Papers by Keyword: Magnetic Nanoparticles

Abstract: Magnetite (Fe₃O₄) nanoparticles have garnered significant attention in biomedicine due to their distinctive magnetic properties, biocompatibility, and ease of functionalization for diverse applications. In this study, Fe₃O₄ nanoparticles were synthesized via the co-precipitation method, followed by the synthesis of a SiO₂ coating on Fe₃O₄ (Fe₃O₄@SiO₂) and an amino group coating on Fe₃O₄@SiO₂ (Fe₃O₄@SiO₂_NH₂) before chitosan coating. Chitosan concentration was varied at 1% and 5% to improve their stability and biocompatibility. Characterization of the nanoparticles was conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDXS). XRD analysis confirmed that the synthesized nanoparticles were magnetite (Fe₃O₄), while FTIR confirmed the presence of -OH and -NH₂ functional groups, which increased after coating with a chitosan layer on the magnetite surface. SEM/EDX analysis revealed that the average diameter of the uncoated Fe₃O₄ nanoparticles was approximately 12 nm, and EDX analysis indicated the presence of sodium after coating with chitosan. Using chitosan as a coating material enhanced the biocompatibility, stability, and functional versatility of the nanoparticles. The results demonstrated the successful coating of chitosan on the Fe₃O₄ nanoparticles, which retained their superparamagnetic properties, making them promising candidates for drug delivery applications.

Abstract: An electrochemical sensor was enhanced with magnetite nanoparticles for biosensor application. Nanoparticles of magnetite (Fe₃O₄) ranging in size from 5 to 30 nm were produced by the co-precipitation method and further modified with an amine functional group (Fe₃O₄@SiO₂_NH₂). During the process, the functional amine served as a supporting biomaterial and coating agent, regulating particle size and aggregation. The Fe₃O₄@SiO₂_NH₂ nanoparticles were incorporated into gold nanoparticle planes on a conductive graphene electrode in a diluted solution of the ultrafast redox probe K₃[Fe(CN)₆]. Using scanning electron microscopy to investigate the morphology of the modified graphene sheets and gold (Au) nanoparticles on screen printed electrodes (SCPE). The results clearly demonstrated the even distribution of Fe₃O₄ nanoparticles, almost always less than 30 nm in size, on AuNPs and graphene sheets. Adding these magnetite particles has created active sites, facilitating the movement of electrons from redox-active species in the solution. In addition, the electrochemical reduction of flawed graphene sheets has greatly limited the oxygen groups, making the material more conductive or enhancing signal. The sensor was subsequently investigated with the use of magnetite nanocomposites for electrochemical biosensing applications with (bovine serum albumin) BSA.

Abstract: The potential of zircon minerals in Indonesia as valuable adsorbent materials has not been properly developed. Seeing its high potential as an excellent adsorbent for anions/cations in water treatment and industrial wastewater, the raw zircon minerals into zircon oxides which will later be composited with magnetic nanoparticles using one-pot solvothermal processes (Fe₃O₄@ZrO₂). Cadmium is one of the most substances heavy metals toxic at lower concentrations. It is used in many industries, including textiles, paint, and dyes. In drinking water and industrial wastewater, the permissible concentration has been set the concentration level at 0.003 mg/L by the World Health Organization.The adsorbent characterizations of SEM and XRF analysis showed that the Fe₃O₄@ZrO₂ had many different chemical composition and a possibility of high specific surface area due to the nanosize particle for adsorption processes. The Fe₃O₄@ZrO₂ showed high adsorption uptake capacity and selectivity for the cadmium in the aqueous solution. The highest cadmium adsorption capacity was achieved (24.85 mg/g) at pH 6 using the Fe₃O₄@ZrO₂ as adsorbent. The removal efficiency of the Fe₃O₄@ZrO₂ for Cd remains almost 80% after three cycles. Therefore, the Fe₃O₄@ZrO₂ has the potential to be used as an adsorbent in water and wastewater treatment.

Abstract: Targeted drug delivery systems with nanomaterials as drug carriers to specific organs can increase the therapeutic effect and reduce the side effects. Magnetic mesoporous silica nanoparticles are a multifunctional platform in drug delivery and magnetic hyperthermia therapy. In this study, the synthesis was developed with iron sand from Glagah Beach as a source for the magnetic nanoparticles formation and CTAB as a surfactant template. The research method was carried out in three steps, including the synthesis of magnetic nanoparticles (Fe₃O₄), coating of magnetic nanoparticles (Fe₃O₄@SiO₂), and surfactant-templating (Fe₃O₄@SiO₂@CTAB/SiO₂).The SEM analysis results showed that the Fe₃O₄ particles have various sizes. The weight concentration of Fe in Fe₃O₄ increased from 70.25% to 78.58% compared to Fe in iron sand by EDX analysis. The XRD results showed that the crystalline size of Fe₃O₄ and Fe₃O₄@SiO₂ particles are 6.31 nm and 2.37 nm, respectively. From the results of BET analysis, it is known that the longer sonication time, the pore diameter tends to decrease. It may be due to CTAB filling in the pore during the surfactant-templating process. The highest surface area of Fe₃O₄@SiO₂@CTAB/SiO₂ particle obtained was 14.31 m²/g with a pore diameter of 3.915 nm which has a mesoporous structure.

Abstract: Magnetic-bead separation or purification serves as a technique for effective isolation of biomolecules. In presented work we prepared and characterized core-shell magnetic nanoparticle samples consisted of Fe₃O₄ core coated with SiO₂ shell. Samples were subsequently coated with ligands MPTMS (3-(mercaptopropyl)trimethoxysilane), CPTMS (3-(chloropropyl)trimethoxysilane) and MMSP (3-(trimethoxysilyl)propyl methacrylate) with aim to increase the number of active centers for specific binding with RNA. Such samples were further investigated for their magnetic properties, size, and morphology. Magnetic properties were studied in DC field up to 5 T in temperature range 5 – 300 K. Size and morphology were determined from SEM micrographs and elemental compositions of the samples were investigated using EDX analysis. Modification of nanoparticle surface with different ligands leads to modification of active centers on the SiO₂ surface on which the DNA and RNA molecules can be bounded. It also causes the change in magnetic and structural properties of nanoparticles.

Abstract: Magnetic nanoparticles (Fe₃O₄) have considerable attention in various biomedical applications such as biosensors, drug delivery systems in the body, magnetic resonance imaging (MRI), and hyperthermia therapy. Hyperthermia therapy uses heat controlled by applied AC (Alternating Current) magnetic to kill cancer cells. This research aims to determine the effect of changes in temperature caused by the AC magnetic field on the varied magnetic nanoparticle solution. The Synthesize of Fe₃O₄ used the coprecipitation method to produce Fe₃O₄ nanoparticles. Mass of Fe₃O₄ nanoparticles varied of 95 mg and 125 mg. Nanoparticles physical properties were characterized using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and vibrating sample magnetometer (VSM). XRD profiles indicated that magnetic (Fe₃O₄) nanoparticles were successfully synthesized with a crystal size of 7.76 nm. SEM characterization of Fe₃O₄ nanoparticles was carried out at a magnification of 150.000 times and the average diameter of Fe₃O₄ powder nanoparticles was 20 nm. The temperature change measurement was performed using an AC magnetic field of 2.8 mT and frequency of 343 Hz, and time recorded changes temperature in 660 seconds. The temperature changes for solution concentrations of 95 mg and 125 mg were 7.7°C and 9.8°C, respectively. the concentration of solutions affects the value of the Specific Absorption Rate (SAR). The SAR values of each concentration of Fe₃O₄ solution were 0,0069 W/g and 0.0096 W/g. It proves that Fe₃O₃ prepared by coprecipitation method has potential for hyperthermia therapy application.

Abstract: Nowadays, the excessive and uncontrolled discharge of chemicals are imposing major health threats. The demands for clean and safe water amplifies the need to develop improved technologies for environmental contaminant removal. Considering the limitations of conventional methods for contaminants removal, we have prepared magnetic iron oxide nanoparticles functionalised with reduced graphene oxide as a potential material for environmental pollutants removal. The magnetic properties in potential adsorbent materials are highly desirable due to several advantages. Among which are their large adsorptive surface area, low diffusion resistance, high adsorption capacity and fast separation in large volumes of solution. The surface functionalised magnetic iron oxide nanoparticles (MNP) were fabricated using a one-pot hydrothermal method by adding reduced graphene oxide (rGO) into the reaction system. The graphene oxide were reduced prior to the addition in the hydrothemal decomposition step. The resultant rGO-MNP nanocomposites were characterised using FT-IR, SEM and VSM to investigate the functional groups, morphology and magnetic properties, resepectively. We also demonstrated the potential of the hybridised magnetic material with hydrophobic reduced graphene oxide for environmental pollutant removal.

Abstract: The giant magnetoresistance (GMR) thin film with spin valve (SV) structure of Ta (2 nm)/Ir₂₀Mn₈₀(10 nm)/Co₉₀Fe₁₀(3 nm)/Cu (2.2 nm)/Co₈₄Fe₁₀B₄(10 nm)/Ta (5 nm)] fabricated by RF magnetron sputtering method with a magnetoresistance (MR) of 6% was used in this work. Green synthesis of Fe₃O₄ magnetic nanoparticles (MNPs) using Moringa Oleifera (MO) leaf extract have been successfully conducted using the coprecipitation method. Fe₃O₄ MNPs demonstrated the inverse cubic spinel structure with the average crystallite size of 13.8 nm and decreased to 11.8 nm for Fe₃O₄/PEG. Fe₃O₄, as a magnetic label, integrated with a Wheatstone bridge-GMR sensor provides access to GMR-based biosensors. The induced-field increase leads the signal (ΔV) to increase with increasing nanoparticle concentration. It was discovered that a sensor can distinguish different types of magnetic labels. The sensitivity for Fe₃O₄ and MO-green synthesized Fe₃O₄ magnetic label was 0.04 and 0.1 mV/g/L, respectively. The GMR sensor performed the highest sensitivity on the MO-green synthesized Fe₃O₄ label. Thus, the SV thin film as a sensor and the green-synthesized Fe₃O₄ nanoparticles as a superior magnetic label are an excellent combination for biosensor application.

Abstract: The magnetic ferroferric oxide nanoparticles were modified with L-lysine to prepare immobilized carriers(Fe₃O₄-Lys), which was applied to the immobilization of Saccharomyces cerevisiae CGMCC No. 2230. The optimal immobilization conditions for preparation of Fe₃O₄-Lys-Cells were Fe₃O₄-Lys 0.01 g, cell dry weight 3 g, pH 7, 3 h, 30 °C. Ethyl R-4-chloro-3-hydroxybutyrate was gained by asymmetric reduction of ethyl-4-chlorooxobutanoate with Fe₃O₄-Lys-Cells as catalysis. 0.672 mol/L COBE can be converted completely in 40 h in the shaker, while only 24 h in the alternating magnetic field. The conversion and enantiomeric excess(e.e.) of (R)-CHBE reached 100% and more than 99.9%, respectively.

Abstract: Porous silicon has generated interest in scientific community after its photoluminescence discovery and thereafter, research was focused on to the chemical functionalization of silicon and subsequent anchoring of nanoparticles onto silicon surface. In the present work, the porous silicon has been effectively modified with magnetic nanoparticles which were prepared through metallorganic approach. The as-fabricated magnetic-porous silicon composites were characterised using FTIR and Raman spectroscopies, Scanning Electron Microscopy (SEM) as well as magnetic measurements.