Highly cross-linked and biocompatible polyphosphazene-coated superparamagnetic Fe3O4 nanoparticles for magnetic resonance imaging

Combined Approach of Compression Molding and Magnetic Attraction to Micropatterning of Magnetic Polydimethylsiloxane Composite Surfaces with Excellent Anti-Icing/Deicing Performance

The accumulation of ice and contaminants on the surface of composite insulators will cause high energy consumption or even major hazards to power systems. In this work, the polydimethylsiloxane (PDMS) silicone rubber was modified by surface micropatterning and material compositing. Highly crosslinked poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) (PZS) was used to directly coat ferroferric oxide (Fe₃O₄) nanoparticles. The obtained core-shell Fe₃O₄@PZS microspheres were loaded with carbon nanotubes (CNTs) to get CNTs/Fe₃O₄@PZS as the photothermal magnetic filler. The PDMS/CNTs/Fe₃O₄@PZS surfaces with micronscale truncated cones were prepared via a combined method of compression molding and magnetic attraction. The 1H,1H,2H,2H-perfluorodecyltrichlorosilane-coated template and magnetic field can increase the height of the microstructure to ∼76 μm and maintain the contact angle of microstructured PDMS/CNTs/Fe₃O₄@PZS surfaces at a high level (∼152°). Compared with the flat PDMS surface, the micronscale truncated cones extend the freezing time from 4.5 to 11.5 min and also undermine the ice adhesion strength from ∼25 to ∼17 kPa for the microstructured PDMS/CNTs/Fe₃O₄@PZS surface. The temperature of the PDMS/CNTs/Fe₃O₄@PZS surface molded with magnetic attraction increases linearly with time and the internal magnetic fillers and achieves 280 °C in 10 s. The efficiency of temperature rise is increased by ∼46%, and hence the entire frozen water droplet can melt within 20 s. The strategy combining active deicing with passive anti-icing undoubtedly promotes the development of high efficiency anti-icing materials and can be applied on insulators to prevent icing flashover.

Facile Assembly of Thermosensitive Liposomes for Active Targeting Imaging and Synergetic Chemo-/Magnetic Hyperthermia Therapy

Cancer stem cells (CSCs) are thought to be responsible for the recurrence of liver cancer, highlighting the urgent need for the development of effective treatment regimens. In this study, 17-allylamino-17-demethoxygeldanamycin (17-AAG) and thermosensitive magnetoliposomes (TMs) conjugated to anti-CD90 (CD90@17-AAG/TMs) were developed for temperature-responsive CD90-targeted synergetic chemo-/magnetic hyperthermia therapy and simultaneous imaging in vivo. The targeting ability of CD90@DiR/TMs was studied with near-infrared (NIR) resonance imaging and magnetic resonance imaging (MRI), and the antitumor effect of CD90@17-AAG/TM-mediated magnetic thermotherapy was evaluated in vivo. After treatment, the tumors were analyzed with Western blotting, hematoxylin and eosin staining, and immunohistochemical (IHC) staining. The relative intensity of fluorescence was approximately twofold higher in the targeted group than in the non-targeted group, while the T₂ relaxation time was significantly lower in the targeted group than in the non-targeted group. The combined treatment of chemotherapy, thermotherapy, and targeting therapy exhibited the most significant antitumor effect as compared to any of the treatments alone. The anti-CD90 monoclonal antibody (mAb)-targeted delivery system, CD90@17-AAG/TMs, exhibited powerful targeting and antitumor efficacies against CD90⁺ liver cancer stem cells in vivo.

Green Synthesized Montmorillonite/Carrageenan/Fe3O4 Nanocomposites for pH-Responsive Release of Protocatechuic Acid and Its Anticancer Activity

Discovery of a novel anticancer drug delivery agent is important to replace conventional cancer therapies which are often accompanied by undesired side effects. This study demonstrated the synthesis of superparamagnetic magnetite nanocomposites (Fe₃O₄-NCs) using a green method. Montmorillonite (MMT) was used as matrix support, while Fe₃O₄ nanoparticles (NPs) and carrageenan (CR) were used as filler and stabilizer, respectively. The combination of these materials resulted in a novel nanocomposite (MMT/CR/Fe₃O₄-NCs). A series of characterization experiments was conducted. The purity of MMT/CR/Fe₃O₄-NCs was confirmed by X-ray diffraction (XRD) analysis. High resolution transmission electron microscopy (HRTEM) analysis revealed the uniform and spherical shape of Fe₃O₄ NPs with an average particle size of 9.3 ± 1.2 nm. Vibrating sample magnetometer (VSM) analysis showed an M_s value of 2.16 emu/g with negligible coercivity which confirmed the superparamagnetic properties. Protocatechuic acid (PCA) was loaded onto the MMT/CR/Fe₃O₄-NCs and a drug release study showed that 15% and 92% of PCA was released at pH 7.4 and 4.8, respectively. Cytotoxicity assays showed that both MMT/CR/Fe₃O₄-NCs and MMT/CR/Fe₃O₄-PCA effectively killed HCT116 which is a colorectal cancer cell line. Dose-dependent inhibition was seen and the killing was enhanced two-fold by the PCA-loaded NCs (IC₅₀–0.734 mg/mL) compared to the unloaded NCs (IC₅₀–1.5 mg/mL). This study highlights the potential use of MMT/CR/Fe₃O₄-NCs as a biologically active pH-responsive drug delivery agent. Further investigations are warranted to delineate the mechanism of cell entry and cancer cell killing as well as to improve the therapeutic potential of MMT/CR/Fe₃O₄-NCs.

Acid-Responsive and Biologically Degradable Polyphosphazene Nanodrugs for Efficient Drug Delivery

To enhance the therapeutic effects and reduce the damage to normal tissues in cancer chemotherapy, it is indispensable to develop drug delivery carriers with controllable release and good biocompatibility. In this work, acid-responsive and degradable polyphosphazene (PPZ) nanoparticles were synthesized by the reaction of hexachlorotripolyphosphonitrile (HCCP) with 4-hydroxy-benzoic acid (4-hydroxy-benzylidene)-hydrazide (HBHBH) and anticancer drug doxorubicin (DOX). The controlled release of DOX could be realized based on the acid responsiveness of acylhydrazone in HBHBH. Experimental results showed that polyphosphazene nanoparticles remained stable in the body's normal fluids (pH ∼ 7.4), while they were degraded and controllable release of DOX in an acidic environment such as tumors (pH ∼ 6.8) and lysosome and endosome (∼5.0) in cancer cells In particular, the doxorubicin (DOX)-loading ratio was fair high and could be tuned from 10.6 to 52.6% by changing the dosing ratio of DOX to HBHBH. Meanwhile, the polyphosphazene nanodrugs showed excellent toxicity to tumor cells and reduced the side effect to normal cells both in vitro and in vivo due to their enhanced permeability and retention (EPR) effect and pH-sensitive degradation properties. Therefore, the constructed pH-sensitive drug delivery system has great potential for cancer chemotherapy.

Heavily superparamagnetic magnetite-loaded polymeric worm-like micelles that have an ultrahigh T2 relaxivity

Composite worm-like micelles with an ultrahigh T₂ relaxivity fabricated via two-stage self-assembly of SMNPs guided by PEG-b-P4VP and DNA.

Preparation and Characterization of Fe3O4@MTX Magnetic Nanoparticles for Thermochemotherapy of Primary Central Nervous System Lymphoma in vitro and in vivo

Background

Primary central nervous system lymphomas (PCNSL) are extranodal malignant non-Hodgkin lymphomas (NHL) that arise exclusively in central nervous system (CNS). Diffuse large B-cell lymphoma (DLBCL) is the most common histological subtype.

Purpose

To evaluate whether nano drug-loading system-mediated magnetic-targeted thermochemotherapy could produce a better therapeutic effect than single chemotherapy while reducing the use of chemotherapeutic drugs.

Methods

Six groups (control, Fe₃O₄, MTX, Fe₃O₄@MTX, Fe₃O₄ with hyperthermia and Fe₃O₄@MTX with hyperthermia) were set. Tumor cell apoptosis in each treatment group was detected by flow cytometry. Apoptosis-related gene expressions Caspase-3, Bax and Bcl-2 were detected by qPCR and Western blot; intracranial tumor model of PCNSL was established by intracranial injection of OCI-LY18 tumor cells into BALB/c-Nude mice. Magnetic resonance imaging (MRI) was used to monitor tumor progression and H&E staining was used to observe pathological changes of the tumor tissue.

Results

In vitro, compared with chemotherapy alone, apoptosis rate of Fe₃O₄@MTX mediated thermochemotherapy group was significantly increased, and expression of apoptosis-inducing gene Caspase-3 and Bax were significantly upregulated in OCI-LY18 cells, while expression of apoptosis-inhibiting Bcl-2 gene was significantly downregulated. In vivo, MRI showed successful generation of intracranial tumor, and tumor volume was significantly smaller in combined thermochemotherapy group than in single chemotherapy group. H&E staining result of tumor tissues in each group was consistent with MRI; tumor cells were significantly reduced in thermochemotherapy group. Expression of apoptosis-related gene Caspase-3 and Bax were significantly upregulated in tumor tissues, while expression of Bcl-2 gene was significantly downregulated.

Conclusion

These results demonstrated in vivo and in vitro that the combined thermochemotherapy of Fe₃O₄@MTX MNPs was superior to the single MTX chemotherapy with less dosage, which may promote apoptosis of DLBCL cells through the mitochondrial apoptotic pathway and provided a new way for the treatment of PCNSL.

Biodegradable Cyclomatrix Polyphosphazene Nanoparticles: A Novel pH-Responsive Drug Self-Framed Delivery System

Traditional drug delivery systems suffer from low drug-loading and relatively weak therapeutic efficacy, therefore, development of new drug delivery systems with high-efficiency has become more urgent. In this report, a novel-innovative drug delivery strategy, namely drug self-framed delivery system (DSFDS), is prepared via using anticancer drugs as polymer frame without using any carriers. The drug molecules (exemplified by doxorubicin) containing more than two nucleophilic functional groups (diols/diamines) directly reacted with hexachlorocyclotriphosphazene via mild precipitation polycondensation under ambient conditions, forming biocompatible drug self-framed delivery nanoparticles. Because of the covalent bonding of the drug molecules, DSFD nanoparticles (DSFDs) with super high drug-loading were stable in the circulation during delivery. However, sustained release of drug in the acidic environment within cells endowed DSFDs with long-term anticancer therapeutic efficacy. This strategy is applicable for diverse hydrophilic and hydrophobic drugs and may be a new platform for designing high drug-loading and release-controllable drug delivery systems.

Melamine-containing polyphosphazene wrapped ammonium polyphosphate: A novel multifunctional organic-inorganic hybrid flame retardant

To achieve superior fire safety epoxy resins (EP), a novel multifunctional organic-inorganic hybrid, melamine-containing polyphosphazene wrapped ammonium polyphosphate (PZMA@APP) with rich amino groups was prepared and used as an efficient flame retardant. Thanks to the cross-linked polyphosphazene part, PZMA@APP exhibited high flame retardant efficiency and smoke suppression to the EP composites. Thermogravimetric analysis indicated that PZMA@APP significantly enhanced the thermal stability of EP composites. The obtained sample passed UL-94 V-0 rating with 10.0wt% addition of PZMA@APP. Notably, inclusion of incorporating PZMA@APP leads to significantly decrease on fire hazards of EP, for instance, bring about a 75.6% maximum decrease in peak heat release rate and 65.9% maximum reduction in total heat release, accompanied with lower smoke production rate and higher graphitized char layer. With regards to mechanical property, the glass transition temperature of EP/PZMA@APP10.0 was as high as 184.5°C. In particular, the addition of PZMA@APP did not worsen the mechanical properties, compared to pure APP. It was confirmed that the participation of melamine-containing polyphosphazene could significantly enhance the quality of char layer and thereby resulting the higher flame retardant efficiency of PZMA@APP.

Microfluidic-Assisted Production of Size-Controlled Superparamagnetic Iron Oxide Nanoparticles-Loaded Poly(methyl methacrylate) Nanohybrids

In this paper, superparamagnetic iron oxide nanoparticles (SPIONs, around 6 nm) encapsulated in poly(methyl methacrylate) nanoparticles (PMMA NPs) with controlled sizes ranging from 100 to 200 nm have been successfully produced. The hybrid polymeric NPs were prepared following two different methods: (1) nanoprecipitation and (2) nanoemulsification-evaporation. These two methods were implemented in two different microprocesses based on the use of an impact jet micromixer and an elongational-flow microemulsifier. SPIONs-loaded PMMA NPs synthesized by the two methods presented completely different physicochemical properties. The polymeric NPs prepared with the micromixer-assisted nanoprecipitation method showed a heterogeneous dispersion of SPIONs inside the polymer matrix, an encapsulation efficiency close to 100 wt %, and an irregular shape. In contrast, the polymeric NPs prepared with the microfluidic-assisted nanoemulsification-evaporation method showed a homogeneous dispersion, an almost complete encapsulation, and a spherical shape. The properties of the polymeric NPs have been characterized by dynamic light scattering, thermogravimetric analysis, and transmission electron microscope. In vitro cytotoxicity assays were also performed on the nanohybrids and pure PMMA NPs.

Cyclotriphosphazene core-based dendrimers for biomedical applications: an update on recent advances

This review is focused on the recent use of cyclotriphosphazene-based dendrimers in biomedicine. Since its synthesis for the first time in 1834, cyclotriphosphazene has been an important compound of phosphorus chemistry as a scaffold, and a large number of cyclotriphosphazene derivatives have been synthesized and applied in various fields such as biology, catalysis, fluorescence, nanomaterials, etc. Today, one of the most important uses concerns its biomedical applications. In this review, the recent developments (since 2012) of cyclotriphosphazene for major pharmaceutical applications are highlighted and analyzed.

Fe3+-Enhanced NIR-to-NIR upconversion nanocrystals for tumor-targeted trimodal bioimaging

Fe³⁺-Enhanced NIR-to-NIR multifunctional upconversion luminescence nanocrystals were synthesized for excellent tumor-targeted UCL/MRI/X-ray trimodal bioimaging.

Iron oxide magnetic nanoparticles combined with actein suppress non-small-cell lung cancer growth in a p53-dependent manner

Actein (AT) is a triterpene glycoside isolated from the rhizomes of Cimicifuga foetida that has been investigated for its antitumor effects. AT treatment leads to apoptosis in various cell types, including breast cancer cells, by regulating different signaling pathways. Iron oxide (Fe₃O₄) magnetic nanoparticles (MNPs) are nanomaterials with biocompatible activity and low toxicity. In the present study, the possible benefits of AT in combination with MNPs on non-small-cell lung cancer (NSCLC) were explored in in vitro and in vivo studies. AT-MNP treatment contributed to apoptosis in NSCLC cells, as evidenced by activation of the caspase 3-signaling pathway, which was accompanied by downregulation of the antiapoptotic proteins Bcl2 and BclXL, and upregulation of the proapoptotic signals Bax and Bad. The death receptors of TRAIL were also elevated following AT-MNP treatment in a p53-dependent manner. Furthermore, a mouse xenograft model in vivo revealed that AT-MNP treatment exhibited no toxicity and suppressed NSCLC growth compared to either AT or MNP monotherapies. In conclusion, this study suggests a novel therapy to induce apoptosis in suppressing NSCLC growth in a p53-dependent manner by combining AT with Fe₃O₄ MNPs.

Hydrophilic Magnetite Nanoparticles Enhance Anticancer Activity of Anthracyclines In Vitro

A novel method for enhancing the anticancer activity of anthracyclines in vitro was proposed by using hydrophilic magnetic nanoparticles. Citric acid-coated magnetite nanoparticles Fe3O4 (nano-Fe3O4-CA) interacted with anthracyclines by electrostatic and hydrophobic forces, resulting in the formation of aggregates (nano-Fe3O4-CA-drug). The aggregate was studied by resonance light scattering and fluorescence spectroscopy. The results indicated that in comparison with anthracyclines, the nano-Fe3O4-CA-drug showed high activity towards incorporation in the DNA chain. Furthermore, the cytotoxicity of nano-Fe3O4-CA-drug was investigated by cytotoxicity experiment and cell morphology study. The results confirmed that the nano-Fe3O4-CA-drug could inhibit the growth of cells more effectively than the drug alone. In conclusion, usage of nano-Fe3O4-CA affords reduction of the dosage of anthracyclines in vitro.

Functionalization of α-zirconium phosphate by polyphosphazene and its effect on the flame retardance of an intumescent flame retardant polypropylene system

α-ZrP was combined with polyphosphazene and formed a core–shell structure, which has a significant synergistic flame retardant performance in polypropylene.

A strategy for the synthesis of cyclomatrix-polyphosphazene nanoparticles from non-aromatic monomers

Cyclomatrix-polyphosphazenes (C-PPZs) are a new class of nanomaterials that have attracted significant interest owing to their unique inorganic–organic hybrid structure and tunable properties.

Ultra-high relaxivity iron oxide nanoparticles confined in polymer nanospheres for tumor MR imaging

Superparamagnetic iron oxide nanoparticles encapsulated in hydrophilic chitosan nanospheres were prepared by nonsolvent-aided counterion complexation completely in an aqueous solution. The T₂ relaxation of these hybrid nanospheres in vitro and in vivo was investigated. It was found that the molar transverse relaxivity rate r₂ of hybrid nanospheres highly depends upon the payload of iron oxide nanoparticles within hybrid nanospheres. Compared to free iron oxide nanoparticles, the molar transverse relaxivity rate, r₂ of hybrid nanospheres shows an approximately 8-fold increase and reaches the maximum of 533 Fe mM^-1 s^-1. Such a high r₂ value is probably associated with the clustering effect of iron oxide nanoparticles, which are confined in the chitosan nanospheres. The in vivo magnetic resonance imaging (MRI) demonstrates that the hybrid nanospheres shorten transverse relaxation time, T₂ and significantly decrease the signal intensity of the tumor area, giving rise to high contrast tumor MR imaging at a relatively low dose.

Fluorescent and cross-linked organic-inorganic hybrid nanoshells for monitoring drug delivery

Functionalized and monodisperse nanoshells have attracted significant attention owing to their well-defined structure, unique properties, and wide range of potential applications. Here, the synthesis of cross-linked organic-inorganic hybrid nanoshells with strong fluorescence properties was reported via a facile precipitation polymerization of hexachlorocyclotriphosphazene (HCCP) and fluorescein on silica particles used as templates. The resulting poly(cyclotriphosphazene-co-fluorescein) (PCTPF) nanoshells were firm cross-linked shells with ∼2.2 nm mesopores that facilitated the transport of drug molecules. The fluorescent nanoshells also exhibited excellent water dispersibility and biocompatibility; thus, they can be considered as ideal drug vehicles with high doxorubicin storage capacity (26.2 wt %) and excellent sustained release (up to 14 days). Compared to doxorubicin (DOX) alone, the PCTPF nanoshells more efficiently delivered DOX into and killed cancer cells. Moreover, the PCTPF nanoshells also exhibited remarkable fluorescent emission properties and improved photobleaching stability in both suspension and solid state owing to the covalent immobilization of fluorescein in the highly cross-linked organic-inorganic hybrids. The exceptional fluorescent properties enabled the release of DOX as well as the distribution of nanoshells and DOX to be monitored.

Magnetic colloidal superparticles of Co, Mn and Ni ferrite featured with comb-type and/or linear amphiphilic polyelectrolytes; NMR and MRI relaxometry

Hydrophobically-modified magnetic superparticles (MSPs) of MFe₂O₄ NPs were synthesized in the presence of amphiphilic polymers with different architectures and evaluated through NMR and MRI relaxivity measurements.

One-pot synthesis of fluorescent and cross-linked polyphosphazene nanoparticles for highly sensitive and selective detection of dopamine in body fluids

Highly cross-linked and monodisperse polyphosphazene (PZS) nanoparticles exhibiting strong fluorescence were prepared by the facile one-pot polycondensation of hexachlorocyclotriphosphazene and 4′,5′-dibromofluorescein (DBF).

Glycosylation of polyphosphazenes by thiol-yne click chemistry for lectin recognition

Strong carbohydrate–lectin binding interactions in biological systems can be mimicked through the synthesis of glucose containing macromolecules, particularly glycosylated polymers.

Magnetite/dextran-functionalized graphene oxide nanosheets for in vivo positive contrast magnetic resonance imaging

In vivo positive contrast MRI by magnetite/dextran-functionalized graphene oxide (SPIO-Dex-FGO) as compared to Magnevist® (the right rat).

One-pot synthesis of highly cross-linked fluorescent polyphosphazene nanoparticles for cell imaging

Highly cross-linked and fluorescent polyphosphazene nanoparticles with excellent biocompatibility and improved resistance to photobleaching and protein interference were prepared for cell imaging.

Magnetic nanoparticle-based therapeutic agents for thermo-chemotherapy treatment of cancer

Magnetic nanoparticles have been widely investigated for their great potential as mediators of heat for localised hyperthermia therapy. Nanocarriers have also attracted increasing attention due to the possibility of delivering drugs at specific locations, therefore limiting systematic effects. The enhancement of the anti-cancer effect of chemotherapy with application of concurrent hyperthermia was noticed more than thirty years ago. However, combining magnetic nanoparticles with molecules of drugs in the same nanoformulation has only recently emerged as a promising tool for the application of hyperthermia with combined chemotherapy in the treatment of cancer. The main feature of this review is to present the recent advances in the development of multifunctional therapeutic nanosystems incorporating both magnetic nanoparticles and drugs, and their superior efficacy in treating cancer compared to either hyperthermia or chemotherapy as standalone therapies. The principle of magnetic fluid hyperthermia is also presented.

Development of Fe/Fe3O4 core-shell nanocubes as a promising magnetic resonance imaging contrast agent

Here, we report the synthesis, characterization, and properties of Fe/Fe3O4 core-shell nanocubes prepared via a simple route. It includes NaBH4 reduction of FeCl3 in an ethylene glycol solution in the presence of 2-mercaptopropionic acid (surfactant) and trisodium citrate (cosurfactant) followed by surface oxidation with trimethylamine N-oxide. The morphology and structure of Fe/Fe3O4 core-shell nanocubes were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, X-ray powder diffraction, and X-ray photoelectron spectroscopy. All of the methods confirm a Fe/Fe3O4 core-shell structure of nanocubes. Magnetic measurements revealed that the Fe/Fe3O4 core/shell nanocubes are superparamagnetic at 300 K with a saturation magnetization of 129 emu/g. The T2 weighted imaging and the T2 relaxation time showed high MRI contrast and sensitivity, making these nanocubes viable candidates as enhanced MRI contrast agents.