Generation of Integration‐Free Induced Neurons Using Graphene Oxide‐Polyethylenimine

Direct conversion of somatic cells into induced neurons (iNs) without inducing pluripotency has great therapeutic potential for treating central nervous system diseases. Reprogramming of somatic cells to iNs requires the introduction of several factors that drive cell‐fate conversion, and viruses are commonly used to deliver these factors into somatic cells. However, novel gene‐delivery systems that do not integrate transgenes into the genome are required to generate iNs for safe human clinical applications. In this study, it is investigated whether graphene oxide‐polyethylenimine (GO‐PEI) complexes are an efficient and safe system for messenger RNA delivery for direct reprogramming of iNs. The GO‐PEI complexes show low cytotoxicity, high delivery efficiency, and directly converted fibroblasts into iNs without integrating factors into the genome. Moreover, in vivo transduction of reprogramming factors into the brain with GO‐PEI complexes facilitates the production of iNs that alleviated Parkinson's disease symptoms in a mouse model. Thus, the GO‐PEI delivery system may be used to safely obtain iNs and could be used to develop direct cell reprogramming‐based therapies for neurodegenerative diseases.     

A Biomimetic Polymer Magnetic Nanocarrier Polarizing Tumor‐Associated Macrophages for Potentiating Immunotherapy

The progress of antitumor immunotherapy is usually limited by tumor‐associated macrophages (TAMs) that account for the highest proportion of immunosuppressive cells in the tumor microenvironment, and the TAMs can also be reversed by modulating the M2‐like phenotype. Herein, a biomimetic polymer magnetic nanocarrier is developed with selectively targeting and polarizing TAMs for potentiating immunotherapy of breast cancer. This nanocarrier PLGA‐ION‐R837 @ M (PIR @ M) is achieved, first, by the fabrication of magnetic polymer nanoparticles (NPs) encapsulating Fe₃O₄ NPs and Toll‐like receptor 7 (TLR7) agonist imiquimod (R837) and, second, by the coating of the lipopolysaccharide (LPS)‐ treated macrophage membranes on the surface of the NPs for targeting TAMs. The intracellular uptake of the PIR @ M can greatly polarize TAMs from M2 to antitumor M1 phenotype with the synergy of Fe₃O₄ NPs and R837. The relevant mechanism of the polarization is deeply studied through analyzing the mRNA expression of the signaling pathways. Different from previous reports, the polarization is ascribed to the fact that Fe₃O₄ NPs mainly activate the IRF5 signaling pathway via iron ions instead of the reactive oxygen species‐induced NF‐κB signaling pathway. The anticancer effect can be effectively enhanced through potentiating immunotherapy by the polarization of the TAMs in the combination of Fe₃O₄ NPs and R837.     

The effect of polyethylenimine on the microwave absorbing properties of a hybrid microwave absorber of Fe3O4/MWNTs

The hybrid microwave absorber of Fe₃O₄/multi-walled carbon nanotubes (MWNTs)modified with polyethylenimine (PEI) polymers was fabricated by chemical co-precipitation. The structure and morphology of hybrids are characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron-microscopy (TEM). The effect of PEI on the distribution of Fe₃O₄ nanoparticles and the microwave absorbing properties of hybrid microwave absorber of Fe₃O₄/MWNTs were investigated. The TEM results show that Fe₃O₄ nanoparticles are attached homogeneously on MWNTs, which indicates that the adding of PEI is effective to control the distribution of Fe₃O₄ nanoparticles on the surface of MWNTs. The microwave absorbing properties results show that the maximum reflection loss (RL) of PEI modified Fe₃O₄/MWNTs hybrids is improved significantly, which is ?30.69 dB at 7.24 GHz and ?10 dB bandwidth is 1.84 GHz. However, the RL of the Fe₃O₄/MWNTs without PEI is ?21.96 dB at 7.02 GHz and ?10 dB bandwidth is 1.2 GHz.     

Using Graphene Oxide to Enhance the Barrier Properties of Poly(lactic acid) Film

The ultra‐thin (polyethyleneimine/graphene oxide)_n [(PEI/GO)_n]multilayer films on poly(lactic acid) (PLA) were constructed via the layer‐by‐layer assembly. Here, the electrostatic interactions between PEI and GO were used to obtain the nanoscale composite membrane of (PEI/GO)_n on the surface of PLA film. With the number of assembling layers increased, the oxygen permeability (PO₂) of PLA film decreased substantially. As a 0.06 wt% GO solution was used with only four layers, the PO₂ decreased from 53.8 to 0.377 × 10^?4 cm³/m²/d/Pa, only 0.7% of the original PLA film. At the same time, the coated PLA film also presented a good transparency and better mechanical properties. It is a novel way to use GO on biodegradable packaging materials. Copyright © 2014 John Wiley & Sons, Ltd.     

Electrostatic Self‐Assembly of Au Nanoparticles onto Thermosensitive Magnetic Core‐Shell Microgels for Thermally Tunable and Magnetically Recyclable Catalysis

A facile route to fabricate a nanocomposite of Fe₃O₄@poly[N‐isopropylacrylamide (NIPAM)‐co‐2‐(dimethylamino)ethyl methacrylate (DMAEMA)]@Au (Fe₃O₄@PND@Au) is developed for magnetically recyclable and thermally tunable catalysis. The negatively charged Au nanoparticles with an average diameter of 10 nm are homogeneously loaded onto positively charged thermoresponsive magnetic core‐shell microgels of Fe₃O₄@poly(NIPAM‐co‐DMAEMA) (Fe₃O₄@PND) through electrostatic self‐assembly. This type of attachment offers perspectives for using charged polymeric shell on a broad variety of nanoparticles to immobilize the opposite‐charged nanoparticles. The thermosensitive PND shell with swollen or collapsed properties can be as a retractable Au carrier, thereby tuning the aggregation or dispersion of Au nanoparticles, which leads to an increase or decrease of catalytic activity. Therefore, the catalytic activity of Fe₃O₄@PND@Au can be modulated by the volume transition of thermosensitive microgel shells. Importantly, the mode of tuning the aggregation or dispersion of Au nanoparticles using a thermosensitive carrier offers a novel strategy to adjust and control the catalytic activity, which is completely different with the traditional regulation mode of controlling the diffusion of reactants toward the catalytic Au core using the thermosensitive poly(N‐isopropylacrylamide) network as a nanogate. Concurrent with the thermally tunable catalysis, the magnetic susceptibility of magnetic cores enables the Fe₃O₄@PND@Au nanocomposites to be capable of serving as smart nanoreactors for thermally tunable and magnetically recyclable catalysis.     

Platelet Membrane‐Camouflaged Magnetic Nanoparticles for Ferroptosis‐Enhanced Cancer Immunotherapy

Although cancer immunotherapy has emerged as a tremendously promising cancer therapy method, it remains effective only for several cancers. Photoimmunotherapy (e.g., photodynamic/photothermal therapy) could synergistically enhance the immune response of immunotherapy. However, excessively generated immunogenicity will cause serious inflammatory response syndrome. Herein, biomimetic magnetic nanoparticles, Fe₃O₄‐SAS @ PLT, are reported as a novel approach to sensitize effective ferroptosis and generate mild immunogenicity, enhancing the response rate of non‐inflamed tumors for cancer immunotherapy. Fe₃O₄‐SAS@PLT are built from sulfasalazine (SAS)‐loaded mesoporous magnetic nanoparticles (Fe₃O₄) and platelet (PLT) membrane camouflage and triggered a ferroptotic cell death via inhibiting the glutamate‐cystine antiporter system X_c^? pathway. Fe₃O₄‐SAS @ PLT‐mediated ferroptosis significantly improves the efficacy of programmed cell death 1 immune checkpoint blockade therapy and achieves a continuous tumor elimination in a mouse model of 4T1 metastatic tumors. Proteomics studies reveal that Fe₃O₄‐SAS @ PLT‐mediated ferroptosis could not only induce tumor‐specific immune response but also efficiently repolarize macrophages from immunosuppressive M2 phenotype to antitumor M1 phenotype. Therefore, the concomitant of Fe₃O₄‐SAS @ PLT‐mediated ferroptosis with immunotherapy are expected to provide great potential in the clinical treatment of tumor metastasis.     

Enhanced In Vitro Biocompatibility and Water Dispersibility of Magnetite and Cobalt Ferrite Nanoparticles Employed as ROS Formation Enhancer in Radiation Cancer Therapy

Efficient magnetic reactive oxygen species (ROS) formation enhancing agents after X‐ray treatment are realized by functionalizing superparamagnetic magnetite (Fe₃O₄) and Co‐ferrite (CoFe₂O₄) nanoparticles with self‐assembled monolayers (SAMs). The Fe₃O₄ and CoFe₂O₄ nanoparticles are synthesized using Massart's coprecipitation technique. Successful surface modification with the SAM forming compounds 1‐methyl‐3‐(dodecylphosphonic acid) imidazolium bromide, or (2‐{2‐[2‐hydroxy‐ethoxy]‐ethoxy}‐ethyl phosphonic acid provides biocompatibility and long‐term stability of the Fe₃O₄ and CoFe₂O₄ nanoparticles in cell media. The SAM‐stabilized ferrite nanoparticles are characterized with dynamic light scattering, X‐ray powder diffraction, a superconducting quantum interference device, Fourier transform infrared attenuated total reflectance spectroscopy, zeta potential measurements, and thermogravimetric analysis. The impact of the SAM‐stabilized nanoparticles on the viability of the MCF‐7 cells and healthy human umbilical vein endothelial cells (HUVECs) is assessed using the neutral red assay. Under X‐ray exposure with a single dosage of 1 Gy the intracellular SAM stabilized Fe₃O₄ and CoFe₂O₄ nanoparticles are observed to increase the level of ROS in MCF‐7 breast cancer cells but not in healthy HUVECs. The drastic ROS enhancement is associated with very low dose modifying factors for a survival fraction of 50%. This significant ROS enhancement effect by SAM‐stabilized Fe₃O₄ and CoFe₂O₄ nanoparticles constitutes their excellent applicability in radiation therapy.     

Smart Carbon Nanotubes with Laser‐Controlled Behavior in Gene Delivery and Therapy through a Non‐Digestive Trafficking Pathway

Near‐infrared (NIR) laser‐controlled gene delivery presents some benefits in gene therapy, inducing enhanced gene transfection efficiency. In this study, a “photothermal transfection” agent is obtained by wrapping poly(ethylenimine)‐cholesterol derivatives (PEI‐Chol) around single‐walled carbon nanotubes (SWNTs). The PEI‐Chol modified SWNTs (PCS) are effective in compressing DNA molecules and protecting them from DNaseI degradation. Compared to the complexes formed by PEI with DNA (PEI/DNA), complexes of PCS and DNA that are formed (PCS/DNA) exhibit a little lower toxicity to HEK293 and HeLa cells under the same PEI molecule weight and weight ratios. Notably, caveolae‐mediated cellular uptake of PCS/DNA occurs, which results in a safer intracellular transport of the gene due to the decreased lysosomal degradation in comparison with that of PEI/DNA whose internalization mainly depends on clathrin rather than caveolae. Furthermore, unlike PEI/DNA, PCS/DNA exhibits a photothermal conversion ability, which promotes DNA release from PCS under NIR laser irradiation. The NIR laser‐mediated photothermal transfection of PCS_10K/plasmid TP53 (pTP53) results in more apoptosis and necrosis of HeLa cells in vitro than other groups, and achieves a higher tumor‐growth inhibition in vivo than naked pTP53, PEI_25K/pTP53, and PCS_10K/pTP53 alone. The enhanced transfection efficiency of PCS/DNA can be attributed to more efficient DNA internalization into the tumor cells, promotes detachment of DNA from PCS under the mediation of NIR laser and higher DNA stability in the cells due to caveolae‐mediated cellular uptake of the complexes.     

Sandwiched Electrochemiluminescent Peptide Biosensor for the Detection of Prognostic Indicator in Early‐Stage Cancer Based on Hollow,Magnetic, and Self‐Enhanced Nanosheets

Currently, peptide‐based protein‐recognition has been recognized as an effective and promising approach for protein assays. However, sandwiched peptide‐based biosensor with high sensitivity and low background has not been proposed before. Herein, a sandwiched electrochemiluminescence (ECL) peptide‐based biosensor is constructed for Cyclin A₂ (CA2), a prognostic indicator in early stage of multiple cancers, based on nanosheets with hollow, magnetic, and ECL self‐enhanced properties. First, hollow and magnetic manganese oxide nanocrystals (H‐Mn₃O₄) are synthesized using triblock copolymeric micelles with core–shell–corona architecture as templates. Then, polyethyleneimine (PEI) and the composite of platinum nanoparticles and tris (4,4′‐dicarboxylicacid‐2,2′‐bipyridyl) ruthenium (II) (PtNPs–Ru) are immobilized on H‐Mn₃O₄ to form H‐Mn₃O₄–PEI–PtNPs–Ru nanocomposite, in which PEI as coreactant can effectively enhance the luminous efficiency and PtNPs as nanochannels can greatly accelerate the electron transfer. Finally, due to the coordination between Eu³⁺ and carboxyl, the obtained H‐Mn₃O₄–PEI–PtNPs–Ru aggregates locally to form sheet‐like nanostructures ((H‐Mn₃O₄–PEI–PtNPs–Ru)_n–Eu³⁺), by which the luminous efficiency is further increased. Based on the nanosheets and two designed peptides, a sandwiched ECL biosensor, using palladium nanocages synthesized through galvanic replacement reaction as substrate, is proposed for CA2 with a linear range from 0.001 to 100 ng mL^?1 and a detection limit of 0.3 pg mL^?1.     

Magnetic Fe3O4-chitosan micro- and nanoparticles for wastewater treatment

In this study, first, magnetic nanoparticles (MNP) were synthesized using a coprecipitation method and the synthesized particles were characterized using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic light scattering (DLS), and vibrating sample magnetometry (VSM). According to DLS and VSM analyses results, it was seen that the size of the MNP was smaller than 10?nm and they exhibited superparamagnetic properties, respectively. Then, magnetic Fe₃O₄-chitosan micro/nanoparticles were synthesized using a suspension cross-linking method in the presence of the MNP. Fe₃O₄-chitosan microparticles (Fe₃O₄-CMs) and Fe₃O₄-chitosan nanoparticles (Fe₃O₄-CNs), which have different structural, morphological, and magnetic properties, were obtained. All of the particles were characterized using transmission electron microscopy (TEM), FTIR, TGA, DLS, and VSM. In the second part of the study, the dye adsorption properties of the two different adsorbents from aqueous solution were investigated. For these purposes, Bromothymol Blue (BB) was used as a dye and the parameters affecting adsorption of BB (contact time, initial dye concentration, temperature and pH) were investigated. When the optimum adsorption conditions were provided for each adsorbent, the adsorption capacities of Fe₃O₄-CNs and Fe₃O₄-CMs were 82.2 and 193.3?mg/g, respectively.     

The formation of magnetite nanoparticles on the sidewalls of multi-walled carbon nanotubes

Linear polyethyleneimine (PEI) was used as a non-covalent functionalizing agent to modify multi-walled carbon nanotubes (MWCNTs). Fe₃O₄ nanoparticles were then formed along the sidewalls of the as-modified MWCNTs through a simple solvothermal method. X-ray diffraction, Fourier transform infrared spectrometry, transmission electron microscopy, and vibrating sample magnetometry were used to characterize the MWCNT/Fe₃O₄ nanocomposites. Results indicated that Fe₃O₄ nanoparticles with diameters ranging from 50 to 200 nm were attached to the surface of the MWCNTs by electrostatic interaction. PEI was found to improve the electrical conductivity of the MWCNT/Fe₃O₄ nanocomposites. The magnetic saturation value of these magnetic nanocomposites was 61.8 emu g⁻¹. These magnetic MWCNT/Fe₃O₄ nanocomposites are expected to have wide applications in bionanoscience and technology.     

Physicochemical properties and operational stability of Taguchi design-optimized Candida rugosa lipase supported on biogenic silica/magnetite/graphene oxide for ethyl valerate synthesis

Biobased ternary nanocomposites can stabilize enzymes for greater stability, catalytic activity and easy recovery. This study aimed to optimize biogenic silica/magnetite/graphene oxide nanocomposite supported Candida rugosa lipase (CRL/SiO₂/Fe₃O₄/GO) for ethyl valerate (EV) synthesis and characterize the biocatalysts’ physicochemical properties and operational stability. CRL conjugated-oil palm leaves-derived biogenic SiO₂/Fe₃O₄/GO nanocomposite showed a maximum immobilized protein of 44.13 ± 2.1 mg/g with a specific activity (534.87 ± 9.5 U/mg), than free CRL (≥700 U/mg). GL-A-SiO₂/Fe₃O₄/GO exhibited the highest surface area (260.87 m²/g) alongside superior thermal stability in TGA/DTG. XRD revealed an amorphous SiO₂ (crystallinity = 26.7%), while Fe₃O₄ existed as cubic spinel crystal (crystallinity = 90.2%). Taguchi Design-optimization found that CRL/SiO₂/Fe₃O₄/GO best catalyzed the EV synthesis (90.4% in 3 h) at 40 ℃ using 3 mg/mL of biocatalyst, valeric acid/ethanol molar ratio of 1:2, in 10% (m/v) molecular sieves with stirring in heptane at 200 rpm. EV production was confirmed by FTIR- (C=O: 1738 cm^?1 and C–O–C: 1174 cm^?1) and GC–MS ([M]⁺ m/z = 130, C₇H₁₄O₂). CRL/SiO₂/Fe₃O₄/GO’s reusability for 11 successive esterification cycles demonstrated the SiO₂/Fe₃O₄/GO’s exceptional hyperactivation and stabilization properties on immobilized CRL. These findings conveyed the SiO₂/Fe₃O₄/GO’s efficacy to alter CRL's physicochemical properties and operational stability for catalyzing higher yields EV.     

PEI用于磁性纳米颗粒载药及联合载药抗肿瘤的研究进展

聚乙烯亚胺(PEI)作为一种阳离子聚合物在药物负载中受到了广泛的关注。PEI具有载药高效、易于修饰粒子和生物相容性好等特点,成为了研究热点。综述了目前PEI的研究现状,介绍了PEI修饰磁性纳米颗粒的制备方法,并对其载药治疗癌症的相关进展进行了讨论,重点阐述了PEI在联合载药抗肿瘤方面的应用,最后指出了PEI在肿瘤治疗过程中仍需解决的问题和未来发展趋势。     

Magnetic monolayer film of oleic acid-stabilized Fe3O4 particles fabricated via Langmuir-Blodgett technique

The fabrication of monolayer film of surfactant-stabilized magnetic Fe₃O₄ particles with a size range of 90–150 nm via the Langmuir-Blodgett method is described in this paper. Magnetic Fe₃O₄ particles coated with oleic acid were firstly synthesized by a hydrothermal process, and then the particles were dispersed into chloroform. After that, the Fe₃O₄ suspension was spread to the interface of air/water and transferred to the glass surface. The formation of the Langmuir monolayer of oleic acid-stabilized Fe₃O₄ particles at air/water interface was revealed with the pressure-area isotherm curves. The results of the surface pressure-area isotherm and Atomic Force Microscopy showed that this film is a well compressed monolayer of 2-dimensional Fe₃O₄ particles assembly. Magnetometry results showed that the saturation magnetization of Fe₃O₄ magnetic particles is 86.1 A·m²/kg at room temperature with an applied field of 0.6 T.     

Efficient in situ growth of platinum nanoclusters on the surface of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> for the detection of latent fingermarks

Hydrophobic Fe₃O₄ nanoparticles were modified with polyethyleneimine (PEI) to obtain hydrophilic Fe₃O₄ nanoparticles. By reducing the content of H₂PtCl₆ solution by using l-ascorbic acid (AA) as a reductive agent, fluorescent platinum nanoclusters (Pt NCs) were incubated into the PEI-modified Fe₃O₄ nanoparticles. The prepared Fe₃O₄@Pt NCs microspheres possessed a uniform size, improved monodispersity, high magnetization (40.8 emu/g) and high fluorescence quantum yield (9.0%). Moreover, compared to the reported methods, this method demonstrated that the incubation of Pt NCs on the surface of PEI-Fe₃O₄ was more convenient and needed less reaction time (about 10 min). The experimental results showed that latent fingermarks developing with Fe₃O₄@Pt NCs powder exhibit excellent ridge details. The Fe₃O₄@Pt NCs with superparamagnetism and excellent fluorescence showed great potential in forensic science.     

Multifunctional Magnetic Gd3+‐Based Coordination Polymer Nanoparticles: Combination of Magnetic Resonance and Multispectral Optoacoustic Detections for Tumor‐Targeted Imaging in vivo

To overcome traditional barriers in optical imaging and microscopy, optoacoustic‐imaging has been changed to combine the accuracy of spectroscopy with the depth resolution of ultrasound, achieving a novel modality with powerful in vivo imaging. However, magnetic resonance imaging provides better spatial and anatomical resolution. Thus, a single hybrid nanoprobe that allows for simultaneous multimodal imaging is significant not only for cutting edge research in imaging science, but also for accurate clinical diagnosis. A core‐shell‐structured coordination polymer composite microsphere has been designed for in vivo multimodality imaging. It consists of a Fe₃O₄ nanocluster core, a carbon sandwiched layer, and a carbocyanine‐Gd^III (Cy‐Gd^III) coordination polymer outer shell (Fe₃O₄@C@Cy‐Gd^III). Folic acid‐conjugated poly(ethylene glycol) chains are embedded within the coordination polymer shell to achieve extended circulation and targeted delivery of probe particles in vivo. Control of Fe₃O₄ core grain sizes results in optimal r₂ relaxivity (224.5 × 10^–3 m ⁻¹ s^‐1) for T₂‐weighted magnetic resonance imaging. Cy‐Gd^III coordination polymers are also regulated to obtain a maximum 25.1% of Cy ligands and 5.2% of Gd^III ions for near‐infrared fluorescence and T₁‐weighted magnetic resonance imaging, respectively. The results demonstrate their impressive abilities for targeted, multimodal, and reliable imaging.     

S‐Doped TiSe2 Nanoplates/Fe3O4 Nanoparticles Heterostructure

2D Sulfur‐doped TiSe₂/Fe₃O₄ (named as S‐TiSe₂/Fe₃O₄) heterostructures are synthesized successfully based on a facile oil phase process. The Fe₃O₄ nanoparticles, with an average size of 8 nm, grow uniformly on the surface of S‐doped TiSe₂ (named as S‐TiSe₂) nanoplates (300 nm in diameter and 15 nm in thickness). These heterostructures combine the advantages of both S‐TiSe₂ with good electrical conductivity and Fe₃O₄ with high theoretical Li storage capacity. As demonstrated potential applications for energy storage, the S‐TiSe₂/Fe₃O₄ heterostructures possess high reversible capacities (707.4 mAh g⁻¹ at 0.1 A g⁻¹ during the 100th cycle), excellent cycling stability (432.3 mAh g⁻¹ after 200 cycles at 5 A g⁻¹), and good rate capability (e.g., 301.7 mAh g⁻¹ at 20 A g⁻¹) in lithium‐ion batteries. As for sodium‐ion batteries, the S‐TiSe₂/Fe₃O₄ heterostructures also maintain reversible capacities of 402.3 mAh g⁻¹ at 0.1 A g⁻¹ after 100 cycles, and a high rate capacity of 203.3 mAh g⁻¹ at 4 A g⁻¹.     

Benzoboroxole‐Functionalized Magnetic Core/Shell Microspheres for Highly Specific Enrichment of Glycoproteins under Physiological Conditions

Efficient enrichment of specific glycoproteins from complex biological samples is of great importance towards the discovery of disease biomarkers in biological systems. Recently, phenylboronic acid‐based functional materials have been widely used for enrichment of glycoproteins. However, such enrichment was mainly carried out under alkaline conditions, which is different to the status of glycoproteins in neutral physiological conditions and may cause some unpredictable degradation. In this study, on‐demand neutral enrichment of glycoproteins from crude biological samples is accomplished by utilizing the reversible interaction between the cis‐diols of glycoproteins and benzoboroxole‐functionalized magnetic composite microspheres (Fe₃O₄/PAA‐AOPB). The Fe₃O₄/PAA‐AOPB composite microspheres are deliberately designed and constructed with a high‐magnetic‐response magnetic supraparticle (MSP) core and a crosslinked poly(acrylic acid) (PAA) shell anchoring abundant benzoboroxole functional groups on the surface. These nanocomposites possessed many merits, such as large enrichment capacity (93.9 mg/g, protein/beads), low non‐specific adsorption, quick enrichment process (10 min) and magnetic separation speed (20 s), and high recovery efficiency. Furthermore, the as‐prepared Fe₃O₄/PAA‐AOPB microspheres display high selectivity to glycoproteins even in the E. coli lysate or fetal bovine serum, showing great potential in the identify of low‐abundance glycoproteins as biomarkers in real complex biological systems for clinical diagnoses.     

Streptomycin-modified Fe<Subscript>3</Subscript>O<Subscript>4</Subscript>–Au@Ag core–satellite magnetic nanoparticles as an effective antibacterial agent

The fabrication of ideal Ag-modified magnetic nanoparticles (MNPs) as a recyclable antibacterial agent that possesses good dispersibility, strong magnetic responsiveness, and high bactericidal activity is still a challenge. In this study, we described a simple polyethyleneimine (PEI)-assisted connection method for fabricating high-performance Au@Ag-loaded MNPs (Fe₃O₄–Au@Ag). The Fe₃O₄ cores are first modified with uniform PEI shell (2 nm) through self-assembly under sonication. And then, the negatively charged Au@Ag NPs with a uniform size of 5 nm are adsorbed on the surface of the Fe₃O₄ cores through electrostatic interaction. The Au@Ag-loaded MNPs were obtained within 30 min, and they were highly uniform in size and shape with good dispersibility and strong magnetic responsivity. With the aid of the magnetic core, the residual nanoparticles can be recycled from solution through an external magnetic field. These dense Au@Ag NPs acted as antibacterial satellites in highly active areas for Ag ion releasing and bacteria contacting. The Fe₃O₄–Au@AgMNPs exhibited good antibacterial activity against both Gram-negative and Gram-positive bacteria. Moreover, the antibacterial activity of Fe₃O₄–Au@AgMNPs was significantly improved by streptomycin antibiotic modification. Enhancement of the bactericidal efficiency of Fe₃O₄–Au@Ag-streptomycin revealed the presence of a synergistic effect between the MNPs and the introduced antibiotic.     

Giant Magnetic Heat Induction of Magnesium‐Doped γ‐Fe2O3 Superparamagnetic Nanoparticles for Completely Killing Tumors

Magnetic fluid hyperthermia has been recently considered as a Renaissance of cancer treatment modality due to its remarkably low side effects and high treatment efficacy compared to conventional chemotheraphy or radiotheraphy. However, insufficient AC induction heating power at a biological safe range of AC magnetic field (H_appl·f_appl < 3.0–5.0 × 10⁹ A m^?1 s^?1), and highly required biocompatibility of superparamagnetic nanoparticle (SPNP) hyperthermia agents are still remained as critical challenges for successful clinical hyperthermia applications. Here, newly developed highly biocompatible magnesium shallow doped γ‐Fe₂O₃ (Mg_0.13‐γFe₂O₃) SPNPs with exceptionally high intrinsic loss power (ILP) in a range of 14 nH m² kg^?1, which is an ≈100 times higher than that of commercial Fe₃O₄ (Feridex, ILP = 0.15 nH m² kg^?1) at H_appl·f_appl = 1.23 × 10⁹ A m^?1 s^?1 are reported. The significantly enhanced heat induction characteristics of Mg_0.13‐γFe₂O₃ are primarily due to the dramatically enhanced out‐of‐phase magnetic susceptibility and magnetically tailored AC/DC magnetic softness resulted from the systematically controlled Mg²⁺ cations distribution and concentrations in octahedral site Fe vacancies of γ‐Fe₂O₃ instead of well‐known Fe₃O₄ SPNPs. In vitro and in vivo magnetic hyperthermia studies using Mg_0.13‐γFe₂O₃ nanofluids are conducted to estimate bioavailability and biofeasibility. Mg_0.13‐γFe₂O₃ nanofluids show promising hyperthermia effects to completely kill the tumors.