Mesoporous Silica Shell Research Articles

Al-Doped Core-Shell-Structured Ni@Mesoporous Silica for Highly Selective Hydrodeoxygenation of Lignin-Derived Aldehydes.

Selective deoxygenation of chemicals using non-noble metal-based catalysts poses a significant challenge toward upgrading biomass-derived oxygenates into advanced fuels and fine chemicals. Herein, we report a bifunctional core-shell catalyst (Ni@Al3-mSiO2) consisting of Ni nanoparticles closely encapsulated by the Al-doped mesoporous silica shell that achieves 100% vanillin conversion and >99% yield of 2-methoxy-4-methylphenol under 1 MPa H2 at 130 °C in water. Due to the unique mesoporous core-shell structure, no significant decrease in catalytic activity was observed after 10 recycles. Furthermore, incorporating Al atoms into the silica shell significantly increased the number of acidic sites. Density functional theory calculations reveal the reaction pathway of the vanillin hydrodeoxygenation process and uncover the intrinsic influence of the Al sites. This work not only provides an efficient and cost-effective bifunctional hydrodeoxygenation catalyst but also offers a new synthetic protocol to rationally design promising non-noble metal catalysts for biomass valorization or other widespread applications.

Synthesis of Methotrexate-Loaded Dumbbell-Shaped Titanium Dioxide/Gold Nanorods Coated with Mesoporous Silica and Decorated with Upconversion Nanoparticles for Near-Infrared-Driven Trimodal Cancer Treatment.

This study prepared dumbbell-shaped titanium dioxide (TiO2)/gold nanorods (AuNRs) coated with mesoporous silica shells (mS) (AuNRs-TiO2@mS). Methotrexate (MTX) was further loaded into the AuNRs-TiO2@mS, and then upconversion nanoparticles (UCNPs) were decorated to form AuNRs-TiO2@mS-MTX: UCNP nanocomposites. TiO2 is used as an intense photosensitizer (PS) to produce cytotoxic reactive oxygen species (ROS), leading to photodynamic therapy (PDT). Concurrently, AuNRs exhibited intense photothermal therapy (PTT) effects and photothermal conversion efficiency. In vitro results suggested that these nanocomposites can kill oral cancer cells (HSC-3) without toxicity through irradiation of NIR laser, owing to the synergistic effect. The in vivo studies indicated that these nanocomposites exhibited excellent antitumor effects through synergistic PDT/PTT/chemotherapy under a near-infrared (NIR) 808 nm laser irradiation. Thus, these AuNRs-TiO2@mS: UCNP nanocomposites have great potential to undergo deep tissue penetration with enhanced synergistic effects through NIR-triggered light for cancer treatment.

Monitoring silica core@shell nanoparticle-bacterial film interactions using the multi-parametric surface plasmon resonance technique.

In a healthcare setting, biofilms are a major source of infection and difficult to eradicate once formed. Nanoparticles (NPs) can be designed to effectively penetrate biofilms to more efficiently either deliver antibiotic drugs throughout the biofilm matrix or elicit inherent antibiofilm activity. Antibacterial cerium oxide (CeO2) NPs were employed as core material and coated with a mesoporous silica shell (MSN) to generate cerium oxide coated mesoporous silica NPs (CeO2@MSN). Detailed studies of NP-biofilm interactions are required to rationally develop NP platforms to prevent biofilm-related infections. This work developed and implemented a unique label-free analysis platform for the real-time monitoring of bacterial biofilm formation and then assessed the interactions of antibacterial NPs. An analysis platform which allows bacterial biofilms to grow and develop in situ in flow within the multi-parametric surface plasmon resonance (MP-SPR) instrument was established. This enabled simultaneous monitoring and detection of biofilm growth phases, structure, and interactions between differentially charged CeO2@MSNs and bacterial biofilms. Positively charged antibacterial NPs (polyethyleneimine functionalized CeO2@MSNs) were found to be the most efficient to penetrate the biofilm. The MP-SPR analysis platform was shown to be a powerful tool for monitoring biofilm development in real-time and to analyze biofilm properties and NP-biofilm interactions.

Fe3O4@C@MCM41-guanidine core–shell nanostructures as a powerful and recyclable nanocatalyst with high performance for synthesis of Knoevenagel reaction

In this study, preparation, characterization and catalytic application of a novel core–shell structured magnetic with carbon and mesoporous silica shells supported guanidine (Fe3O4@C@MCM41-guanidine) are developed. The Fe3O4@C@MCM41-guanidine was prepared via surfactant directed hydrolysis and condensation of tetraethyl orthosilicate around Fe3O4@C NPs followed by treatment with guanidinium chloride. This nanocomposite was characterized by using Fourier transform infrared spectroscopy, vibrating sample magnetometry, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, thermal gravimetric analysis, wide-angle X-ray diffraction and low-angle X-ray diffraction techniques. This nanocomposite have high thermal, chemical stability, and uniform size. Fe3O4@C@MCM41-guanidine catalyst demonstrated high yield (91–98%) to prepare of Knoevenagel derivatives under the solvent free conditions at room temperature in the shortest time. Also, this catalyst was recovered and reused 10 times without significant decrease in efficiency and stability. Fortunately, an excellent level of yield (98–82%) was observed in the 10 consecutive catalyst cycles.

Carboxymethyl β-cyclodextrin grafted hollow copper sulfide@mesoporous silica carriers for stimuli-responsive pesticide delivery

Stimuli-responsive controlled release systems have received extensive attention to improve the pesticide bioavailability and minimize environmental pollution. Herein, a multiple stimuli-responsive IMI@HCuS@mSiO2 @ -ss-CβCD delivery system was constructed using modified carboxymethyl β-cyclodextrin (CβCD-ss-COOH) as sealing materials, hollow copper sulfide nanoparticles with amino-functionalized mesoporous silica shell (HCuS@mSiO2-NH2) as carriers and imidacloprid (IMI) as the model drug. The cavity structure of HCuS@mSiO2-NH2 would provide a large space for pesticide loading. The results revealed that HCuS@mSiO2-ss-CβCD was approximately 230 nm in size and the loading efficiency for IMI was 25.7%, and exhibited better biosafety on bacteria and seed. HCuS carriers were also served as photothermal agent and possessed high photothermal conversion effect (η = 38.4%). IMI@HCuS@mSiO2 @ -ss-CβCD displayed excellent foliage adhesion and multiple stimuli-responsive release properties to pH, α-amylase, GSH, and NIR. The photostability of IMI embedded in CuS@mSiO2 @ -ss-CβCD was approximately 10 times that of IMI solution. This work provides an efficient nanoplatform for realizing pesticide delivery.

Enhanced ferroptosis therapy with a “nano-destructor” by disrupting intracellular redox and iron homeostasis

Ferroptosis is an iron-dependent form of cell death that is also a promising tumor therapeutic modality, however, maintaining redox and iron homeostasis in tumor cells limits the ferroptosis therapeutic effect. Herein, we constructed a GSH-depleting magnetic nanoplatform (D@MOs-P) for enhanced ferroptosis by disruption of redox homeostasis and ferritinophagy-mediated iron disorders. D@MOs-P was constructed by coating disulfide bonds-bridged mesoporous silica shells on magnetic nanoparticles (MNPs) and loaded with dihydroartemisinin (DHA, ROS precursor drug). Upon endocytosis by tumor cells, disulfide bond-mediated glutathione depletion and glutathione peroxidase 4 (GPX4) inactivation will synergize with DHA to disrupt intracellular redox homeostasis. On the other hand, the magnetic hyperthermia generated by D@MOs-P will trigger ferritinophagy to achieve tumor iron dyshomeostasis and enhance ferroptosis. Moreover, the released ferrous ions can activate DHA to produce ROS and further disrupt redox homeostasis. Both in vitro and in vivo results demonstrated that D@MOs-P can significant suppression of tumor growth with minimal side effects through the disturbance of dual homeostasis and the intense ferroptosis of tumor cells. Furthermore, MNPs could also provide excellent T2-weighted MR imaging properties. In this work, magnetic hyperthermia was first proven to trigger autophagy-augmented ferroptosis, and the strategies through multi-pathway intracellular homeostasis disruption described in this article can offer an innovative approach in ferroptosis-based antitumor.

Mesoporous silica shell in a core@shell nanocomposite design enables antibacterial action with multiple modes of action

Core@shell structured nanocomposites have received significant attention for their synergistic mode of antibacterial action. Identification of the accommodated unit’s function in the core@shell nanostructure is necessary in order to determine whether antibacterial synergism against bacterial cell growth that is provided within the same core@shell structure. Herein, a novel nanostructure(s) composed of a cerium oxide core and a porous silica shell (CeO2@pSiO2) accomodating curcumin and lectin was prepared, and the antibacterial synergism provided by the nanocomposite was identified. The resulting spherical-shaped CeO2@pSiO2 nanostructure allowed accommodation of curcumin loading (9 w/w%) and a lectin (concanavalin A) coating (15 w/w%). The antibacterial synergism was tested using a minimal inhibitory concentration assay against an Escherichia coli Gram-negative bacterial strain. Furthermore, the mechanisms of bacterial cell disruption induced by the curcumin-loaded and concanavalin A-coated CeO2@pSiO2 core@shell structure, namely the nanoantibiotic (nano-AB) and its design components, were identified. Our findings reveal that the mesoporous silica shell around the CeO2 core within the nano-AB design aids the accommodation of curcumin and concanavalin A and promotes destruction of bacterial cell motility and the permeability of the inner and outer bacterial cell membranes. Our findings strongly indicate the promising potential of a mesoporous silica shell around nanoparticles with a CeO2 core to provide synergistic antibacterial treatment and attack bacterial cells by different mechanisms of action.

Mesoporous colloidal silica cubes with catalytically active cores

Preparation methods of cubic core-shell particles with specific functionality are limited. Here we demonstrate the possibility to transform cuprous oxide cubes coated with mesoporous silica into functional core-shell particles, while retaining their cubic shape. Cuprous oxide nanocubes are coated with mesoporous silica using cetyltrimethylammonium bromide as a template, after which the cuprous oxide core is transformed using liquid phase calcination and galvanic replacement. Nitrogen physisorption and electron microscopy confirm that mesoporous silica coatings are obtained with tuneable thickness. The successful transformation of cuprous oxide into gold and silver is assessed via UV–VIS spectroscopy and energy dispersive X-ray spectroscopy. Particles with a silver core and a cubic mesoporous silica shell are demonstrated to be catalytically active in the degradation of the dye Congo red.Graphical abstract

Molecular-Weight-Dependent Infiltration and Adsorption of Polymers into Nanochannels.

The mesoporous silica shell coating hydrogenolysis nano-catalysts alters the molecular weight distributions of cleaved polymer chains compared to catalysts without a shell. The shell, composed of radially aligned narrow cylindrical nanopores, reduces the formation of low-valued gaseous products and increases the median molecular weight of the product, thus enhancing the value of the products for polymer upcycling. To understand the role of the mesoporous shell, we have studied the spatial distribution of polystyrene chains, used as a model polymer, in the nanochannels in both the melt phase and solution phase. In the melt, we observed from small-angle X-ray scattering experiments that the infiltration rate of the polymer into the nanochannels is inversely proportional to the molecular weight, which is consistent with theory. In theta solution experiments using UV-vis spectroscopy, we found that the shell significantly enhances polymer adsorption compared to nanoparticles without pores. In addition, the degree of polymer adsorption is not a monotonic function of molecular weight but initially increases with the molecular weight before eventually decreasing. The molecular weight for the peak adsorption increases with the pore diameter. This adsorption behavior is rationalized as resulting from a balance between the mixing entropy gain by surface adsorption and the conformational entropy penalty incurred by chains confined in the nanochannels. The spatial distribution of polymer chains in the nanochannels is visualized by energy-dispersive X-ray spectroscopy (EDX), and inverse Abel-transformed data reveals a less uniform polymer distribution along the primary pore axis for longer chains.

Wnt3a Loaded Hydroxyapatite Nanowire@Mesoporous Silica Core-Shell Nanocomposite Promotes the Regeneration of Dentin-Pulp Complex via Angiogenesis, Oxidative Stress Resistance and Odontogenic Induction of Stem Cells.

Pulp exposure often leads to pulp necrosis, root fractures and ultimate tooth loss. The repair of exposure site with pulp capping treatment is of great significance to preserve pulp vitality, but its efficacy is impaired by the low bioactivity of capping materials and cell injuries from the local accumulation of oxidative stress. This study develops a Wnt3a loaded hydroxyapatite nanowire@mesoporous silica (Wnt3a-HANW@MpSi) core-shell nanocomposite for the pulp capping treatments. The ultralong and highly flexible hydroxyapatite nanowires provide the framework for the composites, and the mesoporous silica shell endows the composite with the capacity of efficiently loading/releasing Wnt3a and Si ions. Under the in vitro investigation, Wnt3a-HANW@MpSi not only promotes the oxidative stress resistance of dental pulp stem cells (DPSCs), enhances their migration and odontogenic differentiation, but also exhibits superior property of angiogenesis in vitro. Revealed by the transcriptome analysis, the underlying mechanisms of odontogenic enhancement by Wnt3a-HANW@MpSi are closely related to multiple biological processes and signaling pathways toward pulp/dentin regeneration. Besides, an animal model of subcutaneous transplantation demonstrates the significant reinforcement of the formation of dentin-pulp complex-like tissues and blood vessels by Wnt3a-HANW@MpSi in vivo. These results indicate promising potential of Wnt3a-HANW@MpSi in treatments of dental pulp exposure. This article is protected by copyright. All rights reserved.

Direct synthesis of LPG from syngas over Cu modified FeMg@SiO2 nano-level core@shell catalyst

Direct synthesis of liquefied petroleum gas from syngas via Fischer-Tropsch synthesis route was systematically investigated over a nano-level core@shell catalyst. We introduced an incorporation of FeMg catalyst into mesoporous silica shell, with a further modification of Cu particles on the silica surface. The modified Cu/FeMg@SiO2 nano core-shell catalysts were synthesized by the combination of co-precipitation, modified sol-gel and facile impregnation methods. The as-synthesized catalysts' physicochemical property was characterized by XRD, TEM, N2 adsorption-desorption, H2-TPR, XPS and CO2-TPD techniques. The catalytic performance of Cu/FeMg@SiO2 catalyst shows a high CO conversion of 96.6%, rather low CO2 selectivity of 21.9% and considerable LPG selectivity of 37.9%. The catalytic results indicate that the SiO2 shell restrains the formation of CH4 and contributes to increasing long-chain products. Meanwhile, the enhanced CO conversion of Cu/FeMg@SiO2 was ascribed to the active metal Cu dispersed on SiO2 shell, which also promote olefin hydrogenation and cracking of C5+ hydrocarbons products. The proposed catalyst preparation method will provide a new strategy for the synthesis of nano level catalyst with combinations of metal- and zeolite-based catalyst.

Dual Targeted Delivery of Liposomal Hybrid Gold Nano-Assembly for Enhanced Photothermal Therapy against Lung Carcinomas

The delivery and accumulation of therapeutic drugs into cancer cells without affecting healthy cells are a major challenge for antitumor therapy. Here, we report the synthesis of a liposomal hybrid gold nano-assembly with enhanced photothermal activity for lung cancer treatment. The core components of the nano-assembly include gold nanorods coated with a mesoporous silica shell that offers an excellent drug-loading surface for encapsulation of doxorubicin. To enhance the photothermal capacity of nano-assembly, IR 780 dye was loaded inside a thermo-sensitive liposome, and then, the core nano-assembly was wrapped within the liposome, and GE-11 peptide and folic acid were conjugated onto the surface of the liposome to give the final nano-assembly [(GM@Dox) LI]-PF. The dual targeting approach of [(GM@Dox) LI]-PF leads to enhanced cellular uptake and improves the accumulation of nano-assemblies in cancer cells that overexpress the epidermal growth factor receptor and folate. The exposure of near-infrared laser irradiation can trigger photothermal-induced structural disruption of the nano-assembly, which allows for the precise and controllable release of Dox at targeted sites. Additionally, chemo-photothermal therapy was shown to be 11 times more effective in cancer cell treatment when compared to Dox alone. Our systematic study suggests that the nano-assemblies facilitate the cancer cells undergoing apoptosis via an intrinsic mitochondrial pathway that can be directly triggered by the chemo-photothermal treatment. This study offers an appealing candidate that holds great promise for synergistic cancer treatment.

Aggregation of magnetic nanoparticles functionalized with trans-resveratrol in aqueous solution

In the framework of a protein–ligand-fishing strategy to identify proteins that bind to trans-resveratrol, a natural phenolic compound with pharmacological benefits, we have developed magnetic nanoparticles covalently linked to trans-resveratrol through three different derivatives and examined their aggregation behavior in aqueous solution. The monodispersed magnetic core (18 nm diameter) with its mesoporous silica shell (93 nm diameter) exhibited a notable superparamagnetic behavior useful for magnetic bioseparation. The hydrodynamic diameter, deduced from dynamic light scattering analysis, of the nanoparticle increased from 100 to 800 nm when the aqueous buffer changed from pH 10.0–3.0. A size polydispersion occurred from pH 7.0–3.0. In parallel, the value of the extinction cross section increased according to a negative power law of the UV wavelength. This was mainly due to light scattering by mesoporous silica, whereas the absorbance cross section remained very low in the 230–400 nm domain. The three types of resveratrol-grafted magnetic nanoparticles exhibited similar scattering properties, but their absorbance spectrum was consistent with the presence of trans-resveratrol. Their functionalization increased their negative zeta potential when pH increased from 3.0 to 10.0. The mesoporous nanoparticles were monodispersed in alkaline conditions, where their anionic surface strongly repulsed each other but aggregated progressively under van der Waals forces and hydrogen bonding when negative zeta potential decreased. The characterized results of nanoparticle behavior in aqueous solution provide critical insight for further study of nanoparticles with proteins in biological environment.

ROS-Responsive Janus Au/Mesoporous Silica Core/Shell Nanoparticles for Drug Delivery and Long-Term CT Imaging Tracking of MSCs in Pulmonary Fibrosis Treatment.

Mesenchymal stem cell (MSC) therapy has been proven to be a potentially effective approach for idiopathic pulmonary fibrosis (IPF) treatment. However, this strategy is currently limited by the poor curative effect and an insufficient comprehension of the in vivo condition of the transplanted MSCs in the remedy of IPF. To address these issues, herein, a nanosystem composed of Janus Au/mesoporous silica core/shell nanoparticles (Janus NPs) is designed for effective therapeutic and real-time tracing of MSCs in MSC-based IPF therapy. The Janus NPs consist of a Au core and a pirfenidone (PFD)-loaded mesoporous silica shell asymmetrically decorated with two targeting moieties: one is reactive oxygen species (ROS)-sensitive thioketal grafted methoxy poly(ethylene glycol) (mPEG-TK), and the other is 1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE). The asymmetric decoration on each side of the particle allows long-term anchoring of the Janus NPs on the cell membrane to facilitate the responsive release of PFD in the ROS environment of the fibrotic lung, thereby enhancing the therapeutic efficacy of the transplanted MSCs by improving the microenvironment. Following drug release, the Janus NPs quickly enter into MSCs, achieving long-term computed tomography (CT) imaging tracing of MSCs in IPF model mice for an in-depth comprehension of the cell therapy mechanism. Overall, this work reports on Janus Au/PFD-loaded mesoporous silica core/shell NPs that combine the drug delivery and imaging tracking of MSCs, which may provide a strategy for the stem cell-based treatment of IPF.

Rough Surface Enhanced Interfacial Synthesis of Core‐Shell Magnetic Fluorescent Microspheres for Enhanced Latent Fingerprint Visualization

AbstractDeveloping latent fingerprints is extremely significant for personal identification and criminal investigation. Sub‐micrometer core‐shell structured magnetic fluorescent composite which combines the merits of noncontact magnetic responsiveness and strong fluorescence emission is highly desired for the visualization of latent fingerprint on various substrates with high resolutions. However, it remains a great challenge to synthesize uniform magnetic fluorescent composites with well‐defined structure and functionalities due to the uncontrollable heterogeneous growth. Herein, a urea‐assisted rough interface precipitation method is proposed to controllably synthesize uniform core‐shell structured magnetic fluorescent composite microspheres (Fe3O4@mesoSiO2@Y2O3:Eu3+). The composite microspheres with magnetic core and mesoporous silica shell (Fe3O4@mesoSiO2) possess huge guest‐host interface, numerous nucleation sites, and rough surface morphology, facilitating the efficient adsorption of Y3+/Eu3+ ions, and further controllable interface deposition of metal (Y, Eu) hydroxides induced by slow release of OH− and CO32− anions via the in‐solution decomposition of urea. After subsequent thermal annealing, the obtained Fe3O4@mesoSiO2@Y2O3:Eu3+ microspheres possess high magnetization for convenient magnetic manipulation, strong fluorescence intensity and negligible quenching effect, enabling a superior performance in latent fingerprint visualization with high contrast and resolution on various substrates.

Low-dose pleiotropic radiosensitive nanoformulations for three-pronged radiochemotherapy of hypoxic brain glioblastoma under BOLD/DWI monitoring

BackgroundHypoxia-mediated radioresistance is the main obstacle to the successful treatment of glioblastoma (GBM). Enhancing hypoxic radiosensitivity and alleviating tumor hypoxia are both effective means to improve therapeutic efficacy, and the combination of the two is highly desirable and meaningful.ResultsHerein, we construct a low-dose pleiotropic radiosensitive nanoformulation consisting of a high-Z atomic nanocrystal core and mesoporous silica shell, surface-modified with angiopep-2 (ANG) peptide and loaded with nitric oxide (NO) donor and hypoxia-activated prodrug (AQ4N). Benefiting from ANG-mediated transcytosis, this nanoformulation can efficiently cross the BBB and accumulate preferentially in the brain. Low-dose radiation triggers this nanoformulation to exert a three-pronged synergistic therapeutic effect through high-Z-atom-dependent dose deposition enhancement, NO-mediated hypoxia relief, and AQ4N-induced hypoxia-selective killing, thereby significantly inhibiting GBM in situ growth while prolonging survival and maintaining stable body weight in the glioma-bearing mice. Meanwhile, the proposed in vivo 9.4 T BOLD/DWI can realize real-time dynamic assessment of local oxygen supply and radiosensitivity to monitor the therapeutic response of GBM.ConclusionsThis work provides a promising alternative for hypoxia-specific GBM-targeted comprehensive therapy, noninvasive monitoring, and precise prognosis.Graphical

Assembling Near-Infrared Dye on the Surface of Near-Infrared Silica-Coated Copper Sulphide Plasmonic Nanoparticles.

Functionalization of colloidal nanoparticles with organic dyes, which absorb photons in complementary spectral ranges, brings a synergistic effect for harvesting additional light energy. Here, we show functionalization of near-infrared (NIR) plasmonic nanoparticles (NPs) of bare and amino-group functionalized mesoporous silica-coated copper sulphide (Cu2-xS@MSS and Cu2-xS@MSS-NH2) with specific tricarbocyanine NIR dye possessing sulfonate end groups. The role of specific surface chemistry in dye assembling on the surface of NPs is demonstrated, depending on the organic polar liquids or water used as a dispersant solvent. It is shown that dye binding to the NP surfaces occurs with different efficiency, but mostly in the monomer form in polar organic solvents. Conversely, the aqueous medium leads to different scenarios according to the NP surface chemistry. Predominant formation of the disordered dye monomers occurs on the bare surface of mesoporous silica shell (MSS), whereas the amino-group functionalized MSS accepts dye predominantly in the form of dimers. It is found that the dye-NP interaction overcomes the dye-dye interaction, leading to disruption of dye J-aggregates in the presence of the NPs. The different organization of the dye molecules on the surface of silica-coated copper sulphide NPs provides tuning of their specific functional properties, such as hot-band absorption and photoluminescence.

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.

Fe/Fe3O4@mSiO2 Core–Shell Nanostructures for Broad-Band Microwave Absorption

Fe/Fe3O4 composite particles with mesoporous silica (mSiO2) shells were successfully prepared via solvothermal reaction combined with hydrogen-thermal reduction. The introduction of mSiO2 on the surfaces of Fe3O4 constructs a ventilated frame and thereafter sustains the dispersion of the fine Fe particles that emerge from the reduction reaction. The conversion of Fe3O4 to Fe nanoparticles enhances the ferromagnetic loss, while the Fe3O4/Fe/mSiO2 interfaces induce an intensified dielectric loss. Fe/Fe3O4@mSiO2-500 (FFm-500) presents excellent electromagnetic wave-absorbing performances. The coating using FFm-500 as fillers presents a minimum reflection loss of −26.81 dB, together with an effective absorption bandwidth of 6.66 GHz. The results revealed the key role of mSiO2 in the synthesis of Fe/Fe3O4 nanostructures and the unique potential of Fe/Fe3O4@mSiO2 as broad-band EMA fillers.

Conservation of the enzyme-like activity and biocompatibility of CeO2 nanozymes in simulated body fluids.

Cerium oxide nanozymes (CeO2NZs) are attracting vast attention due to their antioxidant and catalytic properties and mimic the activities of multiple endogenous enzymes. However, as is the case for nanomedicines in general, the success in showing their unique medical applications has not been matched by an understanding of their pharmacokinetics, which is delaying their implementation in clinical settings. Furthermore, the data of their modifications in body fluids and the impact on their activity are scarce. Herein, two types of widely used CeO2NZs, electrostatically stabilized and coated with a mesoporous silica shell, were exposed to simulated saliva and lung, gastric and intestinal fluids, and cell culture media. Their physicochemical modifications and bioactivity were tracked over time up to 15 days combining the data of different characterization techniques and biological assays. The results show that the biocompatibility and antioxidant activity are retained in all cases despite the different evolution behaviors in different fluids, including agglomeration. This work provides an experimental basis from a pharmacokinetic perspective that supports the therapeutic effectiveness of CeO2NZs observed in vivo for the treatment of many conditions related to chronic inflammation and cancer, and suggests that they can be safely administered through different portals of entry including intravenous injection, oral ingestion or inhalation.