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Si, N-codoped carbon dots: preparation and application in iron overload diagnosis
摘要： Heteroatom doping is a straightforward and smart strategy to improve the fluorescence efficiency of carbon dots (CDs). We synthesized the Si, N-codoped CDs (SiNCDs) with high quantum yield up to 29.7% through one-step hydrothermal method. The linear range for Fe3+ was between 0 and 200 μM, and the limit of detection was about 5 μM, which presented potential for Fe quantification in serum to diagnose Fe overload. In addition, the SiNCDs demonstrated good selectivity to Fe3+ among high concentrations of metal ions, amino acids and H2O2, so there is no need to mix additional reagents as the colorimetric method does in clinic, making SiNCDs more competitive in clinical application. Furthermore, we explored the practicability of SiNCDs by detecting Fe in serum from five healthy volunteers and three patients suffering Fe overload. The recovery rate was from 87.1 to 113.6%, which confirmed the application prospect of SiNCDs in clinical diagnostics.
关键词： N-codoped carbon dots,hydrothermal method,Si,iron overload diagnosis,fluorescence efficiency,quantum yield
更新于2025-09-23 15:21:21
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Ferrous-Supply-Regeneration Nanoengineering for Cancer Cell Specific Ferroptosis in Combination with Imaging-Guided Photodynamic Therapy
摘要： Non-apoptotic ferroptosis is of clinical importance because it offers a solution to surmount the inevitable bio-carriers of traditional apoptotic therapeutic means. Inspired by industrial Electro-Fenton technology featured with electrochemical iron cycling, we construct a ferrous-supply-regeneration nanoengineering to intervene tumorous iron metabolism for enhanced ferroptosis. Fe3+ ion and naturally derived tannic acid (TA) spontaneously form network-like corona onto sorafenib (SRF) nanocore. The formed SRF@FeIIITA nanoparticles can respond to lysosomal acid environment with corona dissociation, permitting SRF release to inhibit GPX4 enzyme for ferroptosis initiation. TA is arranged to chemically reduce the liberated and the ferroptosis-generated Fe3+ to Fe2+, offering iron redox cycling thus to effectively produce lipid peroxide required in ferroptosis. Sustained Fe2+ supply leads to long-term cytotoxicity, which is identified to be specific to H2O2-overloaded cancer cells but minimal in normal cells. SRF@FeIIITA-mediated cell death proves to follow ferroptosis pathway and strongly inhibits tumor proliferation. Moreover, SRF@FeIIITA provides a powerful platform capable of versatile integration between apoptosis and non-apoptosis means. Typically, photosensitizer-adsorbed SRF@FeIIITA demonstrates rapid tumor imaging owing to the acid-responsive fluorescence recovery. Together with ferroptosis, imaging-guided photodynamic therapy induces complete tumor elimination. This study offers ideas about how to advance anticancer ferroptosis through rational material design.
关键词： iron redox cycling,iron-tannic acid network,photodynamic therapy,ferroptosis,Electro-Fenton technology
更新于2025-09-23 15:21:01
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Challenges in Tracking of Fluorochrome-Labelled Nanoparticles in Mice via Whole Body NIRF Imaging
摘要： Fluorochrome-labelled iron oxide magnetic nanoparticles (MNP) have been of great help in elucidating biological processes. Here, we used dually-fluorochrome-labelled MNP and studied to what extent fluorescence detection could reflect their fate in living animals. One day after application in mice (200 μmol Fe/kg body weight), the fluorescence of the dye attached to the core (DY-730) was very prominent and in agreement with the increase of iron in the liver and spleen of mice, but inconspicuous at time points thereafter. We attribute this fluorescence behavior to early degradation processes of the MNP′s core in the cellular lysosomal compartment. In contrast, the fluorescence of the dye DY-555 stuck to the PEG coating was not detectable in vivo. In summary, labelling of MNP with dyes at their metallic core could be of help when detecting first incidences of MNP biodegradation in vivo, as opposed to dyes attached to the MNP coating.
关键词： nanoparticle labelling,iron oxide,nanoparticle tracking,fluorescence,nanoparticles
更新于2025-09-23 15:21:01
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The Structure of Iron Powder Aggregation Obtained by Selective Laser Melting
摘要： A powder of different fractional composition was obtained from the iron ingot using the melt atomization method, from which samples for further studies were grown on the EOSint M270 unit using the selective laser melting (SLM) method. When considering the thin sections of the samples, we observed equiaxed recrystallized grains up to 20 μm in size, randomly distributed particles in the form of fragments up to 5 μm in size and equally oriented non-axial crystallites, forming groups in the form of arcuate layers with a front width of 800 μm and depth from 10 to 30 microns. Between them, narrow zones of increased chemical content were found, which are interpreted as probable traces of the stoppages of thermal fronts. We recorded traces of mass localized microplastic flow in the form of extended (up to 350x40 μm) and curved microregions with unequal-sized grains bordering microregions filled with equiaxial recrystallized grains due to the action of non-uniform thermal fields. Thus, in metal objects produced by the SLM, the complex morphology of the structure indicates a combination of different-scale mechanisms of structural changes. It has been established that in non-stationary temperature conditions of structure formation, the role of kinetic processes increases.
关键词： powdered iron,kinetic processes,selective laser melting,additive technologies
更新于2025-09-23 15:21:01
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Preparation and comparison of Fe3O4@graphene oxide nanoclusters for analysis of glimepiride in urine by surface-assisted laser desorption/ionization time-of-flight mass spectrometry
摘要： Graphene oxide (GO) has the ability to absorb certain compounds, and it can be modified with functional groups for different purposes; for instance, iron oxide (IO) nanoparticles can be used to concentrate analyte by a magnet. Recently, many kinds of GO have been developed, such as single-layer GO (SLGO), two-to-four layers of GO (i.e., few-layer GO, FLGO2–4), and four-to-eight layers of GO (i.e., multi-layer GO, MLGO4–8). However, the abilities of these layered GO coated with IO nanoparticles have not been investigated. In this study, we conducted a novel analysis of glimepiride by using layered GO-coated magnetic clusters of IO nanoparticles that were synthesized through a simple and facile emulsion-solvent evaporation method. The methodology is based on (i) enrichment of glimepiride using the layered GO-coated magnetic clusters of IO nanoparticles (IO@SLGO, IO@FLGO2–4, and IO@MLGO4–8), and (ii) rapid determination using magnetic cluster–based surface-assisted laser desorption/ionization time-of-flight mass spectrometry (SALDI-TOFMS). We found that IO@MLGO4–8, the magnetic cluster with the greatest number of GO layers, had the best limit of detection (28.6 pmol/μL for glimepiride). The number of GO layers played a significant role in increasing the sensitivity of the SALDI-MS, indicating that the size of GO in the magnetic clusters contributed to the desorption/ionization efficiency. To the best of our knowledge, this is the first study to enrich glimepiride using magnetic clusters of different GO types and to show that the glimepiride in HLB purified urine adsorbed by magnetic clusters can be analyzed by SALDI-TOFMS.
关键词： Mass spectrometry,Iron oxide,Glimepiride,Nanocluster,SALDI,Graphene oxide
更新于2025-09-23 15:21:01
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Morphology and magnetic properties of grain-oriented steel scribed using different picosecond lasers
摘要： Micro-scribing experiments were conducted to investigate the characteristics of the associated ablative behavior and the improvements to the magnetic properties of grain-oriented steel using both a 532 nm and a 1064 nm wavelength ultra-fast picosecond laser. Ablative morphological characteristic analysis and elemental analysis were carried out using a 3D confocal microscope, a scanning electron microscope, and energy-dispersive spectroscopy. The damage mechanisms were analyzed by comparing the ablation morphologies. Furthermore, an iron loss tester and magnetic domain observation instrument were used to analyze the dynamic hysteresis loop, macroscopic magnetic property parameters, and to observe the microscopic structure of the magnetic domains. The magnetization behavior, loop characteristics, and magnetic domain refinement mechanisms were discussed. The results indicated that the magnetic domains were clearly refined and that the magnetic properties were significantly improved after picosecond laser scribing of the grain-oriented steel. The sample scribed using an ultra-fast wavelength 532 nm laser was more effectively scribed: the magnetic domain was slightly more refined, the iron loss was reduced by 15.73%, the coercivity was reduced by 24.42%, the residual magnetism was reduced by 20.8%, and the relative permeability was increased by 10.3%. The surface was of a high quality, but there were traces of stress damage caused by high-pressure steam in the scribed area. The 1064 nm wavelength ultra-fast laser clearly showed the effects of heat accumulation in the scribed area. Defects due to thermal damage were more common. The improvement to the macroscopic magnetic properties depended largely on the surface quality of the scribing and the penetration depth of the residual stress in the sample.
关键词： Magnetic domains,Laser surface treatment,Scanning electron microscopy,Iron core loss,Magnetic properties,Grain-oriented silicon steel
更新于2025-09-23 15:21:01
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Developing an Analytical Method Based on Graphene Quantum Dots for Quantification of Deferiprone in Plasma
摘要： In the world of nanotechnology, graphene quantum dots (GQDs) have been considerably employed in numerous optical sensing and bioanalytical applications. Herein, a simple and cost-efficient methodology was developed to the quantification of deferiprone in plasma samples by utilizing the selective interaction of the GQDs and drug in the presence of Fe3+ ions. GQDs were synthesized by a bottom-up technique as an advantageous fluorescent probe. Increasing levels of deferiprone ranging from 5 to 50 mg.L?1, leads to significant fluorescence quenching of GQDs. In addition, the calibration curve was revealed a linear response in this range with a sensitivity of 5 mg.L?1. The method validation was carried out according to the FDA guidelines to confirm the accuracy, precision, stability and selectivity of the developed method. The results show that this green and low-cost fluorescent probe could be used for the analysis of deferiprone.
关键词： Graphene quantum dots (GQDs),Fluorescent,Plasma,Deferiprone,Iron
更新于2025-09-23 15:21:01
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Biocompatible superparamagnetic core-shell nanoparticles for potential use in hyperthermia-enabled drug release and as an enhanced contrast agent
摘要： Superparamagnetic iron oxide nanoparticles (SPIONs) and core-shell type nanoparticles, consisting of SPIONs coated with mesoporous silica and/or lipid, were synthesized and tested for their potential theranostic applications in drug delivery, magnetic hyperthermia and as a contrast agent. Transmission Electron Microscopy (TEM) confirmed the size of bare and coated SPIONs was in the range of 5-20 nm and 100-200 nm respectively. The superparamagnetic nature of all the prepared nanomaterials as indicated by Vibrating Sample Magnetometry (VSM) and their heating properties under an AC field confirm their potential for hyperthermia applications. Scanning Column Magnetometry (SCM) data showed that extrusion of bare-SPION (b-SPION) dispersions through a 100 nm polycarbonate membrane significantly improved the dispersion stability of the sample. No sedimentation was apparent after 18 hours compared to a pre-extrusion estimate of 43% settled at the bottom of the tube over the same time. Lipid coating also enhanced dispersion stability. Transversal relaxation time (T2) measurements for the nanoparticles, using a bench-top relaxometer, displayed a significantly lower value of 46 ms, with a narrow relaxation time distribution, for lipid silica coated SPIONs (Lip-SiSPIONs) as compared to that of 1316 ms for the b-SPIONs. Entrapment efficiency of the anticancer drug, Doxorubicin (DOX) for Lip-SPIONs was observed to be 35% which increased to 58% for Lip-SiSPIONs. Moreover, initial in-vitro cytotoxicity studies against human breast adenocarcinoma, MCF-7 cells showed that % cell viability increased from 57% for bSPIONs to 82% for Lip-SPIONs and to 87% for Lip-SiSPIONs. This suggests that silica and lipid coatings improve the biocompatibility of bSPIONs significantly and enhance the suitability of these particles as drug carriers. Hence, the magnetic nanomaterials prepared in this work have potential theranostic properties as a drug carrier for hyperthermia cancer therapy and also offer enhancement of contrast agent efficacy and a route to a significant increase in dispersion stability.
关键词： magnetoliposomes,drug carrier,cancer therapy,colloidal stability,hyperthermia,theranostic,Superparamagnetic iron oxide nanoparticles
更新于2025-09-23 15:21:01
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Laser cavitation peening of gray cast iron: Effect of coverage layer on the surface integrity
摘要： Copper coverage layer was employed to the laser cavitation peening (LCP) of HT200 gray cast iron. The process of bubble evolution, velocity field of bubble, impact of water-jet, deformation and stress of material were simulated. The effects of coverage layer on the surface integrity (surface morphology and roughness, residual stress, micro-hardness) of LCP treated HT200 under various laser energies and defocusing amounts were systemically investigated. The results indicate that the maximum velocity of water-jet is 380 m/s and the diameter is 0.1 mm. The surface roughness of HT200 increases after the treatment of LCP. The presence of Copper coverage layer makes the HT200 surface more flat and the surface roughness decreases by half. At the case of no coverage layer, the parameters of 200 mJ laser energy and 1 mm defocusing amount are optimal for roughness, compressive residual stress and micro-hardness. Higher laser energy produces higher magnitude of micro-hardness and compressive residual stress in the case of coverage layer, and the optimal defocusing amount is 0 mm.
关键词： Coverage layer,surface integrity,simulation,Laser cavitation peening,HT200 gray cast iron
更新于2025-09-23 15:21:01
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Luminescence and reactivity of a charge-transfer excited iron complex with nanosecond lifetime
摘要： Iron’s abundance and rich coordination chemistry are potentially appealing features for photochemical applications. However, the photoexcitable charge-transfer (CT) states of most Fe complexes are limited by picosecond or sub-picosecond deactivation through low-lying metal centered (MC) states, resulting in inefficient electron transfer reactivity and complete lack of photoluminescence. Here we show that octahedral coordination of Fe(III) by two mono-anionic facial tris-carbene ligands can suppress such deactivation dramatically. The resulting complex [Fe(phtmeimb)2]+, where phtmeimb is [phenyl(tris(3-methylimidazol-1-ylidene))borate]-, exhibits strong, visible, room temperature photoluminescence with a 2.0 ns lifetime and 2% quantum yield via spin-allowed transition from a ligand-to-metal charge-transfer (2LMCT) state to the ground state (2GS). Reductive and oxidative electron transfer reactions were observed for the 2LMCT state of [Fe(phtmeimb)2]+ in bimolecular quenching studies with methylviologen and diphenylamine.
关键词： charge-transfer,iron complex,electron transfer,photoluminescence,N-heterocyclic carbene
更新于2025-09-23 15:21:01