Fe3O4 Nanoparticles Research Articles

Construction of Hierarchically Biomimetic Iron Oxide Nanosystems for Macrophage Repolarization-Promoted Immune Checkpoint Blockade of Cancer Immunotherapy.

Cancer immunotherapy is developing as the mainstream strategy for treatment of cancer. However, the interaction between the programmed cell death protein-1 (PD-1) and the programmed death ligand 1 (PD-L1) restricts T cell proliferation, resulting in the immune escape of tumor cells. Recently, immune checkpoint inhibitor therapy has achieved clinical success in tumor treatment through blocking the PD-1/PD-L1 checkpoint pathway. However, the presence of M2 tumor-associated macrophages (TAMs) in the tumor microenvironment (TME) will inhibit antitumor immune responses and facilitate tumor growth, which can weaken the effectiveness of immune checkpoint inhibitor therapy. The repolarization of M2 TAMs into M1 TAMs can induce the immune response to secrete proinflammatory factors and active T cells to attack tumor cells. Herein, hollow iron oxide (Fe3O4) nanoparticles (NPs) were prepared for reprogramming M2 TAMs into M1 TAMs. BMS-202, a small-molecule PD-1/PD-L1 inhibitor that has a lower price, higher stability, lower immunogenicity, and higher tumor penetration ability compared with antibodies, was loaded together with pH-sensitive NaHCO3 inside hollow Fe3O4 NPs, followed by wrapping with macrophage membranes. The formed biomimetic FBN@M could produce gaseous carbon dioxide (CO2) from NaHCO3 in response to the acidic TME, breaking up the macrophage membranes to release BMS-202. A series of in vitro and in vivo assessments revealed that FBN@M could reprogram M2 TAMs into M1 TAMs and block the PD-1/PD-L1 pathway, which eventually induced T cell activation and the secretion of TNF-α and IFN-γ to kill the tumor cells. FBN@M has shown a significant immunotherapeutic efficacy for tumor treatment.

Architecting ultra-thin SiO2 shell for high magnetic performance of Fe3O4 nanoparticles for biomedical applications

This research focuses on the architectural design of the silica shell on the Fe3O4 nanoparticle to precisely control and minimize its thickness, with the aim of achieving a final product with optimal saturation magnetization (Ms) for biomedical applications. A rapid and facile microwave-assisted synthesis method was developed for the synthesis of Fe3O4@SiO2 and Fe3O4@SiO2@NH2 core–shell nanoparticles with ultra-thin SiO2 shells and excellent magnetic performance. The particle size distribution of the Fe3O4@SiO2 nanoparticles was in the range of 15–35 nm, with a mean particle size of approximately 21 nm. The mean thickness of the SiO2 shells on the Fe3O4 cores was found to be 3 nm. FTIR analysis also confirmed the successful silica coating on Fe3O4 nanoparticles and the successful amino-functionalization of silica-coated Fe3O4 nanoparticles. The Ms of Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@NH2 nanoparticles were found to be 64.4, 59.8, and 52.4 emu/g, respectively. It has been confirmed that the ultra-thin SiO2 coating has a negligible effect on the magnetic characteristics of the nanoparticles. The developed microwave-assisted synthesis method in this study not only provides an interesting, rapid, and facile synthesis route but also results in a product with a narrow particle size distribution, an ultra-thin SiO2 shell, favorable magnetic properties, and improved cell compatibility, which may be used in several different applications, particularly biomedical applications.

Foam drainage agent with enhanced foam stability through modified Fe3O4 nanoparticles

A nanofoam drainage agent was developed to address the challenges of inadequate foam stability and foaming efficiency in the gas recovery process of foam drainage. The formulation of the primary foam drainage agent was obtained by screening and combining conventional anionic and amphoteric surfactants. Experimental results revealed a synergistic interaction between α-olefin sulfonate (AOS) and lauramidopropyl betaine (LAB-35). Specifically, when a mixture of 0.4 wt.% AOS and 0.1 wt.% LAB-35 was used, the surface tension of the primary foam drainage agent was measured to be 23.32 mN/m. Furthermore, modification of Fe3O4 nanoparticles with the silane coupling agent γ-(methacryloxy)propyl trimethoxysilane (KH-570) was performed to improve the dispersibility in aqueous solutions and enhance foam stability. The results of infrared spectroscopy, x-ray diffraction, thermogravimetric analysis, and contact angle measurements revealed the effective bonding of KH-570 to the surface of Fe3O4 nanoparticles. Additionally, the particle size distribution in the aqueous solution showed the excellent dispersion of the modified Fe3O4 nanoparticles. Through the incorporation of the modified Fe3O4 nanoparticles into the primary foam drainage agent, a nanofoam drainage agent with a half-life of 989 ± 6.5 s was developed. Microscopic observations of foam coarsening behavior revealed the mechanism behind foam stability. Performance testing of the foam drainage agent demonstrated the agent’s outstanding resistance against salinity, temperature, and oil and its remarkable liquid-carrying capacity.

Comparable Antibacterial Effects of Silver and Iron Oxide Nanoparticles on Urinary Calculi Obtained After Percutaneous Nephrolithotomy

Background: In recent years, science and industry have focused on preparing nanoparticles (NPs). Due to the resistance of bacteria to antibiotics, there is an overwhelming need to find effective antimicrobials with fewer side effects. Objectives: The aim of this study was to synthesize silver and iron oxide NPs and investigate their antimicrobial effects on bacteria isolated from urinary stones. Methods: Cases of urolithiasis from 45 patients with staghorn stones, extracted through percutaneous nephrolithotomy (PCNL), were included in the study. Urinary stone cultures were performed, and the isolation and identification of bacteria were done using standard microbiological techniques. Silver and iron oxide NPs were synthesized, and the minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) were evaluated for the isolates. Results: Seventeen (60.7%) out of 28 positive cultured cases of the isolated bacteria were gram-negative, and 11 (39.3%) were gram-positive. The most abundant isolated bacterium was Escherichia coli, with 13 cases (46.4%). The antibacterial effects of silver and iron oxide NPs revealed that the maximum inhibitory zone for Ag NPs at 1000 ppm was 23 mm, and for Fe3O4 NPs, it was 18.5 mm. The MIC was 180 µg/mL for Ag and 250 µg/mL for Fe3O4. The MBC was 228 µg/mL for Ag and 300 µg/mL for Fe3O4. Conclusions: Nanoparticles exhibited antibacterial effects on the bacteria studied in a concentration-dependent manner. Ag NPs showed a more pronounced bactericidal effect than Fe3O4 NPs. As a result, these two NPs demonstrated effective antibacterial activity against both gram-positive and gram-negative bacteria.

New Fe3O4-Based Coatings with Enhanced Anti-Biofilm Activity for Medical Devices.

With the increasing use of invasive, interventional, indwelling, and implanted medical devices, healthcare-associated infections caused by pathogenic biofilms have become a major cause of morbidity and mortality. Herein, we present the fabrication, characterization, and in vitro evaluation of biocompatibility and anti-biofilm properties of new coatings based on Fe3O4 nanoparticles (NPs) loaded with usnic acid (UA) and ceftriaxone (CEF). Sodium lauryl sulfate (SLS) was employed as a stabilizer and modulator of the polarity, dispersibility, shape, and anti-biofilm properties of the magnetite nanoparticles. The resulting Fe3O4 functionalized NPs, namely Fe3O4@SLS, Fe3O4@SLS/UA, and Fe3O4@SLS/CEF, respectively, were prepared by co-precipitation method and fully characterized by XRD, TEM, SAED, SEM, FTIR, and TGA. They were further used to produce nanostructured coatings by matrix-assisted pulsed laser evaporation (MAPLE) technique. The biocompatibility of the coatings was assessed by measuring the cell viability, lactate dehydrogenase release, and nitric oxide level in the culture medium and by evaluating the actin cytoskeleton morphology of murine pre-osteoblasts. All prepared nanostructured coatings exhibited good biocompatibility. Biofilm growth inhibition ability was tested at 24 h and 48 h against Staphylococcus aureus and Pseudomonas aeruginosa as representative models for Gram-positive and Gram-negative bacteria. The coatings demonstrated good biocompatibility, promoting osteoblast adhesion, migration, and growth without significant impact on cell viability or morphology, highlighting their potential for developing safe and effective antibacterial surfaces.

Enhanced biodegradation of 2, 4-dichlorophenol in packed bed biofilm reactor by impregnation of polyurethane foam with Fe3O4 nanoparticles: Bio-kinetics, process optimization, performance evaluation and toxicity assessment

In this work, an effort has been made to enhance the efficacy of biological process for the effective degradation of 2, 4-dichlorophenol (2, 4-DCP) from wastewater. The polyurethane foam was modified with Fe3O4 nanoparticles and combined with polyvinyl alcohol, sodium alginate, and bacterial consortium for biodegradation of 2, 4-DCP in a packed bed biofilm reactor. The maximum removal efficiency of 2, 4-DCP chemical oxygen demand, and total organic carbon were found to be 92.51 ± 0.83 %, 86.85 ± 1.32, and 91.78 ± 1.24 %, respectively, in 4 days and 100 mg L−1 of 2, 4-DCP concentration at an influent loading rate of 2 mg L−1h−1 and hydraulic retention time of 50 h. Packed bed biofilm reactor was effective for up to four cycles to remove 2, 4-DCP. Growth inhibition kinetics were evaluated using the Edward model, yielding maximum growth rate of 0.45 day−1, inhibition constant of 110.6 mg L−1, and saturation constant of 62.3 mg L−1.

Synthesis and characterisation of novel beta-cyclodextrin based Fe3O4 nanocomposite: adsorption behaviour and photocatalytic dye degradation studies

ABSTRACT Novel Beta-Cyclodextrin-based Fe3O4 nanocomposite has been synthesised through copolymerisation by incorporating Fe3O4 nanoparticles into the polymer matrix. Ultraviolet-Visible (UV-Visible) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Thermogravimetric (TGA) analysis, Point of Zero Charge, X-ray diffraction (XRD), and Scanning electron microscopy (SEM) analysis have been used to characterise the Fe3O4 Nanoparticles and β-CDHs@Fe3O4 nanocomposite. The synthesised β-CDHs@Fe3O4 nanocomposite has been utilised for the adsorption of methylene blue (MB) dye from aqueous solutions. The maximum percentage removal of MB dye at optimum pH 7 and was found to be 98.51%. The adsorption capacity (qe) of β-CDHs@Fe3O4 nanocomposite has been found to be 268.09 mg/g at optimum dosages 1.2 g/L, pH 7, temperature 25°C, concentration 100 mg/L and an agitation speed of 200 rpm. Adsorption data have been fitted with three isotherm models namely Langmuir, Freundlich, and Temkin, and it was found to be the best fit with the Langmuir isotherm model. Kinetic studies like the pseudo-first order, pseudo-second order, and intra-particle diffusion model were also performed to study the adsorption mechanism. Further, thermodynamic studies demonstrate that the reaction was exothermic and spontaneous. Photocatalytic degradation of MB dye under visible light has also been studied, and 79.01% degradation of the dye was observed. Also, desorption of the nanocomposite was performed, and it was found to be reusable up to 5 times with 90% dye-desorption in the fifth cycle.

Cellulose–derived carbon scaffolds with bidirectional gradient Fe3O4 distribution: Integration of green EMI shielding and thermal management

Cellulose papers (CPs) possess a pore structure, rendering them ideal precursors for carbon scaffolds because of their renewability. However, achieving a tradeoff between high electromagnetic shielding effectiveness and low reflection coefficient poses a tremendous challenge for CP-based carbon scaffolds. To meet the challenge, leveraging the synergistic effect of gravity and evaporation dynamics, laminar CP-based carbon scaffolds with a bidirectional gradient distribution of Fe3O4 nanoparticles were fabricated via immersion, drying, and carbonization processes. The resulting carbon scaffold, owing to the bidirectional gradient structure of magnetic nanoparticles and unique laminar arrangement, exhibited excellent in-plane electrical conductivity (96.3 S/m), superior electromagnetic shielding efficiency (1805.9 dB/cm2 g), low reflection coefficients (0.23), and a high green index (gs, 3.38), suggesting its green shielding capabilities. Furthermore, the laminar structure conferred upon the resultant carbon scaffold a surprisingly anisotropic thermal conductivity, with an in-plane thermal conductivity of 1.73 W/m K compared to a through-plane value of only 0.07 W/m K, confirming the integration of thermal insulation and thermal management functionalities. These green electromagnetic interference shielding materials, coupled with thermal insulation and thermal management properties, hold promising prospects for applications in sensitive devices.

Sustainable Co(III)/Co(II) cycles triggered by Co-Zn bimetallic MOF encapsulating Fe nanoparticles for high-efficiency peracetic acid activation to degrade sulfamethoxazole: Enhanced performance and synergistic mechanism

Herein, a dual-metal-organic framework (MOF) assisted strategy to construct a core-shell structure magnetic Fe3O4@ZIFs composites was proposed for peracetic acid (PAA) activation. Results showed that the Fe3O4@ZIFs displayed superior activity relative to analogous counterparts, achieving 99.3 % degradation of SMX within 30 min. Both the radical pathways of CH3C(O)OO· and non-radical 1O2 were recognized as the primary mechanisms in SMX oxidation, while the radicals such as ·OH, CH3C(O)O·, and ·O2– along with high-valent metal species (CoIVO2+ and FeIVO2+) demonstrated a limited contribution. During the process, the Co sites on the surface of ZIFs, serving as the primary active sites, activated the PAA through the redox cycle of Co(II)/Co(III) to generate reactive oxygen species (ROS). The encapsulated Fe3O4 nanoparticles were subjected to precise electron transmission, benefiting Co(II) recovery for enhanced Co(II)/Co(III) cycling. Besides, the strong interaction between Zn and Co in outer bimetallic ZIFs effectively mitigated Co leaching, highlighting the synergy effect of the catalytic system with multiple active sites. The Fe3O4@ZIFs composites retained excellent catalytic proficiency after four successive cycles. This study provides a strategy to accelerate Co(II)/Co(III) circulation in heterogeneous systems and highlights the significant potential of MOFs in the construction of high-efficiency Co-based catalysts for PAA activation in environmental remediation.

Anisotropic topological scaffolds synergizing non-invasive wireless magnetic stimulation for accelerating long-distance peripheral nerve regeneration

Long-distance peripheral nerve regeneration is the challenging clinical problem that needs to be resolved urgently. In this study, an anisotropic topological Chitosan@Artemisia sphaerocephala (CS@AS) scaffold containing Fe3O4 nanoparticles for achieving non-invasive wireless magnetic stimulation on nerve regeneration process under external static magnetic field (SMF) was developed using surface modification and micro-molding method, aiming to provide a synergistic stimulus for the repair of long-distance peripheral nerve injury. The results showed that the anisotropic topological scaffolds and non-invasive wireless magnetic stimulation under exogenous SMF could synergistically regulate the morphological change, proliferation and oriented growth of Schwann cells. In vivo experiments confirmed that magnetic CS@AS nerve conduit could better promote the functional recovery and reconstruction of the long-distance injured sciatic nerve under SMF, close to that of the autograft transplantation. Further on, the scaffolds were found to activate the magnetic induction receptors, promote the gene expression related to proliferation, migration and myelin formation, regulate the homeostasis of intracellular Ca2+ and enhance the signal transduction via cGMP-PKG, VEGF, MAPK, and TNF signaling pathways. Therefore, the combination of anisotropic topological nerve grafts and non-invasive wireless magnetic stimulation under external SMF can promote the repair and functional recovery of long-distance nerve injury, providing a new strategy for the treatment of peripheral nerve injury.

Technology and research on the influence of liquid crystal cladding doped with magnetic Fe3O4 nanoparticles on light propagation in an optical taper sensor

The results obtained for new dual-cladding optical fiber tapers surrounded by liquid crystal (LC) doped with Fe3O4 nanoparticles in a specially developed glass cell are presented. The created structures are sensitive to changes in refractive index values in the surrounding medium caused by modifying external environment parameters. In this investigation, cells are filled with nematic LCs 6CHBT and with the same mixture doped with 0.1 wt% and 0.5 wt% of magnetic nanoparticles (Fe3O4 NPs). The taper is made on a standard single-mode telecommunication fiber, stretched out to a length of 20.0 ± 0.5 mm, and the diameter of the tapers is approximately 15.0 ± 0.3 μm, with a loss lower than 0.5 dB @ 1,550 nm. Measurements are carried out in a wide range covering the visible and infrared ranges in two setups: 1) without a magnetic field, with steering only by voltage and 2) with an applied magnetic field. The presented spectrum results are divided into two ranges according to the parameters of optical spectrum analyzers: 350–1,200 nm and 1,200–2,400 nm. For all investigations, a steering voltage is chosen from the range of 0 to 200 V, which allows for establishing the influence of dopants on transmitted power and time response at different arrangements. Due to the sensitivity of LCs to temperature changes, this paper focuses on measuring at room temperature the effect of the magnetic field on propagation in a fiber optic taper. The proposed solution demonstrates the technology for creating advanced components as a combination of fiber optic technology, LCs, and nanoparticles. The presented results show the possibility of creating new sensors of various external factors such as magnetic or electric fields in miniaturized dimensions.

MXene-derived titanate heterojunctions with lightweight and heat-resistant properties for electromagnetic wave absorption

The development of high-efficiency titanate-based electromagnetic wave (EMW) absorbers presents a significant challenge, primarily due to the limited number of loss mechanisms available in such materials. Herein, an innovative approach has been employed, utilizing g-C3N4 as a connecting bridge linking KTi8O16.5 nanorods with Fe2O3 nanoparticles, thereby crafting a KTO/Fe2O3–CN absorber with a dual heterojunction architecture. This sophisticated structure is realized through a detailed freeze-drying process followed by heat treatment. In this structure, g-C3N4 and KTi8O16.5 originate from melamine and MXene precursors, respectively, while Fe2O3 component is derived from the thermal decomposition of FeSO4. The integrated KTO/Fe2O3–CN system fosters enhanced interfacial and dipole polarization, as well as conduction and magnetic loss, all collaboratively aiding in the attenuation of EM waves. In addition, the specially designed EMW absorber is notable for its lightweight nature, along with impressive heat dissipation and resistant performance. It demonstrates exceptional thermal stability, capable of withstanding temperatures as high as 500 °C and sustaining repeated thermal cycles at 400 °C. This strategy not only elevates the efficacy of titanate-based EMW absorbers but also paves the way for the conceptualization of high-performance, multifunctional EMW absorption materials. Such advancements hold the promise of transforming a wide range of applications that necessitate effective EM wave attenuation, marking a significant leap forward in the field.

Olive leaf extract-assisted preparation of nanoferrite for adsorptive removal of cationic dye

In this work, magnetic Fe3O4 nanoparticles synthesized with olive leaf extract were used to investigate the adsorption of Basic violet 16 from aqueous solutions. The physicochemical characteristics of Fe3O4 nanoparticles were evaluated by DLS, zeta potential, XRD, FTIR SEM, EDX, N2 adsorption-desorption, TEM, and VSM analyses. Using DLS analysis, the average size of the Fe3O4 nanoparticles was found to be 231.2 nm. Zeta potential studies indicated that the synthesized nanoparticles were moderately stable, and zeta potential was calculated as −14.9 mV. According to TEM analysis, the synthesized nanoparticles ranged in size from 6.28 to 17.3 nm. The optimum parameters for the adsorption of basic violet 16 with Fe3O4 nanoparticles were determined as pH: 9.0, adsorbent dose: 0.8 g, contact time: 210 min, stirring speed: 250 rpm. Langmuir, Freundlich, Dubinin Radushkevich (D-R) and Temkin isotherm models were used to characterize the basic violet 16 sorption data onto Fe3O4 nanoparticles and it was seen that Basic violet 16 adsorption onto the Fe3O4 nanoparticles followed Langmuir isotherm model at all temperatures. The maximum adsorption capacity of Basic violet 16 with Fe3O4 nanoparticles was determined as 117.64 mg/g at 318 K. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to describe the adsorption kinetics at 298–318 K. The adsorption followed the pseudo-second-order kinetic model. Adsorption of Basic violet 16 onto Fe3O4 nanoparticles occurred spontaneously and endothermically. Characteristic peaks Fe3O4 nanoparticles were visible in the XRD analysis. The SBET surface area dropped from 110.42 m2/g to 91.27 m2/g after dye adsorption. Peaks in the FTIR analysis showed that Basic violet 16 had been successfully adsorbed on Fe3O4 nanoparticles.

A Minimalist Iron Oxide Nanoprobe for the High-Resolution Depiction of Stroke by Susceptibility-Weighted Imaging.

The precise mapping of collateral circulation and ischemic penumbra is crucial for diagnosing and treating acute ischemic stroke (AIS). Unfortunately, there exists a significant shortage of high-sensitivity and high-resolution in vivo imaging techniques to fulfill this requirement. Herein, a contrast enhanced susceptibility-weighted imaging (CE-SWI) using the minimalist dextran-modified Fe3O4 nanoparticles (Fe3O4@Dextran NPs) are introduced for the highly sensitive and high-resolution AIS depiction under 9.4 T for the first time. The Fe3O4@Dextran NPs are synthesized via a simple one-pot coprecipitation method using commercial reagents under room temperature. It shows merits of small size (hydrodynamic size 25.8nm), good solubility, high transverse relaxivity (r2) of 51.3 mM-1s-1 at 9.4 T, and superior biocompatibility. The Fe3O4@Dextran NPs-enhanced SWI can highlight the cerebral vessels readily with significantly improved contrast and ultrahigh resolution of 0.1mm under 9.4 T MR scanner, enabling the clear spatial identification of collateral circulation in the middle cerebral artery occlusion (MCAO) rat model. Furthermore, Fe3O4@Dextran NPs-enhanced SWI facilitates the precise depiction of ischemia core, collaterals, and ischemic penumbra post AIS through matching analysis with other multimodal MR sequences. The proposed Fe3O4@Dextran NPs-enhanced SWI offers a high-sensitivity and high-resolution imaging tool for individualized characterization and personally precise theranostics of stroke patients.

Polymeric nanocarrier-based adjuvants to enhance a locally produced mucosal coryza vaccine in chicken

Infectious coryza (IC) is an acute upper respiratory disease of chicken caused by Avibacterium (A.) paragallinarum. This disease results in an increased culling rate in meat chicken and a marked decrease in egg production (10% to more than 40%) in laying and breeding hens. Vaccines were first used against IC and effectively controlled the disease. Nanotechnology provides an excellent way to develop a new generation of vaccines. NPs have been widely used in vaccine design as adjuvants and antigen delivery vehicles and as antibacterial agents; thus, they can be used as inactivators for bacterial culture. In this research, the antibacterial effects of several nanoparticles (NPs), such as silicon dioxide with chitosan (SiO2-CS), oleoyl-chitosan (O.CS), silicon dioxide (SiO2), and iron oxide (Fe3O4), on A. paragallinarum were studied. Additionally, different A. paragallinarum vaccines were made using the same nanomaterials at a concentration of 400 µg/ml to help control infectious coryza disease in chicken. A concentration of 400 µg/ml of all the NPs tested was the best concentration for the inactivation of A. paragallinarum. Additionally, this study showed that the infectious coryza vaccine adjuvanted with SiO2 NPs had the highest immune response, followed by the infectious coryza vaccine adjuvanted with Fe3O4 NPs, the infectious coryza vaccine adjuvanted with SiO2-CS NPs, and the infectious coryza vaccine adjuvanted with O.CS NPs in comparison with the infectious coryza vaccine adjuvanted with liquid paraffin (a commercial vaccine).

Fe3O4@CNTs/PANI/PI fabric with magnetic–dielectric nanonetwork as a highly efficient microwave absorber

Since the matching between the complex permittivity and permeability plays a dominant role in the performance of microwave absorbing, magnetic-dielectric materials have been increasingly used for microwave absorption. In this paper, Fe3O4 nanoparticles anchored on carbon nanotubes (Fe3O4@CNTs) were fabricated via a self-assembled technique. The efficient microwave-absorbing fabric was synthesized by building polyaniline nanofibers (PANI NFs) and Fe3O4@CNTs magnetic–dielectric network on the surface of polyimide (PI) fabric. The results of SEM, FTIR, and XRD demonstrated the presence of Fe3O4@CNTs on the fabric surface. The decomposition temperature (Td) of the fabric was beyond 580.0 °C and the fabric exhibited strong hydrophobicity (water contact angle 125.0°). The Fe3O4@CNTs/PANI/PI fabric possessed a minimum reflection loss (RL) value of −62.61 dB (>99.9 % absorption) with a matching thickness of 1.58 mm. The excellent microwave absorption capacity is attributed to the well impendence match, dielectric and magnetic loss, and the scattering loss of the special cell structure.

Reuseable Fe3O4@PEI-DTC-Au@Ag magnetic nanocomposites: A versatile and sensitive SERS substrate for food safety assessment

A novel recyclable SERS substrate with magnetic manipulation capability and surface-enhanced Raman scattering (SERS) effect based on Fe3O4@PEI-DTC-Au@Ag (FPDAA) core-shell nanocomposites has been successfully prepared by engineered hydrothermal deposition and seed deposition techniques. The uniformity and SERS efficacy of these substrates, incorporating various Au@Ag core-shell nanocomposites with differing Ag shell thicknesses, were evaluated using 4-aminothiophenol (4-ATP) molecules. The optimal SERS substrate, Fe3O4@PEI-DTC-Au@Ag-3 (FPDAA-3), exhibited an enhancement factor (EF) of up to 1.121×106. This remarkable performance can be attributed to the synergistic effect between the magnetic plasmon of the Fe3O4 nanoparticles (NPs) core and the surface plasmonic resonance properties of Au@Ag core-shell nanocomposites, which create abundant interparticle hotspots within the FPDAA nanocomposites. Furthermore, the FPDAA-3 nanocomposite was employed as a SERS substrate for rapid thiram detection, achieving a minimum detectable concentration of 1×10−9 M. Notably, the relative standard deviation of SERS measurements from 50 randomly selected points was found to be less than 12.13 %, and the SERS spectra intensity showed minimal variation after 5 cycling tests, underscoring the excellent uniformity and recyclability of the FPDAA-3 substrate. The highly reusable and reliable FPDAA-3 nanocomposites enable direct on-site detection of thiram pesticide residues on fruit skins, thereby offering significant implications for food safety assessment and spectroscopic identification.

Characterization of Nanoparticles in Ethanolic Suspension Using Single Particle Inductively Coupled Plasma Mass Spectrometry: Application for Cementitious Systems.

Single particle inductively coupled plasma mass spectrometry (spICP-MS) is a well-established technique to characterize the size, particle number concentration (PNC), and elemental composition of engineered nanoparticles (NPs) and colloids in aqueous suspensions. However, a method capable of directly analyzing water-sensitive or highly reactive NPs in alcoholic suspension has not been reported yet. Here, we present a novel spICP-MS method for characterizing the main cement hydration product, i.e., calcium-silicate-hydrate (C-S-H) NPs, in ethanolic suspensions, responsible for cement strength. The method viability was tested on a wide range of NP compositions and sizes (i.e., from Au, SiO2, and Fe3O4 NP certified reference materials (CRMs) to synthetic C-S-H phases with known Ca/Si ratios and industrial cement hardening accelerators, X-Seed 100/500). Method validation includes comparisons to nanoparticle tracking analysis (NTA) and transmission/scanning electron microscopy (TEM/SEM). Results show that size distributions from spICP-MS were in good agreement with TEM and NTA for CRMs ≥ 51 nm and the synthetic C-S-H phases. The X-Seed samples showed significant differences in NP sizes depending on the elemental composition, i.e. CaO and SiO2 NPs were bigger than Al2O3 NPs. PNC via spICP-MS was successfully validated with an accuracy of 1 order of magnitude for CRMs and C-S-H phases. The spICP-MS Ca/Si ratios matched known ratios from synthetic C-S-H phases (0.6, 0.8, and 1.0). Overall, our method is applicable for the direct and element-specific quantification of fast nucleation and/or mineral formation processes characterizing NPs (ca. 50-1000 nm) in alcoholic suspensions.

Fe3O4 Nanoparticles That Modulate the Polarisation of Tumor-Associated Macrophages Synergize with Photothermal Therapy and Immunotherapy (PD-1/PD-L1 Inhibitors) to Enhance Anti-Tumor Therapy.

Traditional surgical resection, radiotherapy, and chemotherapy have been the treatment options for patients with head and neck squamous cell carcinoma (HNSCC) over the past few decades. Nevertheless, the five-year survival rate for patients has remained essentially unchanged, and research into treatments has been relatively stagnant. The combined application of photothermal therapy (PTT) and immunotherapy for treating HNSCC has considerable potential. Live-dead cell staining and CCK-8 assays proved that Fe3O4 nanoparticles are biocompatible in vitro. In vitro, cellular experiments utilized flow cytometry and immunofluorescence staining to verify the effect of Fe3O4 nanoparticles on the polarisation of tumor-associated macrophages. In vivo, animal experiments were conducted to assess the inhibitory effect of Fe3O4 nanoparticles on tumor proliferation under the photothermal effect in conjunction with BMS-1. Tumour tissue sections were stained to observe the effects of apoptosis and the inhibition of tumor cell proliferation. The histological damage to animal organs was analyzed by hematoxylin and eosin (H&E) staining. The stable photothermal properties of Fe3O4 nanoparticles were validated by in vitro cellular and in vivo animal experiments. Fe3O4 photothermal action not only directly triggered immunogenic cell death (ICD) and enhanced the immunogenicity of the tumor microenvironment but also regulated the expression of tumor-associated macrophages (TAMs), up-regulating CD86 and down-regulating CD206 to inhibit tumor growth. The PD-1/PD-L1 inhibitor promoted tumor suppression, and reduced tumor recurrence and metastasis. In vivo studies demonstrated that the photothermal action exhibited a synergistic effect when combined with immunotherapy, resulting in significant suppression of primary tumors and an extension of survival. In this study, we applied Fe3O4 photothermolysis in a biomedical context, combining photothermolysis with immunotherapy, exploring a novel pathway for treating HNSCC and providing a new strategy for effectively treating HNSCC.

One Pot Facile Bio-Synthesis of Anti-angiogenic Iron Oxide Nanoparticles Using the Bio-Reductant Sida spinosa

Abstract Owing to the superior characteristics of the iron oxide nanoparticles Fe2O3 (SS-Fe) attracted a lot of attentions in various applications due to their unique physical and chemical properties. Moreover, due to their excellent surface area, compatible nano size spherical shape and ecofriendly synthesis route make them preferable and prudent in industrial and pharmacological applications. Based on this view, it aims to the bio-fabrication of iron oxide nanoparticles Fe2O3 (SS-Fe) by Sida spinosa extract as bio-reductant and stabilizing agent. The reports reveal that the nanoparticles have effective pharmacological applications. Highly economical and environmentally benign methodology supports the derivation of Fe2O3 (SS-Fe) nanoparticles in high yield. The SEM images reveals that, Fe2O3 (SS-Fe) nanoparticles possess spherical shape and the size of 81.72nm. The corresponding Fe-O band observed at 560.93 cm−1 indicates the formation of the nanoparticles. The EDX signals further confirms the nanoparticles by the peaks obtained for iron and oxygen atoms only. The absorbance peak at 374.00nm in UV-Visible spectrum evidently proves the synthesis of iron oxide nanoparticles. The λex = 645.18nm of the emission spectrum further supports the confirmation. The fabricated iron oxide nanoparticles show moderate antibacterial and a good antifungal efficacy. The iron oxide nanoparticles effectively inhibit the protein supply to the cancer cells which were injected to the egg yolk at 50µg/ml concentration gives 60.86% of inhibition.