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Structural characterization of Nd-Fe <sub/>3</sub> O <sub/>4</sub> nanoparticles prepared by hydrothermal synthesis method
摘要： Magnetic nanoparticles of Nd-Fe3O4 were prepared by hydrothermal synthesis method, using NdCl3·6H2O and FeCl3·6H2O as the starting materials in this paper. The structure and morphology of nanoparticles were investigated by XRD, FTIR, EDS and TEM. The results showed that, while the addition of Nd at 10% in mole ratio, resulted in the formation of Nd2O3 crystal peak in cubic Fe3O4 nanocrystallites by XRD. The absorption bands of Fe–O, –OH, –O–C–O– and –CH2– were accordant to the correspondent chemical groups by FTIR. The morphology of the prepared nanoparticles exhibited spherical structure and evenly distributed without agglomeration phenomenon by TEM. The elemental composition were mainly consistent with the precursor materials used in the experiment.
关键词： magnetic nanoparticles,hydrothermal synthesis,Nd-Fe3O4,Structural characterization
更新于2025-09-23 15:22:29
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A Recombinant Fluorescent Peptidomimetic Tracer for Immunodetection of Imidaclothiz
摘要： Peptidomimetic and anti-immunocomplex peptides, which could be readily isolated from phage display library, have shown a great potential for small molecule immunoassay development because they typically improve the sensitivity and avoid the use of chemical haptens as coating or tracers antigens. However, the phage borne peptides are unconventional immunoassay reagent, which greatly limits their use in commercial applications and requires secondary reagents for detection. In order to overcome these limitations, we used C2-15, a peptidomimetic of imidaclothiz, as a model peptide fused to emerald green fluorescent protein (EmGFP) at the N terminus (C2-15-EmGFP) and C terminus (EmGFP-C2-15) to generate novel fluorescent peptide tracers. Both recombinant fluorophores reacted with similar affinity to the anti-imidaclothiz monoclonal antibody 1E7, but due to its higher expression C2-15-EmGFP was chosen to develop a competitive magnetic separation fluorescence immunoassay (MSFIA). After a competitive step with the analyte, the C2-15-EmGFP/antibody complex bound to the magnetic beads was separated with a magnet, and due to the fast dissociation of the peptide-antibody interaction, the fluorescence signal was detected following the spontaneous dissociation of the complex in fresh buffer. The concentration of imidaclothiz causing the 50% inhibitory concentration (IC50) was 11.00 ng mL-1, and the MSFIA performed with excellent recovery and good correlation with high-performance liquid chromatography in different matrices.
关键词： Magnetic nanoparticles,Emerald green fluorescent protein,Recombinant peptide,Imidaclothiz,Peptidomimetic
更新于2025-09-23 15:21:01
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[IEEE 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Rome, Italy (2019.6.17-2019.6.20)] 2019 PhotonIcs & Electromagnetics Research Symposium - Spring (PIERS-Spring) - Design and Implementation of Fiber-embedded Plasmonic Structures in Microwires
摘要： General principles are developed using a finite element model regarding how time-dependent power dissipation of magnetic nanoparticles can be used to optimize hyperthermia selectivity. To make the simulation more realistic, the finite size and spatial location of each individual nanoparticle is taken into consideration. When energy input into the system and duration of treatment is held constant, increasing the maximum power dissipation of nanoparticles increases concentrations of energy in the tumor. Furthermore, when the power dissipation of magnetic nanoparticles rises linearly, the temperature gradient on the edge of the tumor increases exponentially. With energy input held constant, the location and duration of maximum power dissipation in the treatment time scheme will affect the final energy concentration inside the tumor. Finally, connections are made between the simulation results and optimization of the design of nanoparticle power dissipation time-schemes for hyperthermia.
关键词： treatment planning,finite-element modeling,Hyperthermia optimization,magnetic nanoparticles
更新于2025-09-23 15:21:01
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Usefulness of magnetically-controlled MNPs-enzymes microreactors for the fluorimetric determination of total cholesterol in serum
摘要： A new dynamic method containing a magnetically retained enzyme reactor (MRER) located in the reaction/detection zone of a flow injection (FI) system, has been used for the determination of total cholesterol in serum samples. The MRER was formed by a mixture ratio of 2/1 of immobilized enzymes cholesterol esterase (ChE) and cholesterol oxidase (COx) on magnetic nanoparticles (MNPs). The analytical signal is based on the fluorescence decreasing of the fluorophore naphtofluorescein (NF) due to its oxidation by the H2O2 formed in the enzymatic reactions. The dynamic range of the calibration graph was 1.55–100 mmol L?1 expressed as total cholesterol concentration (r2 = 0.9995, n = 5, r = 3), and the detection limit was 0.65 mmol L?1. The precision expressed as relative standard deviation (RSD %) was in the range of 4.7 and 0.6%. The method showed a sampling frequency of 10 h?1 and this method was applied to the determination of cholesterol in serum samples. The results were compared with those obtained using a previous automated clinical analyzer (ILab 600 analyzer). Also, recovery values ranging between 88.5 and 101.5% were achieved.
关键词： Fluorimetric,Naphtofluorescein,Electromagnet retention,Cholesterol,Serum,Enzyme magnetic nanoparticles
更新于2025-09-23 15:19:57
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Rapidly detecting antibiotics with magnetic nanoparticle coated CdTe quantum dots
摘要： A reusable magnetic-quantum dot material (MNP–SiO2–QD) with good magnetic properties and high ?uorescence retention was successfully fabricated from linked magnetic nanoparticles and quantum dots. The resulting material can qualitatively and quantitatively detect four kinds of antibiotics and maintain high recovery rates.
关键词： reusability,antibiotics detection,fluorescence,magnetic nanoparticles,quantum dots
更新于2025-09-23 15:19:57
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Controllable movement of single-photon source in multifunctional magneto-photonic structures
摘要： Quantum dot (QD) coupling in nanophotonics has been widely studied for various potential applications in quantum technologies. Micro-machining has also attracted substantial research interest due to its capacity to use miniature robotic tools to make precise controlled movements. In this work, we combine fluorescent QDs and magnetic nanoparticles (NPs) to realize multifunctional microrobotic structures and demonstrate the manipulation of a coupled single-photon source (SPS) in 3D space via an external magnetic field. By employing the low one photon absorption (LOPA) direct laser writing (DLW) technique, the fabrication of 2D and 3D magneto-photonic devices containing a single QD is performed on a hybrid material consisting of colloidal CdSe/CdS QDs, magnetite Fe3O4 NPs, and SU-8 photoresist. Two types of devices, contact-free and in-contact structures, are investigated to demonstrate their magnetic and photoradiative responses. the coupled SPS in the devices is driven by the external magnetic field to perform different movements in a 3D fluidic environment. The optical properties of the single QD in the devices are characterized.
关键词： Quantum dot,direct laser writing,single-photon source,magnetic nanoparticles,magneto-photonic structures
更新于2025-09-23 15:19:57
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A Microfluidic Biosensor Based on Magnetic Nanoparticle Separation, Quantum Dots Labeling and MnO2 Nanoflower Amplification for Rapid and Sensitive Detection of Salmonella Typhimurium
摘要： Screening of foodborne pathogens is an effective way to prevent microbial food poisoning. A microfluidic biosensor was developed for rapid and sensitive detection of Salmonella Typhimurium using quantum dots (QDs) as fluorescent probes for sensor readout and manganese dioxide nanoflowers (MnO2 NFs) and as QDs nanocarriers for signal amplification. Prior to testing, amino‐modified MnO2 nanoflowers (MnO2‐NH2 NFs) were conjugated with carboxyl‐modified QDs through EDC/NHSS method to form MnO2‐QD NFs, and MnO2‐QD NFs were functionalized with polyclonal antibodies (pAbs) to form MnO2‐QD‐pAb NFs. First, the mixture of target Salmonella Typhimurium cells and magnetic nanoparticles (MNPs) modified with monoclonal antibodies (mAbs) was injected with MnO2‐QD‐pAb NFs into a microfluidic chip to form MNP‐bacteria‐QD‐MnO2 complexes. Then, glutathione (GSH) was injected to dissolve MnO2 on the complexes into Mn2+, resulting in the release of QDs. Finally, fluorescent intensity of the released QDs was measured using the fluorescent detector to determine the amount of Salmonella. A linear relationship between fluorescent intensity and bacterial concentration from 1.0 × 102 to 1.0 × 107 CFU/mL was found with a low detection limit of 43 CFU/mL and mean recovery of 99.7% for Salmonella in spiked chicken meats, indicating the feasibility of this biosensor for practical applications.
关键词： quantum dots,manganese dioxide nanoflowers,Salmonella Typhimurium,Microfluidic biosensor,magnetic nanoparticles
更新于2025-09-23 15:19:57
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Ultrafast pulse generation for Er- and Tm- doped fiber lasers with Sb thin film saturable absorber
摘要： General principles are developed using a finite element model regarding how time-dependent power dissipation of magnetic nanoparticles can be used to optimize hyperthermia selectivity. To make the simulation more realistic, the finite size and spatial location of each individual nanoparticle is taken into consideration. When energy input into the system and duration of treatment is held constant, increasing the maximum power dissipation of nanoparticles increases concentrations of energy in the tumor. Furthermore, when the power dissipation of magnetic nanoparticles rises linearly, the temperature gradient on the edge of the tumor increases exponentially. With energy input held constant, the location and duration of maximum power dissipation in the treatment time scheme will affect the final energy concentration inside the tumor. Finally, connections are made between the simulation results and optimization of the design of nanoparticle power dissipation time-schemes for hyperthermia.
关键词： treatment planning,finite-element modeling,Hyperthermia optimization,magnetic nanoparticles
更新于2025-09-23 15:19:57
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Bioinspired magnetic nanoparticles as multimodal photoacoustic, photothermal and photomechanical contrast agents
摘要： Nanoparticles from magnetotactic bacteria have been used in conventional imaging, drug delivery, and magnetic manipulations. Here, we show that these natural nanoparticles and their bioinspired hybrids with near-infrared gold nanorods and folic acid can serve as molecular high-contrast photoacoustic probes for single-cell diagnostics and as photothermal agents for single-cell therapy using laser-induced vapor nanobubbles and magnetic field as significant signal and therapy amplifiers. These theranostics agents enable the detection and photomechanical killing of triple negative breast cancer cells that are resistant to conventional chemotherapy, with just one or a few low-energy laser pulses. In studies in vivo, we discovered that circulating tumor cells labeled with the nanohybrids generate transient ultrasharp photoacoustic resonances directly in the bloodstream as the basis for new super-resolution photoacoustic flow cytometry in vivo. These properties make natural and bioinspired magnetic nanoparticles promising biocompatible, multimodal, high-contrast, and clinically relevant cellular probes for many in vitro and in vivo biomedical applications.
关键词： theranostics,super-resolution,contrast agents,photomechanical,photoacoustic,magnetic nanoparticles,photothermal,circulating tumor cells,bioinspired,magnetotactic bacteria
更新于2025-09-19 17:15:36
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Multifunctional luminescent immuno-magnetic nanoparticles: toward fast, efficient, cell-friendly capture and recovery of circulating tumor cells
摘要： Highly efficient isolation and recovery of viable circulating tumor cells (CTCs) from the blood of patients is an important precondition to address the current dilemma of insufficient CTC studies, and can promote the development of individualized antitumor therapies. Herein, a cell-friendly CTC isolation and recovery nanoplatform with luminescent labelling was established using a layer-by-layer (LbL) assembly technique and a stimulated cellular-release strategy. In particular, the anti-epithelial cell adhesion molecule (anti-EpCAM) antibody was introduced with a disulfide bond-containing linker for further bio-friendly recovery of the CTCs. Quantum dots (QDs) were deposited onto fast magnet-responsive Fe3O4 nanoparticles through a facile LbL assembly method to monitor the capture and recovery process in real time. The obtained PEGylated immuno-magnetic nanospheres (PIMNs) can all be magnetically collected within 2 min. Capture efficiencies above 90% can be achieved from blood samples with 5–200 CTCs per mL after only 1–2 min incubation. Nearly all PIMNs on the surface of the CTCs were detached after 15 min of glutathione (GSH) treatment with the disappearance of QD signals. Recovered CTCs could be directly used for culture (cell viability, 98%), and their invasiveness and migration characteristics remained unchanged. Furthermore, the PIMNs were successfully applied to isolate CTCs in cancer patients’ peripheral blood samples, and an average of 8.6 ± 5.8 CTCs per mL was detected. The results above suggested that PIMNs may serve as a powerful nanoplatform for CTC screening, isolation and recovery.
关键词： layer-by-layer assembly,circulating tumor cells,capture and recovery,Multifunctional luminescent immuno-magnetic nanoparticles,quantum dots,glutathione treatment
更新于2025-09-19 17:15:36