Search Results (30)

Grafting of paramagnetic transition and rare earth metal ions onto the surface of detonation nanodiamonds (DNDs) was successfully implemented in the recent decade and opened new opportunities in the biomedical application of these compounds, particularly as novel contrast agents for magnetic resonance imaging. The grafting was studied mainly using EPR, NMR, and magnetic measurements. Such a highly surface-sensitive, quantitative, chemical analytic technique as X-ray photoelectron spectroscopy (XPS) was very rarely used. In this paper, we report the XPS study of grafting transition and rare-earth metal ions (Cu²⁺, Co²⁺, Mn²⁺, and Gd³⁺) onto the surface of DNDs. Binding energies for metal, carbon, oxygen, and nitrogen atoms were determined and attributed to the corresponding ion states and atomic groups. Comparing XPS and EPR findings, we showed that the developed synthesis route resulted in almost complete grafting of manganese and gadolinium atoms in the form of paramagnetic ions Mn²⁺ and Gd³⁺ to the diamond surface, while only 30% of the copper atoms on the surface are in the paramagnetic state Cu²⁺, and the rest 70% are in the non-magnetic Cu⁺ state. It was not possible to draw a similar conclusion regarding Co²⁺ ions due to the lack of data on the amount of these paramagnetic ions on the DND surface. Full article

Optically active color centers in diamond and nanodiamonds can be utilized as quantum sensors for measuring various physical parameters, particularly magnetic and electric fields, as well as temperature. Due to their small size and possible surface functionalization, fluorescent nanodiamonds are extremely attractive systems for biological and medical applications since they can be used for intracellular experiments. This review focuses on fluorescent nanodiamonds for thermometry with high sensitivity and a nanoscale spatial resolution for the investigation of living systems. The current state of the art, possible further development, and potential limitations of fluorescent nanodiamonds as thermometers will be discussed here. Full article

This study introduces a novel magnetic nanohybrid material consisting of ferromagnetic (FM) bcc Fe–Co nanoparticles (NPs) grown on nanodiamond (ND) nanotemplates. A combination of wet chemistry, which produces chemical precursors and their subsequent thermal treatment under vacuum, was utilized for its development. The characterization and study of the prepared samples performed with a range of specialized experimental techniques reveal that thermal treatment of the as-prepared hybrid precursors under a range of annealing conditions leads to the development of Co-rich Fe–Co alloy NPs, with average sizes in the range of 6–10 nm, that exhibit uniform distribution on the surfaces of the ND nanotemplates and demonstrate FM behavior throughout a temperature range from 2 K to 400 K, with maximum magnetization values ranging between 18.9 and 21.1 emu/g and coercivities ranging between 112 and 881 Oe. Moreover, ⁵⁷Fe Mössbauer spectroscopy reveals that apart from the predominant bcc FM Fe–Co phase, iron atoms also participate in the formation of a secondary martensitic-type Fe–Co phase. The emergence of this distinctive phase is attributed to the diffusion of carbon atoms within the Fe–Co lattices during their formation at elevated temperatures. The source of these carbon atoms is related to the unique morphological properties of the ND growth matrices, which facilitate surface sp² formations. Apart from their diffusion within the Fe–Co NP lattice, the carbon atoms also reconstruct layered graphitic-type nanostructures enveloping the metallic alloy NPs. These non-typical nanohybrid materials, reported here for the first time in the literature, hold significant potential for use in applications related, but not limited to, biomedicine, biopharmaceutics, catalysis, and other various contemporary technological fields. Full article

The administration of magnetic resonance imaging (MRI) contrast agents (CAs) has been conducted since 1988 by clinicians to enhance the clarity and interpretability of MR images. CAs based on gadolinium chelates are the clinical standard used worldwide for the diagnosis of various pathologies, such as the detection of brain lesions, the visualization of blood vessels, and the assessment of soft tissue disorders. However, due to ongoing concerns associated with the safety of gadolinium-based contrast agents, considerable efforts have been directed towards developing contrast agents with better relaxivities, reduced toxicity, and eventually combined therapeutic modalities. In this context, grafting (or encapsulating) paramagnetic metals or chelates onto (within) carbon-based nanoparticles is a straightforward approach enabling the production of contrast agents with high relaxivities while providing extensive tuneability regarding the functionalization of the nanoparticles. Here, we provide an overview of the parameters defining the efficacy of lanthanide-based contrast agents and the subsequent developments in the field of nanoparticular-based contrast agents incorporating paramagnetic species. Full article

In this study, nano-diamond (ND) and MoS₂ powder are used as additives in a carbonyl iron-based magnetorheological fluid (MRF) to improve its tribological performance. MRFs are prepared by dispersing 35 wt.% of CI particles in silicone oil and adding different proportions (0, 1, 3, or 5 wt.%) of ND and MoS₂ additives. Seven kinds of MRFs are made and tested using reciprocating friction and wear tester under different normal loads, and then the friction characteristics are evaluated by analyzing the experimental results. The morphological properties of MRFs and contacting surfaces before and after the tests are also observed using a scanning electron microscope and analyzed via energy-dispersive X-ray spectroscopy. The results show that the appropriate weight percentage of MoS₂ additives may decrease the friction coefficient and wear zone. It is also demonstrated from detailed analyses of worn surfaces that the wear mechanism is influenced not only by additives, but also by the applied normal load and magnetic field strength. Full article

The magnetic characteristics of a system of triply charged gadolinium ions Gd³⁺ chelated with carboxyls on the surface of detonation nanodiamond (DND) particles have been studied. Gd³⁺ ions demonstrate almost perfect spin (S = 7/2) paramagnetism with negligible antiferromagnetic interaction between spins (Weiss temperature about −0.35 K) for a wide range of concentrations up to ~18 ions per 5 nm particle. The study of the concentration dependence of the electron paramagnetic resonance signal for DND intrinsic defects with spin ½ (g = 2.0027) shows that Gd³⁺ ions are located on average at a distance of no more than 1.4 nm from shallow subsurface defects with spin ¹/₂. At the same time, they are located (according to density functional theory calculations) at a distance of about or at least 0.28 nm from the particle surface. Magnetic studies also confirm the isolated nature of the gadolinium chelate complexes on the surface of DND particles. DND particles turn out to be an optimal carrier for high-spin 4f- ions (gadolinium) in a highly concentrated isolated state. This property makes DND-Gd particles a candidate for the role of a contrast agent for magnetic resonance imaging. Full article

The worldwide death toll claimed by Acute Respiratory Syndrome Coronavirus Disease 2019 (SARS-CoV), including its prevailed variants, is 6,812,785 (worldometer.com accessed on 14 March 2023). Rapid, reliable, cost-effective, and accurate diagnostic procedures are required to manage pandemics. In this regard, we bring attention to quantum spin magnetic resonance detection using fluorescent nanodiamonds for biosensing, ensuring the benefits of artificial intelligence-based biosensor design on an individual patient level for disease prediction and data interpretation. We compile the relevant literature regarding fluorescent nanodiamonds-based SARS-CoV-2 detection along with a short description of viral proliferation and incubation in the cells. We also propose a potentially effective strategy for artificial intelligence-enhanced SARS-CoV-2 biosensing. A concise overview of the implementation of artificial intelligence algorithms with diamond magnetic nanosensing is included, covering this roadmap’s benefits, challenges, and prospects. Some mutations are alpha, beta, gamma, delta, and Omicron with possible symptoms, viz. runny nose, fever, sore throat, diarrhea, and difficulty breathing accompanied by severe body pain. The recommended strategy would deliver reliable and improved diagnostics against possible threats due to SARS-CoV mutations, including possible pathogens in the future. Full article

Nanodiamonds (NDs) are emerging as a promising candidate for multimodal bioimaging on account of their optical and spectroscopic properties. NDs are extensively utilized for bioimaging probes due to their defects and admixtures in their crystal lattice. There are many optically active defects presented in NDs called color centers, which are highly photostable, extremely sensitive to bioimaging, and capable of electron leap in the forbidden band; further, they absorb or emit light when leaping, enabling the nanodiamond to fluoresce. Fluorescent imaging plays a significant role in bioscience research, but traditional fluorescent dyes have some drawbacks in physical, optical and toxicity aspects. As a novel fluorescent labeling tool, NDs have become the focus of research in the field of biomarkers in recent years because of their various irreplaceable advantages. This review primarily focuses on the recent application progress of nanodiamonds in the field of bioimaging. In this paper, we will summarize the progress of ND research from the following aspects (including fluorescence imaging, Raman imaging, X-ray imaging, magnetic modulation fluorescence imaging, magnetic resonance imaging, cathodoluminescence imaging, and optical coherence tomography imaging) and expect to supply an outlook contribution for future nanodiamond exploration in bioimaging. Full article

Shape memory nanocomposites are excellent smart materials which can switch between a variable temporary shape and their original shape upon exposure to external stimuli such as heat, light, electricity, magnetic fields, moisture, chemicals, pH, etc. Numerous nanofillers have been introduced in shape memory polymers such as carbon nanotubes, graphene, nanodiamonds, carbon nanofibers, etc. Among nanocarbons, graphene has attracted research interest for the development of shape memory polymer/graphene nanocomposites. Graphene is a unique one-atom-thick two-dimensional nanosheet of sp²-hybridized carbon atoms. Graphene has been used as an effective nanofiller in shape memory polymeric nanocomposites owing to its remarkable electrical conductivity, flexibility, strength, and heat stability. Thermoplastics as well as thermoset matrices have been used to form the shape memory nanomaterials with graphene nanofiller. In shape memory polymer/graphene nanocomposites, their shape has been fixed above the transition temperature and then transformed to the original shape through an external stimulus. The inclusion of graphene in nanocomposites can cause fast switching of their temporary shape to their original shape. Fine graphene dispersion, matrix–nanofiller interactions, and compatible interface development can lead to high-performance shape memory graphene-derived nanocomposites. Consequently, this review focuses on an important class of shape memory graphene-based nanocomposites. The fabrication, physical properties, and shape memory actuation of polymer/graphene nanocomposites are discussed. The stimuli-responsive polymer/graphene nanocomposites mostly revealed heat-, electricity-, and light-induced effects. The inclusion of graphene enhanced the physical/covalent linking, shape recovery, shape fixity, flexibility, and crystallization effects in the polymers. Furthermore, potential applications of these materials are observed in the aerospace/automobile industries, civil engineering, and biomaterials. Full article

Nanodiamonds with magnetic resonance imaging (MRI) and targeted drug delivery to exert combined effects for biomedical applications have been considered to be an urgent challenge. Herein, a novel bio-nanoarchitectonics (Fe₃O₄@NDs) with simultaneous imaging and therapeutic capacities was fabricated by covalently conjugating nanodiamonds (NDs) with Fe₃O₄. Fe₃O₄@NDs exhibited better biocompatibility and excellent photothermal stability with superb photothermal conversion performance (37.2%). Fe₃O₄@NDs has high doxorubicin (DOX) loading capacity (193 mg/g) with pH and NIR-responsive release characteristics. Fe₃O₄@NDs loading DOX showed a combined chemo-photothermal inhibitory effect on the tumor cells. Enhanced T₂-weighted MRI contrast toward the tumor, with the assistance of a magnetic field, convinced the Fe₃O₄@NDs gathered in the tumor more efficiently and could be used for MRI-based cancer diagnosis. Our results revealed an effective strategy to achieve a stimuli-sensitive nanoplatform for multifunctional theranostics by the combined action. Full article

To improve the material removal efficiency and surface quality of single-crystal silicon after magnetorheological finishing, a novel green chemical-mechanical magnetorheological finishing (CMMRF) fluid was developed. The main components of the CMMRF fluid are nano-Fe₃O₄, H₂O₂, CH₃COOH, nanodiamond, carbonyl iron powder, and deionized water. The novel CMMRF fluid can simultaneously achieve Ra 0.32 nm (0.47 mm × 0.35 mm measurement area), Ra 0.22 nm (5 μm × 5 μm measurement area), and 1.91 × 10⁻² mm³/min material removal efficiency. Comprehensive studies utilizing a scanning electron microscope and a magnetic rheometer show that the CMMRF fluid has a high mechanical removal effect due to the well-dispersed nanodiamond and nano-Fe₃O₄ particles. The results of Fourier transform infrared spectra and Young’s modulus test reveal the mechanism of the chemical reaction and the mechanical characteristics deterioration of the modified layer. Under co-enhanced chemical and mechanical effects, an ultra-smooth and highly efficient MRF technology for single-crystal silicon is realized. Full article

The ability to precisely monitor the intracellular temperature directly contributes to the essential understanding of biological metabolism, intracellular signaling, thermogenesis, and respiration. The intracellular heat generation and its measurement can also assist in the prediction of the pathogenesis of chronic diseases. However, intracellular thermometry without altering the biochemical reactions and cellular membrane damage is challenging, requiring appropriately biocompatible, nontoxic, and efficient biosensors. Bright, photostable, and functionalized fluorescent nanodiamonds (FNDs) have emerged as excellent probes for intracellular thermometry and magnetometry with the spatial resolution on a nanometer scale. The temperature and magnetic field-dependent luminescence of naturally occurring defects in diamonds are key to high-sensitivity biosensing applications. Alterations in the surface chemistry of FNDs and conjugation with polymer, metallic, and magnetic nanoparticles have opened vast possibilities for drug delivery, diagnosis, nanomedicine, and magnetic hyperthermia. This study covers some recently reported research focusing on intracellular thermometry, magnetic sensing, and emerging applications of artificial intelligence (AI) in biomedical imaging. We extend the application of FNDs as biosensors toward disease diagnosis by using intracellular, stationary, and time-dependent information. Furthermore, the potential of machine learning (ML) and AI algorithms for developing biosensors can revolutionize any future outbreak. Full article

A novel endeavor based on the synthesis, characterization and study of a hybrid crystalline magnetic nanostructured material composed of bimetallic iron–rhodium nanoalloys, grown on nanodiamond nanotemplates, is reported in this study. The development of this hybrid magnetic nanomaterial is grounded in the combination of wet chemistry and thermal annealing under vacuum. In order to assess, evaluate and interpret the role and special properties of the nanodiamond supporting nanotemplates on the growth and properties of the bimetallic ferromagnetic Fe–Rh nanoparticles on their surfaces, unsupported free FeRh nanoparticles of the same nominal stoichiometry as for the hybrid sample were also synthesized. The characterization and study of the prepared samples with a range of specialized experimental techniques, including X-ray diffraction, transmission and scanning transmission electron microscopy with energy dispersive X-ray analysis, magnetization and magnetic susceptibility measurements and ⁵⁷Fe Mössbauer spectroscopy, reveal that thermal annealing of the hybrid sample under specific conditions (vacuum, 700 °C, 30 min) leads to the formation of a rhodium-rich FeRh alloy nanostructured phase, with an average particle size of 4 nm and good dispersion on the surfaces of the nanodiamond nanotemplates and hard ferromagnetic characteristics at room temperature (coercivity of ~500 Oe). In contrast, thermal annealing of the unsupported free nanoparticle sample under the same conditions fails to deliver ferromagnetic characteristics to the FeRh nanostructured alloy phase, which shows only paramagnetic characteristics at room temperature and spin glass ordering at low temperatures. The ferromagnetic nanohybrids are proposed to be exploited in a variety of important technological applications, such as magnetic recording, magnetic resonance imaging contrast and magnetic hyperthermia agents. Full article

This work concentrated on the improvement of the surface roughness of a magnetic head, through the use of an ultrafine nanodiamond slurry, and a novel floating grinding process, which optimize different experimental factors required for the fine grinding of a magnetic head. The preparation of the grinding plate was confirmed by the observation of the surface change, depth detection, and flatness after ultrafine nanodiamonds were embedded into it by a Keyence high-power microscope at a 20 K magnification. The flatness was measured by a TOTO instrument. The optimum conditions were found to be a pit ratio reach of 30:70 and a plate flatness (average) of 1.8 μm. The rotation speed and vibration frequency were 0.3 and 10 rpm, respectively, for the grinding process. The morphology, size, and elemental composition of blackspots were investigated by SEM, AES, AFM, and transmission electron microscopy (TEM) analysis, which showed that the diameter of the diamonds in the slurry was important for grinding surface improvement. A novel method was proposed in this study to fine grind a magnetic head using a small-sized diamond slurry (100 nm) in conjunction with a novel float lapping method. Comparison experiments were performed under both normal conditions and improved conditions. The results show that by using the novel float lapping method with a small-sized diamond slurry, the minimum roughness was obtained. The finest roughness obtained for the slider surface reached 0.165 nm without blackspots or scratches. Full article

Copper has several biological functions, but also some toxicity, as it can act as a catalyst for oxidative damage to tissues. This is especially relevant in the presence of H₂O₂, a by-product of oxygen metabolism. In this study, the reactions of copper with H₂O₂ have been investigated with spectroscopic techniques. These results were complemented by a new quantum sensing technique (relaxometry), which allows nanoscale magnetic resonance measurements at room temperature, and at nanomolar concentrations. For this purpose, we used fluorescent nanodiamonds (FNDs) containing ensembles of specific defects called nitrogen-vacancy (NV) centers. More specifically, we performed so-called T1 measurements. We use this method to provide real-time measurements of copper during a Fenton-like reaction. Unlike with other chemical fluorescent probes, we can determine both the increase and decrease in copper formed in real time. Full article