Pectic Galactan Polysaccharide-Based Gene Delivery System for Targeting Neuroinflammation

Treating neuroinflammation-related injuries and disorders through manipulation of neuroinflammation functions is being heralded as a new therapeutic strategy. In this study, a novel pectic galactan (PG) polysaccharide based gene therapy approach is developed for targeting reactive gliosis in neuroinflammation. Galectin-3 (Gal-3) is a cell protein with a high affinity to β-galactoside sugars and is highly expressed in reactive gliosis. Since PG carries galactans, it can target reactive gliosis via specific carbohydrate interaction between galactan and Gal-3 on the cell membrane, and therefore can be utilized as a carrier for delivering genes to these cells. The carrier is synthesized by modifying quaternary ammonium groups on the PG. The resulting quaternized PG (QPG) is found to form complexes with plasmid DNA with a mean diameter of 100 nm and have the characteristics required for targeted gene therapy. The complexes efficiently condense large amounts of plasmid per particle and successfully bind to Gal-3. The in vivo study shows that the complexes are biocompatible and safe for administration and can selectively transfect reactive glial cells of an induced cortical lesion. The results confirm that this PG-based delivery system is a promising platform for targeting Gal-3 overexpressing neuroinflammation cells for treating neuroinflammation-related injuries and neurodegenerative diseases.     

Tumor Intracellular‐Environment Responsive Materials Shielded Nano‐Complexes for Highly Efficient Light‐Triggered Gene Delivery without Cargo Gene Damage

Gene therapy has great potential to bring tremendous improvement to cancer therapy. Recently, photochemical internalization (PCI) has provided the opportunity to overcome endo‐lysosomal sequestration, which is one of the main bottlenecks in both gene and chemotherapeutic delivery. Despite PCI having shown great potential in gene delivery systems, it still remains difficult to perform due to the photo‐oxidation of exogenous cargo genes by reactive oxygen species (ROS) generated from activated photosensitizers (PSs). In this paper, a new type of a stable light‐triggered gene delivery system is demonstrated based on endo‐lysosomal pH‐responsive polymeric PSs, which serve as shielding material for the polymer/gene complex. By taking advantage of the endo‐lysosomal pH‐sensitive de‐shielding ability of the pH‐responsive shielding material incorporated in the ternary gene complexes (pH‐TCs), a more significant photo‐triggered gene expression effect is achieved without damage to the gene from ROS. In contrast, pH‐insensitive material‐shielded nanocarriers cause photo‐oxidation of the payload and do not generate a notable transfection efficacy. Importantly, with the benefit of our newly developed gene delivery system, the deep penetration issue can be resolved. Finally, the light‐triggered gene delivery system using pH‐TCs is applied to deliver the therapeutic p53 gene in melanoma K‐1735 bearing mice, showing excellent therapeutic potential for cancer.     

Magnetic Helical Microswimmers Functionalized with Lipoplexes for Targeted Gene Delivery

Artificial micro‐/nanoswimmers have various potential applications including minimally invasive diagnosis and targeted therapies, environmental sensing and monitoring, cell manipulation and analysis, and lab‐on‐a‐chip devices. Inspired by natural motile bacteria such as E. Coli, artificial bacterial flagella (ABFs) are one kind of magnetic helical microswimmers. ABFs can perform 3D navigation in a controllable fashion with micrometer precision under low‐strength rotating magnetic fields (<10 mT) and are promising tools for targeted drug delivery in vitro and in vivo. In this work, the successful wirelessly targeted and single‐cell gene delivery to human embryonic kidney (HEK 293) cells using ABFs loaded with plasmid DNA (pDNA) in vitro is demonstrated for the first time. The ABFs are functionalized with lipoplexes containing pDNA to generate functionalized ABFs (f‐ABFs). The f‐ABFs are steered wirelessly by low‐strength rotating magnetic fields and deliver the loaded pDNA into targeted cells. The cells targeted by f‐ABFs are successfully transfected by the transported pDNA and expressed the encoding protein. These f‐ABFs may also be useful for in vivo gene delivery and other applications such as sensors, actuators, cell biology, and lab‐on‐a‐chip environments.     

Reductively Dissociable siRNA‐Polymer Hybrid Nanogels for Efficient Targeted Gene Silencing

A highly efficient approach for target‐specific gene silencing based on a reductively dissociable nanogel incorporating small interfering RNA (siRNA) crosslinked with linear polyethylenimine (LPEI) via disulfide bonds is presented. Thiol‐terminated siRNA at both 3′‐ends is electrostatically complexed with thiol‐grafted LPEI. The prepared siRNA/LPEI complex contains inter‐ and intramolecular linkages, generating a mutually crosslinked siRNA/LPEI nanogel (MCN) that exhibits excellent structural stability against the addition of heparin but is readily disintegrated to biologically active, monomeric siRNA upon exposure to reductive conditions. Accordingly, the highly condensed, stable MCN shows greatly enhanced cellular uptake and gene silencing efficiency compared to the siRNA/LPEI complexes without crosslinks or with only LPEI‐mediated crosslinks.     

Aminoglycoside-Based Biomaterials: From Material Design to Antibacterial and Gene Delivery Applications

Aminoglycosides are a family of naturally isolated or chemically semi-synthesized antibiotics consisting of aminocyclitols with several amino and saccharide units. The unique molecule structures render aminoglycosides promising building blocks with high reactivity to perform various non-covalent and covalent reactions, and they are further employed to rationally fabricate versatile materials, such as hydrogels, amphiphiles, hyperbranched polymers, biointerfaces, and nanoparticles. Despite aminoglycosides are widely used in clinics to treat bacterial infections, almost all the efforts are focused on molecular modifications to reduce their toxicities and overcome antibiotic resistance, while their actions as building blocks to construct biomaterials are scarcely discussed. In this feature article, the current progress on the rational design, emergent properties, and promising biological applications of aminoglycoside-based biomaterials are summarized. It is believed that this paper may provide guidance to develop new biomaterials using natural functional molecules as building blocks, and start a new life of aminoglycosides from the view of materials science.     

Nucleus‐Targeting Gold Nanoclusters for Simultaneous In Vivo Fluorescence Imaging,Gene Delivery,and NIR‐Light Activated Photodynamic Therapy

The nucleus is one of the most important cellular organelles and molecular anticancer drugs, such as cisplatin and doxorubicin, that target DNA inside the nucleus, are proving to be more effective at killing cancer cells than those targeting at cytoplasm. Nucleus‐targeting nanomaterials are very rare. It is a grand challenge to design highly efficient nucleus‐targeting multifunctional nanomaterials that are able to perform simultaneous bioimaging and therapy for the destruction of cancer cells. Here, unique nucleus‐targeting gold nanoclusters (TAT peptide–Au NCs) are designed to perform simultaneous in vitro and in vivo fluorescence imaging, gene delivery, and near‐infrared (NIR) light activated photodynamic therapy for effective cancer cell killing. Confocal laser scanning microscopy observations reveal that TAT peptide–Au NCs are distributed throughout the cytoplasm region with a significant fraction entering into the nucleus. The TAT peptide–Au NCs can also act as DNA nanocargoes to achieve very high gene transfection efficiencies (≈81%) in HeLa cells and in zebrafish. Furthermore, TAT peptide–Au NCs are also able to sensitize formation of singlet oxygen (¹O₂) without the co‐presence of organic photosensitizers for the destruction of cancer cells upon NIR light photoexcitation.     

Photothermo-Promoted Nanocatalysis Combined with H2S-Mediated Respiration Inhibition for Efficient Cancer Therapy

Nanocatalytic medicine has emerged as a promising method for the specific cancer therapy by mediating the interaction between tumor microenvironment biomarkers and nanoagents. However, the produced antitumor cell killing molecules, such as reactive oxygen species (ROS), by catalysis are insufficient to inhibit tumor growth. Herein, a novel kind of polyvinyl pyrrolidone modified multifunctional iron sulfide nanoparticles (Fe_1−xS-PVP NPs) is developed via a one-step hydrothermal method, which exhibits high photothermal (PT) conversion efficiency (η = 24%) under the irradiation of 808 nm near-infrared laser. The increased temperature further facilitates the Fenton reaction to generate abundant •OH radicals. More importantly, under an acidic (pH = 6.5) condition within tumor environment, the Fe_1−xS-PVP NPs can in situ produce H₂S gas, which is evidenced to suppress the activity of enzyme cytochrome c oxidase (COX IV) in cancer cells, contributing to inhibit the growth of tumor. Both in vitro and in vivo results demonstrate that the H₂S-mediated gas therapy in combination with PT enhanced ROS achieves excellent antitumor performance, which can open up a new approach for the design of gas-mediated cancer treatment.     

Multimodal Magnetic Nanoclusters for Gene Delivery,Directed Migration,and Tracking of Stem Cells

This study develops multimodal magnetic nanoclusters (M‐MNCs) for gene transfer, directed migration, and tracking of human mesenchymal stem cells (hMSCs). The M‐MNCs are designed with 5 nm iron oxide nanoparticles and a fluorescent dye (i.e., Rhodamine B) in the matrix of the Food and Drug Administration approved polymer poly(lactide‐co‐glycolide) using a nanoemulsion method. The synthesized M‐MNCs have a hydrodynamic diameter of ≈150 nm, are internalized by stem cells via endocytosis, and deliver genes with high efficiency. The cellular internalization and gene expression efficiency of the clustered nanoparticles are significantly higher than that of single nanoparticles. The M‐MNC‐labeled hMSCs migrate upon application of a magnetic force and can be visualized by both optical and magnetic resonance (MR) imaging. In animal models, the M‐MNC‐labeled hMSCs are also successfully tracked using optical and MR imaging. Thus, the M‐MNCs not only allow the efficient delivery of genes to stem cells but also the tracking of cells in animal models. Taken together, the results show that this new type of nanocomposite can be of great help in future stem cell research and in the development of cell‐based therapeutic agents.     

Optimizing the Size of Micellar Nanoparticles for Efficient siRNA Delivery

Delivery of small interfering RNA (siRNA) by nanocarriers has shown promising therapeutic potential in cancer therapy. However, poor understanding of the correlation between the physicochemical properties of nanocarriers and their interactions with biological systems has significantly hindered its anticancer efficacy. Herein, in order to identify the optimal size of nanocarriers for siRNA delivery, different sized cationic micellar nanoparticles (MNPs) (40, 90, 130, and 180 nm) are developed that exhibit similar siRNA binding efficacies, shapes, surface charges, and surface chemistries (PEGylation) to ensure size is the only variable. Size‐dependent biological effects are carefully and comprehensively evaluated through both in vitro and in vivo experiments. Among these nanocarriers, the 90 nm MNPs show the optimal balance of prolonged circulation and cellular uptake by tumor cells, which result in the highest retention in tumor cells. In contrast, larger MNPs are rapidly cleared from the circulation and smaller MNPs are inefficiently taken up by tumor cells. Accordingly, 90 nm MNPs carrying polo‐like kinase 1 (Plk1)‐specific siRNA (siPlk1) show superior antitumor efficacy, indicating that 90 nm could either be the optimal size for systemic delivery of siRNA or close to it. Our findings provide valuable information for rationally designing nanocarriers for siRNA‐based cancer therapy in the future.     

Dual Acid‐Responsive Micelle‐Forming Anticancer Polymers as New Anticancer Therapeutics

Cinnamaldehyde, a major active compound of cinnamon, is known to induce apoptotic cell death in numerous human cancer cells. Here, dual acid‐responsive polymeric micelle‐forming cinnamaldehyde prodrugs, poly[(3‐phenylprop‐2‐ene‐1,1‐diyl)bis(oxy)bis(ethane‐2,1‐diyl)diacrylate]‐co‐4,4’(trimethylene dipiperidine)‐co‐poly(ethylene glycol), termed PCAE copolymers, are reported. PCAE is designed to incorporate cinnamaldehyde via acid‐cleavable acetal linkages in its pH‐sensitive hydrophobic backbone and self assemble to form stable micelles which can encapsulate camptothecin (CPT). PCAE self assembles to form micelles which release CPT and cinnamaldehyde in pH‐dependent manners. PCAE micelles induce apoptotic cell death through the generation of intracellular reactive oxygen species (ROS) and exert synergistic anticancer effects with a payload of CPT in vitro and in vivo model of SW620 human colon tumor‐bearing mice. It is anticipated that dual acid‐sensitive micelle‐forming PCAE with intrinsic anticancer activities has enormous potential as novel anticancer therapeutics.     

Disrupting the Redox Balance with a Diselenide Drug Delivery System: Synergistic or Antagonistic?

Effective on-demand release of therapeutics at an intracellular drug supply hub, the cytosol, is among the important steps for successful drug delivery. To improve cytosolic drug release, this study selects diselenide because the bond is cleaved by both glutathione (GSH) and reactive oxygen species (ROS) in the cytosol. Specifically, upon diselenide cleavage, the levels of GSH or ROS are reduced, resulting in decreased or increased cell viability and either the synergistic or antagonistic death of cancer cells with an anticancer drug, respectively, because GSH and ROS trigger two conflicting functions (i.e., antioxidant vs prooxidant activity). Thus, this study designs a diselenide-based drug carrier to determine which trigger is the major cause of diselenide degradation, how the disrupted balance between GSH and ROS levels influences cell viability and drug efficacy, and whether the combined use of a diselenide drug carrier and a drug has a synergistic or antagonistic effect. Using a multiple diselenide-containing nanoparticle (MSePCL-NP), the study shows that diselenide is cleaved to a greater extent by GSH than by ROS; MSePCL-NP induces a greater decrease in the viability of cancer cells, but not normal cells; a combination of DOX@MSePCL-NP synergistically kills cancer cells and inhibits tumor growth in vivo.     

Bioengineered Extracellular Membranous Nanovesicles for Efficient Small‐Interfering RNA Delivery: Versatile Platforms for Stem Cell Engineering and In Vivo Delivery

Naturally derived nanovesicles secreted from various cell types and found in body fluids can provide effective platforms for the delivery of various cargoes because of their intrinsic ability to be internalized for intercellular signal transmission and membrane recycling. In this study, the versatility of bioengineered extracellular membranous nanovesicles as potent carriers of small‐interfering RNAs (siRNAs) for stem cell engineering and in vivo delivery has been explored. Here, exosomes have been engineered, one of the cell‐derived vesicle types, to overexpress exosomal proteins fused with cell‐adhesion or cell‐penetrating peptides for enhanced intracellular gene transfer. To devise a more effective delivery system with potential for mass production, a new siRNA delivery system has also been developed by artificially inducing the outward budding of plasma membrane nanovesicles. Those nanovesicles have been engineered by overexpressing E‐cadherin to facilitate siRNA delivery to human stem cells with resistance to intracellular gene transfer. Both types of engineered nanovesicles deliver siRNAs to human stem cells for lineage specification with negligible cytotoxicity. The nanovesicles are efficient in delivering siRNA in vivo, suggesting feasibility for gene therapy. Cell‐derived, bioengineered nanovesicles used for siRNA delivery can provide functional platforms enabling effective stem cell therapeutics and in vivo gene therapy.     

Simple and Efficient Targeted Intracellular Protein Delivery with Self‐Assembled Nanovehicles for Effective Cancer Therapy

Protein therapy offers promising prospects for the treatment of various important diseases, thus it is highly desirable to develop a robust carrier that can deliver active proteins into cells. The development of a novel protein delivery platform based on the self‐assembly of multiarmed amphiphilic cyclodextrins (CDEH) is reported. CDEH can self‐assemble into nanoparticles in aqueous solution and achieve superior encapsulation of protein (loading capacity > 30% w/w) simply by mixing with protein solution without introducing any subsequent cumbersome steps that may inactivate proteins. More importantly, CDEH nanovehicles can be easily further modified with various targeting groups based on host–guest complexation. Using saporin as a therapeutic protein, AS1411‐aptamer‐modified CDEH nanovehicles can preferentially accumulate in tumors and efficiently inhibit tumor growth in a MDA‐MB‐231 xenograft mouse model. Moreover, folate‐targeted CDEH nanovehicles can also deliver Cas9 protein and Plk1‐targeting sgRNA into Hela cells, leading to 47.1% gene deletion and 64.1% Plk1 protein reduction in HeLa tumor tissue, thereby effectively suppressing the tumor progression. All these results indicate the potential of targeted CDEH nanovehicles in intracellular protein delivery for improving protein therapeutics.     

Components Simulation of Viral Envelope via Amino Acid Modified Chitosans for Efficient Nucleic Acid Delivery: In Vitro and In Vivo Study

Novel nonviral gene vectors of alkaline amino acids such as arginine‐ (Arg), histidine‐ (His), and lysine‐ (Lys) modified chitosans (AAA‐CSs) are developed to simulate the components of viral envelopes to enhance transfection efficiency. The structures of the modified chitosans are characterized using ¹H NMR spectroscopy. Acid‐base titration results indicate that the modified chitosans exhibit strong buffering capacity. The morphology of the AAA‐CSs/pDNA complexes is observed by use of transmission electron microscopy and atomic force microscopy. The complexes are spherical nanoparticles with a mean size around 100 nm. Zeta potential tests reveal that the complexes are positively charged and their zeta potentials vary from +0.1 to +19.5 mV. The MTT assay and agarose gel electrophoresis demonstrate that the AAA‐CSs are non‐cytotoxic and have excellent DNA condensation and protection abilities. Cellular uptake investigation of the AAA‐CSs/pDNA complexes demonstrates that Arg‐CS and His‐CS have better cellular internalization property than the unmodified chitosan. The in vitro gene transfection is evaluated in HEK293 and NIH3T3 cell lines and in vivo transfection is carried out in tibialis anterior muscles. The results reveal that the arginine‐modified chitosan could significantly enhance gene‐transfection efficiency both in vitro and in vivo.     

Adenoviral Gene Delivery from Multilayered Polyelectrolyte Architectures

The alternate layer‐by‐layer (LBL) deposition of polycations and polyanions for the build up of multilayered polyelectrolyte films is an original approach that allows the preparation of tunable, biologically active surfaces. The resulting supramolecular nanoarchitectures can be functionalized with drugs, peptides, and proteins, or DNA molecules that are able to transfect cells in vitro. We monitor, for the first time, the embedding of a bioactive adenoviral (Ad) vector in multilayered polyelectrolyte films. Ad efficiently adsorbs on poly(L ‐lysine)–poly(L ‐glutamic acid) (PLL–PGA), PLL–HA (HA: hyaluronan), poly(allylamin hydrochloride)–poly(sodium‐4‐styrenesulfonate) (PAH–PSS), and CHI–HA (CHI: chitosan) films; it preserves its transduction capacity (which can reach 95 %) for a large number of cell types, and also allows vector uptake into receptor‐deficient cells, thus abrogating the restricted tropism of Ad.     

A Novel Ultrafine Needle (UN) for Innocuous and Efficient Subcutaneous Insulin Delivery

Subcutaneous (SC) insulin injection has been demonstrated to be the most effective method for treatment of diabetes mellitus but is conventionally performed by hypodermic needles, leading to poor management of diabetes because of the pain, needle phobia, and tissue trauma. Identification of a viable, safe, and pain‐free alternative method has been a longstanding challenge in modern health care. Here, the thermoplastic droplet stretching technique is developed to create an ultrahigh‐aspect‐ratio needle mold with simple microstructure control. The optimized ultrafine needle (UN) with 4 mm length, minimized 120 µm outer diameter, and 15° sharp bevel angle is formed via electroplating of a metallic layer on the surface of a needle mold with forcing sharp tip. This novel UN enables minimally invasive 4 mm skin insertion to deliver insulin in the targeted SC layer. The similar relative areas under the curves of insulin concentration within UN and 31G needle in vivo insulin administration indicate that UN can ensure stable insulin absorption for secure blood glucose management. Additionally, the proposed fabrication method may facilitate industrialization and commercialization of the UN, holding great promise for replacement of hypodermic needles and for improvement of quality of life among patients with diabetes.