A multifunctional envelope type nano device (MEND) for gene delivery to tumours based on the EPR effect: a strategy for overcoming the PEG dilemma

Inhalable lipid-based nanocarriers covered by polydopamine for effective mucus penetration and pulmonary retention

To overcome the critical challenge in drug inhalation for pulmonary diseases, we innovatively proposed that polydopamine (PDA) as a surface modification material had great potential to improve the mucus permeation and pulmonary retention of inhalable lipid-based nanocarriers. We prepared PDA coated lipid nanoemulsions/solid lipid nanoparticles/liposomes and systematically evaluated their interactions with mucin and pulmonary retention after inhalation. PDA-coated lipid-based nanocarriers exhibited weaker interactions with mucins, higher mucus permeability and cellular uptake by the respiratory epithelium cells compared to PEGylated lipid-based nanocarriers. However, the pulmonary retention advantage of PDA coating was shown in lipid nanoemulsions (< 50 nm) and solid lipid nanoparticles (< 100 nm). Liposomes (∼ 150 nm) with PEGylation possessed higher pulmonary retention than that coated by PDA. It was suggested that PEGylated liposomes were liable to be phagocytosed by alveolar macrophages due to binding with specific antibodies. Overall, this work suggests that PDA as a surface modification material of inhalable lipid-based nanocarriers holds promise for effective mucus penetration and pulmonary retention.

Exploring the promise of lipoplexes: From concept to clinical applications

Lipoplexes are non-viral lipid vectors that effectively form complexes with genetic material, positioning them as promising alternatives to viral vectors in gene therapy. Their advantages include lower toxicity, reduced immunogenicity, improved targetability, and ease of large-scale production. A typical lipoplex is composed of cationic lipids, neutral lipids, and anionic nucleic acids (e.g., DNA, mRNA, miRNA, siRNA, shRNA). Neutral lipids play an auxiliary role and are often used as transfection enhancers. Enhancing lipoplex efficiency often involves modifying the cationic lipid structure through functional groups like PEG polymers and targeting ligands. The assembly of lipoplexes occurs spontaneously. This process involves the binding of the positively charged polar head group of the cationic lipid to the negatively charged DNA spontaneously as a result of electrostatic interaction, then irreversible rearrangement and condensation of the lipoplex occurs to form either lamellar or hexagonal structures. The transfection process encompasses several steps: cellular entry, endosomal escape and cargo release, cytoplasmic trafficking, and nuclear entry. The physicochemical and biological properties of lipoplexes are influenced by factors such as lipid structure, charge ratio, and environmental conditions. Despite certain limitations like low gene transfer efficiency and rapid clearance by serum proteins, lipoplexes show promise for clinical applications. They can be administered through various routes, offering potential treatments for diseases such as cancer, bone damage, infection, and cystic fibrosis. The study aims to examine the potential of lipoplexes as a promising vehicle for delivering therapeutic agents and their progression from theoretical concepts to practical clinical applications.

Development of a messenger RNA vaccine using pH-responsive dipeptide-conjugated lipids exhibiting reduced inflammatory properties

Lipid nanoparticles (LNPs) are used to encapsulate messenger ribonucleic acids (mRNAs) and enhance mRNA vaccine efficacy by producing inflammatory mediators. However, the overproduction of inflammatory mediators via LNP injection causes severe side effects, presenting a potential limitation. To resolve this issue, we developed pH-responsive dipeptide-conjugated lipid (DPL)-based LNPs (DPL-LNPs) for efficient small interfering RNA delivery with excellent biocompatibility. In detail, we optimized the dipeptide sequence and lipid-tail length of DPL, the helper-lipid compositions, and the molecular weight and lipid-tail length of the polyethylene glycol (PEG)-lipid to achieve highly efficient and safe mRNA delivery. Our results revealed that the LNPs prepared using glutamic acid (E)- and arginine (R)-conjugated DPL (DPL-ER) displayed higher protein-expression efficacy than DPL-threonine-R- and DPL-aspartic acid-R-based LNPs. Additionally, the lipid-tail length of the C22-bearing DPL-ER (DPL-ER-C22)-based LNPs displayed higher protein-expression efficacies than their C18 (DPL-ER-C18)- and C24 (DPL-ER-C24)-based LNPs. Moreover, the DPL-ER-C22-based LNPs incorporating low-lipid-tail-length phospholipids and PEG-lipids exhibited efficient protein expression. Most importantly, the injection of optimized DPL-LNPs exhibited comparable antigen-specific antibody production levels, with significantly lower inflammatory-mediator production compared with those of the commercially available LNPs. These results indicate that DPL-based LNPs (DPL-LNPs) can be deployed as highly efficient, safe carriers for mRNA delivery for developing mRNA vaccine formulations.

Recent advances in poly(amino acids), polypeptides, and their derivatives in drug delivery

Poly(amino acids), polypeptides, and their derivatives have demonstrated significant potential as biodegradable biomaterials in the field of drug delivery. As degradable drug carriers, they can effectively load or conjugate drug molecules including small molecule drugs, nucleic acids, peptides, and protein-based drugs, enhancing the stability and targeting of the drugs in vivo. This strategy ultimately facilitates precise drug delivery and controlled release, thereby improving therapeutic efficacy and reducing side effects within the body. This review systematically describes the structural characteristics and preparation methods of poly(amino acids) and polypeptides, summarizes the advantages of poly(amino acids), polypeptides, and their derivatives in drug delivery, and detailedly introduces the latest advancements in this area. The review also discusses current challenges and opportunities associated with poly(amino acids), peptides, and their derivatives, and offers insights into the future directions for these biodegradable materials. This review aims to provide valuable references for scientific research and clinical translation of biodegradable biomaterials based on poly(amino acids) and peptides.

Surface modification of extracellular vesicles with polyoxazolines to enhance their plasma stability and tumor accumulation

Extracellular vesicles (EVs) are future promising therapeutics, but their instability in vivo after administration remains an important barrier to their further development. Many groups evaluated EV surface modification strategies to add a targeting group with the aim of controlling EV biodistribution. Conversely, fewer groups focused on their stabilization to obtain "stealth" allogenic EVs. Modulating their stabilization and biodistribution is an essential prerequisite for their development as nano-therapeutics. Here, we explored polyoxazolines with lipid anchors association to the EV membrane (POxylation as an alternative to PEGylation) to stabilize EVs in plasma and control their biodistribution, while preserving their native properties. We found that this modification maintained and seemed to potentiate the immunomodulatory properties of EVs derived from mesenchymal stem/stromal cells (MSC). Using a radiolabeling protocol to track EVs at a therapeutically relevant concentration in vivo, we demonstrated that POxylation is a promising option to stabilize EVs in plasma because it increased EV half-life by 6 fold at 6 h post-injection. Moreover, EV accumulation in tumors was higher after POxylation than after PEGylation.

Toward a Complete Elucidation of the Primary Structure-Activity in Pentaerythritol-Based One-Component Ionizable Amphiphilic Janus Dendrimers for In Vivo Delivery of Luc-mRNA

Four-component lipid nanoparticles (LNPs) and viral vectors are key for mRNA vaccine and therapeutics delivery. LNPs contain ionizable lipids, phospholipids, cholesterol, and polyethylene glycol (PEG)-conjugated lipids and deliver mRNA for COVID-19 vaccines to liver when injected intravenously or intramuscularly. In 2021, we elaborated one-component ionizable amphiphilic Janus dendrimers (IAJDs) accessing targeted delivery of mRNA. Simplified synthesis and assembly processes allow for rapid IAJD screening for discovery. The role of the primary structure of IAJDs in activity indicated, with preliminary investigations, that ionizable amine (IA), sequence, and architecture of hydrophilic and hydrophobic domains are important for in vivo targeted delivery. Here, we study the role of the interconnecting linker length between the IA and the hydrophobic domain of pentaerythritol-based IAJDs. The linker length determines, through inductive effects, the position of the IA and the pKa of the IAJDs and through flexibility, the stability of the DNPs, highlighting their extraordinarily important role in effective targeted delivery.

[Development of Tumor-targeting Drug Delivery Systems Based on an Understanding of Polymer Characteristics and the Tumor-specific Environment]

Tumor-specific active drug release from macromolecular antitumor drugs after tumor delivery is critical to achieve efficient cellular uptake of the active drug, thereby ensuring therapeutic efficacy. Upon reaching the tumor tissue, protease-facilitated depegylation of pegylated zinc protoporphyrin with ester bonds between PEG and ZnPP (esPEG-ZnPP) occurs, leading to a faster cellular uptake and superior antitumor efficacy compared to PEG-ZnPP with ether bonds (etPEG-ZnPP). This finding provides a viable strategy for achieving efficient tumor-specific drug release by utilizing an ester linkage between PEG and antitumor drugs. Another strategy involves using styrene-maleic acid copolymer (SMA), an amphiphilic polymer. Drug-encapsulating SMA aggregates disintegrate upon interaction with cell membrane components, releasing the encapsulated active drug. The author has demonstrated an improvement in the tumor accumulation of SMA-based macromolecular drugs by conjugating pirarubicin (THP), an anthracycline antitumor drug, with SMA. Furthermore, by conjugating various molecular weights of N-(2-hydroxypropyl)methacrylamide (HPMA) to THP via a hydrazone bond (P-THP, DP-THP, and SP-THP), the author has established a positive correlation between HPMA molecular weight and therapeutic efficacy as well as toxicity. Notably, P-THPs release THP under acidic conditions within tumor tissue; however, this release occurs solely outside tumor cells due to HPMA-mediated inhibition of cellular uptake. The author is currently developing macromolecular anticancer drugs using albumin for the tumor-targeted release of anticancer agents both intra- and extracellularly. The strategic development of tumor-targeting macromolecular antitumor drugs based on a comprehensive understanding of polymer characteristics and the tumor-specific environment is imperative for effective cancer therapy.

β-Cyclodextrin-based geometrically frustrated amphiphiles as one-component, cell-specific and organ-specific nucleic acid delivery systems

We introduce an innovative β-cyclodextrin (βCD)-prototype for delivering nucleic acids: "geometrically frustrated amphiphiles (GFAs)." GFAs are designed with cationic centers evenly distributed across the primary O6 and secondary O2 positions of the βCD scaffold, while hydrophobic tails are anchored at the seven O3 positions. Such distribution of functional elements differs from Janus-type architectures and enlarges the capacity for accessing strictly monodisperse variants. Changes at the molecular level can then be correlated with preferred self-assembly and plasmid DNA (pDNA) co-assembly behaviors. Specifically, GFAs undergo pH-dependent transition between bilayered to monolayered vesicles or individual molecules. GFA-pDNA nanocomplexes exhibit topological and internal order characteristics that are also a function of the GFA molecular architecture. Notably, adjusting the pKa of the cationic heads and the hydrophilic-hydrophobic balance, pupa-like arrangements implying axial alignments of GFA units flanked by quasi-parallel pDNA segments are preferred. In vitro cell transfection studies revealed remarkable differences in relative performances, which corresponded to distinct organ targeting outcomes in vivo. This allowed for preferential delivery to the liver and lung, kidney or spleen. The results collectively highlight cyclodextrin-based GFAs as a promising class of molecular vectors capable of finely tuning cell and organ transfection selectivity.

Treating acute lung injury through scavenging of cell-free DNA by cationic nanoparticles

Acute lung injury (ALI) and acute respiratory distress syndrome are life-threatening conditions induced by inflammatory responses, in which cell-free DNA (cfDNA) plays a pivotal role. This study investigated the therapeutic potential of biodegradable cationic nanoparticles (cNPs) in alleviating ALI. Using a mouse model of lipopolysaccharide-induced ALI, we examined the impact of intravenously administered cNPs. Our findings indicate that cNPs possess robust DNA binding capability, enhanced accumulation in inflamed lungs, and a favorable safety profile in vivo. Furthermore, cNPs attenuate the inflammatory response in LPS-induced ALI mice by scavenging cfDNA, mainly derived from neutrophil extracellular traps, and activating the macrophage-mediated cGAS-STING pathway. The findings suggest a potential treatment for ALI by targeting cfDNA with cNPs. This approach has demonstrated efficacy in mitigating lung injury and merits further exploration.

Innovative Approaches to Enhancing the Biomedical Properties of Liposomes

Liposomes represent a promising class of drug delivery systems that enhance the therapeutic efficacy and safety of various pharmaceutical agents. Also, they offer numerous advantages compared to traditional drug delivery methods, including targeted delivery to specific sites, controlled release, and fewer side effects. This review meticulously examines the methodologies employed in the preparation and characterization of liposomal formulations. With the rising incidence of adverse drug reactions, there is a pressing need for innovative delivery strategies that prioritize selectivity, specificity, and safety. Nanomedicine promises to revolutionize diagnostics and treatments, addressing current limitations and improving disease management, including cancer, which remains a major global health challenge. This paper aims to conduct a comprehensive study on the interest of biomedical research regarding nanotechnology and its implications for further applications.

Preparation and Characterization of Hydrophobin 4-Coated Liposomes for Doxorubicin Delivery to Cancer Cells

Background: The properties of nanoparticle surfaces are crucial in influencing their interaction with biological environments, as well as their stability, biocompatibility, targeting abilities, and cellular uptake. Hydrophobin 4 (HFB4) is a class II HFB protein produced by filamentous fungi that has a natural ability to self-assemble at hydrophobic-hydrophilic interfaces. The biocompatible, non-toxic, biodegradable, and amphipathic properties of HFB4 render it valuable for improving the solubility and bioavailability of hydrophobic drugs. We have investigated the physicochemical properties, cellular uptake, and anticancer effects of empty and Doxorubicin (Dox)-loaded HFB4 liposomes (HFB4L) and compared them to those of PEGylated liposomes (PPL). Methods: The Pichia pastoris KM71H strain was used for HFB4 purification. Liposomes were prepared through the thin film hydration method and characterized. The cytotoxic effects of free Dox, Dox-HFB4, and Dox-PPL were assessed in MCF7 cells using the SRB Assay. Results: All formulations showed good size homogeneity and a spherical shape. The HFB4 coating enhanced the physicochemical stability of Dox-HFB4L over 60 days at 4 °C without significantly affecting Dox release from HFB4L. It increased Dox release at pH 5.4 compared to pH 7.4, indicating higher delivery of drugs into acidic tumor environments, similar to Dox-PPL. While both formulations showed increased cellular uptake compared to free Dox, they exhibited a lower anticancer effect due to the sustained release of Dox. Notably, Dox-HFB4L displayed greater cytotoxicity than Dox-PPL in MCF7 cells. Conclusions: HFB4L may offer superior benefits in terms of delivering drugs to an acidic tumor environment in a stable, non-toxic, and sustained manner.

Delivery of small interfering ribonucleic acid using lipid nanoparticles prepared with pH-responsive dipeptide-conjugated lipids

The development of lipid nanoparticles (LNPs) has enabled the clinical application of small interfering ribonucleic acid (siRNA)-based therapies. Accordingly, various unique ionizable lipids have been explored for efficient siRNA delivery. However, safety concerns related to the structure of ionizable lipids have been raised. Here, we developed a pH-responsive dipeptide-conjugated lipid (DPL) for efficient, high safety siRNA delivery. We synthesized a DPL library by varying the dipeptide sequence and established a strong correlation between the knockdown efficiency of the DPL-based LNPs and the dipeptide sequence. The LNPs prepared with a DPL containing arginine (R) and glutamic acid (E) (DPL-ER) exhibited the highest knockdown efficiency. In addition, the DPL-ER-based LNPs with relatively long lipid tails (DPL-ER-C22:C22) exhibited a higher knockdown efficiency than those with short ones (DPL-ER-18:C18). The zeta potential of the DPL-ER-C22:C22-based LNPs increased as the pH decreased from 7.4 (physiological condition) to 5.5 (endosomal condition). Importantly, the DPL-ER-C22:C22-based LNPs exhibited a higher knockdown efficiency than the LNPs prepared using commercially available ionizable lipids. These results suggest that the DPL-based LNPs are safe and efficient siRNA delivery carriers.

The drug release of PLGA-based nanoparticles and their application in treatment of gastrointestinal cancers

The poly (lactic-co-glycolic acid) (PLGA) based nanoparticles have been applied for drug delivery due to their simple preparation, biodegradability, and ideal biocompatibility. In this study, the factors affecting the degradation of PLGA-based nanoparticles are reviewed, encompassing the ratio of PLA to PGA, relative molecular weight, crystallinity, and preparation process of PLGA nanoparticles. The drug release behavior of PLGA-based nanoparticles, such as the degradation environment, encapsulated drug properties of polymers, and drug loading rates, are also discussed. Since gastrointestinal cancer is one of the major global threats to human health, this paper comprehensively summarizes the application of PLGA nanoparticles in gastrointestinal cancers from diagnosis, chemotherapy, radiotherapy, and novel tumor treatment methods (immunotherapy, gene therapy, and photothermal therapy). Finally, the future application of PLGA-based drug delivery systems in treating gastrointestinal cancers is discussed. The bottleneck of application status and the prospect of PLGA-nanoparticles in gastrointestinal tumor application are presented. To truly realize the great and wide application of PLGA-based nanoparticles, collaborative progress in the field of nanomaterials and life sciences is needed.

Enhancing siRNA cancer therapy: Multifaceted strategies with lipid and polymer-based carrier systems

Cancers are increasing in prevalence and many challenges remain for their treatment, such as chemoresistance and toxicity. In this context, siRNA-based therapeutics have many potential advantages for cancer therapies as a result of their ability to reduce or prevent expression of specific cancer-related genes. However, the direct delivery of naked siRNA is hindered by issues like enzymatic degradation, insufficient cellular uptake, and poor pharmacokinetics. Hence, the discovery of a safe and efficient delivery vehicle is essential. This review explores various lipid and polymer-based delivery systems for siRNA in cancer treatment. Both polymers and lipids have garnered considerable attention as carriers for siRNA delivery. While all of these systems protect siRNA and enhance transfection efficacy, each exhibits its unique strengths. Lipid-based delivery systems, for instance, demonstrate high entrapment efficacy and utilize cost-effective materials. Conversely, polymeric-based delivery systems offer advantages through chemical modifications. Nonetheless, certain drawbacks still limit their usage. To address these limitations, combining different materials in formulations (lipid, polymer, or targeting agent) could enhance pharmaceutical properties, boost transfection efficacy, and reduce side effects. Furthermore, co-delivery of siRNA with other therapeutic agents presents a promising strategy to overcome cancer resistance. Lipid-based delivery systems have been demonstrated to encapsulate many therapeutic agents and with high efficiency, but most are limited in terms of the functionalities they display. In contrast, polymeric-based delivery systems can be chemically modified by a wide variety of routes to include multiple components, such as release or targeting elements, from the same materials backbone. Accordingly, by incorporating multiple materials such as lipids, polymers, and/or targeting agents in RNA formulations it is possible to improve the pharmaceutical properties and therapeutic efficacy while reducing side effects. This review focuses on strategies to improve siRNA cancer treatments and discusses future prospects in this important field.

Effects of phospholipid type and particle size on lipid nanoparticle distribution in vivo and in pancreatic islets

Lipid nanoparticles (LNPs) have recently been used as nanocarriers in drug delivery systems for nucleic acid drugs. Their practical applications are currently primarily limited to the liver and specific organs. However, altering the type and composition ratio of phospholipids improves their distribution in organs other than the liver, such as the spleen and lungs. This study aimed to elucidate the effects of LNP components and particle size on in vivo distribution through systemic circulation to pancreatic islets to achieve better targeting of islets, which are a fundamental therapeutic target for diabetes. Fluorescence-labeled LNPs were prepared using three phospholipids: 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), with particle sizes of 30-160 nm (diameter) using a microfluidic device. Baffled-structured iLiNP devices with adjusted flow-rate ratios and total flow rates were used. After the intravenous administration of LNPs to C57BL/6 J mice, the distribution of each LNP type to the major organs, including the pancreas and pancreatic islets, was compared using ex vivo fluorescence imaging and observation of pancreatic tissue sections. DSPC-LNPs- and DOPE-LNPs showed the highest distribution in the spleen and liver, respectively. In contrast, the DOPC-LNPs showed the highest distribution in the pancreas and the lowest distribution in the liver and spleen. In addition, smaller particles showed better distribution throughout the pancreas. The most significant LNP distribution in the islets was observed for DOPC-LNPs with a particle size of 160 nm. Furthermore, larger LNPs tended to be distributed in the islets, whereas smaller LNPs tended to be distributed in the exocrine glands. DOPC-LNPs were distributed in the islets at all cholesterol concentrations, with a high distribution observed at >40% cholesterol and > 3% PEG and the distribution was higher at 24 h than at 4 h. Thus, LNP composition and particle size significantly affected islet distribution characteristics, indicating that DOPC-LNPs may be a drug delivery system for effectively targeting the pancreas and islets.

Carrier-free nano-prodrugs for minimally invasive cancer therapy

An anticancer nanodrug with few side effects that does not require the use of a nanocarrier, polyethylene glycol, or other additives has been developed. We have fabricated nano-prodrugs (NPDs) composed only of homodimeric prodrugs of the anticancer agent SN-38, which contains a disulfide bond. The prodrugs are stable against hydrolysis but selectively release SN-38 when the disulfide bond is cleaved by glutathione, which is present in high concentrations in cancer cells. The best-performing NPDs showed good dispersion stability in nanoparticle form, and animal experiments revealed that they possess much higher antitumor activity than irinotecan, a clinically applied prodrug of SN-38. This performance was achieved by improving tumor accumulation due to the size effect and targeted drug release mechanism. The present study provides an insight into the development of non-invasive NPDs with high pharmacological activity, and also offers new possibilities for designing prodrug molecules that can release drugs in response to various kinds of triggers.

Diffusive delivery of plasmid DNA using zwitterionic carboxyalkyl poly(1-vinylimidazole) into skeletal muscle in vivo

Zwitterionic carboxyalkyl poly(1-vinylimidazole) (CA-PVIm) polymers with imidazolium cations and carboxylate anions have been synthesized as a carrier for the in vivo delivery of plasmid DNA (pDNA) to skeletal muscle. From differential scanning calorimetry measurements, resulting CA-PVIm had intermediate water in hydration water as a biocompatible polymer. Notably, when the pDNA and resulting CA-PVIm were mixed, slight retarded bands of the pDNA were observed in agarose gel electrophoresis, suggesting the polyion complex (PIC) formation between the pDNA and CA-PVIm despite zwitterionic polymers. Resulting PICs maintained the higher-order structure of the pDNA. Using resulting pDNA PICs, the highest pDNA expression by intramuscular injection was achieved in the PIC with 7 mol% carboxymethylated PVIm, that is, CA1(7)-PVIm, observed in a widespread area by in vivo imaging system. These results suggest that the CA1(7)-PVIm/pDNA PIC is effective for the diffusive delivery of the pDNA into skeletal muscle for the treatment of serious muscle diseases.

A large-scale machine learning analysis of inorganic nanoparticles in preclinical cancer research

Owing to their distinct physical and chemical properties, inorganic nanoparticles (NPs) have shown promising results in preclinical cancer therapy, but designing and engineering them for effective therapeutic purposes remains a challenge. Although a comprehensive database of inorganic NP research is not currently available, it is crucial for developing effective cancer therapies. In this context, machine learning (ML) has emerged as a transformative tool, but its adaptation to nanomedicine is hindered by inexistent or small datasets. Here we assembled a large database of inorganic NPs, comprising experimental datasets from 745 preclinical studies in cancer nanomedicine. Using descriptive statistics and explainable ML models we mined this database to gain knowledge of inorganic NP design patterns and inform future NP research for cancer treatment. Our analyses suggest that NP shape and therapy type are prominent features in determining in vivo efficacy, measured as a percentage of tumour reduction. Moreover, our database provides a large-scale open-access resource for discriminative ML that the broader nanotechnology community can utilize. Our work blueprints data mining for translational cancer research and offers evidence for standardizing NP reporting to accelerate and de-risk inorganic NP-based drug delivery, which may help to improve patient outcomes in clinical settings.

Surface Modification of Mesoporous Silica Nanoparticles for Application in Targeted Delivery Systems of Antitumour Drugs

The problem of tumour therapy has attracted the attention of many researchers for many decades. One of the promising strategies for the development of new dosage forms to improve oncology treatment efficacy and minimise side effects is the development of nanoparticle-based targeted transport systems for anticancer drugs. Among inorganic nanoparticles, mesoporous silica deserves special attention due to its outstanding surface properties and drug-loading capability. This review analyses the various factors affecting the cytotoxicity, cellular uptake, and biocompatibility of mesoporous silica nanoparticles (MSNs), constituting a key aspect in the development of safe and effective drug delivery systems. Special attention is paid to technological approaches to chemically modifying MSNs to alter their surface properties. The stimuli that regulate drug release from nanoparticles are also discussed, contributing to the effective control of the delivery process in the body. The findings emphasise the importance of modifying MSNs with different surface functional groups, bio-recognisable molecules, and polymers for their potential use in anticancer drug delivery systems.

Fine tuning of the net charge alternation of polyzwitterion surfaced lipid nanoparticles to enhance cellular uptake and membrane fusion potential

Lipid nanoparticles (LNPs) coated with functional and biocompatible polymers have been widely used as carriers to deliver oligonucleotide and messenger RNA therapeutics to treat diseases. Poly(ethylene glycol) (PEG) is a representative material used for the surface coating, but the PEG surface-coated LNPs often have reduced cellular uptake efficiency and pharmacological activity. Here, we demonstrate the effect of pH-responsive ethylenediamine-based polycarboxybetaines with different molecular weights as an alternative structural component to PEG for the coating of LNPs. We found that appropriate tuning of the molecular weight around polycarboxybetaine-modified LNP, which incorporated small interfering RNA, could enhance the cellular uptake and membrane fusion potential in cancerous pH condition, thereby facilitating the gene silencing effect. This study demonstrates the importance of the design and molecular length of polymers on the LNP surface to provide effective drug delivery to cancer cells.

Dynamic carriers for therapeutic RNA delivery

Carriers for RNA delivery must be dynamic, first stabilizing and protecting therapeutic RNA during delivery to the target tissue and across cellular membrane barriers and then releasing the cargo in bioactive form. The chemical space of carriers ranges from small cationic lipids applied in lipoplexes and lipid nanoparticles, over medium-sized sequence-defined xenopeptides, to macromolecular polycations applied in polyplexes and polymer micelles. This perspective highlights the discovery of distinct virus-inspired dynamic processes that capitalize on mutual nanoparticle-host interactions to achieve potent RNA delivery. From the host side, subtle alterations of pH, ion concentration, redox potential, presence of specific proteins, receptors, or enzymes are cues, which must be recognized by the RNA nanocarrier via dynamic chemical designs including cleavable bonds, alterable physicochemical properties, and supramolecular assembly-disassembly processes to respond to changing biological microenvironment during delivery.

Nano-Bio Interactions: Exploring the Biological Behavior and the Fate of Lipid-Based Gene Delivery Systems

Gene therapy for many diseases is rapidly becoming a reality, as demonstrated by the recent approval of various nucleic acid-based therapeutics. Non-viral systems such as lipid-based carriers, lipid nanoparticles (LNPs), for delivering different payloads including small interfering RNA, plasmid DNA, and messenger RNA have been particularly extensively explored and developed for clinical uses. One of the most important issues in LNP development is delivery to extrahepatic tissues. To achieve this, various lipids and lipid-like materials are being examined and screened. Several LNP formulations that target extrahepatic tissues, such as the spleen and the lungs have been developed by adjusting the lipid compositions of LNPs. However, mechanistic details of how the characteristics of LNPs affect delivery efficiency remains unclear. The purpose of this review is to provide an overview of LNP-based nucleic acid delivery focusing on LNP components and their structures, as well as discussing biological factors, such as biomolecular corona and cellular responses related to the delivery efficiency.

Nanoparticles with Active Targeting Ability and Acid Responsiveness for an Enhanced Antitumor Effect of Docetaxel

Docetaxel (DOC) is commonly used in cancer treatment, especially for breast cancer. However, there are severe side effects in clinical application. In order to deliver docetaxel more effectively, a novel, active targeting acid-responsive polymer called cRGD-PAE-PEG-DSPE was developed. The polymer structure incorporated poly(ethylene glycol) (PEG) as the hydrophilic segment, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) as the hydrophobic segment, and poly(β-amino ester) (PAE) as the acid-responsive group, which was grafted onto the PEG. Furthermore, c(RGDyC) was grafted onto PAE to confer active targeting capability. Through self-assembly, docetaxel was encapsulated in RAED@DOC. Through in vitro experiments, it was confirmed that RAED@DOC had good serum stability and acid responsiveness, as well as enhanced uptake by MDA-MB-231 cells. Additionally, the antitumor efficiency in vivo and histopathological analysis showed that RAED@DOC exhibited higher antitumor activity and lower systemic toxicity in comparison to free docetaxel. These results suggested that RAED@DOC had considerable potential clinical use.

Reversible Stabilization of Nanofiber-Polyplexes through Introducing Cross-Linkages

Non-viral gene delivery systems are typically designed vector systems with contradictory properties, namely sufficient stability before cellular uptake and instability to ensure the release of nucleic acid cargoes in the transcription process after being taken up into cells. We reported previously that poly-(L-lysine) terminally bearing a multi-arm PEG (maPEG-PLL) formed nanofiber-polyplexes that suppressed excessive DNA condensation via steric repulsion among maPEGs and exhibited effective transcriptional capability in PCR amplification experiments and a cell-free gene expression system. In this study, the reversible stabilization of a nanofiber-polyplex without impairing the effective transcriptional capability was investigated by introducing cross-links between the PLL side chains within the polyplex using a cross-linking reagent with disulfide (SS) bonds that can be disrupted under reducing conditions. In the presence of dextran sulfate and/or dithiothreitol, the stability of the polyplex and the reactivity of the pDNA were evaluated using agarose gel electrophoresis and real-time PCR. We succeeded in reversibly stabilizing nanofiber-polyplexes using dithiobis (succinimidyl propionate) (DSP) as the cross-linking reagent. The effect of the reversible stabilization was confirmed in experiments using cultured cells, and the DSP-crosslinked polyplexes exhibited gene expression superior to that of polyethyleneimine polyplexes, which are typical polyplexes.

Sustained release of therapeutic gene by injectable hydrogel for hepatocellular carcinoma

Gene therapy has shown remarkable effectiveness in the management of disease like cancer and inflammation as a revolutionary therapeutic. Nonetheless, therapeutic drug target discovery, efficient gene delivery, and gene delivery vehicles continue to be significant obstacles. Due to their effective gene transport capabilities and low immunogenicity, supramolecular polymers have garnered significant interest. Herein, ABHD5 is identified as a potential therapeutic target since it is dysregulated in hepatocellular carcinoma (HCC). Interestingly, the downregulation of ABHD5 could induce programmed death-ligand 1 (PD-L1) expression in liver cancer, which may contribute to the immunosuppression. To overcome the immunosuppression caused by PD-L1, an injectable hydrogel is designed to achieve efficient abhydrolase domain containing 5 (ABHD5) gene delivery via the host-guest interaction with branched polyethyleneimine-g-poly (ethylene glycol), poly (ethylene oxide) and poly (propylene oxide) block copolymers and α-CD (PPA/CD), demonstrating the capability for sustained gene release. The co-assembly hydrogel demonstrates good biocompatibility and enhanced gene transfection efficiency, efficiently triggering tumor cell apoptosis. Overall, the results of this study suggest that ABHD5 is a potential therapeutic target, and that a host-guest-based supramolecular hydrogel could serve as a promising platform for the inhibition of HCC.

Polysialic acid-functionalized liposomes for efficient honokiol delivery to inhibit breast cancer growth and metastasis

To improve the anti-metastasis effects of honokiol (HNK) on breast cancer, we designed cationic liposomes (Lip) in which HNK was encapsulated into Lip, and its surface was modified with negatively charged polysialic acid (PSA-Lip-HNK) for efficient treatment of breast cancer. PSA-Lip-HNK possessed a homogeneous spherical shape and high encapsulation efficiency. In vitro 4T1 cell experiments indicated that PSA-Lip-HNK increased cellular uptake and cytotoxicity via the endocytosis pathway mediated by PSA and selectin receptors. Furthermore, the significant antitumor metastasis impact of PSA-Lip-HNK was confirmed by wound healing and cell migration and invasion. Enhanced in vivo tumor accumulation of the PSA-Lip-HNK was observed in 4T1 tumor-bearing mice by living fluorescence imaging. For in vivo antitumor experiments using 4T1 tumor-bearing mice, PSA-Lip-HNK exhibited a higher tumor growth and metastasis inhibition compared with unmodified liposomes. Therefore, we believe that PSA-Lip-HNK well combined biocompatible PSA nano-delivery and chemotherapy, providing a promising drug delivery approach for metastatic breast cancer therapy.

Biodegradable polyester-based nano drug delivery system in cancer chemotherapy: a review of recent progress (2021-2023)

Cancer presents a formidable threat to human health, with the majority of cases currently lacking a complete cure. Frequently, chemotherapy drugs are required to impede its progression. However, these drugs frequently suffer from drawbacks such as poor selectivity, limited water solubility, low bioavailability, and a propensity for causing organ toxicity. Consequently, a concerted effort has been made to seek improved drug delivery systems. Nano-drug delivery systems based on biodegradable polyesters have emerged as a subject of widespread interest in this pursuit. Extensive research has demonstrated their potential for offering high bioavailability, effective encapsulation, controlled release, and minimal toxicity. Notably, poly (ε-caprolactone) (PCL), poly (lactic-co-glycolic acid) (PLGA), and polylactic acid (PLA) have gained prominence as the most widely utilized options as carriers of the nano drug delivery system. This paper comprehensively reviews recent research on these materials as nano-carriers for delivering chemotherapeutic drugs, summarizing their latest advancements, acknowledging their limitations, and forecasting future research directions.

Co-delivery of dimeric camptothecin and chlorin e6 via polypeptide-based micelles for chemo-photodynamic synergistic therapy

BACKGROUND

The integration of photodynamic therapy with a chemical drug-delivery system has displayed great potential in enhancing anticancer therapy. However, the solubility and non-specific biodistribution of both chemotherapeutic agents and photosensitizers continue to pose challenges that hinder their clinical applications.

METHOD

A polypeptide-based nanoscale drug delivery system was fabricated to address the prementioned issues. An amphiphilic polymer was formed by conjugating the photosensitizer chlorin e6 (Ce6) onto a polypeptide poly-(L-lysine)-b-polyphenylalanine (PKF) for encapsulating the model drug dimeric camptothecin (DCPT), and the nanoparticles (PCD) with high drug loading efficiency were further modified with acid-sensitive polyethylene glycol (PEG) to yield the drug delivery sytem (PPCD).

RESULTS

The DCPT and Ce6 encapsulation efficiency were analyzed as 99% and 73.5%, respectively. In phosphate-buffered saline (PBS) solution at a pH of 7.4, the PEG shell improved the stability of micelles and shielded their positive charge while in the acidic tumor microenvironment, the pH-sensitive PEG layer was removed to expose the cationic nanoparticles, thus facilitating the cellular uptake of PPCD micelles. Benefiting from the enhanced cellular internalization, the amount of intracellular reactive oxygen species (ROS) treated with PCD and PPCD micelles were obviously increased. Furthermore, the enhanced anti-cancer efficacy prompted by PPCD micelles was validated through cellular and animal study.

CONCLUSION

This study presents a promising method to promote the solubility and biodistribution of both chemotherapeutic agent and photosensitizer, thereby facilitating the further application of chemo-photodynamic cancer therapy.

Facile preparation of PEGylated polyethylenimine polymers as vaccine carriers with reduced cytotoxicity and enhanced Interleukin-2 (IL-2) production

Developing low-cost, easy-to-prepare, biocompatible and highly efficient vaccine carriers is a promising approach to realize practical cancer immunotherapy. In this study, through facile modification of mPEG5k-4-toluenesulfonate (mPEG5k-OTs) on PEI25k under mild conditions, a series of "stealth" mPEG5k-PEI25k polymers (PP1, PP2 and PP3) were prepared, their structures and physicochemical properties were characterized and theoretically analyzed. The polymers could bind/load ovalbumin (OVA) to form mPEG5k-PEI25k/OVA complexes as negatively charged nanoparticles with small hydrodynamic particle size (80-210 nm) and narrow size distribution. Compared to PEI25k/OVA, lower cytotoxicity could be achieved on mPEG5k-PEI25k/OVA complexes in dendritic cells (DCs). In DCs-RF 33.70 T-cells co-culture system, the mPEG5k-PEI25k/OVA complexes could bring about higher IL-2 production /secretion than that of PEI25k/OVA, notably, the optimum IL-2 secretion could reach 9.3-folds of the PEI25k/OVA under serum condition (10% FBS). Moreover, the cell biological features could be optimized by selecting suitable mPEG5k-grafting ratios and/or mPEG5k-PEI25k/OVA weight ratios. Intracellular imaging results showed that the mPEG5k-PEI25k(PP3)/Rhodamine-OVA complexes mainly localized inside lysosomes. Taken together, this work provided a facile method to prepare "stealth" PEGylated-PEI25k polymers with reduced cytotoxicity, promoted OVA cross-presentation efficiency and improved serum compatibility towards cancer immunotherapy.

A Comparison of Cellular Uptake Mechanisms, Delivery Efficacy, and Intracellular Fate between Liposomes and Extracellular Vesicles

A key aspect for successful drug delivery via lipid-based nanoparticles is their internalization in target cells. Two prominent examples of such drug delivery systems are artificial phospholipid-based carriers, such as liposomes, and their biological counterparts, the extracellular vesicles (EVs). Despite a wealth of literature, it remains unclear which mechanisms precisely orchestrate nanoparticle-mediated cargo delivery to recipient cells and the subsequent intracellular fate of therapeutic cargo. In this review, internalization mechanisms involved in the uptake of liposomes and EVs by recipient cells are evaluated, also exploring their intracellular fate after intracellular trafficking. Opportunities are highlighted to tweak these internalization mechanisms and intracellular fates to enhance the therapeutic efficacy of these drug delivery systems. Overall, literature to date shows that both liposomes and EVs are predominantly internalized through classical endocytosis mechanisms, sharing a common fate: accumulation inside lysosomes. Studies tackling the differences between liposomes and EVs, with respect to cellular uptake, intracellular delivery and therapy efficacy, remain scarce, despite its importance for the selection of an appropriate drug delivery system. In addition, further exploration of functionalization strategies of both liposomes and EVs represents an important avenue to pursue in order to control internalization and fate, thereby improving therapeutic efficacy.

The Commonly Used Stabilizers for Phytochemical-Based Nanoparticles: Stabilization Effects, Mechanisms, and Applications

Phytochemicals, such as resveratrol, curcumin, and quercetin, have many benefits for health, but most of them have a low bioavailability due to their poor water solubility and stability, quick metabolism, and clearance, which restricts the scope of their potential applications. To overcome these issues, different types of nanoparticles (NPs), especially biocompatible and biodegradable NPs, have been developed. NPs can carry phytochemicals and increase their solubility, stability, target specificity, and oral bioavailability. However, NPs are prone to irreversible aggregation, which leads to NP instability and loss of functions. To remedy this shortcoming, stabilizers like polymers and surfactants are incorporated on NPs. Stabilizers not only increase the stability of NPs, but also improve their characteristics. The current review focused on discussing the state of the art in research on synthesizing phytochemical-based NPs and their commonly employed stabilizers. Furthermore, stabilizers in these NPs were also discussed in terms of their applications, effects, and underlying mechanisms. This review aimed to provide more references for developing stabilizers and NPs for future research.

Targeted and Equally Distributed Delivery of mRNA to Organs with Pentaerythritol-Based One-Component Ionizable Amphiphilic Janus Dendrimers

Delivery of nucleic acids with viral and synthetic vectors has pioneered genetic nanomedicine. Four-component lipid nanoparticles (LNPs) consisting of ionizable lipids, phospholipids, cholesterol, and PEG-conjugated lipids, assembled by microfluidic or T-tube, are the benchmark synthetic vector for delivery of mRNA. One-component multifunctional sequence-defined ionizable amphiphilic Janus dendrimer (IAJD) delivery systems for mRNA were developed by us to complement LNPs. IAJDs consist of multifunctional hydrophilic low-generation dendrons or minidendrons conjugated to hydrophobic dendrons. They were inspired by amphiphilic Janus dendrimers and glycodendrimers. IAJDs coassemble with mRNA into predictable-size vesicles, named dendrimersome nanoparticles (DNPs), by simple injection in acetate buffer, rather than by the complex technology required by LNPs. Assembly of DNPs by simple injection together with sequence design in the hydrophilic and hydrophobic modules of IAJDs endowed rapid screening to access discovery. Molecular design principles for targeted delivery were elaborated when the branching points of IAJDs were constructed from symmetrically and nonsymmetrically substituted plant phenolic acids interconnected by pentaerythritol (PE). Here, we report the first library containing simplified IAJDs constructed in only three steps from symmetrically trialkylated PE in the hydrophobic domain and four different piperazine-based ionizable amines in the hydrophilic part. Rapid coassembly with mRNA and in vivo screening led to the discovery of the two most active IAJDs targeting the spleen, liver, and lymph nodes, one predominantly to the spleen and liver and six delivering equally to the spleen, liver, lung, and lymph nodes. These IAJDs represent the simplest synthetic vectors and the first viral or synthetic system delivering equally to multiple organs.

Efficient delivery of mesenchymal stem/stromal cells to injured liver by surface PEGylation

BACKGROUND

Mesenchymal stem/stromal cells (MSCs) have been used in clinical trials for various diseases. These have certain notable functions such as homing to inflammation sites, tissue repair, and immune regulation. In many pre-clinical studies, MSCs administered into peripheral veins demonstrated effective therapeutic outcomes. However, most of the intravenously administered MSCs were entrapped in the lung, and homing to target sites was less than 1%. This occurred mainly because of the adhesion of MSCs to vascular endothelial cells in the lung. To prevent this adhesion, we modified the surface of MSCs with polyethylene glycol (PEG; a biocompatible polymer) using the avidin-biotin complex (ABC) method.

METHODS

The surface of MSCs was modified with PEG using the ABC method. Then, the cell adhesion to mouse aortic endothelial cells and the tissue distribution of PEG-modified MSCs were evaluated. Moreover, the homing to the injured liver and therapeutic effect of PEG-modified MSCs were evaluated using carbon tetrachloride-induced acute liver failure model mice.

RESULTS

The PEG modification significantly suppressed the adhesion of MSCs to cultured mouse aortic endothelial cells as well as the entrapment of MSCs in the lungs after intravenous injection in mice. PEG-modified MSCs efficiently homed to the injured liver of carbon tetrachloride-induced acute liver failure model mice. More importantly, the cells significantly suppressed serum transaminase levels and leukocyte infiltration into the injured liver.

CONCLUSION

These results indicate that PEG modification to the surface of MSCs can suppress the lung entrapment of intravenously administered MSCs and improve their homing to the injured liver.

DPA-Zinc around Polyplexes Acts Like PEG to Reduce Protein Binding While Targeting Cancer Cells

Gene therapy holds great promise as an effective treatment for many diseases of genetic origin. Gene therapy works by employing cationic polymers, liposomes, and nanoparticles to condense DNA into polyplexes via electronic interactions. Then, a therapeutic gene is introduced into target cells, thereby restoring or changing cellular function. However, gene transfection efficiency remains low in vivo due to high protein binding, poor targeting ability, and substantial endosomal entrapment. Artificial sheaths containing PEG, anions, or zwitterions can be introduced onto the surface of gene carriers to prevent interaction with proteins; however, they reduce the cellular uptake efficacy, endosomal escape, targeting ability, thereby, lowering gene transfection. Here, it is reported that linking dipicolylamine-zinc (DPA-Zn) ions onto polyplex nanoparticles can produce a strong hydration water layer around the polyplex, mimicking the function of PEGylation to reduce protein binding while targeting cancer cells, augmenting cellular uptake and endosomal escape. The polyplexes with a strong hydration water layer on the surface can achieve a high gene transfection even in a 50% serum environment. This strategy provides a new solution for preventing protein adsorption while improving cellular uptake and endosomal escape.

Analysis of PEG-lipid anchor length on lipid nanoparticle pharmacokinetics and activity in a mouse model of traumatic brain injury

Traumatic brain injury (TBI) affects millions of people worldwide, yet there are currently no therapeutics that address the long-term impairments that develop in a large portion of survivors. Lipid nanoparticles (LNPs) are a promising therapeutic strategy that may address the molecular basis of TBI pathophysiology. LNPs are the only non-viral gene delivery platform to achieve clinical success, but systemically administered formulations have only been established for targets in the liver. In this work, we evaluated the pharmacokinetics and activity of LNPs formulated with polyethylene glycol (PEG)-lipids of different anchor lengths when systemically administered to a mouse model of TBI. We observed an increase in LNP accumulation and activity in the injured brain hemisphere compared to the uninjured contralateral brain hemisphere. Interestingly, transgene expression mediated by LNPs was more durable in injured brain tissue compared to off-target organs when compared between 4 and 24 hours. The PEG-lipid is an important component of LNP formulation necessary for the stable formation and storage of LNPs, but the PEG-lipid structure and content also has an impact on LNP function. LNP formulations containing various ratios of PEG-lipid with C18 (DSPE-PEG) and C14 (DMG-PEG) anchors displayed similar physicochemical properties, independent of the PEG-lipid compositions. As the proportion of DSPE-PEG was increased in formulations, blood circulation times of LNPs increased and the duration of expression increased. We also evaluated diffusion of LNPs after convection enhanced delivery (CED) in healthy brains and found LNPs distributed >1 mm away from the injection site. Understanding LNP pharmacokinetics and activity in TBI models and the impact of PEG-lipid anchor length informs the design of LNP-based therapies for TBI after systemic administration.

A comprehensive review on novel targeted therapy methods and nanotechnology-based gene delivery systems in melanoma

Melanoma, a malignant form of skin cancer, has been swiftly increasing in recent years. Although there have been significant advancements in clinical treatment underlying a well-understanding of melanoma-susceptible genes and the molecular basis of melanoma pathogenesis, the permanency of response to therapy is frequently constrained by the emergence of acquired resistance and systemic toxicity. Conventional therapies, including surgical resection, chemotherapy, radiotherapy, and immunotherapy, have already been used to treat melanoma and are dependent on the cancer stage. Nevertheless, ineffective side effects and the heterogeneity of tumors pose major obstacles to the therapeutic treatment of malignant melanoma through such strategies. In light of this, advanced therapies including nucleic acid therapies (ncRNA, aptamers), suicide gene therapies, and gene therapy using tumor suppressor genes, have lately gained immense attention in the field of cancer treatment. Furthermore, nanomedicine and targeted therapy based on gene editing tools have been applied to the treatment of melanoma as potential cancer treatment approaches nowadays. Indeed, nanovectors enable delivery of the therapeutic agents into the tumor sites by passive or active targeting, improving therapeutic efficiency and minimizing adverse effects. Accordingly, in this review, we summarized the recent findings related to novel targeted therapy methods as well as nanotechnology-based gene systems in melanoma. We also discussed current issues along with potential directions for future research, paving the way for the next-generation of melanoma treatments.

Screening Libraries to Discover Molecular Design Principles for the Targeted Delivery of mRNA with One-Component Ionizable Amphiphilic Janus Dendrimers Derived from Plant Phenolic Acids

Viral and synthetic vectors to deliver nucleic acids were key to the rapid development of extraordinarily efficient COVID-19 vaccines. The four-component lipid nanoparticles (LNPs), containing phospholipids, PEG-conjugated lipids, cholesterol, and ionizable lipids, co-assembled with mRNA via a microfluidic technology, are the leading nonviral delivery vector used by BioNTech/Pfizer and Moderna to access COVID-19 mRNA vaccines. LNPs exhibit a statistical distribution of their four components when delivering mRNA. Here, we report a methodology that involves screening libraries to discover the molecular design principles required to realize organ-targeted mRNA delivery and mediate activity with a one-component ionizable multifunctional amphiphilic Janus dendrimer (IAJD) derived from plant phenolic acids. IAJDs co-assemble with mRNA into monodisperse dendrimersome nanoparticles (DNPs) with predictable dimensions, via the simple injection of their ethanol solution in a buffer. The precise location of the functional groups in one-component IAJDs demonstrated that the targeted organs, including the liver, spleen, lymph nodes, and lung, are selected based on the hydrophilic region, while activity is associated with the hydrophobic domain of IAJDs. These principles, and a mechanistic hypothesis to explain activity, simplify the synthesis of IAJDs, the assembly of DNPs, handling, and storage of vaccines, and reduce price, despite employing renewable plant starting materials. Using simple molecular design principles will lead to increased accessibility to a large diversity of mRNA-based vaccines and nanotherapeutics.

Combined chemo and photo therapy of programmable prodrug carriers to overcome delivery barriers against nasopharyngeal carcinoma

Indocyanine green (ICG) has been employed in medical diagnostics due to its superior photophysical characteristics. However, these advantages are offset by its quick body clearance and inferior photo-stability. In this work, programmable prodrug carriers for chemotherapy/PDT/PTT against nasopharyngeal carcinoma (NPC) were created in order to increase photo-stability and get around biochemical hurdles. The programmable prodrug carriers (PEG-PLA@DIT-PAMAM) that proactively penetrated deeply into NPC tumors and produced the deep phototherapy and selective drug release under laser irradiation was created by dendrimer-DOX/ICG/TPP (DIT-PAMAM) and PEGylated poly (α-lipoic acid) (PLA) copolymer. Long circulation times and minimal toxicity to mammalian cells are two benefits of PEG-coated carriers. The overexpressed GSH on the tumor cell or vascular endothelial cell of the NPC disintegrated the PEG-g-PLA chains and released the DIT-PAMAM nanoparticles after the carriers had reached the NPC tumor periphery. Small, positively charged DIT-PAMAM nanoparticles may penetrate tumors effectively and remain inside tumor for an extended period of time. In addition, the induced ROS cleaved the thioketal linkers for both DOX and nanoparticles and product hyperthermia (PTT) to kill cancer cells under laser irradiation, facilitating faster diffusion of nanoparticles and more effective tumor penetration with a programmable publication of DOX. The programmable prodrug carries showed high photo-stability high photo-stability, which enabled very effective PDT, PTT, and tumor-specific DOX release. With the goal of combining the effects of chemotherapy, PDT, and PTT against NPC, this research showed the great efficacy of programmable prodrug carriers.

Cancer Immunotherapy Elicited by Immunogenic Cell Death Based on Smart Nanomaterials

Cancer immunotherapy has been a revolutionary cancer treatment modality because it can not only eliminate primary tumors but also prevent metastases and recurrent tumors. Immunogenic cell death (ICD) induced by various treatment modalities, including chemotherapy, phototherapy, and radiotherapy, converts dead cancer cells into therapeutic vaccines, eliciting a systemic antigen-specific antitumor. However, the outcome effect of cancer immunotherapy induced by ICD has been limited due to the low accumulation efficiency of ICD inducers in the tumor site and concomitant damage to normal tissues. The boom in smart nanomaterials is conducive to overcoming these hurdles owing to their virtues of good stability, targeted lesion site, high bioavailability, on-demand release, and good biocompatibility. Herein, the design of targeted nanomaterials, various ICD inducers, and the applications of nanomaterials responsive to different stimuli, including pH, enzymes, reactive oxygen species, or dual responses are summarized. Furthermore, the prospect and challenges are briefly outlined to provide reference and inspiration for designing novel smart nanomaterials for immunotherapy induced by ICD.

Degradable Poly(amino acid) Vesicles Modulate DNA-Induced Inflammation after Traumatic Brain Injury

Following brain trauma, secondary injury from molecular and cellular changes causes progressive cerebral tissue damage. Acute/chronic neuroinflammation following traumatic brain injury (TBI) is a key player in the development of secondary injury. Rapidly elevated cell-free DNAs (cfDNAs) due to cell death could lead to production of inflammatory cytokines that aggravate TBI. Herein, we designed poly(amino acid)-based cationic nanoparticles (cNPs) and applied them intravenously in a TBI mice model with the purpose of scavenging cfDNA in the brain and suppressing the acute inflammation. In turn, these cNPs could effectively eliminate endogenous cfDNA, inhibit excessive activation of inflammation, and promote neural functional recovery.

Smart Metabolism Nanovalve Reprograms Cancer Energy Homeostasis for Maximizing Photometabolism Therapy

Better understanding of important roles of metabolic reprogramming in therapeutic resistance provides insights into advancing cancer treatment. Herein, we present a photoactive metabolic reprogramming strategy (termed as photometabolism therapy, PMT), in which photoregulation of mitochondria leads to cancer cell metabolic crisis, and consequently overcomes therapeutic resistance while improving treatment efficacy. In specific, a stimuli-responsive metabolism NanoValve is developed for improving cascade cancer therapy through blocking mitochondrial energy supply. NanoValve is composed of an onion-like architecture with a gold nanorod core, a mesoporous silica shell encapsulating photosensitizer chlorin e6 and oxygen-saturated perfluorocarbon, and cationic liposomal coating with MMP2-cleavable polyethylene glycol corona, which together initiate mitochondria-specific PMT. NanoValve selectively responds to tumor-overexpressed MMP2 and achieves size decrease and charge reversal, which consequently enhances tumor penetration, cancer cell uptake, endosome escape, and most critically, mitochondrial accumulation. Importantly, NanoValve-mediated phototherapy can strongly destruct mitochondrial energy metabolism, thereby minimizing therapy resistance. Particularly, perfluorocarbon supplies oxygen to further overcome the tumor hypoxia-associated therapeutic barrier and maximizes synergistic anticancer effects. In vivo studies show that NanoValve can effectively eliminate tumors without side effects, thereby dramatically prolonging the survival of tumor-bearing mice. Thus, NanoValve provides a modular PMT approach and has the potential of advancing the treatment of malignancy.

Tumor-Targeted Erythrocyte Membrane Nanoparticles for Theranostics of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) cells do not contain various receptors for targeted treatment, a reason behind the poor prognosis of this disease. In this study, biocompatible theranostic erythrocyte-derived nanoparticles (EDNs) were developed and evaluated for effective early diagnosis and treatment of TNBC. The anti-cancer drug, doxorubicin (DOX), was encapsulated into the EDNs and diagnostic quantum dots (QDs) were incorporated into the lipid bilayers of EDNs for tumor bio-imaging. Then, anti-epidermal growth factor receptor (EGFR) antibody molecules were conjugated to the surface of EDNs for TNBC targeting (iEDNs). According to the confocal microscopic analyses and biodistribution assay, iEDNs showed a higher accumulation in EGFR-positive MDA-MB-231 cancers in vitro as well as in vivo, compared to untargeted EDNs. iEDNs containing doxorubicin (iEDNs-DOX) showed a stronger inhibition of target tumor growth than untargeted ones. The resulting anti-EGFR iEDNs exhibited strong biocompatibility, prolonged blood circulation, and efficient targeting of TNBC in mice. Therefore, iEDNs may be used as potential TNBC-targeted co-delivery systems for therapeutics and diagnostics.

In vitro magnetic hyperthermia properties of angle-shaped superparamagnetic iron oxide nanoparticles synthesized by a bromide-assisted polyol method

Currently, research on superparamagnetic iron oxide nanoparticles (SPIONs) for magnetic hyperthermia applications is steadily increasing. In this work, SPIONs were synthesized by the bromide-assisted polyol method and angle-shaped SPIONs were successfully generated with the optimized concentration of bromide. The influence of bromide concentration on the shape of the generated SPIONs as well as the heating characteristics under an alternating magnetic field (AMF) was thoroughly investigated. At a concentration of 20 mg mL^-1 of the angle-shaped SPIONs, the highest temperature curve up to 23 °C was observed under AMF with 140 Oe and 100 kHz for 10 min. With the biotoxicity assay, no significant cytotoxicity was observed in the normal fibroblast of HFB-141103 as well as tumor cells of U87MG and FSall treated with the angle-shaped SPIONs at a concentration below 100 μg mL^-1. However, significantly decreased cellular viability was observed in tumor cells of U87MG and FSall treated with 100 μg mL^-1 of the angle-shaped SPIONs under AMF with 140 Oe and 100 kHz. Based on these results, it is thought that the angle-shaped SPIONs synthesized by the bromide-assisted polyol method will provide highly efficient magnetic hyperthermia therapy for cancers under biologically safe AMF with 140 Oe and 100 kHz.

Cell membrane-camouflaged DOX-loaded β-glucan nanoparticles for highly efficient cancer immunochemotherapy

Biomimetics plays an important role in cancer treatment since it can prolong the circulation of nanoparticles, enhance their delivery and retention in target tissues, and reduce the systemic toxicity of drugs and their carriers. In this study, we developed a biomimetic nanosystem consisting of chemotherapeutic and immunotherapeutic agents wrapped in cell membranes. Specifically, the anti-tumor drug doxorubicin (DOX) was loaded into a bacterial-derived immunomodulatory agent (low molecular weight curdlan, lCUR), and the lCUR-DOX was further wrapped in the red blood cell membrane for camouflage and prolonged circulation. The successful preparation of the lCUR-DOX@RBC nanosystem was supported by various optical and morphological characterizations. In vitro studies indicated that the nanosystem can escape uptake by macrophages, inhibit the invasion of tumor cells, and reprogram M2 macrophages with an immunosuppressive phenotype into M1 macrophages with an immunopromoting phenotype via the MAPK signaling pathway while promoting the phagocytosis of macrophages. In vivo studies showed that the nanosystem effectively inhibits tumor growth in the A-375 tumor-bearing mouse model. Taken together, the above results support further development of the lCUR-DOX@RBC platform for cancer immunochemotherapy in clinical applications.

NIR-triggered ligand-presenting nanocarriers for enhancing synergistic photothermal-chemotherapy

Surface PEGylation of nanomedicine is effective for prolonging blood circulation time and facilitating the EPR effect, whereas the hydrophilic stealth surface inhibits effective cellular uptake and hinders active targeting. To address the dilemma, herein, a NIR light-triggered dePEGylation/ligand-presenting strategy based on thermal decomposition of azo bonds is developed, whereby Dox/Pz-IR nanoparticle is self-assembled from thermo-labile azo molecule-linked long PEG chain polymer (Pz-IR), cRGD-conjugated IR783 with short PEG chains (rP-IR) and doxorubicin. The long PEG chains could mask cRGD peptides in the blood circulation, preventing serum degradation and nonspecific interaction with normal cells. Once exposed to NIR laser, the PEG corona is stripped off owing to the rupture of azo bonds through the photothermal effect of IR783, and the masked cRGD peptides are exposed, which remarkably enhances cellular uptake by tumor cells and improves tumor accumulation. Dox/Pz-IR achieves the optimal synergy of photothermal-chemotherapy at mild temperature through progressive tumor accumulation, precisely regulated photothermal effect and NIR-PTT induced pulsated drug release. The strategy of NIR photo-driven dePEGylation/targeting offers a new approach to overcoming the "PEG dilemma", and provides a noval avenue for programmed tumor-targeted drug delivery.

A Winning New Combination? Toward Clinical Application in Oncology

Immunotherapy has substantial attention in oncology due to the success of CTLA-4 and PD-1 inhibitors in the treatment of melanoma, lung cancer, head and neck cancer, renal cell carcinoma, and Hodgkin's lymphoma. A deeper understanding of interaction of tumor with its environment and the immune system provides best guide for oncology research. Recent studies in oncology have explained how a tumor alters antigen presentation, avoids detection, and activation of the host immune system to live and develop. Understanding the connections between the tumor and the immune system has resulted in several innovative therapy options. The extensive field of gene therapy has provided a number of cutting-edge medicines that are expected to play an important role in lowering cancer-related mortality. This article explains the history, important breakthroughs, and future prospects for three separate gene therapy treatment modalities: immunotherapy, oncolytic virotherapy, and gene transfer. Immunotherapies have completely changed how cancer is treated, especially for individuals whose condition was previously thought to be incurable. Examples include ACT (adoptive cell therapy) and ICB (immune checkpoint blockade). This review article will discuss the relationship between the immune response to cancer and the mechanisms of immunotherapy resistance. It will cover combination drugs authorized by the US Food and Drug Administration and provide a thorough overview of how these drugs are doing clinically right now. Cytokines, vaccines, and other soluble immunoregulatory agents, innate immune modifiers, ACT, virotherapy, and other treatment modalities will all be covered in detail.

Engineering Poly(ethylene glycol) Nanoparticles for Accelerated Blood Clearance Inhibition and Targeted Drug Delivery

Surface modification with poly(ethylene glycol) (PEGylation) is an effective strategy to improve the colloidal stability of nanoparticles (NPs) and is often used to minimize cellular uptake and clearance of NPs by the immune system. However, PEGylation can also trigger the accelerated blood clearance (ABC) phenomenon, which is known to reduce the circulation time of PEGylated NPs. Herein, we report the engineering of stealth PEG NPs that can avoid the ABC phenomenon and, when modified with hyaluronic acid (HA), show specific cancer cell targeting and drug delivery. PEG NPs cross-linked with disulfide bonds are prepared by using zeolitic imidazolate framework-8 NPs as templates. The reported templating strategy enables the simultaneous removal of the template and formation of PEG NPs under mild conditions (pH 5.5 buffer). Compared to PEGylated liposomes, PEG NPs avoid the secretion of anti-PEG antibodies and the presence of anti-PEG IgM and IgG did not significantly accelerate the blood clearance of PEG NPs, indicating the inhibition of the ABC effect for the PEG NPs. Functionalization of the PEG NPs with HA affords PEG NPs that retain their stealth properties against macrophages, target CD44-expressed cancer cells and, when loaded with the anticancer drug doxorubicin, effectively inhibit tumor growth. The innovation of this study lies in the engineering of PEG NPs that can circumvent the ABC phenomenon and that can be functionalized for the improved and targeted delivery of drugs.