Search Results (170)

The pharmaceutical contamination of water, especially by widely used drugs, presents important environmental and health concerns due to the inefficiency of conventional treatment methods. The present study proposes a sustainable solution using biochar (Bch) obtained from tomato waste, functionalized with Fe₃O₄ and MnO₂ nanoparticles, for the removal of paracetamol from aqueous solutions. The composite materials were synthesized, characterized, and evaluated under varying conditions, including pH, temperature, contact time, initial drug concentration, and adsorbent dose. The materials exhibited porous structures with wide pore size distributions. Optimal removal efficiency was achieved for 30 mg L⁻¹ paracetamol concentration, pH 2, 25 °C, 0.3 g L⁻¹ adsorbent dose, and 20 min contact time. The Freundlich isotherm provided the best fit for the adsorption data. Kinetic studies revealed that the pseudo-second-order model best described the adsorption process. Thermodynamic parameters indicated that the process was spontaneous, feasible, and exothermic. Compared with similar materials derived from agricultural waste, the tomato waste-based composites demonstrated competitive adsorption capacities. These findings suggest that Bch-HCl/MnO₂ and Bch-HCl/Fe₃O₄/MnO₂ are promising, cost-effective adsorbents for mitigating pharmaceutical pollutants in wastewater. Full article

This review examines the emerging role of manganese-based nanoparticles (Mn-NPs) in detecting heavy metal pollutants in environmental matrices. Heavy metals such as cadmium, lead, zinc, and copper pose serious environmental and health concerns due to their tendency to persist in ecosystems and accumulate in living organisms. As a result, there is a growing need for reliable methods to detect and remove these pollutants. Manganese nanoparticles offer unique advantages that scientists could consider as replacing other metal nanoparticles, which may be more expensive or more toxic. The physicochemical properties of Mn-NPs—including their multiple oxidation states, magnetic susceptibility, catalytic capabilities, and semiconductor conductivity—enable the development of multi-modal sensing platforms with exceptional sensitivity and selectivity. While Mn-NPs exhibit inherently low electrical conductivity, strategies such as transition metal doping and the formation of composites with conductive materials have successfully addressed this limitation. Compared to noble metal nanoparticles (Au, Ag, Pd) and other base metal nanoparticles (Bi, Fe₃O₄), Mn-NPs demonstrate competitive performance without the drawbacks of high cost, complex synthesis, poor distribution control, or significant aggregation. Preliminary studies retrieved from the Scopus database highlight promising applications of manganese-based nanomaterials in electrochemical sensing of heavy metals, with recent developments showing detection limits in the sub-ppb range. Future research directions should focus on addressing challenges related to scalability, cost-effectiveness, and integration with existing water treatment infrastructure to accelerate the transition from laboratory findings to practical environmental applications. Full article

In the pursuit of environmental sustainability, reduced emissions, and alignment with circular economy principles, bio-epoxy resin nanocomposites have emerged as a promising alternative to traditional petroleum-based resins. This study investigates the development of novel bio-epoxy nanocomposites incorporating iron-oxide nanoparticles (Fe₂O₃, MnP) as multifunctional fillers at loadings of 0.5 wt.% and 3.0 wt.%. MnP nanoparticles were synthesized and subsequently functionalized with citric acid (MnP-CA) to enhance their surface properties. Comprehensive characterization of MnP and MnP-CA was performed using X-ray diffraction (XRD) to determine the crystalline structure, attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA), and zeta potential measurements to confirm surface functionalization. The bio-epoxy resins matrix (bio-EP), optimized for compatibility with MnP and MnP-CA, was thoroughly analyzed in terms of chemical structure, thermal stability, curing behavior, dynamic–mechanical properties, and surface characteristics. Non-isothermal differential scanning calorimetry (DSC) was employed to evaluate the curing kinetics of both the neat (bio-EP) and the MnP/MnP-CA-reinforced composites, offering insights into the influence of nanoparticle functionalization on the resin system. Surface zeta potential measurements further elucidated the effect of filler content on the surface charge and hydrophilicity. Magnetic characterization revealed superparamagnetic behavior in all MnP- and MnP-CA-reinforced (bio-EP) composites. This research provides a foundational framework for the design of green bio-epoxy nanocomposites, demonstrating their potential as environmentally friendly materials and representing an emerging class of sustainable alternatives. The results underscore the viability of bio-epoxy systems as a transformative solution for advancing sustainable resin technologies across eco-conscious industries. Full article

We have investigated for the first time the temperature, size, and ion-doping concentration dependence of the magnetic properties, band-gap energy, and specific heat of CuFeO₂ in both bulk materials and nanoparticles using a microscopic model (the s-d model) and Green’s function theory. Variations in the ionic radii of the dopant elements compared to those of the host ions introduce strain effects, which alter the exchange-interaction constants. Consequently, the influence of ion doping on the various properties of CuFeO₂ nanoparticles has been elucidated at a microscopic level. The magnetization exhibits an increase when CuFeO₂ is doped with Mn at the Fe site or Li and Ca at the Cu site, whereas doping with Sc or Mg at the Fe site leads to a decrease in magnetization. Regarding the band-gap energy, it increases upon doping with Mg and Sc at the Fe site, while doping with Mn at the Fe site or with Li and Ca at the Cu site results in a decrease. The temperature dependence of the specific heat reveals two distinct peaks, corresponding to the two magnetic phase-transition temperatures. The theoretical results show good qualitative agreement with experimental data, confirming the validity of the proposed model. Full article

Clinical root canal therapy which takes place through mechanical and chemical strategies is faced with challenges in eliminating bacteria owing to the intricate and curved nature of the root canal system. Moreover, the plaque biofilm within the root canal hinders drug penetration and limits treatment efficacy. Hence, efficient root canal therapy hinges on penetrating into the root canal and overcoming the barriers presented by the plaque biofilms. To penetrate and eradicate biofilms effectively at the root canal, we designed a novel magnetic nanoparticle (MN)-based nanoplatform which was synthesized by the self-polymerization of dopamine on the surface of Fe₃O₄ MNs, and then loaded minocycline through the electrostatic interaction. The therapeutic efficacy of minocycline-loaded magnetic nanoparticles (FDM MNs) under a magnetostatic field was observed by various antibacterial experiments. The synthesized FDM MNs exhibited favorable biocompatibility and robust anti-biofilm efficacy. The designed nanoparticles could effectively navigate biofilms to eradicate bacteria residing deep with the assistance of magnetic force. Furthermore, FDM MNs penetrated into dentin tubules under a magnetic field, effectively disrupting biofilms for deep sterilization. The significant results offered valuable experimental evidence to support the potential clinical utility of magnetic nanoparticles for managing pulpitis and periapical inflammation. Full article

Background/Objectives: Non-surgical neutering strategies have long been pursued for male animals. A previous study from our group showed that magnetic nanoparticle hyperthermia (MNH) applied directly to the testicles is a promising non-surgical sterilization method for male animals, causing testicular atrophy and complete disappearance of seminiferous tubules by the end of a 56 day observation. This long-term study was conducted to verify the long-term efficacy and safety of the method. Methods: Wistar rats treated with testicular MNH received an intratesticular injection of a magnetic fluid composed of manganese-ferrite nanoparticles functionalized with citrate (MnFe₂O₄-citrate) and were subsequently subjected to an alternating magnetic field. Reproductive parameters and animal health were evaluated by blood tests and abdominal ultrasound for 12 months. Results: All MNH-treated animals presented testicular degeneration and atrophy, together with severely reduced or undetectable serum testosterone levels. By the end of the experiment, all but two animals had no identifiable gonads. The only two animals still displaying gonadal-like structures were azoospermic, and histopathology revealed the remaining tissue was non-functional. The procedure was well-tolerated and MNH-treated animals presented no long-term side effects. Hemogram, ALT, AST, urea and creatinine levels were within the normal parameters for Wistar rats over the 12 month period. The liver, spleen, kidneys and lungs had normal structures as revealed by abdominal ultrasound and histopathological exams, with no nanoparticle accumulation in the organs over the long term. Conclusions: In conclusion, testicular MNH caused irreversible infertility in rats in a single application, with no adverse effects on general animal health. Full article

The widespread use of gadolinium (Gd) in medical and industrial applications, especially as a contrast agent in magnetic resonance imaging (MRI), has led to its increasing presence in surface waters, disrupting natural geochemical cycles and posing risks to aquatic ecosystems. Addressing this challenge, recent studies have explored the potential of magnetic materials, such as spinel ferrite nanoparticles, in the removal of Gd from contaminated water sources. The present study specifically focused on the use of MnFe₂O₄ nanoparticles to remove Gd from contaminated solutions, employing response surface methodology (RSM) to optimize sorption conditions. Key variables evaluated included salinity (0–30 g/L), initial Gd concentration (1–5 μmol/L), and sorbent dose (20–180 mg/L), at a fixed pH of 6. The results revealed that salinity had a minimal impact on Gd sorption, likely due to the high sorbent mass used. Optimal conditions were identified as a sorbent dose of 165 mg/L, an initial Gd concentration of 1.3 μmol/L, and a salinity level of 13.4 g/L, at pH 6. The process was efficient and rapid, achieving over 90% Gd removal within 1 h in both freshwater and saline conditions, and over 75% removal in mineral water within 3 h. The high efficiency and celerity of this method suggest that MnFe₂O₄ nanoparticles are a promising solution for treating Gd-contaminated hospital effluents. Future research should focus on validating these results in real-world effluent matrices and addressing the environmental and economic aspects of large-scale implementation, thereby contributing to sustainable water remediation strategies. Full article

Maize (Zea mays L.), an important crop used for animal feed and human consumption, is currently threatened by water shortage. Recently, the usage of nanomaterials has attracted worldwide attention due to their applications in various fields. This research aimed to evaluate the comparative efficacy of different metal oxide nanoparticles for mitigating drought stress in maize. Iron oxide, manganese oxide, and copper nanoparticles were biosynthesized from the leaf extract of Conocarpus erectus L. and characterized via UV-Vis, XRD, FTIR, and SEM. The synthesized nanomaterials were initially optimized at different concentrations (0, 25, 50, 75, and 100 ppm). The optimized doses of each nanoparticle were then applied to maize plants under different drought stress levels (50% FC, 75% FC, and 100% FC). Compared to the control, the application of nanomaterials significantly improved the growth parameters of the maize by 30% at 50% FC, 27% at 75% FC, and 26% at 100% FC. The chlorophyll content also improved significantly at different levels of drought stress by 35%, 32%, and 29% as compared to the control, respectively. The antioxidants (CAT, POD, SOD, and APX) also improved significantly at different levels of drought by 37%, 34%, and 31%, as compared to control, respectively. Moreover, the use of nanoparticles resulted in a significant decrease in cellular oxidative stress (MDA, H₂O₂) parameters by 23% at 50%FC, 26% at 75% FC, and 27% at 100% FC. Biosynthesized FeO NPs, MnO NPs, and Cu NPs have demonstrated significant potential in mitigating drought stress in maize, suggesting a promising approach to enhance crop performance under water-limited conditions. Further research is recommended to explore the long-term impacts and practical applications of these findings in sustainable agriculture. Full article

Ascorbic acid (AA) and glutathione (GSH) play a pivotal role in health assessment, drug development, and quality control of nutritional supplements. The development of a new and efficient method for their detection is highly desired. In this work, we fabricated magnetic core–shell nanocomposites (Fe₃O₄@MnPc-NDs) by a one-pot hydrothermal method with citric acid and manganese tetraamino phthalocyanine (MnTAPc) as precursors. Fe₃O₄@MnPc-NDs exhibited enhanced peroxidase activity compared to bare Fe₃O₄ nanoparticles, enabling catalytic oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue ox-TMB in the presence of H₂O₂. Leveraging the antioxidant properties of AA/GSH to reduce ox-TMB, a colorimetric assay achieved a low detection limit of 0.161 μM for AA and 0.188 μM for GSH with broad linear ranges. Moreover, this method displayed high specificity against 12 interfering substances and excellent recyclability (>90% activity after five cycles). Finally, the Fe₃O₄@MnPc-NDs could act as an efficient colorimetric sensor for accurately detecting AA in genuine VC tablets and GSH in whitening serums with high accuracy. Therefore, Fe₃O₄@MnPc-NDs exhibited great potential in bioassay applications, benefiting from their outstanding sensitivity and high recycling rate. Full article

Background/Objectives: Magnetic hyperthermia (MH) has emerged as a promising alternative to conventional cancer treatments, offering targeted tumor destruction with minimal damage to healthy tissues. In this study, we synthesized manganese-doped magnetic nanoflowers (Mn-NFs) using a polyol-mediated approach to enhance heating efficiency and biocompatibility for MH applications. Our objective was to evaluate their structural, magnetic, and in vitro hyperthermic properties to determine their potential for lung cancer therapy. Methods: Mn-NFs, with the general formula MnxFe₃-xO₄ (x = 0, 0.3, 0.5, 0.7), were synthesized via a one-step polyol method and characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Their heating efficiency was assessed through specific absorption rate (SAR) measurements in aqueous and solid environments under an alternating magnetic field (AMF). Cytocompatibility was evaluated using the Alamar Blue assay on A549 lung carcinoma cells. Cellular uptake was quantified via a colorimetric iron determination method, while in vitro MH efficacy was tested by subjecting Mn-NF-loaded A549 cells to AMF exposure at different field strengths and nanoparticle concentrations. Results: Mn-NFs exhibited a flower-like morphology with enhanced magnetic properties, achieving high SAR values, particularly in immobilized conditions. Cytotoxicity assays confirmed high biocompatibility at relevant doses, with Mn-NFs of x = 0.3 showing optimal cellular uptake. MH studies demonstrated significant cancer cell death at AMF intensities of around 30 kA/m, with increased effectiveness following static magnetic field pre-alignment. Conclusions: The results highlight Mn-NFs, particularly those with a Mn content of x = 0.3, as promising candidates for MH-based lung cancer therapy, combining high heating efficiency, biocompatibility, and effective intracellular uptake. Further studies are needed to validate their therapeutic potential in vivo. Full article

Ciprofloxacin (CPL) is an effective antibiotic against Pseudomonas aeruginosa. However, its use is limited by the emergence of multi-resistant strains. In this study, 8–15 nm manganese ferrite (MnFe₂O₄) nanoparticles, aminated and/or PEGylated, have been used as drug-delivery systems of CPL. The magnetic nanoparticles (MNPs) were prepared in the presence of the aliphatic amines octadecylamine (ODA), oleylamine (OAm), or PEG8000 to achieve the appropriate surface chemistry for the direct conjugation of CPL and drug loading into the PEG matrix, respectively. The primary MNPs proved to be biocompatible in calf thymus (CT)-DNA interaction studies, with binding constant values K_b in the range of 4.43–6.5 × 10⁴ (g/mL)⁻¹. ODA as a coater gave rise to MnFe₂O₄ MNPs, with a high percentage of free amines that further allowed for the conjugation of 90.9% CPL, which gradually released via a non-Fickian anomalous transport motif. The 25.1% CPL that loaded in the PEGylated MNPs led to a partial transformation of the nanoflowers into more aggregated forms. The release profile, although steeper, is described by the same model. The isolated magnetic nanocarrier with a high content of CPL was evaluated for its antimicrobial activity against a multi-resistant strain of P. aeruginosa using an automated industrial instrument (BacT/ALERT^®3D), and its molecular profile was outlined by studying its interaction with plasmid DNA (pDNA). The prototype use of BacT/ALERT^®3D allows for the simultaneous screening of multiple samples, while it foreshadows the transition to a preclinical phase. Full article

Developing more effective gold–support synergy is essential for enhancing the catalytic performance of supported gold nanoparticles (AuNPs) in the gas-phase oxidation of ethanol to acetaldehyde (AC) at lower temperatures. This study demonstrates a significantly improved Au–support synergy achieved by copper doping in LaMO₃ (M = Mn, Fe, Co, Ni) perovskites. Among the various Au/LaMCuO₃ catalysts, Au/LaMnCuO₃ exhibited exceptional catalytic activity, achieving an AC yield of up to 91% and the highest space-time yield of 764 g_AC g_Au⁻¹ h⁻¹ at 225 °C. Notably, this catalyst showed excellent hydrothermal stability, maintaining performance for at least 100 h without significant deactivation when fed with 50% aqueous ethanol. Comprehensive characterization reveals that Cu doping facilitates the formation of surface oxygen vacancies on the Au/LaMCuO₃ catalysts and enhances Au–support interactions. The LaMnCuO₃ perovskite stabilizes the crucial Cu⁺ species, resulting in a stable Au-Mn-Cu synergy within the Au/LaMnCuO₃ catalyst, which facilitates the activation of O₂ and ethanol at lower temperatures. The optimization of the reaction conditions further improves AC productivity. Kinetic studies indicate that the cleavages of both the O-H bond and the α-C-H bond of ethanol are the rate-controlling steps. Full article

Co_1−xMn_xFe₂O₄ nanoparticles (0 ≤ x ≤ 1) have been prepared via the hydrothermal method. The prepared samples were studied using X-ray diffraction measurements (XRD), transmission electron microscopy (TEM), Raman spectroscopy, and magnetic measurements. All studied samples were found to be single phases and to have a cubic Fd-3m structure. The average crystalline sizes are between 7.8 and 15 nm. EDS analysis confirmed the presence of cobalt, manganese, iron, and oxygen in all prepared samples. It was found by Raman spectroscopy that Fe³⁺ would be placed on octahedral sites while Fe²⁺ would, in turn, be displaced to tetrahedral sites while Mn ions will be placed on both sites. Both Mn²⁺ and Mn⁴⁺ are present in studied ferrites. The experimental saturation magnetizations for doped samples are much higher when compared with previous reports, reaching values between 3.71 and 6.7 μ_B/f.u. The doping with Mn in nanocrystalline cobalt ferrite enhanced the magnetic properties due to changes in the cation distribution between the two sublattices. The higher magnetic moments are explained by the presence of Mn⁴⁺ ions located preferentially on tetrahedral sites while Mn²⁺ prefer octahedral sites, and by the high quality and crystallinity of our samples the nanoparticles being almost monodomain. Large values of the coercive field were found at 4.2 K while the hysteresis is almost absent in all investigated samples at room temperature. Full article

Zinc oxide nanoparticles (ZnO NPs) are one of the most widely used nanoparticulate materials due to their antimicrobial properties. However, the current use of ZnO NPs is hindered by their potential cytotoxicity concerns, which are likely attributed to the generation of reactive oxygen species (ROS) and the dissolution of particles to ionic zinc. To reduce the cytotoxicity of ZnO NPs, transitional metals are introduced into ZnO lattices to modulate the ROS production and NP dissolution. However, the influence of the doping element, doping concentration, and particle size on the cytotoxicity and antimicrobial properties remains unexplored. This study presents a comprehensive investigation of a library of doped ZnO NPs to elucidate the relationship between their physicochemical properties, antimicrobial activity against Escherichia coli (E. coli), and cytotoxicity to mammalian cells. The library comprises 30 variants, incorporating three different dopant metals—iron, manganese, and cobalt—at concentrations of 0.25%, 1%, and 2%, and calcined at three temperatures (350 °C, 500 °C, and 600 °C), resulting in varied particle sizes. These ZnO NPs were prepared by low temperature co-precipitation followed by high-temperature calcination. Our results reveal that the choice of dopant elements significantly influences both antimicrobial efficacy and cytotoxicity, while dopant concentration and particle size have comparatively minor effects. High-throughput UV–visible spectroscopic analysis identified Mn- and Co-doped ZnO NPs as highly effective against E. coli under standard conditions. Compared with undoped ZnO particles, Mn- and Co-doping significantly increased the oxidative stress, and the Zn ion release from NPs was increased by Mn doping and reduced by Fe doping. The combined effects of these factors increased the cytotoxicity of Mn-doped ZnO particles. As a result, Co-doped ZnO particles, especially those with 2 wt.% doping, exhibited the most favourable balance between enhanced antibacterial activity and minimized cytotoxicity, making them promising candidates for antimicrobial applications. Full article

Eco-friendly iron and manganese oxide nanoparticles (Fe₂O₃ and Mn₂O₃) were synthesized and integrated into graphene sheets to form uniform composites. These composites were then embedded in polyvinyl alcohol (PVA) fibers using electrospinning. Comprehensive characterization of the composites and the final composite fibers was conducted using XRD, FE-SEM, and FTIR to analyze their structural complexity and morphological differences. The antibacterial efficacy of the resulting PVA nanofibers was evaluated against Escherichia coli, which is a common pathogen in hospital environments. The results show a significant bactericidal effect against these bacteria, which highlights their potential in medical applications, such as functional bandages and wound dressings. This study paves the way for potential commercial applications of these nanofibers in healthcare settings. Full article