Unsymmetrical Low-Generation Cationic Phosphorus Dendrimers as a Nonviral Vector to Deliver MicroRNA for Breast Cancer Therapy.

The development of nonviral dendritic polymers with a simple molecular backbone and great gene delivery efficiency to effectively tackle cancer remains a great challenge. Phosphorus dendrimers or dendrons are promising vectors due to their structural uniformity, rigid molecular backbones, and tunable surface functionalities. Here, we report the development of a new low-generation unsymmetrical cationic phosphorus dendrimer bearing 5 pyrrolidinium groups and one amino group as a nonviral gene delivery vector. The created AB5-type dendrimers with simple molecular backbone can compress microRNA-30d (miR-30d) to form polyplexes with desired hydrodynamic sizes and surface potentials and can effectively transfect miR-30d to cancer cells to suppress the glycolysis-associated SLC2A1 and HK1 expression, thus significantly inhibiting the migration and invasion of a murine breast cancer cell line in vitro and the corresponding subcutaneous tumor mouse model in vivo. Such unsymmetrical low-generation phosphorus dendrimers may be extended to deliver other genetic materials to tackle other diseases.

Structural and Property Characterizations of Dual-Responsive Core-Shell Tecto Dendrimers for Tumor Penetration and Gene Delivery Applications.

Core-shell tecto dendrimers (CSTDs) with excellent physicochemical properties and good tumor penetration and gene transfection efficiency have been demonstrated to have the potential to replace high-generation dendrimers in biomedical applications. However, their characterization and related biological properties of CSTDs for enhanced tumor penetration and gene delivery still lack in-depth investigation. Herein, three types of dual-responsive CSTDs are designed for thorough physicochemical characterization and investigation of their tumor penetration and gene delivery efficiency. Three types of CSTDs are prepared through phenylborate ester bonds of phenylboronic acid (PBA)-decorated generation 5 (G5) poly(amidoamine) (PAMAM) dendrimers as cores and monose (galactose, glucose, or mannose)-conjugated G3 PAMAM dendrimers as shells and thoroughly characterized via NMR and other techniques. It is shown that the produced CSTDs display strong correlation signals between the PBA and monose protons, similar hydrodynamic diameters, and dual reactive oxygen species- and pH-responsivenesses. The dual-responsive CSTDs are proven to have structure-dependent tumor penetration property and gene delivery efficiency in terms of small interference RNA for gene silencing and plasmid DNA for gene editing, thus revealing a great potential for different biomedical applications.

Activatable Semiconducting Polymer Nanoinducers Amplify Oxidative Damage via Sono-Ferroptosis for Synergistic Therapy of Bone Metastasis.

Bone metastases are secondary malignant tumors that commonly occur after the spread of advanced cancer cells. We herein report the activatable semiconducting polymer nanoinducers (ASPNFP) that can amplify oxidative damage via sono-ferroptosis for bone metastasis treatment. ASPNFP are constructed by encapsulating plasma amine oxidase-based semiconducting polymer nanoparticles (SPNP) and Fe3O4 nanoparticles into singlet oxygen (1O2)-responsive nanocarriers. ASPNFP generate 1O2 under ultrasound (US) irradiation via a sonodynamic effect to destroy the stability of 1O2-responsive nanocarriers, allowing US-triggered releases of SPNP and Fe3O4 nanoparticles. SPNP decompose polyamines in tumor cells to produce acrolein and hydrogen peroxide (H2O2), in which H2O2 promotes Fenton reaction mediated by Fe3O4 nanoparticles for inducing enhanced ferroptosis and generation of hydroxyl radicals (•OH). The generated acrolein, 1O2, and •OH can simultaneously amplify the oxidative damage. ASPNFP thus mediate an amplified sono-ferroptosis effect to inhibit the growth of bone metastasis and restrict tumor metastasis.

Thiacalixarene Carboxylic Acid Derivatives as Inhibitors of Lysozyme Fibrillation.

Amyloid fibroproliferation leads to organ damage and is associated with a number of neurodegenerative diseases affecting populations worldwide. There are several ways to protect against fibril formation, including inhibition. A variety of organic compounds based on molecular recognition of amino acids within the protein have been proposed for the design of such inhibitors. However, the role of macrocyclic compounds, i.e., thiacalix[4]arenes, in inhibiting fibrillation is still almost unknown. In the present work, the use of water-soluble thiacalix[4]arene derivatives for the inhibition of hen egg-white lysozyme (HEWL) amyloid fibrillation is proposed for the first time. The binding of HEWL by the synthesized thiacalix[4]arenes (logKa = 5.05-5.13, 1:1 stoichiometry) leads to the formation of stable supramolecular systems capable of stabilizing the protein structure and protecting against fibrillation by 29-45%. The macrocycle conformation has little effect on protein binding strength, and the native HEWL secondary structure does not change via interaction. The synthesized compounds are non-toxic to the A549 cell line in the range of 0.5-250 µg/mL. The results obtained may be useful for further investigation of the anti-amyloidogenic role of thiacalix[4]arenes, and also open up future prospects for the creation of new ways to prevent neurodegenerative diseases.

An Intelligent Vascular Disrupting Dendritic Nanodevice Incorporating Copper Sulfide Nanoparticles for Immune Modulation-Mediated Combination Tumor Therapy.

Development of intelligent nanoplatforms that can simultaneously target multiple factors associated with tumor growth and metastasis remains an extreme challenge. Here, an intelligent dendritic nanodevice incorporating both copper sulfide nanoparticles (CuS NPs) and 5,6-dimethylxanthenone-4-acetic acid (DMXAA, a vascular disrupting agent) within the dendrimer internal cavities and surface modified with a targeting agent LyP-1 peptide is reported. The resulting generation 5 (G5) dendrimer-based nanodevice, known as G5-PEG-LyP-1-CuS-DMXAA NPs (GLCD NPs), possess good colloidal stability, pH-sensitive drug release kinetics, and high photothermal conversion efficiency (59.3%). These functional GLCD NPs exert a LyP-1-targeted killing effect on breast tumors by combining CuS-mediated photothermal therapy (PTT) and DMXAA-induced vascular disruption, while also triggering antitumor immune responses through PTT-induced immunogenic cell death and DMXAA-mediated immune regulation via M1 polarization of tumor-associated macrophages and dendritic cell maturation. In addition, with the LyP-1-mediated proapoptotic activity, the GLCD NPs can specifically kill tumor lymphatic endothelial cells. The simultaneous disruption of tumor blood vessels and lymphatic vessels cuts off the two main pathways of tumor metastasis, which plays a two-pronged role in inhibiting lung metastasis of the breast cancer model. Thus, the developed GLCD NPs represent an advanced intelligent nanoformulation for immune modulation-mediated combination tumor therapy with potential for clinical translations.

Dendrimer-Mediated Intracellular Delivery of Fibronectin Guides Macrophage Polarization to Alleviate Acute Lung Injury.

Fibronectin (FN) is an essential glycoprotein in the extracellular matrix with favorable biological functions for potential applications in various biomedical fields including wound healing, regenerative medicine, tissue engineering, as well as diagnosis and treatment of cancer and inflammatory diseases. Herein, we aim to explore the influence of intracellular FN delivery on macrophage functions and its possible therapeutic applications. We prepared phenylboronic acid (PBA)-functionalized generation 5 (G5) poly(amidoamine) dendrimers (G5.NH2-PBA) as a nanocarrier to load FN, and reveal that the obtained dendrimers enable efficient intracellular delivery of FN at an optimized dendrimer-to-FN weight ratio of 8, which guides macrophages toward anti-inflammatory M2 phenotype polarization. Studies on action mechanisms show that the dendrimer-mediated FN intracellular delivery acts strongly on suppressing the nuclear factor-κB pathway, leading to reduced pro-inflammatory cytokine secretion and enhanced reactive oxygen species depletion in lipopolysaccharide (LPS)-activated macrophages. Further investigation in vivo using an LPS-induced mouse model of acute lung injury (ALI) shows that the dendrimer-mediated FN delivery can effectively alleviate the ALI symptoms through alleviation of lung inflammation and oxidation stress. Our work suggests a general approach to using dendrimers for mediating intracellular delivery of FN, thereby offering many opportunities to explore the biological functions of FN for different therapeutic applications toward inflammation-associated diseases.

Multifunctional Low-Generation Dendrimer Nanogels as an Emerging Probe for Tumor-Specific CT/MR Dual-Modal Imaging.

The development of nanoprobes that have amplified enhanced permeability and retention (EPR) effect is crucial for their precise cancer diagnosis performance. Here, we present the development of functional dendrimer-based nanogels (DNGs) with the generation three primary amine-terminated poly(amidoamine) (PAMAM) dendrimers (G3·NH2) cross-linked by N,N'-bis(acryloyl) cystamine (BAC). The DNGs were prepared through a Michael addition reaction between G3·NH2 dendrimers and BAC via an inverse microemulsion method and entrapped with gold nanoparticles (Au NPs) to form Au-DNGs. The Au-DNGs were sequentially modified with diethylenetriamine penta-acetic acid (DTPA)-gadolinium (Gd) complex, poly(ethylene glycol) (PEG)-linked arginine-glycine-aspartic (RGD) peptide, and 1,3-propanesultone (1,3-PS). The formed multifunctional RGD-Gd@Au-DNGs-PS (R-G@ADP) possessing an average diameter of 122 nm are colloidally stable and display a high X-ray attenuation coefficient, excellent r1 relaxivity (9.13 mM-1 s-1), desired protein resistance rendered by the zwitterionic modification, and cytocompatibility. With the targeting specificity mediated by RGD and the much better tumor penetration capability than the counterpart material of single dendrimer-entrapped Au NPs, the developed multifunctional R-G@ADP enable targeted and enhanced computed tomography (CT)/magnetic resonance (MR) dual-modal imaging of a pancreatic tumor model in vivo. The current work demonstrates a unique design of targeted and zwitterionic DNGs with prolonged blood circulation time as an emerging nanoprobe for specific tumor CT/MR imaging through amplified passive EPR effect.

Amphiphilic Phosphorus Dendrons Associated with Anti-inflammatory siRNA Reduce Symptoms in Murine Collagen-Induced Arthritis.

Small interfering RNA (siRNA) holds promise for treating rheumatoid arthritis by inhibiting major cytokines such as tumor necrosis factor-α (TNF-α). We developed original cationic amphiphilic phosphorus dendrons to produce dendriplexes associated with TNF-α siRNA. The dendrons were made of 10 pyrrolidinium end groups and a C17 aliphatic chain. The dendriplexes demonstrated the ability to protect siRNA from nuclease degradation and to promote macrophage uptake. Moreover, they led to potent inhibition of TNF-α expression in the lipopolysaccharide-activated mouse macrophage cell line RAW264.7 in vitro model. A significant anti-inflammatory effect in the murine collagen-induced arthritis model was observed through arthritis scoring and histological observations. These results open up essential perspectives in using this original amphiphilic dendron to reduce the disease burden and improve outcomes in chronic inflammatory diseases.

Dendrimer-Based Nanogels for Cancer Nanomedicine Applications.

Recent advances in the field of nanotechnology bring an alternative approach to personalized medicine in cancer treatment. Nanogels (NGs) are among the nanosized superconstructs composed of amphiphilic or hydrophilic polymer networks. The design of different types of biodegradable polymer-based NGs in various biomedical applications has received extensive attention, due to their unique physicochemical properties such as highly porous structure, stimuli-responsiveness, and mimicking of some biological properties. In this review, we concisely surveyed the synthesis of dendrimer-based NGs synthesized via different methods including covalent conjugation, inverse nanoprecipitation, physical cross-linking, or self-assembly for various cancer nanomedicine applications, particularly for drug delivery, gene delivery, photothermal therapy, and combination therapy, as well as for biological imaging-guided chemotherapy. Additionally, we provide herein future perspective toward the new design of dendrimer-based NGs for different cancer nanomedicine uses.

Efficient Capture and Separation of Cancer Cells Using Hyaluronic Acid-Modified Magnetic Beads in a Microfluidic Chip.

The efficient isolation and specific discrimination of circulating tumor cells (CTCs) is expected to provide valuable information for understanding tumor metastasis and play an important role in the treatment of cancer patients. In this study, we developed a novel and rapid method for efficient capture and specific identification of cancer cells using hyaluronic acid (HA)-modified SiO2-coated magnetic beads in a microfluidic chip. First, polyacrylamide-surfaced SiO2-coated magnetic beads (SiO2@MBs) were covalently conjugated with HA, and the created HA-modified SiO2@MBs (HA-SiO2@MBs) display binding specificity to HeLa cells (a human cervical carcinoma cell line) overexpressing CD44 receptors. After incubating the HA-SiO2@MBs with cancer cells for 1 h, the mixture of MBs and cells was drawn into a designed microfluidic channel with two inlets and outlets. Through the formation of lamellar flow, cells specifically bound with the HA-SiO2@MBs can be separated under an external magnetic field with a capture efficiency of up to 92.0%. The developed method is simple, fast, and promising for CTC separation and cancer diagnostics applications.

Genetic Engineering of Dendritic Cells Using Partially Zwitterionic Dendrimer-Entrapped Gold Nanoparticles Boosts Efficient Tumor Immunotherapy.

Effective processing and cross-priming of tumor neoantigen by dendritic cells (DCs) to T cells for spontaneous immune response generation to effectively kill cancer cells remain challenging in cancer immunotherapy. Here, we report a general approach to genetically engineer DCs through silencing their YTHDF1 protein (an important reader protein responsible for RNA m6A methylation) expression via a dendrimeric non-viral vector to boost effective tumor immunotherapy. Poly(amidoamine) dendrimers of generation 5 were partially decorated with mannose and 1,3-propanesultone and then entrapped with gold (Au) nanoparticles. The created dendrimer nanoplatform has an Au core size of 1.8 nm; possesses desired stability, good cytocompatibility, and excellent YTHDF1 siRNA compression ability; and enables targeted gene silencing of DCs overexpressing mannose receptors to upregulate the expression of CD80 and CD86, markers of DCs maturation, potentially leading to tumor antigen cross-presentation. With these properties owned, the combination of YTHDF1 silencing of DCs with programmed cell death-ligand 1 antibody can boost the best immunotherapy of a xenografted melanoma tumor model through the created antitumor immune responses. Findings in this study demonstrate a general approach of genetic engineering of DCs via a dendrimeric non-viral vector to effectively boost antitumor immunotherapy.

Engineered Stable Bioactive Per Se Amphiphilic Phosphorus Dendron Nanomicelles as a Highly Efficient Drug Delivery System To Take Down Breast Cancer In Vivo.

Conventional small molecular chemical drugs always have challenging limitations in cancer therapy due to their high systemic toxicity and low therapeutic efficacy. Nanotechnology has been applied in drug delivery, bringing new promising potential to realize effective cancer treatment. In this context, we develop here a new nanomicellar drug delivery platform generated by amphiphilic phosphorus dendrons (1-C17G3.HCl), which could form micelles for effective encapsulation of a hydrophobic anticancer drug doxorubicin (DOX) with a high drug loading content (42.4%) and encapsulation efficiency (96.7%). Owing to the unique dendritic rigid structure and surface hydrophilic groups, large steady void space of micelles can be created for drug encapsulation. The created DOX-loaded micelles with a mean diameter of 26.3 nm have good colloidal stability. Strikingly, we show that the drug-free micelles possess good intrinsic anticancer activity and act collectively with DOX to take down breast cancer cells in vitro and the xenografted tumor model in vivo through upregulation of Bax, PTEN, and p53 proteins for enhanced cell apoptosis. Meanwhile, the resulting 1-C17G3.HCl@DOX micelles significantly abolish the toxicity relevant to the free drug. The findings of this study demonstrate a unique nanomicelle-based drug delivery system created with the self-assembling amphiphilic phosphorus dendrons that may be adapted for chemotherapy of different cancer types.

A tumor microenvironment-responsive poly(amidoamine) dendrimer nanoplatform for hypoxia-responsive chemo/chemodynamic therapy.

BACKGROUND: Chemodynamic therapy is a promising cancer treatment with specific therapeutic effect at tumor sites, as toxic hydroxyl radical (·OH) could only be generated by Fenton or Fenton-like reaction in the tumor microenvironment (TME) with low pH and high level of endogenous hydrogen peroxide. However, the low concentration of catalytic metal ions, excessive glutathione (GSH) and aggressive hypoxia at tumor site seriously restrict the curative outcomes of conventional chemodynamic therapy. RESULTS: In this study, polyethylene glycol-phenylboronic acid (PEG-PBA)-modified generation 5 (G5) poly(amidoamine) (PAMAM) dendrimers were synthesized as a targeted nanocarrier to chelate Cu(II) and then encapsulate hypoxia-sensitive drug tirapazamine (TPZ) by the formation of hydrophobic Cu(II)/TPZ complex for hypoxia-enhanced chemo/chemodynamic therapy. The formed G5.NHAc-PEG-PBA@Cu(II)/TPZ (GPPCT) nanoplatform has good stability and hemocompatibility, and could release Cu(II) ions and TPZ quickly in weakly acidic tumor sites via pH-sensitive dissociation of Cu(II)/TPZ. In vitro experiments showed that the GPPCT nanoplatforms can efficiently target murine breast cancer cells (4T1) cells overexpressing sialic acid residues, and show a significantly enhanced inhibitory effect on hypoxic cells by the activation of TPZ. The excessive GSH in tumors could be depleted by the reduction of Cu(II) to Cu(I), and abundant of toxic ·OH would be generated in tumor cells by Fenton reaction for chemodynamic therapy. In vivo experiments demonstrated that the GPPCT nanoplatform could specifically accumulate at tumors, effectively inhibit the growth and metastasis of tumors by the combination of CDT and chemotherapy, and be metabolized with no systemic toxicity. CONCLUSIONS: The targeted GPPCT nanoplatform may represent an effective model for the synergistic inhibition of different tumor types by hypoxia-enhanced chemo/chemodynamic therapy.

Multifunctional nanoprobe for real-time in vivo monitoring of T cell activation.

Genetically engineered T cells are a powerful new modality for cancer immunotherapy. However, their clinical application for solid tumors is challenging, and crucial knowledge on cell functionality in vivo is lacking. Here, we fabricated a nanoprobe composed of dendrimers incorporating a calcium sensor and gold nanoparticles, for dual-modal monitoring of engineered T cells within a solid tumor. T cells engineered to express a melanoma-specific T-cell receptor and loaded with the nanoprobe were longitudinally monitored within melanoma xenografts in mice. Fluorescent imaging of the nanoprobe's calcium sensor revealed increased intra-tumoral activation of the T cells over time, up to 24 h. Computed tomography imaging of the nanoprobe's gold nanoparticles revealed the cells' intra-tumoral distribution pattern. Quantitative analysis revealed the intra-tumoral T cell quantities. Thus, this nanoprobe reveals intra-tumoral persistence, penetration and functional status of genetically engineered T cells, which can advance T cell-based immunotherapy and promote next-generation live cell imaging.

Analysis of the Magnetic Field Magnetoinductive Wave Characteristics of a Wireless Power Transfer System.

This study analyzes the magnetic field wave characteristics of a wireless power transfer (WPT) system from a time-varying view in the nonradiative near field. Phenomena of both forward and backward traveling waves were found. These wave phenomena refer to magnetoinductive waves (MIWs) according to the findings in this study and MIW theory and characteristics. A traditional MIW only appears in the MIW waveguide, which is always constructed by many parallel coils. However, this study analyzed MIWs in a two-coil WPT system, proving that MIWs exist not only in a multi-coil system but also in a basic two-coil system. The velocity of MIWs, a kind of a phase velocity, was calculated. An approximate equation for evaluating wave velocity is proposed. Furthermore, the MIWs in the two-coil WPT system were extended into a more general situation. In this general situation, two separated standing waves were set, and a traveling wave was generated by those two standing waves. The result explains the mechanisms of MIWs in a general situation from a time-varying view. Lastly, a simulation was conducted to verify the accuracy of the study. The results demonstrated that MIWs exist, and the approximate equation is correct. This study presents a novel view on the mechanisms of the WPT system from a wave view.

Cyclotriphosphazene-Based "Butterfly" Fluorescence Probe for Lysosome Targeting.

A cyclotriphosphazene-based "butterfly" fluorescence probe HCCP-MNI bearing two naphthalimide and morpholine units were developed for lysosome targeting. The synthesized HCCP-MNI exhibited stable fluorescence signals and was cytocompatible in the given concentration range. Co-localization experimental results showed that cells treated with the HCCP-MNI and a commercial dye (Lyso-Tracker Red DND-99) had overlapped fluorescence signals, demonstrating its targeting specificity to lysosomes. The developed HCCP-MNI may be used for cell tracking applications associated with the functionalities of lysosomes.

Synthesis and Shaping of Core-Shell Tecto Dendrimers for Biomedical Applications.

In recent years, the use of poly(amidoamine) (PAMAM) dendrimers of different generations as building blocks or reactive modules to construct core-shell tecto dendrimers (CSTDs) that are superior to the performance of single-generation dendrimers has received great attention in the field of biomedical applications. The CSTDs are always based on high-generation dendrimers as the core and low-generation dendrimers as the shell; not only do they have excellent properties similar to single high-generation dendrimers, but they also have overcome some of the shortcomings (e.g., limited drug loading capacity or enhanced permeability and retention effect due to small size) of single-generation dendrimers in biomedical applications. Herein, the recent advances of CSTDs synthesized by different approaches as nanoplatforms for different biomedical applications, particularly for chemotherapy, gene delivery, and combination therapy, as well as biological imaging, are summarized. In addition, the current challenges and future perspectives of CSTDs are also discussed.

Facile Synthesis of Amphiphilic Fluorescent Phosphorus Dendron-Based Micelles as Antiproliferative Agents: First Investigations.

We designed and synthesized several families of novel amphiphilic fluorescent phosphorus dendron-based micelles showing relevant antiproliferative activities for use in the field of theranostic nanomedicine. Based on straightforward synthesis pathways, 12 amphiphilic phosphorus dendrons bearing 10 protonated cyclic amino groups (generation one), or 20 protonated amino groups (generation two), and 1 hydrophobic chain carrying 1 fluorophore moiety were created. The amphiphilic dendron micelles had the capacity to aggregate in solution using hydrophilic/hydrophobic interactions, which promoted the formation of polymeric micelles. These dendron-based micelles showed moderate to high antiproliferative activities against a panel of tumor cell lines. This paper presents for the first time the synthesis and our first investigations of new phosphorus dendron-based micelles for cancer therapy applications.

Multivalent Copper(II)-Conjugated Phosphorus Dendrimers with Noteworthy In Vitro and In Vivo Antitumor Activities: A Concise Overview.

Dendrimers are macromolecules with well-defined, homogeneous, and monodispersed structures that form a branch-like structure. In general, they have a symmetric core, inner shells, and an outer shell. Over the past decade, metallodendritic architectures have developed into a new area in nanomedicine. Due to their versatility and facile customization, phosphorus dendrimers represent interesting platforms for biomedical applications. Metallo-conjugated phosphorus dendrimers have been developed within the dendrimer space, an important part of the chemical space. The first investigation was made using phosphorus dendrimers bearing copper(II) groups on their surface as the original anticancer drug candidates. The aim of this minireview is to present our powerful strategy to find and develop original multivalent copper(II)-conjugated phosphorus dendrimers. The most potent of them is G3 dendrimers with N-(pyridine-2-ylmethylene)ethanamine as the chelating motif complexed with Cu(II) (1G3-Cu), showing very good in vitro and in vivo antiproliferative efficacy. On the basis of these results, 1G3-Cu is a potential clinical candidate having progressed from hit to preclinical candidate status.

Dendritic Macromolecular Architectures: Dendrimer-Based Polyion Complex Micelles.

Polymeric micelles are nanoassemblies that are formed by spontaneous arrangement of amphiphilic block copolymers in aqueous solutions at critical micelle concentration (CMC). They represent an effective system for drug delivery of, for instance, poorly water-soluble anticancer drugs. Then, the development of polyion complexes (PICs) were emphasized. The morphology of these complexes depends on the topology of the polyelectrolytes used and the way they are assembled. For instance, ionic-hydrophilic block copolymers have been used for the preparation of PIC micelles. The main limitation in the use of PIC micelles is their potential instability during the self-assembly/disassembly processes, influenced by several parameters, such as polyelectrolyte concentration, deionization associated with pH, ionic strength due to salt medium effects, mixing ratio, and PIC particle cross-linking. To overcome these issues, the preparation of stable PIC micelles by increasing the rigidity of their dendritic architecture by the introduction of dendrimers and controlling their number within micelle scaffold was highlighted. In this original concise Review, we will describe the preparation, molecular characteristics, and pharmacological profile of these stable nanoassemblies.