by membrane fusion, and the PEGylated yolk (LM) was subsequently released into the cytosol, indicating the execution of an internalization pathway similar to that of an enveloped virus. The incoming PEGylated LM further underwent efficient trafficking throughout the cytoskeletal filament network, leading to enhanced perinuclear aggregation. Ultimately, CCM@LM, which co-encapsulated low-dose doxorubicin and the poly(ADP-ribose) polymerase inhibitor, mefuparib hydrochloride, exhibited a significantly stronger antitumor effect than the first-line chemotherapeutic drug Doxil. Our findings highlight that NPs that can undergo facilitated tumor penetration and robust intracellular trafficking have a promising future in cancer chemotherapy.

Organelle-specific targeting of polymersomes into the cell nucleus

Organelle-specific nanocarriers (NCs) are highly sought after for delivering therapeutic agents into the cell nucleus. This necessitates nucleocytoplasmic transport (NCT) to bypass nuclear pore complexes (NPCs). However, little is known as to how comparably large NCs infiltrate this vital intracellular barrier to enter the nuclear interior. Here, we developed nuclear localization signal (NLS)-conjugated polymersome nanocarriers (NLS-NCs) and studied the NCT mechanism underlying their selective nuclear uptake. Detailed chemical, biophysical, and cellular analyses show that karyopherin receptors are required to authenticate, bind, and escort NLS-NCs through NPCs while Ran guanosine triphosphate (RanGTP) promotes their release from NPCs into the nuclear interior. Ultrastructural analysis by regressive staining transmission electron microscopy further resolves the NLS-NCs on transit in NPCs and inside the nucleus. By elucidating their ability to utilize NCT, these findings demonstrate the efficacy of polymersomes to deliver encapsulated payloads directly into cell nuclei.

Dual and multi-targeted nanoparticles for site-specific brain drug delivery

In recent years, nanomedicines have emerged as a promising method for central nervous system drug delivery, enabling the drugs to overcome the blood-brain barrier and accumulate preferentially in the brain. Despite the current success of brain-targeted nanomedicines, limitations still exist in terms of the targeting specificity. Based on the molecular mechanism, the exact cell populations and subcellular organelles where the injury occurs and the drugs take effect have been increasingly accepted as a more specific target for the next generation of nanomedicines. Dual and multi-targeted nanoparticles integrate different targeting functionalities and have provided a paradigm for precisely delivering the drug to the pathological site inside the brain. The targeting process often involves the sequential or synchronized navigation of the targeting moieties, which allows highly controlled drug delivery compared to conventional targeting strategies. Herein, we focus on the up-to-date design of pathological site-specific nanoparticles for brain drug delivery, highlighting the dual and multi-targeting strategies that were employed and their impact on improving targeting specificity and therapeutic effects. Furthermore, the background discussion of the basic properties of a brain-targeted nanoparticle and the common lesion features classified by neurological pathology are systematically summarized.

Enhanced intracellular and intranuclear drug delivery mediated by biomimetic peptide SVS-1 for anticancer therapy

Tumor cell nucleus is the ultimate target of many first-line chemotherapeutics and therapeutic genes. However, nuclear drug delivery is always hampered by multiple intracellular obstacles especially low efficiency of cellular uptake and insufficient nuclear trafficking. It is urgent to establish novel nuclear drug delivery systems to simultaneously overcome barriers including cell membranes and nuclear envelope. Herein, an N-(2-hydroxypropyl) methacrylamide (HPMA) polymer-based drug delivery system was designed to achieve enhanced intracellular and intranuclear drug delivery. A biomimetic peptide (SVS-1), derived from antimicrobial peptides, which was reported to efficiently penetrate cell membranes and translocate rapidly into nucleus without decreasing cell viability, was conjugated to the HPMA copolymer backbone. The in vitro studies showed that SVS-1 could enhance the uptake and nuclei accumulation of HPMA copolymer by 4.1 and 7.0-fold on human cervical cancer cells (HeLa) separately compared with corresponding non-SVS-1 modified HPMA copolymers (P-DOX). This also transferred to greater DNA damage, more apoptosis and superior cytotoxicity (2.4-fold) of doxorubicin which was chosen as the model drug and attached to SVS-1 modified HPMA copolymer (SVS-1-P-DOX). Furthermore, the in vivo investigation revealed that compared with free doxorubicin, SVS-1-P-DOX not only showed prolonged blood circulation and preferential tumor accumulation, but also suppressed tumor growth more efficiently with tumor growth inhibition of 78.7% in HeLa tumor-bearing BALB/c nude mice without causing noticeable physiological change in major organs. These results demonstrated that the SVS-1 modification was a promising strategy for contemporaneously overcome cell membranes and nuclear envelope, which might provide new opportunities for constructing nucleus-targeted anticancer therapy.

Direct Nucleus-Targeted Drug Delivery Using Cascade pHe /Photo Dual-Sensitive Polymeric Nanocarrier for Cancer Therapy

The cell nucleus-targeted delivery of therapeutic agents plays a critical role in cancer therapy, since the biological target of many anticancer therapeutics is the cell nucleus. However, multiple physiological barriers limit the delivery efficiency of free drugs, resulting in unsatisfactory therapeutic effects. Herein, thioketal crosslinked polyphosphoester-based nanoparticles with a tumor acidity (pH_e )-sensitive transactivator of transcription (TAT) peptide (DA-masked TAT-decorating reactive oxygen species (ROS)-sensitive Ce6/DOX-loaded hyperbranched nanoparticles (^D TRCD)) are explored for cascade nucleus-targeted drug delivery. Following administration, ^D TRCD experiences prolonged circulation by masking the targeting effect of its TAT peptide and then achieves enhanced tumor cell uptake and improved translocation into the perinuclear region by reactivating the TAT targeting capability in tumor tissue. Subsequently, ROS generated by ^D TRCD under 660 nm laser not only disrupts the nuclear membrane to allow entry into the nuclei but also triggers intracellular release of the payload in the nuclei. As evidenced by in vivo experiments, such pH_e /photo dual-sensitive polymeric nanocarriers offer remarkable therapeutic effects, efficiently suppressing tumor growth. This multistage cascade nucleus-targeted drug delivery concept provides new avenues to develop nucleus-targeted drug delivery systems.