Ultrasmall Fe3O4 Nanoparticles Research Articles

Surface ligand-regulated renal clearance of MRI/SPECT dual-modality nanoprobes for tumor imaging

BackgroundThe general sluggish clearance kinetics of functional inorganic nanoparticles tend to raise potential biosafety concerns for in vivo applications. Renal clearance is a possible elimination pathway for functional inorganic nanoparticles delivered through intravenous injection, but largely depending on the surface physical chemical properties of a given particle apart from its size and shape.ResultsIn this study, three small-molecule ligands that bear a diphosphonate (DP) group, but different terminal groups on the other side, i.e., anionic, cationic, and zwitterionic groups, were synthesized and used to modify ultrasmall Fe3O4 nanoparticles for evaluating the surface structure-dependent renal clearance behaviors. Systematic studies suggested that the variation of the surface ligands did not significantly increase the hydrodynamic diameter of ultrasmall Fe3O4 nanoparticles, nor influence their magnetic resonance imaging (MRI) contrast enhancement effects. Among the three particle samples, Fe3O4 nanoparticle coated with zwitterionic ligands, i.e., Fe3O4@DMSA, exhibited optimal renal clearance efficiency and reduced reticuloendothelial uptake. Therefore, this sample was further labeled with 99mTc through the DP moieties to achieve a renal-clearable MRI/single-photon emission computed tomography (SPECT) dual-modality imaging nanoprobe. The resulting nanoprobe showed satisfactory imaging capacities in a 4T1 xenograft tumor mouse model. Furthermore, the biocompatibility of Fe3O4@DMSA was evaluated both in vitro and in vivo through safety assessment experiments.ConclusionsWe believe that the current investigations offer a simple and effective strategy for constructing renal-clearable nanoparticles for precise disease diagnosis.Graphical

Ultrasmall Fe3O4 nanoparticles self-assembly induced dual-mode T1/T2-weighted magnetic resonance imaging and enhanced tumor synergetic theranostics

Individual theranostic agents with dual-mode MRI responses and therapeutic efficacy have attracted extensive interest due to the real-time monitor and high effective treatment, which endow the providential treatment and avoid the repeated medication with side effects. However, it is difficult to achieve the integrated strategy of MRI and therapeutic drug due to complicated synthesis route, low efficiency and potential biosafety issues. In this study, novel self-assembled ultrasmall Fe3O4 nanoclusters were developed for tumor-targeted dual-mode T1/T2-weighted magnetic resonance imaging (MRI) guided synergetic chemodynamic therapy (CDT) and chemotherapy. The self-assembled ultrasmall Fe3O4 nanoclusters synthesized by facilely modifying ultrasmall Fe3O4 nanoparticles with 2,3-dimercaptosuccinic acid (DMSA) molecule possess long-term stability and mass production ability. The proposed ultrasmall Fe3O4 nanoclusters shows excellent dual-mode T1 and T2 MRI capacities as well as favorable CDT ability due to the appropriate size effect and the abundant Fe ion on the surface of ultrasmall Fe3O4 nanoclusters. After conjugation with the tumor targeting ligand Arg-Gly-Asp (RGD) and chemotherapy drug doxorubicin (Dox), the functionalized Fe3O4 nanoclusters achieve enhanced tumor accumulation and retention effects and synergetic CDT and chemotherapy function, which serve as a powerful integrated theranostic platform for cancer treatment.

Design of Water-Soluble Rotaxane-Capped Superparamagnetic, Ultrasmall Fe3O4 Nanoparticles for Targeted NIR Fluorescence Imaging in Combination with Magnetic Resonance Imaging.

Integrating an NIR fluorescent probe with a magnetic resonance imaging (MRI) agent to harvest complementary imaging information is challenging. Here, we have designed water-soluble, biocompatible, noncytotoxic, bright-NIR-emitting, sugar-functionalized, mechanically interlocked molecules (MIMs)-capped superparamagnetic ultrasmall Fe3O4 NPs for targeted multimodal imaging. Dual-functional stoppers containing an unsymmetrical NIR squaraine dye interlocked within a macrocycle to construct multifunctional MIMs are developed with enhanced NIR fluorescence efficiency and durability. One of the stoppers of the axle is composed of a lipophilic cationic TPP+ functionality to target mitochondria, and the other stopper comprises a dopamine-containing catechol group to anchor at the surface of the synthesized Fe3O4 NPs. Fe3O4 NPs surface-coated with targeted NIR rotaxanes help to deliver ultrasmall magnetic NPs specifically inside the mitochondria. Two carbohydrate moieties are conjugated with the macrocycle of the rotaxane via click chemistry to improve the water solubility of MitoSQRot-(Carb-OH)2-DOPA-Fe3O4 NPs. Water-soluble, rotaxane-capped Fe3O4 NPs are used for live-cell mitochondria-targeted NIR fluorescence confocal imaging, 3D and multicolor imaging in combination with T2-weighted MRI on a 9.4 T MR scanner with a high relaxation rate (r2) of 180.7 mM-1 s-1. Biocompatible, noncytotoxic, ultrabright NIR rotaxane-capped superparamagnetic ultrasmall monodisperse Fe3O4 NPs could be a promising agent for targeted multimodal imaging applications.

Renal Clearable Magnetic Nanoreporter for Colorimetric Urinalysis of Tumor.

The convenience and availability are of great significance for the early screening of cancer. Herein, a magnetic nanoreporter with renal clearable capability and activatable catalytic activity was developed for colorimetric urinalysis of tumors. The magnetic nanoreporters were prepared by loading 3.2 nm Fe3O4 nanoparticles (NPs) and glucose oxidase (GOD) into macrophage cell-derived microvesicles (MVs) through electroporation, and these compositions serve as renal clearable catalytic reporters, synergistic catalysts, and targeted delivery carriers, respectively. The magnetic nanoreporters can convert the H2O2 in the mildly acidic tumor microenvironment into hydroxyl radicals through the synergistic catalysis of Fe3O4 NPs and GOD. Then the MVs can be disintegrated by the radicals, and ultrasmall Fe3O4 NPs will be released from the MVs at the tumor site, enabling rapid clearance of the Fe3O4 NPs into urine and a direct colorimetric urinalysis of the tumor within 4 h. The magnetic nanoreporters had good biocompatibility, and the released Fe3O4 NPs were rapidly excreted from the body, avoiding the potential toxicity. We envision that the magnetic nanoreporters can be used for convenient and rapid cancer screening.

On the rising extra storage capacity of ultra-small Fe[formula omitted]O[formula omitted] particles functionalized with HCS and their potential as high-performance anode material for electrochemical energy storage

We report a nanocomposite material exhibiting ultra-small Fe3O4 nanoparticles uniformly decorated on hollow carbon spheres (Fe3O4@HCS). The unique hierarchically-structured material displays excellent electrochemical cycling performance that exceeds the theoretical bulk capacity of Fe3O4 when used as an anode in lithium-ion batteries. In particular, it features increasing reversible capacity upon cycling yielding 1050 mAh g−1at 0.1 A g−1 in cycle 250. Comprehensive scanning and transmission electron microscopy images combined with detailed electrochemical analysis demonstrate that the outstanding electrochemical performance can be traced back to the formation and decomposition of a capacitative surface layer during dis/charging.

Ultrasmall superparamagnetic iron oxide nanoparticles for enhanced tumor penetration.

The intrinsic pathological characteristics of tumor microenvironments restrict the deep penetration of nanomedicines by passive diffusion. Magnetophoresis is a promising strategy to improve the tumor penetration of nanomedicines aided by the external magnetic propulsive force. However, the research thus far has been focused on large nanoparticles, while ultrasmall superparamagnetic iron oxide (Fe3O4) nanoparticles (<∼20 nm) exhibit better performance in many applications such as cancer diagnosis and treatment. Herein, we aim to determine and understand the penetration of ultrasmall Fe3O4 nanoparticles with various sizes, shapes, surface charges and magnetizations in a 3D tumor spheroid model. The behaviour of the nanoparticles of three sizes (10, 15 and 21 nm), two shapes (spherical and octahedral), and opposite surface charges (negative and positive) was investigated. The results demonstrate that magnetically directed penetration works effectively on ultrasmall Fe3O4 nanoparticles. In the absence of a magnetic field, the shape and the surface charge of the ultrasmall magnetic nanoparticles have a more pronounced effect on their penetration compared to their dimensions. While in the presence of a magnetic field, the advantage of larger magnetic nanoparticles was obvious because they experience higher magnetic driving force due to their higher magnetic moments. Overall, relatively large (21 nm), spherical, and positively charged ultrasmall Fe3O4 nanoparticles showed greater penetration in tumors under a magnetic field. Furthermore, our findings suggest that the penetration efficiency of Fe3O4 nanoparticles is closely related to their cellular internalization ability. Therefore, optimization of the cellular uptake and of the magnetization of magnetic nanoparticles should be considered simultaneously for maximizing their penetration in tumor tissue through magnetophoresis.

Ultrasmall Fe3O4 and Gd2O3 hybrid nanoparticles for T1-weighted MR imaging of cancer

AbstractGadolinium-based contrast agents (GdCAs) have been the most frequently used T1-weighted magnetic resonance imaging (MRI) contrast agents for decades. However, they have serious disadvantages such as low longitudinal relaxivity value (r1) and high dose associated-nephrotoxicity that restrict their wide applications. These emphasize the need for an ideal stable and biocompatible T1-weighted CA with high contrast enhancement performance. Here, we propose a wet-chemical synthesis technique to form a nanocomposite consisting of ultrasmall iron oxide nanoparticles (US-IO) and Gd2O3 hybrid nanoparticles stabilized with dextran (FG-HNPs) for T1-weighted MR imaging. Relaxometry study showed that FG-HNPs have a high r1 value (42.28 mM−1S−1) and low relaxivity ratio (r2/r1: 1.416) at 3.0T. In vivo MRI contrast enhancement factor (ΔSNR) for FG-HNPs (257.025 ± 17.4%) was found to be 1.99-fold higher than US-IO (129.102 ± 15%) and 3.35-fold higher than Dotarem (76.71 ± 14.2%) as routinely used T1-weighted CA. The cytotoxicity assay and histological examination confirmed the biocompatibility of FG-HNPs. The biodistribution study, transmission electron microscopy (TEM) and Prussian blue (PB) staining of tumor tissue proved the effective tumor localization of FG-HNPs. Therefore, FG-HNPs can be suggested as a promising CA for T1-weighted MRI of tumors by virtue of their remarkable relaxivities and high biocompatibility.

Dual-targeting nanozyme for tumor activatable photo-chemodynamic theranostics

Tumor phototheranostics holds a great promise on account of its high spatiotemporal resolution, tumor-specificity, and noninvasiveness. However, physical limitation of light penetration and “always on” properties of conventional photothermal-conversion agents usually cause difficulty in accurate diagnosis and completely elimination of tumor. Meanwhile, nanozymes mediated Fenton reactions can well utilize the tumor microenvironment (TME) to generate hydroxyl radicals for chemodynamic therapy (CDT), but limited by the concentration of H2O2 in TME and the delivery efficiency of nanozymes. To overcome these problems, a dual-targeting nanozyme (FTRNPs) is developed for tumor-specific in situ theranostics, based upon the assembling of ultrasmall Fe3O4 nanoparticles, 3,3’,5,5’-tetrameth-ylbenzidine (TMB) and the RGD peptide. The FTRNPs after H2O2 treatment exhibits superior photothermal stability and high photothermal conversion efficiency (η = 50.9%). FTRNPs shows extraordinary accumulation and retention in the tumor site by biological/physical dual-targeting, which is 3.54-fold higher than that without active targeting. Cascade-dual-response to TME for nanozymes mediated Fenton reactions and TMB oxidation further improves the accuracy of both photoacoustic imaging and photothermal therapy (PTT). The tumor inhibition rate of photo-chemodynamic therapy is ~ 97.76%, which is ~ 4-fold higher than that of PTT or CDT only. Thus, the combination of CDT and PTT to construct “turn on” nanoplatform is of great significance to overcome their respective limitations. Considering its optimized “all-in-one” performance, this new nanoplatform is expected to provide an advanced theranostic strategy for the future treatment of cancers.Graphical abstract

Ultra-small Fe2O3 nanoparticles anchored on ultrasonically exfoliated multilayer graphene for LIB anode application

Graphene oxide (GO) and reduced graphene oxide (rGO) have been widely researched as substrates to anchor Fe2O3 nanoparticles. However, both of them suffer from complicated synthesis processes. Multilayer graphene (MLG), simply obtained by ultrasonic exfoliation with graphite, can reduce the cost of actual application due to the facile synthesis. However, it is still a great challenge to anchor Fe2O3 nanoparticles on MLG because of the absence of chemical active sites on its surface. Herein, a chemical deposition method is used to coat highly dispersed ultra-small Fe2O3 nanoparticles on MLG surface. As a comparison, both GO and rGO are also used as substrates to anchor Fe2O3 by the same method. Results show that the oxygen-containing functional groups on substrates have significant effect on the crystal phase and distribution of Fe2O3. A mechanism is thus suggested for the growth of Fe2O3 on MLG, GO and rGO. Among them, the composite of Fe2O3/MLG shows the highest electrochemical performances for lithium ion battery (LIB) anodes. Specific capacity of 1050 mAh g−1 at 0.1C after 100 cycles are obtained based on the total weight of composite. Low cost, facile synthesis and high electrochemical performances enable Fe2O3/MLG to be a prospect anode material for LIBs.

Multiple valence states of Fe boosting SERS activity of Fe3O4 nanoparticles and enabling effective SERS-MRI bimodal cancer imaging

Developing novel nanoparticle-based bioprobes utilized in clinical settings with imaging resolutions ranging from cell to tissue levels is a major challenge for tumor diagnosis and treatment. Herein, an optimized strategy for designing a Fe3O4-based bioprobe for dual-modal cancer imaging based on surface-enhanced Raman scattering (SERS) and magnetic resonance imaging (MRI) is introduced. Excellent SERS activity of ultrasmall Fe3O4 nanoparticles (NPs) was discovered, and a 5 × 10−9 M limit of detection for crystal violet molecules was successfully obtained. The high-efficiency interfacial photon-induced charge transfer in Fe3O4 NPs was promoted by multiple electronic energy levels ascribed to the multiple valence states of Fe, which was observed using ultraviolet–visible diffuse reflectance spectroscopy. Density functional theory calculations were utilized to reveal that the narrow band gap and high electron density of states of ultrasmall Fe3O4 NPs significantly boosted the vibronic coupling resonances in the SERS system upon illumination. The subtypes of cancer cells were accurately recognized via high-resolution SERS imaging in vitro using the prepared Fe3O4-based bioprobe with high sensitivity and good specificity. Notably, Fe3O4-based bioprobes simultaneously exhibited T1-weighted MRI contrast enhancement with an active targeting capability for tumors in vivo. To the best of our knowledge, this is the first report on the use of pure semiconductor-based SERS-MRI dual-modal nanoprobes in tumor imaging in vivo and in vitro, which has been previously realized only using semiconductor–metal complex materials. The non-metallic materials with SERS–MRI dual-modal imaging established in this report are a promising cancer diagnostic platform, which not only showed excellent performance in early tumor diagnosis but also possesses great potential for image-guided tumor treatment.

One-Step Route to Fe2O3 and FeSe2 Nanoparticles Loaded on Carbon-Sheet for Lithium Storage.

Iron-based anode materials, such as Fe2O3 and FeSe2 have attracted widespread attention for lithium-ion batteries due to their high capacities. However, the capacity decays seriously because of poor conductivity and severe volume expansion. Designing nanostructures combined with carbon are effective means to improve cycling stability. In this work, ultra-small Fe2O3 nanoparticles loaded on a carbon framework were synthesized through a one-step thermal decomposition of the commercial C15H21FeO6 [Iron (III) acetylacetonate], which could be served as the source of Fe, O, and C. As an anode material, the Fe2O3@C anode delivers a specific capacity of 747.8 mAh g−1 after 200 cycles at 200 mA g−1 and 577.8 mAh g−1 after 365 cycles at 500 mA g−1. When selenium powder was introduced into the reaction system, the FeSe2 nano-rods encapsulated in the carbon shell were obtained, which also displayed a relatively good performance in lithium storage capacity (852 mAh g−1 after 150 cycles under the current density of 100 mA·g−1). This study may provide an alternative way to prepare other carbon-composited metal compounds, such as FeNx@C, FePx@C, and FeSx@C, and found their applications in the field of electrochemistry.

Ultrasmall enzyme/light-powered nanomotor facilitates cholesterol detection

Enzymes that can convert chemical energy into mechanical force through biocatalysis have been used as engines for artificial micro/nanomotors. However, most nanomotors are powered by only one engine and have a microscale size range, which greatly limits their application scenarios. Herein, an ultrasmall enzyme/light-powered nanomotor (71.1 ± 8.2 nm) is prepared by directly coupling ultrasmall histidine-modified Fe3O4 nanoparticles (UHFe3O4 NPs, 2.71 ± 0.54 nm) with cholesterol oxidase (ChOx) for cholesterol detection. The chemical engine, ChOx, catalyzes the oxidation of cholesterol to actuate UHFe3O4@ChOx and produce H2O2. Meanwhile, UHFe3O4 NPs that possess peroxidase-mimicking property and photothermal effect act as a nanozyme to catalyze the subsequent chromogenic reaction between H2O2 and 3,3′,5,5′-tetramethylbenzidine for cholesterol detection and simultaneously serve as a photothermal engine power by near-infrared (NIR) irradiation. The nanomotor behavior of UHFe3O4@ChOx results in an enhancement (55%) of ChOx catalytic efficiency. Moreover, due to the outstanding peroxidase-mimicking activity and cascade reaction, UHFe3O4@ChOx works as a cholesterol sensor with improved sensitivity and shortened analysis time; as low as 0.178 μM of cholesterol is detected with a linear response range of 2 to 100 μM. Taken together, the new conceptual synthetic strategy of enzymatic hybrid nanomotor is proven promising for sensing and biocatalytic applications.

Ultrasmall iron oxide nanoparticles cause significant toxicity by specifically inducing acute oxidative stress to multiple organs

BackgroundIron oxide nanoparticles have been approved by food and drug administration for clinical application as magnetic resonance imaging (MRI) and are considered to be a biocompatible material. Large iron oxide nanoparticles are usually used as transversal (T2) contrast agents to exhibit dark contrast in MRI. In contrast, ultrasmall iron oxide nanoparticles (USPIONs) (several nanometers) showed remarkable advantage in longitudinal (T1)-weighted MRI due to the brighten effect. The study of the toxicity mainly focuses on particles with size of tens to hundreds of nanometers, while little is known about the toxicity of USPIONs.ResultsWe fabricated Fe3O4 nanoparticles with diameters of 2.3, 4.2, and 9.3 nm and evaluated their toxicity in mice by intravenous injection. The results indicate that ultrasmall iron oxide nanoparticles with small size (2.3 and 4.2 nm) were highly toxic and were lethal at a dosage of 100 mg/kg. In contrast, no obvious toxicity was observed for iron oxide nanoparticles with size of 9.3 nm. The toxicity of small nanoparticles (2.3 and 4.2 nm) could be reduced when the total dose was split into 4 doses with each interval for 5 min. To study the toxicology, we synthesized different-sized SiO2 and gold nanoparticles. No significant toxicity was observed for ultrasmall SiO2 and gold nanoparticles in the mice. Hence, the toxicity of the ultrasmall Fe3O4 nanoparticles should be attributed to both the iron element and size. In the in vitro experiments, all the ultrasmall nanoparticles (< 5 nm) of Fe3O4, SiO2, and gold induced the generation of the reactive oxygen species (ROS) efficiently, while no obvious ROS was observed in larger nanoparticles groups. However, the ·OH was only detected in Fe3O4 group instead of SiO2 and gold groups. After intravenous injection, significantly elevated ·OH level was observed in heart, serum, and multiple organs. Among these organs, heart showed highest ·OH level due to the high distribution of ultrasmall Fe3O4 nanoparticles, leading to the acute cardiac failure and death.ConclusionUltrasmall Fe3O4 nanoparticles (2.3 and 4.2 nm) showed high toxicity in vivo due to the distinctive capability in inducing the generation of ·OH in multiple organs, especially in heart. The toxicity was related to both the iron element and size. These findings provide novel insight into the toxicology of ultrasmall Fe3O4 nanoparticles, and also highlight the need of comprehensive evaluation for their clinic application.Graphical

Peroxidase-like Active Nanomedicine with Dual Glutathione Depletion Property to Restore Oxaliplatin Chemosensitivity and Promote Programmed Cell Death.

The nanocatalytic activity of nanozymes provides a vision for tumor treatment. However, the glutathione (GSH)-related antioxidant defense system (ADS) formed on the basis of excessive GSH in the tumor microenvironment limits its catalytic activity. Here, dendritic mesoporous silica nanoparticles (DMSNs) were employed as nanocarrier; ultrasmall Fe3O4 nanoparticles, Mn2+ ions, and glutaminase inhibitor Telaglenastat (CB-839) were subsequently integrated into large mesopores of DMSNs, forming DMSN/Fe3O4-Mn@CB-839 (DFMC) nanomedicine. This nanomedicine exhibits peroxidase mimicking activities under acidic conditions, which catalyzes the decomposition of hydrogen peroxide (H2O2) into hydroxyl radical (•OH). This also promotes the formation of lipid peroxides, which is required for ferroptosis. Furthermore, this nanomedicine can effectively deplete the existing GSH, thereby enhancing reactive oxygen species (ROS)-mediated tumor catalytic therapy. Moreover, the introduced CB-839 blocks the endogenous synthesis of GSH, further enhancing GSH depletion performance, which reduces the excretion of oxaliplatin (GSH-related resistance) from tumor cells, thereby restoring the chemical sensitivity of oxaliplatin. The dual GSH depletion property significantly weakens the GSH-related ADS and restores the chemical sensitivity of oxaliplatin, leading to the high DFMC-induced apoptosis and ferroptosis of tumor cells. Our developed nanomedicine based on integrated nanotechnology and clinical drug may aid the development of tumor treatment.

In-situ dispersing ultrafine Fe2O3 nanoparticles in mesoporous silicas for efficient peroxymonosulfate-activated degradation of tetracycline over a broad pH range

The supported ultra-small Fe2O3 nanoparticles, as conventional functional materials for versatile applications, are scarcely investigated for their catalytic properties in peroxymonosulfate-activated reactions to deal with the ever-growing environment issues. In this work, highly dispersed ultrafine Fe2O3 nanoparticles are successfully generated in framework of mesoporous silicas (such as Fe/Si-3, with 3.01 wt% of Fe content) through an in-situ approach with iron phthalocyanine as Fe source. The formation of Fe-N or Fe-C bonds exerted remarkable isolation effect on the generation of the nanoparticles. Fe/Si-3 gave superior activity to other Fe catalysts analogs including bulk Fe2O3 in peroxymonosulfate-triggered degradation of tetracycline. Fe/Si-3 has a wide working pH window of 3–11. It can be recycled for 3 times without significant loss of the degradation activity. The radicals of SO4⋅−, ⋅OH, O2⋅− and 1O2 all contributed to the degradation reaction. The factors for high degradation efficiency and broad working pH range of Fe/Si-3, the mechanism for formation of various radicals, as well as the transformation pathway of tetracycline molecules were proposed.

A “cluster bomb” oral drug delivery system to sequentially overcome the multiple absorption barriers

Oral drugs have been widely used in clinical therapy, but their developments were severely limited by the side effects of drug exposure as well as the multiple biological barriers. In this study, we constructed a “cluster bomb” oral drug delivery system (DOX@PFeL@L100) with core-shell structure to overcome the complex absorption barriers. The inner core termed as “bomb” that contains a lot of ultra-small diameter Fe3O4 nanoparticles (DOX@PFeL NPs) loaded with doxorubicin (DOX) and modified with l-valine, which can efficiently penetrate the epithelial cells via PePT1 receptor mediated endocytosis. The outer shell of this “cluster bomb” is a layer of pH-sensitive polymer (Eudragit®L100) that can be served as a pH-responsive switch and effectively control the “bomb” release in the intestinal microenvironment to improve the antitumor efficiency by the Fenton like reaction of DOX and Fe2+/Fe3+. This study demonstrates that the “cluster comb” oral drug delivery system can sequentially overcome the multiple biological barriers, providing a safe and effective approach for tumor therapy.

Directional design and synthesis of high-yield hollow Fe-MFI zeolite encapsulating ultra-small Fe2O3 nanoparticles by using mother liquid

Directional design and synthesis of high-yield hollow Fe-MFI zeolite encapsulating ultra-small Fe2O3 nanoparticles by using mother liquid

Surface charge transition nano-theranostics based on ultra-small Fe3O4 nanoparticles for enhanced photodynamic and photothermal therapy against nasopharyngeal carcinoma

Platinum-based concurrent chemo-radiotherapy is the most common strategy for the treatment of Nasopharyngeal carcinoma. However, low efficacy and side effects are the two major problems associated with this approach. Therefore, it is urgent need to explore novel therapeutic modalities to meet clinically standards. Photothermal therapy (PTT) and photodynamic therapy (PDT) are non-invasive and light trigger modalities received great attention to overcome the limitations and significantly improved cancer therapy. Here, we developed acidity surface charge transformable nanocluster (NCs) composed of Indocyanine green (ICG), Fe3O4, and Palmitoyl ascorbic acid (PA) with pH-responsive PEG-b-PAEMA-PDMA for enhanced synergistic PDT/PTT. NCs has the neutral hydrophilic surface helps to prolong blood circulation and instantly transformed to positively charged surface at tumoral acidic pH (6.5), which promoted the cellular uptake. Under laser irradiation (808 nm, 1 W/cm2), NCs produced PTT effect, concurrently it converts singlet oxygen (1O2) into H2O2, which can be further involved in Fenton reaction and produce toxic hydroxyl radical (•OH) enhances therapy efficacy. In vitro experiments on HNE-1 cancer cells showed improved intracellular uptake of NCs at low pH and simultaneously induced higher cytotoxicity medicated by synergetic PDT/PTT effect. In vivo therapeutic study revealed that NCs treatment under laser irradiation showed superior inhibition of tumor growth in HNE-1 tumor bearing mice model. Taken together, the present findings suggest that NCs could be used as “all in one” nano theranostic agent for enhanced PDT/PTT of cancer therapy.

In-situ plantation of Fe3O4@C nanoparticles on reduced graphene oxide nanosheet as high-performance anode for lithium/sodium-ion batteries

Fe3O4 is considered to be an ideal substitute for graphite anode due to its high lithium (Li) and sodium (Na) storage capacity, however, its sharp volume change after lithiation/sodiumization and poor electrical conductivity have brought huge challenges to the practical application. In this study, a lamellar Fe3O4-based electrode was constructed via an in-situ plantation of carbon-coated Fe3O4 nanoparticles on the surface of the reduced graphene oxide nanosheet. Owing to the ultra-small carbon-coated Fe3O4 nanoparticles (~12.5 nm) and unique two-dimensional lamellar structure, the obtained sample displays excellent cycle and rate performance in lithium/sodium-ion batteries. A high reversible capacity of 849 mA h g−1 is obtained at 500 mA g−1 after 120 cycles for lithium-ion batteries and a discharge capacity up to 429 mA h g−1 is remained at 100 mA g−1 after 300 cycles for sodium-ion batteries.

Facile synthesis of monodisperse ultrasmall Fe3O4 nanoparticles on graphene nanosheets with excellent microwave absorption performance

Facile synthesis of monodisperse ultrasmall Fe3O4 nanoparticles on graphene nanosheets with excellent microwave absorption performance