Search Results (15)

Single-chip integration technology for multifunctional sensors has become an important development direction due to its low power consumption and versatile functionality. However, the fabrication compatibility between different sensing components remains a key challenge for high-performance integrated sensors, often leading to complex processes and increased costs. This work presents a microfabrication-compatible photo-magnetic integrated sensor chip based on micro–nano processing methods. The integrated sensor chip includes giant magnetoresistance (GMR) and a light-dependent resistor (LDR). The fabrication process was based on standard MEMS fabrication with compatibility and cost-effectiveness. The experimental results demonstrated that the chip can simultaneously realize both optical and magnetic detection with magnetic field sensitivity of 3.74 mV/Oe and photodetection sensitivity of 0.79 $\mathsf{\mu }$A/($\mathsf{\mu }$W/cm²) at a 5 V bias. The integrated sensor features high-sensitivity magnetic performance and weak-light detection capability, with promising application in robotics and advanced manufacturing fields. Full article

The magnetic properties of molecular nanomagnets can be finely modulated by light, which provides great potential in optical switches, smart sensors, and data storage devices. Light-induced spin transition, structure changes, and radical formation could tune the static and dynamic magnetic properties of molecular nanomagnets with high spatial and temporal resolutions. Herein, we summarize the design strategies of photoresponsive molecular nanomagnets and review the recent advances in transition metal/lanthanide molecular nanomagnets with photomagnetic properties. The photoresponsive mechanism based on spin transition, photocyclization, and photogenerated radicals is discussed in detail, providing insights into the photomagnetic properties of molecular nanomagnets for advanced photoresponsive materials. Full article

Dental implant papilla (DIP) is susceptible to bacterial adhesion and biofilm formation, and oral pathogenic biofilms can cause persistent oral infections. Enrichment of bacterial biofilms on implants can lead to soft tissue irritation and adjacent bone resorption, severely compromising dental health and potentially leading to periodontitis, implant loss and costly follow-up care. Nanozymes (NZs) are recently used in biofilm removal as they can induce the production of reactive oxygen species (ROS), which can kill bacteria. However, the short lifespan of ROS limits their diffusion distance, and affects their therapeutic efficacy. In this study, we prepared Fe₃O₄ nanoparticles (NZs) with different morphologies: flower-like (F-Fe₃O₄), hollow spherical (M-Fe₃O₄), octahedral (O-Fe₃O₄), and conventional nanoparticles (N-Fe₃O₄). The ferromagnetic properties of Fe₃O₄ NZs allow them to move and penetrate the biofilm under the action of a magnetic field. The saturation magnetic intensities of the four samples were as follows: F-Fe₃O₄ (23.1 emu g⁻¹), M-Fe₃O₄ (73.34 emu g⁻¹), O-Fe₃O₄ (96.06 emu g⁻¹), and N-Fe₃O₄ (52.15 emu g⁻¹). The synergistic combination of photothermal action and catalytic sterilization can effectively remove the biofilm. In addition, the prepared Fe₃O₄ nanozymes were able to maintain high biological activity on the implant surface with some osteogenic effect. Full article

The antibacterial activity of g-C₃N₄ and Cu-g-C₃N₄ was evaluated against E. coli, with their disinfection capabilities influenced by structural characteristics, photocatalytic properties, and modulation under a static magnetic field. The incorporation of Cu²⁺ does not significantly affect the (210) reflection in XRD analysis, indicating that the alignment of aromatic layers remains stable. However, the presence of copper enables complete disinfection, in contrast to graphitic carbon nitride, which achieves only partial disinfection. Cu²⁺ is likely positioned at N-aliphatic sites and coexists with hydroxylated species, which may influence photocatalytic performance by modifying reactant adsorption and ROS generation. SEM-EDS analysis confirmed that Cu²⁺ modification did not significantly alter the material’s morphology, although a 3% copper content was detected, suggesting a heterogeneous surface distribution. Thermodynamic analysis showed that exposure to a magnetic field increased the Gibbs free energy of adsorption from 6.34 J/m² to 10.52 J/m², reducing interactions with key reactants essential for ROS formation. As a result, both disinfection and photodegradation efficiency were significantly diminished. Additionally, the presence of a magnetic field was found to modify the surface properties of the material, affecting its photocatalytic performance. In Cu-C₃N₄ materials, a decrease in the contact angle suggests enhanced hydrophilicity, while an increase in surface tension may influence the adsorption of water and hydroxyl radicals. This study underscores the effect of a magnetic field on the photocatalytic behavior of materials deposited on polymeric substrates with intrinsic electronic properties, ultimately impacting overall disinfection efficiency. Full article

Previously, we introduced photomagnetic imaging (PMI) that synergistically utilizes laser light to slightly elevate the tissue temperature and magnetic resonance thermometry (MRT) to measure the induced temperature. The MRT temperature maps are then converted into absorption maps using a dedicated PMI image reconstruction algorithm. In the MRT maps, the presence of abnormalities such as tumors would create a notable high contrast due to their higher hemoglobin levels. In this study, we present a new artificial intelligence-based image reconstruction algorithm that improves the accuracy and spatial resolution of the recovered absorption maps while reducing the recovery time. Technically, a supervised machine learning approach was used to detect and delineate the boundary of tumors directly from the MRT maps based on their temperature contrast to the background. This information was further utilized as a soft functional a priori in the standard PMI algorithm to enhance the absorption recovery. Our new method was evaluated on a tissue-like phantom with two inclusions representing tumors. The reconstructed absorption map showed that the well-trained neural network not only increased the PMI spatial resolution but also improved the accuracy of the recovered absorption to as low as a 2% percentage error, reduced the artifacts by 15%, and accelerated the image reconstruction process approximately 9-fold. Full article

In this paper, the luminescent complex Eu(3-thenoyltrifluoroacetonate)₃ was integrated with Fe₃O₄ and gold (Au) nanoparticles to form a multifunctional nanocomposite, Fe₃O₄/Au/Eu(TTA)₃ (FOASET NC), for dual magnetic-photothermal therapy and biomedical imaging. Upon functionalization with amine-NH₂, the FOASET NC exhibits a small size of 60–70 nm and strong, sharp emission at λ_max = 614 nm, enhanced by surface plasmon resonance (SPR) of Au nanoparticles that provided an effective label for HT29 colorectal cancer cells by fluorescence microscopy imaging. In addition, a hyperthermia temperature (42–46 °C) was completely achieved by using these FOASET NCs in an aqueous solution with three heating modes for (i) Magnetic therapy (MT), (ii) Photothermal therapy (PT), and (iii) Dual magnetic-photothermal therapy (MPT). The heating efficiency was improved in the dual magnetic-photothermal heating mode. Full article

This study presents the bio-photocatalytic upgrading of biogas utilising carbon dioxide (CO₂) as a potential option for beginning fossil fuel depletion and the associated environmental risks in the pursuit of sustainable development. Herein, magnetite photocatalyst (Fe-TiO₂) was employed with an integrated anaerobic-photomagnetic system for the decontamination of municipality wastewater for biogas production. The Fe-TiO₂ photocatalyst used, manufactured via a co-precipitation technique, had a specific surface area of 62.73 m²/g, micropore volume of 0.017 cm³/g and pore size of 1.337 nm. The results showed that using the ultraviolet-visible (UV-Vis) photomagnetic system as a post-treatment to the anaerobic digestion (AD) process was very effective with over 85% reduction in colour, chemical oxygen demand (COD) and turbidity. With an organic loading rate (OLR) of 0.394 kg COD/L·d and hydraulic retention time (HTR) of 21 days, a 92% degradation of the organic content (1.64 kgCOD/L) was attained. This maximised the bioenergy production to 5.52 kWh/m³ with over 10% excess energy to offset the energy demand of the UV-Vis lamp. Assuming 33% of the bioenergy produced was used as electricity to power the UV-Vis lamp, the CO₂ emission reduction was 1.74 kg CO₂ e/m³, with good potential for environmental conservation. Full article

The collective magnetic behavior of photoswitchable 11 nm cyanide-bridged nanoparticles based of the Prussian blue analogue CsCoFe were investigated when embedded in two different matrices with different concentrations. The effect of the intensity of light irradiation was studied in the less concentrated sample. Magnetization studies and alternating magnetic susceptibility data are consistent with a collective magnetic behavior due to interparticle dipolar magnetic interaction for the two compounds, even though the objects have a size that place them in the superparamagnetic regime. Full article

Three new ionic salts containing [M(CN)₈]⁴⁻ (M = Mo^IV and W^IV) were prepared using large complex cations based on a non-conventional motif built with the tris(2-aminoethyl)amine (noted hereafter tren) ligand, [{M’(tren)}₃(μ-tren)]⁶⁺ (M’ = Cu^II and Zn^II). The crystal structures of the three compounds show that the atomic arrangement is formed by relatively isolated anionic and cationic entities. The three compounds were irradiated with a blue light at low temperature, and show a significant photomagnetic effect. The remarkable properties of these compounds are (i) the long-lived photomagnetic metastable states for the [Mo(CN)₈]⁴⁻-based compounds well above 200 K and (ii) the rare efficient photomagnetic properties of the [W(CN)₈]⁴⁻-based compound. These photomagnetic properties are compared with the singlet-triplet conversion recently reported for the K₄[Mo(CN)₈]·2H₂O compound. Full article

We have investigated by means of optical microscopy and magnetic measurements the first-order thermal spin transition of the [{Fe(NCSe)(py)₂}₂(m-bpypz)] spin-crossover compound under various shining intensities, far from the light-induced spin-state trapping region. We found evidence of photo-heating effects on the thermally-induced hysteretic response of this spin-crossover material, thus causing the shift of the thermal hysteresis to lower temperature regions. The experimental results are discussed in terms of the apparent crystal temperature and are analyzed theoretically using two evolution equations of motion, written on the high-spin (HS) fraction and heat balance between the crystal and the thermal bath. A very good qualitative agreement was found between experiment and theory in the stationary regime, explaining the experimental observations well and identifying the key factors governing these photo-thermal effects. Full article

In this paper, we report on the synthesis, crystal structure, and photomagnetic properties of the spin-crossover salt of formula [Fe(bpp)₂](C₆H₄NO₂)₂·4H₂O (1·4H₂O) (bpp = 2,6-bis(pyrazol-3-yl)pyridine; C₆H₄NO₂⁻ = nicotinate anion). This compound exhibits a 3D supramolecular architecture built from hydrogen bonds between iron(II) complexes, nicotinate anions, and water molecules. As synthesized, the hydrated material is low-spin and desolvation triggers a low-spin (LS) to high-spin (HS) transformation. Anhydrous phase 1 undergoes a partial spin crossover (T_1/2= 281 K) and a LS to HS photomagnetic conversion with a T(LIESST) value of 56 K. Full article

The use of high intensity chemo-radiotherapies has demonstrated only modest improvement in the treatment of high-risk neuroblastomas. Moreover, undesirable drug specific and radiation therapy-incurred side effects enhance the risk of developing into a second cancer at a later stage. In this study, a safer and alternative multimodal therapeutic strategy involving simultaneous optical and oscillating (AC, Alternating Current) magnetic field stimulation of a multifunctional nanocarrier system has successfully been implemented to guide neuroblastoma cell destruction. This novel technique permitted the use of low-intensity photo-magnetic irradiation and reduced the required nanoparticle dose level. The combination of released cisplatin from the nanodrug reservoirs and photo-magnetic coupled hyperthermia mediated cytotoxicity led to the complete ablation of the B35 neuroblastoma cells in culture. Our study suggests that smart nanostructure-based photo-magnetic hybrid irradiation is a viable approach to remotely guide neuroblastoma cell destruction, which may be adopted in clinical management post modification to treat aggressive cancers. Full article

The spin-crossover properties of the strongly cooperative compound [Fe(PM-PEA)₂(NCS)₂] (with PM-PEA = N-(2′-pyridylmethylene)-4-(phenylethynyl)aniline) have been investigated under external in situ pressure, external ex situ pressure and internal pressure. In situ single-crystal X-ray diffraction investigations under pressure indicate a Spin-Crossover (SCO) at about 400 MPa and room temperature. Interestingly, application of ex situ pressure induces the irreversible enlargement of the hysteresis width, almost independently from the pressure value. Elsewhere, the internal pressure effects are examined through the magnetic and photomagnetic investigations on powders of the solid-solutions based on the Mn ion, [Fe_xMn_1−x(PM-PEA)₂(NCS)₂]. Growing the Mn ratio increases the internal pressure, allowing to control the hysteresis width and the paramagnetic residue but also to enhance the efficiency of the photo-induced SCO. The comparison of the quenching and light-induced behaviors reveals a complex phase-diagram governed by internal pressure, temperature and light. Full article

The research of new molecular materials able to replace classical solid materials in electronics has attracted growing attention over the past decade. Among these compounds photoswitchable Prussian blue analogues (PBA) are particularly interesting for the elaboration of new optical memories. However these coordination polymers are generally synthesised as insoluble powders that cannot be integrated into a real device. Hence their successful integration into real applications depends on an additional processing step. Nanostructured oxides elaborated by sol-gel chemistry combined with surfactant micelle templating can be used as nanoreactors to confine PBA precipitation and organize the functional nano-objects in the three dimensions of space. In this work we present the elaboration of different CoFe PBA/silica nanocomposites. Our synthetic procedure fully controls the synthesis of PBA in the porosity of the silica matrix from the insertion of the precursors up to the formation of the photomagnetic compound. We present results on systems from the simplest to the most elaborate: from disordered xerogels to ordered nanostructured films passing through mesoporous monoliths. Full article