Search Results (413)

In medicine, nanoparticles are used for various purposes, including theranostics, imaging, diagnostics, drug delivery, tissue regeneration and targeted cancer treatments, and to minimize the harmful side effects associated with conventional therapies. Target-specific biomolecules, such as silica nanoparticles (SiNPs) labeled with metallic radionuclides, are becoming increasingly popular. The choice of radionuclide is based on its nuclear properties. Silica has several advantages for nanoparticle synthesis, including high biocompatibility, the capacity for drug encapsulation due to its porous structure, and the potential for extensive surface functionalization, including radiolabeling for imaging and therapeutic applications. A radionuclide can be attached to a silica nanoparticle either directly or through the use of chelators or polymers. Additionally, the capability to encapsulate therapeutic agents within such systems offers significant potential for the development of targeted therapies. This study aims to provide a comprehensive overview of recent developments in the radiolabeling of silica-based nanoparticles, with a focus on their application in nuclear medicine, particularly in diagnostic imaging and targeted radionuclide therapy. Theranostics employs a range of imaging modalities to guide and monitor therapeutic interventions. Principal techniques include positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), and Optical Imaging (such as fluorescence and bioluminescence). These imaging methods enable precise visualization of pathological sites, facilitate tracking of therapeutic agent distribution, and permit real-time assessment of treatment efficacy. Full article

Melittin (Mel) is a membrane-active peptide with potential anticancer activity, but its direct therapeutic application may be limited by nonspecific toxicity and delivery-related challenges. The study aimed to assess melittin-functionalized magnetic nanoparticles (MNPs-Mel) as a strategy to enhance antitumor activity in Caco-2 cells, with/without magnetic hyperthermia (MH) association. BJ fibroblasts were used as a normal human in vitro cellular model. The effects of free Mel (2.5 µg/mL), MNPs, and MNPs-Mel (50 µg/mL both) + MH (30 min at 355 kHz and 25 kA/m) were assessed using colorimetry (for viability), luminescence (ATP), and spectrophotometry (lactate) following different exposure conditions. The mechanism of apoptosis induction was evaluated by ELISA (caspase 8 and 9 levels). Transmission electron microscopy (TEM) was also used to evaluate nanoparticle morphology and treatment-associated cellular ultrastructural changes. Free Mel reduced viability in both cell lines, with Caco-2 cells showing greater sensitivity at lower concentrations. MNPs (with/without MH) produced limited and less consistent effects, whereas MNPs-Mel significantly reduced Caco-2 viability and ATP levels and increased LDH and caspase 9. MH further enhanced the effects of MNPs-Mel: reduced viability (57–58% of the control at 24 h and 72 h), decreased ATP levels (67% of the control at 24 h and 53% at 72 h), increased LDH levels (206% of the control at 24 h and 301% at 72 h), and induced the mitochondrial apoptotic pathway (caspase 9 increased with 2164% of the control at 72 h). TEM proved the internalization of both MNPs and MNPs-Mel and revealed extensive ultrastructural alterations concerning mitochondria and lysosomes produced by MNPs-Mel, particularly in the Caco-2 cells. These modifications were heavily increased by MNPs-Mel + MH exposure. Overall, these findings demonstrate that Mel functionalization increases the antitumor activity of Mel at lower doses and that MH further potentiates this effect in Caco-2 cells. Full article

This paper presents a flight–attachment–crawling robot (FACR) for close-range inspection of large-scale crane structures, aiming to improve access efficiency and contact-based inspection capability in elevated and discontinuous metallic environments. The proposed robot integrates flight, magnetic attachment and crawling units. To clarify the multimodal operating mechanism, dynamic models are established for the flight, wall-supported locomotion, and wall-attachment modes. Computational fluid dynamics simulations are then conducted to analyze near-wall aerodynamic effects, including the influence of wall proximity and lateral-rotor activation on rotor wake interaction, lift variation, and wall-normal support. A prototype platform is developed, and representative staged experiments are carried out to evaluate multimodal operation. The results show that the proposed FACR can support key multimodal operating stages required for crane-oriented inspection and provides a feasible platform-level solution for combining aerial mobility, wall-surface operation, and fixed-point attachment in complex industrial environments. Full article

Nickel ferrite (NiFe₂O₄) is one of the most studied inverse-spinel ferrites because it combines moderate saturation magnetization, comparatively high electrical resistivity, chemical stability, and broad synthesis flexibility. Yet the literature shows that the measured structure and magnetism of NiFe₂O₄ are not intrinsic constants; they evolve strongly with dimensionality, size, thickness, strain state, cation distribution, surface spin disorder, and synthesis pathway. This review develops a unified theoretical and literature-based interpretation of how dimensionality reshapes the structural and magnetic behavior of NiFe₂O₄ across bulk ceramics, nanoparticles, one-dimensional nanostructures, polycrystalline thin films, and ultrathin epitaxial films. The review is anchored in the two uploaded nickel ferrite attachments and expanded using internet-sourced journal literature on spinel inversion, surface effects, mechanochemical synthesis, sputtered and pulsed laser deposited thin films, and epitaxial ultrathin-film anomalies. The central novelty of this article is the formulation of a dimensionality-dependent framework in which the observed magnetic response is governed by a competition among three coupled factors: (i) the cation-distribution function, which controls the A–B superexchange balance and therefore the net ferrimagnetic moment; (ii) the microstructural coherence function, which measures how crystallinity, strain, defects, and anti-phase boundaries preserve or degrade exchange continuity; and (iii) the surface/interface spin-order parameter, which quantifies the loss or reconfiguration of magnetic order at free surfaces and buried interfaces. Within this framework, bulk NiFe₂O₄ behaves as a near-equilibrium inverse spinel with relatively stable magnetization, whereas nanoscale NiFe₂O₄ experiences strong spin canting and finite-size suppression due to the growing fraction of disordered surface spins. Thin films introduce a distinct regime in which strain, texture, anti-phase boundaries, substrate mismatch, and growth kinetics determine both anisotropy and magnetization. In ultrathin epitaxial films, off-equilibrium cation redistribution and interface-controlled electronic reconstruction may even generate magnetization values far above bulk expectations. The review also compares major synthesis routes—solid-state reaction, sol–gel, co-precipitation, hydrothermal growth, reactive milling, combustion, pulsed laser deposition, and radio-frequency sputtering—and explains why each route biases the final dimensionality-dependent properties differently. A set of word-style equations is provided to formalize spinel inversion, finite-size suppression, anisotropy scaling, coercivity trends, and superparamagnetic crossover. Beyond summarizing the field, the review proposes a regime map linking dimensionality to characteristic structural defects and magnetic signatures, and it identifies unresolved questions concerning the true origin of enhanced magnetization in ultrathin NiFe₂O₄, the interplay between anti-phase boundaries and strain, and the distinction between intrinsic inversion changes and extrinsic substrate artifacts. The resulting article offers a submission-ready, originality-focused review that positions dimensionality as the master variable governing structure–magnetism correlations in nickel ferrite. Full article

The rapid growth of electronic waste has created an urgent need for more sustainable product design. Current monitor designs often prioritize aesthetics and performance over repairability, reusability, and recyclability, leading to unnecessary material consumption and short product lifespans. This study focuses on redesigning a 24-inch monitor using the principles of reduce, reuse, and recycle (3R) to enhance environmental sustainability. The research examines five commercially available monitors. The redesign reduces material complexity, enhances modularity, and increases recyclability. The final concept features a lightweight structure (2.4 kg) made from 90% recycled plastic, magnetic bezel attachments for easy disassembly, and clear resin coding for material recovery. Full article

Background/Objectives: An accurate understanding of anterior cruciate ligament (ACL) morphology is essential for individualized surgical planning in ACL reconstruction. Morphometric parameters of the knee, including the femoral notch width and surrounding soft tissue characteristics, may influence native ACL dimensions and potentially assist in preoperative graft sizing. Methods: This retrospective case–control study analyzed medical records, radiographs, and knee magnetic resonance imaging (MRI) performed at a tertiary academic medical center. Variables collected included femoral notch width, thigh thickness, and ACL attachment dimensions at the femoral and tibial insertions. Comparisons between patients with ACL tears and those with intact ACLs were also performed. Correlation analyses were performed to evaluate associations between morphometric parameters and ACL attachment size. Multivariable linear regression models were constructed to identify independent predictors after adjusting for age, sex, body mass index (BMI), limb side (left or right leg), and ACL status. Results: A total of 600 participants were included. The mean femoral notch width was 21.55 ± 6.15 mm, and the mean thigh thickness was 53.05 ± 11.66 mm. The mean ACL femoral and tibial attachment sizes were 8.12 ± 2.57 mm and 11.79 ± 3.89 mm, respectively. Thigh thickness demonstrated weak but significant positive correlations with both ACL femoral (r = 0.168, p = 0.001) and tibial attachment sizes (r = 0.236, p < 0.001). Femoral notch width showed a borderline association with ACL femoral attachment size (r = 0.092, p = 0.068) and a weak but significant correlation with ACL tibial attachment size (r = 0.095, p = 0.039). ACL tear group exhibited smaller thigh thickness measurements compared with controls (49.80 ± 12.00 mm vs. 55.65 ± 14.80 mm, p < 0.001) and smaller femoral notch width measurements compared with controls (21.20 ± 3.40 mm vs. 22.50 ± 3.18 mm, p = 0.001). Moreover, further analysis demonstrated that ACL tear status was associated with smaller measured ACL attachment sizes (p < 0.001). Conclusions: Thigh thickness and femoral notch width demonstrate measurable association with ACL attachment dimensions and differ between patients with ACL tears and those with intact ligaments. These findings indicate that both osseous and soft-tissue morphometric characteristics may influence ACL morphology and susceptibility to injury. Comprehensive preoperative imaging assessment of these anatomical parameters may help to optimize individualized surgical planning in ACL reconstruction. Full article

The field of nanoparticle-based biotechnology has undergone substantial advancement, characterized by progress in targeted drug delivery systems, the development of innovative diagnostic and imaging platforms, the expanded adoption of environmentally sustainable (“green”) synthesis approaches, and an increasing emphasis on the integration of emerging technologies such as artificial intelligence and nanorobotics. Conventional nanoparticle synthesis often involves toxic reducing agents; however, recent advances promote eco-friendly green synthesis methods utilizing biological systems such as bacteria, fungi, algae, yeast, plants, and actinomycetes. These biological approaches are safe, sustainable, cost-effective, and capable of producing highly stable Nanoparticles (NPs). The interaction of nanomaterials with biological systems is crucial for developing intracellular and subcellular drug delivery technologies with minimal toxicity, governed by nano–bio interface mechanisms such as cellular translocation, surface wrapping, embedding, and internal attachment. Key factors influencing NP behavior include morphology, size, surface area, surface charge, and ligand chemistry. Magnetic nanoparticles, particularly iron-based forms, exhibit unique superparamagnetic properties that are strongly influenced by particle size, as explained by the Néel relaxation mechanism, in which thermal energy induces flipping of magnetic moments. Nanoparticles demonstrate diverse modes of action, including antimicrobial activity, reactive oxygen species (ROS)-induced cytotoxicity, genotoxicity, and plant growth promotion. NP performance and biological effects are strongly dependent on their size, shape, dosage, and concentration. This critical review article aims to elucidate evolution, classification, preparation methods, and multifaceted applications of nanoparticles. Full article

This study investigates magnetic harvesting of Chlorella vulgaris cultivated under saline and wastewater conditions using Fe₃O₄ and polyethylene-glycol-coated Fe₃O₄ (Fe₃O₄@PEG) nanoparticles synthesized by ultrasound-assisted coprecipitation. TEM showed agglomerated, quasi-spherical particles with mean diameters of 13 ± 1 nm (Fe₃O₄) and 15 ± 1 nm (Fe₃O₄@PEG). FTIR confirmed the Fe–O vibrational bands of magnetite and the characteristic PEG vibrations in the coated sample. VSM measurements indicated superparamagnetic behavior, with saturation magnetizations of 72.74 emu/g for Fe₃O₄ and 32.25 emu/g for Fe₃O₄@PEG. SEM–EDX of native and functionalized cells verified nanoparticle attachment on the algal surface. Magnetic separation experiments (OD684) showed a decrease in supernatant absorbance with increasing nanoparticle dose, consistent with biomass removal; the PEG-coated system showed a lower apparent biomass concentration after functionalization. Full article

This article presents the design and detailed characterization of a new supersonic wind tunnel at the Aerospace Laboratory for Lasers, ElectroMagnetics, and Optics of Texas A&M University, tailored for optical diagnostic development and sub-scale fundamental compressible fluid dynamics research. A Ludwieg tube tunnel architecture was selected due to its robustness, versatility, and low operational costs. The tunnel consists of a 50-foot-long driver tube constructed from modular Tri-Clamp spools, a Mach 4 nozzle with 3 in. exit diameter configured as a free jet, and a fast-acting valve with 14 ms opening time for high-duty-cycle operation. Such construction proved to be a robust, compact, and affordable solution for academic applications. Characterization methods consisted of simultaneous high-speed dot-schlieren, total and static pressure measurements, and femtosecond laser electronic excitation tagging. Average flow velocity for the first steady-state test time was measured via FLEET at (668.0 ± 5.7) m/s. The Mach number was calculated based on the angles of the attached oblique shocks formed near the 30° cone model. Calculated Mach number was repeatable from run to run and had small oscillations near the average value of 3.96 ± 0.03. Based on the simultaneously measured velocity and Mach number, the static temperature was calculated to be between (68.6 ± 0.3) K and (66.3 ± 0.3) K throughout the 400 ms test time, completely defining the thermodynamic state of the generated freestream flow. Full article

Magnetic resonance imaging (MRI) is one of the most powerful non-invasive methods for cancer diagnostics. To enhance image contrast and, therefore, diagnostic accuracy, contrast agents (CAs) are widely used in clinics. For decades, the clinical standard has been metal-based CAs, primarily gadolinium- and manganese-based chelates, or iron oxide nanoparticles. However, metal-based CAs possess sub-effects, toxicity, and associated adverse health effects, such as nephrogenic systemic fibrosis. As an alternative, metal-free organic radical CAs (ORCAs), based on nitroxides, have been developed. ORCAs are widely used as primary ¹H-MRI agents and offer many advantages, including high biocompatibility, biodegradability, and easy functionalization. Attachment of nitroxides to natural or synthetic polymers enables the development of constructs with prolonged systemic circulation time and tumor-targeted delivery. Furthermore, MR-signal amplification can be achieved through physical hyperpolarization techniques, such as dynamic nuclear polarization (DNP) and Overhauser-enhanced MRI (OMRI), in which nitroxide radicals serve as hyperpolarizing agents, yielding signal enhancements. This review summarizes low-molecular-weight nitroxides, polymeric, and biomacromolecular platforms for ¹H-MRI, focusing on physicochemical properties, preclinical evidence in tumor imaging, and current limitations. One section highlights the use of nitroxides as hyperpolarizing agents for tumor metabolism analysis or OMRI. The review addresses ongoing challenges and outlines future perspectives for the clinical translation of ORCAs in cancer diagnostics. Full article

Introduction: Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating disease of the central nervous system with a highly heterogeneous clinical course. Early identification of patients at risk of aggressive disease progression is crucial for optimizing therapeutic strategies, including eligibility for highly effective treatments. Objective: The aim of this review was to synthesize current data on prognostic factors in multiple sclerosis, with particular emphasis on their significance in the early stages of the disease and potential clinical implications. Methods: A narrative systematic review of the literature was conducted, including observational studies, cohort studies, meta-analyses, and systematic reviews on the natural course of MS, prognostic factors, and clinical, neuroimaging, and laboratory biomarkers. We comprehensively reviewed PubMed and Scopus databases, focusing on English-language publications. Study selection prioritized longitudinal studies and meta-analyses with clear outcome definitions and sufficient follow-up. Formal quality scoring was not applied due to the narrative design of the review. Results: Key adverse prognostic factors include older age at onset, polysymptomatic onset, high relapse activity in the first years, incomplete remission after relapses, and the primary progressive form. Magnetic resonance imaging features, including the number and location of T2 lesions, contrast activity, the presence of spinal cord lesions, PRLs and SELs, and severe brain atrophy, also have significant predictive value. Increasing importance is being attached to laboratory biomarkers, such as oligoclonal bands, light neurofilaments, free kappa light chains, and GFAP. Conclusions: An integrated assessment of clinical, neuroimaging, and laboratory factors enables more effective risk stratification in patients with newly diagnosed MS. Early identification of an unfavorable prognostic profile may provide a basis for individualizing treatment and considering the use of highly effective therapies early in the course of the disease. Full article

This study presents a novel multifunctional Lac@CMC-Cu@Fe₃O₄ nanocomposite for the efficient immobilization of laccase designed to overcome limitations in enzyme stability, reusability, and catalytic performance. The nanocomposite integrates magnetite (Fe₃O₄) for rapid magnetic separation, carboxymethyl cellulose (CMC) as a biocompatible matrix for covalent enzyme attachment, and copper nanoparticles to enhance catalytic activity. The immobilization achieved an impressive yield of 87%, with comprehensive characterization by XRD, FT-IR, FESEM, EDX, BET, and VSM confirming successful synthesis and enzyme attachment. Kinetic analysis revealed a remarkable 37% increase in maximum reaction velocity (Vmax = 111 µmol/min) compared to free laccase (81.3 µmol/min), despite a moderate increase in Km from 1.54 to 3.22 mM. The immobilized biocatalyst demonstrated superior thermal stability, retaining 53% activity at 60 °C versus 17% for the free enzyme, and exhibited a broader pH tolerance, maintaining 41% activity at pH 8.0. Notably, the biocatalyst showed enhanced performance in organic solvents, with 153% activation in acetone. Operational reusability was exceptional, retaining 84% activity after 15 cycles, and storage stability was significantly improved, maintaining 68% activity after 90 days compared to only 11% for free laccase. This magnetically separable nanobiocatalyst represents a promising, scalable platform for sustainable industrial and environmental applications. Full article

The inadequate biosafety of MRI contrast agents (CAs) remains a challenging issue. Both increasing the magnetic relaxivity of CAs and targeting them through conjugation with folates are promising approaches to addressing this issue. Silica nanoparticles (SNs) with Mn²⁺ ions specifically localized in the outer layer were selected as the target for further surface modification for the covalent attachment of folates. It was shown that when Mn-containing SNs are conjugated with folates via preliminary amino modification of the surface silanol groups, the folate-conjugated SNs suffer from colloidal instability. Thus, precoating Mn-containing SNs with unfolded BSA exposes surface amino groups that successfully conjugate with folates without loss of colloidal stability. Partial washout of surface-localized Mn²⁺ follows folate conjugation of Mn-containing SNs, although residual Mn²⁺ ions provide r₁₍₂₎ relaxivities of 62.1 (160.4) mM⁻¹s⁻¹ at 0.47 T. Full article

Background: Three-dimensional (3D) cell cultures are increasingly recognized as effective models for studying diseases and developing cell therapies. In the endocrine pancreas field, organoids/spheroids derived from human islet cells enable advances in diabetes research, drug screening, and tissue engineering. While various 3D culture methods exist, approaches such as magnetic bead-assisted aggregation remain underexplored for endocrine pancreatic cells. Additionally, the use of biological scaffolds, especially those derived from decellularized pancreatic extracellular matrix, provides a biomimetic environment that promotes adhesion, proliferation, and functionality of pancreatic cells. This study presents a protocol for magnetic bead-guided 3D culture of human islet cells within decellularized pancreatic scaffolds. Methods: Human pancreas from adult brain-dead donors was harvested for both islets’ isolation processing and decellularization to generate an acellular pancreatic bioscaffold. Primary human pancreatic islets were first grown in two-dimensional adherent cultures, then enzymatically harvested from the surface and reassembled into three-dimensional clusters using different initial cell amounts (small clusters 0.5 × 10⁴–1 × 10⁴ and larger clusters 2.5 × 10⁴–5 × 10⁴ cells) and then placed within acellular pancreatic slices of different thickness, namely 50 and 90 μm. Optic microscopic examination, scanning electron microscopy analysis, and assessment of insulin and lactate dehydrogenase (LDH) levels were used to evaluate these 3D islet-like cluster cultures. Results: We report the establishment of 3D cultures derived from primary pancreatic islet cells using a magnetic approach in a remarkable 18 h period for the complete formation of 3D clusters. The small clusters (0.5 × 10⁴–1 × 10⁴ cells) exhibited a faster attachment to the acellular matrix, with cells visibly spreading outside the cluster interacting with the bioscaffold slice, when compared to the larger clusters (2.5 × 10⁴–5 × 10⁴ cells). These cells continued to produce insulin, and no statistically significant differences in LDH levels were found under these different conditions. Conclusions: Here, we demonstrate that a magnetic bead-based protocol can be successfully applied to endocrine pancreatic cells, enabling the rapid formation of compact, viable, and functional 3D structures. Despite limitations such as higher cost and prolonged retention of magnetic particles, the approach supports size-dependent interactions with decellularized pancreatic scaffolds. These findings are valuable for researchers designing experiments tailored to specific objectives and underscore the potential of this platform for advancing diabetes research and pancreatic tissue engineering. Full article

The cycloaddition reaction is one of the most common reactions in organic chemistry. It has been applied in various fields. Herein, we focus on the application of cycloaddition reactions in investigating biological molecules and materials using magnetic resonance techniques. To facilitate magnetic resonance studies such as electron paramagnetic resonance (EPR) spectroscopy and paramagnetic nuclear magnetic resonance (NMR) spectroscopy, there is often a requirement to attach spin labels and paramagnetic tags to the system of interest. The cycloaddition reaction is one of the ways to tether these spin labels and paramagnetic tags. In this review, we highlight the applications of various cycloaddition reactions such as the Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction, the strain-promoted azide–alkyne cycloaddition (SPAAC) reaction and the Diels–Alder reaction in the interdisciplinary field of magnetic resonance studies of biomolecules, including proteins, nucleic acids, carbohydrates, lipids and glycans, as well as materials. Full article