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The study focuses on the synthesis of Fe3O4@SiO2-NH2-Au heterostructures with magneto-plasmonic properties composed of well-defined cubic Fe3O4 cores (79 nm) covered with 10 nm silica shell and gold nanoparticles (8 nm) fabricated on silica shell. The surface-anchored MHDA (16-mercaptohexadecanoic acid) linker facilitated cellulase bioconjugation, which was confirmed through Raman spectroscopy. The presence of gold nanoparticle islands on the heterostructure enabled surface-enhanced Raman scattering (SERS), demonstrating the potential for bioactive substance identification. Immobilization of cellulase allowed for pH enhancement and enzyme thermal stability. The optimal pH shifted from 4.0 (free enzyme) to 6.0 while thermal stability increased by 20 °C. The immobilized cellulase kept its 49% activity after five hydrolysis cycles, compared to significantly lower activity for free cellulase. The proposed heterostructures for cellulase immobilization demonstrate potential for practical applications.

Magneto‐plasmonic particles, comprising gold and iron oxide, exhibit substantial potential for biosensing applications due to their distinct properties. Gold nanoparticles (AuNPs) provide plasmonic features, while iron oxide composites, responsive to an external magnetic field, significantly reduce detection time compared to passive diffusion. This study explores core@satellite magneto‐plasmonic particles (CSMPs), featuring magnetic nanoparticle clusters and numerous satellite‐like AuNPs, to amplify the optical response on a nanostructured gold surface. Using a sandwich scheme, target analytes are detected as hybrid nanoparticles bind to the pre‐immobilized target on the AuNPs surface, inducing changes in the immunosensor's extinction spectrum. Application of an external magnetic field notably enhances biosensor response and sensitivity, reducing assay time from hours to minutes. Leveraging the properties of CSMPs, the immunosensor detects specific immune protein at low concentrations within minutes. CSMPs hold considerable promise for precise and sensitive analyte detection, offering potential applications in rapid testing and mass screening. A rapid and sensitive colorimetric immunosensor is developed, by employing core‐satellite magneto‐plasmonic particles to enhance the optical response of a gold nanostructured surface. By applying an external magnetic field, these particles are swiftly attracted and bind to the target analyte, effectively detecting low concentrations of the inflammatory protein pentraxin3 (PTX3) within minutes.

Since acetone has more medical and industrial applications, its detection plays a significant role in indirectly measuring some quantities and controlling human safety in medical and industrial areas. In this research, a surface plasmon resonance image sensor was developed based on chitosan, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), and gold nanoparticles for the detection of acetone. The gold nanoparticles have been fabricated using the laser ablation technique, and chitosan-PEDOT: PSS and chitosan-PEDOT: PSS-gold-nanoparticles composite were used to detect the pure acetone vapor form using a surface plasmon resonance image sensor. The response of the sensor was compared with the sensor’s response when acetone was mixed with methanol and ethanol. Consequently, the sensor’s response to pure acetone was greater than the sensor’s response in the presence of methanol or ethanol. The sensor’s response is very insignificant when the sensing layer is contacted with pure methanol and ethanol.

The Pechini method has been used as a synthetic route for obtaining self-assembling magnetic and plasmonic nanoparticles in hybrid silica nanostructures. This manuscript evaluates the influence of shaking conditions, reaction time, and pH on the size and morphology of the nanostructures produced. The characterization of the nanomaterials was carried out by transmission electron microscopy (TEM) to evaluate the coating and size of the nanomaterials, Fourier-transform infrared spectroscopy (FT-IR) transmission spectra to evaluate the presence of the different coatings, and thermogravimetric analysis (TGA) curves to determine the amount of coating. The results obtained show that the best conditions to obtain core–satellite nanostructures with homogeneous silica shells and controlled sizes (<200 nm) include the use of slightly alkaline media, the ultrasound activation of silica condensation, and reaction times of around 2 h. These findings represent an important framework to establish a new general approach for the click chemistry assembling of inorganic nanostructures.

Iron oxide and gold-based magneto-plasmonic nanostructures exhibit remarkable optical and superparamagnetic properties originating from their two different components. As a consequence, they have improved and broadened the application potential of nanomaterials in medicine. They can be used as multifunctional nanoprobes for magneto-plasmonic heating as well as for magnetic and optical imaging. They can also be used for magnetically assisted optical biosensing, to detect extreme traces of targeted bioanalytes. This review introduces the previous work on magneto-plasmonic hetero-nanostructures including: (i) their synthesis from simple “one-step” to complex “multi-step” routes, including seed-mediated and non-seed-mediated methods; and (ii) the characterization of their multifunctional features, with a special emphasis on the relationships between their synthesis conditions, their structures and their properties. It also focuses on the most important progress made with regard to their use in nanomedicine, keeping in mind the same aim, the correlation between their morphology—namely spherical and non-spherical, core-satellite and core-shell, and the desired applications.

Magneto-plasmonic nanoparticles have gained increasing interest, especially for the synergistic response study of hyperthermia applications. However, some challenges, including the synthesis process, dose optimization of laser, and magnetic field strength besides its frequency, need significant attention. Herein, we prepared magneto-plasmonic Ag/Co nanomaterials for photothermal performance evaluation using dual-beam of the Q-switched Nd:YAG 1064 nm pulsed laser ablation in distilled water, which can avoid any additive, contaminations, complicated route, and multiple purifications processes as they may occur in chemical synthesis processes. Properties, morphologies, and compositions of synthesized nanomaterials were studied, and results suggested that the main constituents of NPs were Ag/Co. The detailed theoretical calculation of the photothermal performance of nanofluid is described, along with an experimental study of nanofluid and the water as a reference medium using NIR 808 nm laser. The overall results suggest that the higher temperatures for Ag/Co nanofluid compared with water alone were recorded as 16.5 °C, 20.9 °C, 24.7 °C, 24.5 °C, 27.7 °C, and 30.2 °C during 808 nm laser irradiation operating at different corresponding powers, respectively. The possible reason for the higher temperature profiles and the rapid temperature rise of nanofluid than water alone is the localized surface plasmon effects of nanoparticles. These results evidence that silver and cobalt nanomaterials composite structures could significantly increase hyperthermia based on an effective and simple synthesis approach.

Background Nano-photothermal therapy (NPTT) has gained wide attention in cancer treatment due to its high efficiency and selective treatment strategy. The biggest challenges in the clinical application are the lack of (i) a reliable platform for mapping the thermal dose and (ii) efficient photothermal agents (PTAs). This study developed a 3D treatment planning for NPTT to reduce the uncertainty of treatment procedures, based on our synthesized nanohybrid. Methods This study aimed to develop a three-dimensional finite element method (FEM) model for in vivo NPTT in mice using magneto-plasmonic nanohybrids, which are complex assemblies of superparamagnetic iron oxide nanoparticles and gold nanorods. The model was based on Pennes' bio-heat equation and utilized a geometrically correct mice whole-body. CT26 colon tumor-bearing BALB/c mice were injected with nanohybrids and imaged using MRI (3 Tesla) before and after injection. MR images were segmented, and STereoLithography (STL) files of mice bodies and nanohybrid distribution in the tumor were established to create a realistic geometry for the model. The accuracy of the temperature predictions was validated by using an infrared (IR) camera. Results The photothermal conversion efficiency of the nanohybrids was experimentally determined to be approximately 30%. The intratumoral (IT) injection group showed the highest temperature increase, with a maximum of 17 °C observed at the hottest point on the surface of the tumor-bearing mice for 300 s of laser exposure at a power density of 1.4 W/cm 2 . Furthermore, the highest level of tissue damage, with a maximum value of Ω = 0.4, was observed in the IT injection group, as determined through a simulation study. Conclusions Our synthesized nanohybrid shows potential as an effective agent for MRI-guided NPTT. The developed model accurately predicted temperature distributions and tissue damage in the tumor. However, the current temperature validation method, which relies on limited 2D measurements, may be too lenient. Further refinement is necessary to improve validation. Nevertheless, the presented FEM model holds great promise for clinical NPTT treatment planning.

In recent years, nanotechnologies have attracted considerable interest, especially in the biomedical field. Among the most investigated particles, magnetic based on iron oxides and Au nanoparticles gained huge interest for their magnetic and plasmonic properties, respectively. These nanoparticles are usually produced starting from processes and reagents that can be the cause of potential human health and environmental concerns. For this reason, there is a need to develop simple, green, low-cost, and non-toxic synthesis methods and reagents. This review aims at providing an overview of the most recently developed processes to produce iron oxide magnetic nanoparticles, Au nanoparticles, and their magneto-plasmonic heterostructures using eco-friendly approaches, focusing the attention on the microorganisms and plant-assisted syntheses and showing the first results of the development of magneto-plasmonic heterostructures.

Magneto-plasmonic nanocomposites can possess properties inherent to both individual components (iron oxide and gold nanoparticles) and are reported to demonstrate high potential in targeted drug delivery and therapy. Herein, we report on Fe3O4/Au magneto-plasmonic nanocomposites (MPNC) synthesized with the use of amino acid tryptophan via chemical and photochemical reduction of Au ions in the presence of nanosized magnetite. The magnetic field (MF) induced aggregation was accompanied by an increase in the absorption in the near-infrared (NIR) spectral region, which was demonstrated to provide an enhanced photothermal (PT) effect under NIR laser irradiation (at 808 nm). A possibility for therapeutic application of the MPNC was illustrated using cancer cells in vitro. Cultured HeLa cells were treated by MPNC in the presence of MF and without it, following laser irradiation and imaging using confocal laser scanning microscopy. After scanning laser irradiation of the MPNC/MF treated cells, a formation and rise of photothermally-induced microbubbles on the cell surfaces was observed, leading to a damage of the cell membrane and cell destruction. We conclude that the synthesized magneto-plasmonic Fe3O4/Au nanosystems exhibit magnetic field-induced reversible aggregation accompanied by an increase in NIR absorption, allowing for an opportunity to magnetophoretically control and locally enhance a NIR light-induced thermal effect, which holds high promise for the application in photothermal therapy.

Bifunctional magneto-plasmonic nanoparticles that exhibit synergistically magnetic and plasmonic properties are advanced substrates for surface-enhanced Raman spectroscopy (SERS) because of their excellent controllability and improved detection potentiality. In this study, composite magneto-plasmonic nanoparticles (Fe3O4@AgNPs) were formed by mixing colloid solutions of 50 nm-sized magnetite nanoparticles with 13 nm-sized silver nanoparticles. After drying of the layer of composite Fe3O4@AgNPs under a strong magnetic field, they outperformed the conventional silver nanoparticles during SERS measurements in terms of signal intensity, spot-to-spot, and sample-to-sample reproducibility. The SERS enhancement factor of Fe3O4@AgNP-adsorbed 4-mercaptobenzoic acid (4-MBA) was estimated to be 3.1 × 107 for a 633 nm excitation. In addition, we show that simply by changing the initial volumes of the colloid solutions, it is possible to control the average density of the silver nanoparticles, which are attached to a single magnetite nanoparticle. UV-Vis and SERS data revealed a possibility to tune the plasmonic resonance frequency of Fe3O4@AgNPs. In this research, the plasmon resonance maximum varied from 470 to 800 nm, suggesting the possibility to choose the most suitable nanoparticle composition for the particular SERS experiment design. We emphasize the increased thermal stability of composite nanoparticles under 532 and 442 nm laser light irradiation compared to that of bare Fe3O4 nanoparticles. The Fe3O4@AgNPs were further characterized by XRD, TEM, and magnetization measurements.