Applied Nano

DNA encoding the 16S rRNA of bacteria is a type of nanometer-sized information storage that can be used to characterize bacterial communities in soils. Reading this molecular ’nano-archive’ is not only of interest for characterizing recent local ecological conditions but can also provide valuable information about human impacts on soils in the past. This is of great interest for archaeology and for understanding the ecological consequences of past human activities on recent ecological conditions. Powerful sequencing methods such as the Illumina process allow many different DNA sequences to be determined in parallel and provide very efficient data sets that reflect the composition of soil bacterial communities in topsoil layers as well as in translocated and covered soils of archaeological sites such as settlements, burials or workplaces. Here, a brief overview of recent developments in the use of these molecular nano-archives for the study of archaeological soil samples is given using typical examples. Full article

Pollution of freshwater by synthetic organic dyes is a major concern due to their high toxicity and mutagenicity. In this study, the degradation of Congo red (CR) and malachite green (MG) dyes was investigated using nanostructured Gd₂O₃. It was prepared using the coprecipitation method, using gadolinium nitrate and concentrated formic acid, with subsequent calcination at 600 °C. Its morphology corresponds to hollow porous microspheres with a size between 0.5 and 7.5 μm. The optical bandgap energy was determined by using the Tauc method, giving 4.8 eV. The degradation of the dyes was evaluated by UV-vis spectroscopy, which revealed that dissociative adsorption (in the dark) played a key role. It is explained by the cleavage and fragmentation of the organic molecules by hydroxyl radicals (^•OH), superoxide radicals (^•${\mathrm{O}}_2^{-}$) and other reactive oxygen species (ROS) produced on the surface of Gd₂O₃. For CR, the degradation percentage was ~56%, through dissociative adsorption, while UV light photocatalysis increased it to ~65%. For MG, these values were ~78% and ~91%, respectively. The difference in degradation percentages is explained in terms of the isoelectric point of solid (IEPS) of Gd₂O₃ and the electrical charge of the dyes. FTIR and XPS spectra provided evidence of the role of ROS in dye degradation. Full article

Interest in the use of nanoparticles in agriculture has grown in recent years due to their potential abilities across a range of applications that could increase agricultural production, improve the efficiency of nutrient delivery, or improve pest management. However, as with any application of nanomaterials, concern exists about potential risks to human health. Because many applications might result in the attachment of nanoparticles to produce surfaces, it is important to understand the conditions under which rinsing is likely to remove nanoparticles from surfaces and the degree to which they can be removed. This work explored the rinsing removal of two types of nanoparticles, titanium dioxide (TiO₂) and zinc oxide (ZnO), from spinach leaf surfaces in the absence and presence of biofilms based on extracellular polymeric substances (EPS). A hypothesis driving the work was that the presence of biofilms might enhance the retention of nanoparticles. The work combined experiments to determine surface energy parameters for fresh and rotten spinach, for use in extended DLVO (xDLVO) calculations, as well as direct rinsing experiments to explore nanoparticle removal from spinach surfaces. Nanoparticles were quantified using backscattered scanning electron microscopy using techniques developed for the work. Results of xDLVO calculations suggest that the presence of biofilms may actually be likely to reduce the retention of nanoparticles by produce surfaces, although this effect was not apparent in rinsing experiments, which exhibited similar removal of high-concentration TiO₂ from spinach leaves. Overall, nanoparticles deposited from high-concentration suspensions were found to be removed to a greater degree by rinsing, while those deposited from low-concentration suspensions exhibited no apparent release, even under conditions where release might be favored. Full article

While microparticles can be removed by a filtration step at a drinking water treatment plant (DWTP), engineered nanoparticles (ENPs), which are widely used in industry, commerce and households, pose a major problem due to their special properties, e.g., size, reactivity and polarity. In addition, many ENPs exhibit toxic potential, which makes their presence in drinking water undesirable. Therefore, this study investigated the removal of ENPs in the laboratory and at a pilot-scale DWTP. Eight ENPs were synthesized and tested for stability in different types of water. Only three of them were stable in natural water: cetyltrimethylammonium bromide-coated gold (CTAB/AuNPs), polyvinylpyrrolidone-stabilized gold and silver nanoparticles (PVP/AuNPs, PVP/AgNPs). Their retention on quartz sand, silica gel and fresh anthracite was low, but CTAB/AuNPs could be retained on fresh river sand and thus should not overcome riverbank filtration, while PVP/AuNPs and PVP/AgNPs showed no retention and may be present in raw water. During ozonation, PVP/AuNPs remained stable while PVP/AgNPs were partially degraded. The advanced oxidation process (AOP) was less effective than ozone. PVP/AgNPs were almost completely retained on the pilot plant anthracite sand filter coated with manganese(IV) oxide and ferrihydrite from raw water treatment. PVP/AuNPs passed the filter with no retention. In contrast to PVP/AuNPs, PVP/AgNPs and CTAB/AuNPs were also retained on activated carbon. The integration of a flocculation step with iron(III) salts can improve ENP removal, with PVP/AuNPs requiring higher flocculant doses than PVP/AgNPs. PVP/AuNPs, in particular, are well-suited for testing the effectiveness of water treatment. Further data on the occurrence of stable ENPs in raw water and their behavior during water treatment are needed to perform a risk assessment and derive the measures. Full article

Flexible nanocomposite sensors hold significant promise in various applications, such as wearable electronics and medical devices. This research aims to tailor the flexibility and sensitivity of 3D-printed piezoresistive nanocomposite pressure sensors through geometric design, by exploring various simple cellular structures. The geometric designs were specifically selected to be 3D printable with a flexible material, allowing evaluation of the impact of different structures on sensor performance. In this study, we used both experimental and finite element (FE) methods to investigate the effect of geometric design on piezoresistive sensors. We fabricated the sensors using a flexible resin mixed with conductive nanoparticles via a Stereolithography (SLA) additive manufacturing technique. Electromechanical testing was carried out to evaluate the performance of four different sensor designs. Finite element (FE) models were developed, and their results were compared with experimental data to validate the simulations. The results demonstrated that auxetic structure exhibited the highest sensitivity and lowest stiffness both in experimental and FE analysis, highlighting its potential for applications requiring highly responsive materials. The validated FE model was further used for a parametric study of one of the promising simple designs, revealing that variations in geometric parameters significantly impact piezoresistive sensitivity. These findings provide valuable insights for advancing the development of pressure sensors with tailored sensitivity characteristics. 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

Silver nanoparticles (AgNPs) demonstrate potential in treating aggressive cancers such as triple-negative breast cancer (TNBC) in preclinical models. To further the development of AgNP-based therapeutics for clinical use, it is essential to clearly define the specific physicochemical characteristics of the nanoparticles and connect these properties to biological outcomes. This study addresses this knowledge gap through detailed investigations into the structural and surface functional relationships, exploring the mechanisms, safety, and efficacy of AgNPs in targeting TNBC. The surface functionality of nanoparticles is crucial not only for their internalization into cancer cells but also for enhancing their toxicity toward tumor cells. Although the nanoparticles internalized into cancer cells, they failed to exhibit their full toxicity against the cancer. Herein we report a solvent-assisted synthesis amine, mercaptohexanol and bifunctional silver nanoparticles and performing comparative study to understand their selectivity and toxicity toward TNBC cells. The nanoparticles are fully characterized by UV–visible absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and dynamic light scattering measurement (DLS). The synthesis method achieves an extremely high yield and surface coating ratio of synthesized colloidal AgNPs. Our findings reveal that the amine-capped AgNPs exhibit significant selective toxicity against TNBC cell lines MCF7 and MDA-MB-231 at a concentration of 40 µg/mL without affecting normal breast cell lines MCF10A. This study underscores the potential of functionalized AgNPs in developing safe and targeted therapeutic approaches for treating aggressive cancers like TNBC, laying the groundwork for future clinical advancements. Full article

Wound healing is rarely seen as a problem in healthy individuals; however, under certain pathophysiological conditions, this process can be impaired, leading to the emergence of chronic wounds, which are themselves a serious public health problem. This work aimed to review the most important recent literature on the use of nanoparticles of Ag, Au, and Zn produced from plant extracts and their application as healing agents. To that end, we provide an insight into the pathophysiology of wound healing and the main routes to obtaining metallic nanoparticles. The methodology of synthesis, which is part of the so-called green synthesis, has been the focus of several studies on the use of medicinal plants as a substrate to produce silver, gold, and zinc nanoparticles. Their use as wound healing agents is closely related to their natural antimicrobial, anti-inflammatory, and cicatrizing properties. Finally, we address in vitro and in vivo studies on the efficiency of metallic nanoparticles (MNPs) synthesized from plant extracts and applied to wound healing in different pharmaceutical forms. For instance, the excellent wound contraction rates obtained from silver and gold NPs, respectively, were obtained from Euphorbia milii (92%) and Plectranthus aliciae (almost 97%) extracts in in vivo and in vitro analyses. Based on the satisfactory results, we find that MNPs are a potential therapeutic alternative compared to traditional synthetic healing agents and foresee the production of new pharmaceutical drugs. Full article

Recent improvements in advanced technology for toxic chemical remediation have involved the application of titanium oxide nanoparticles as a photocatalyst. However, the large energy bandgap associated with titanium oxide nanoparticles (3.0–3.20 eV) is a limitation for their application as a photocatalyst within the solar spectrum. Various structural modification methods have led to significant reductions in the energy bandgap but not without their disadvantages, such as electron recombination. In the current investigation, biochar was made from the leaves of an invasive plant (Acacia saligna) and subsequently applied as a support in the synthesis of titanium oxide nanoparticles. The characterization of biochar-supported titanium oxide nanoparticles was performed using scanning electron microscopy, Fourier transformer infrared, X-ray diffraction, and Brunauer–Emmett–Teller analyses. The results showed that the titanium oxide was successfully immobilized on the biochar’s external surface. The synthesized biochar-supported titanium oxide nanoparticles exhibited the phenomenon of small hysteresis, which represents the typical type IV isotherm attributed to mesoporous materials with low porosity. Meanwhile, X-ray diffraction analysis revealed the presence of a mixture of rutile and anatase crystalline phase titanium oxide. The synthesis of biochar-supported titanium oxide nanoparticles was highly efficient in the degradation of Orange II Sodium dye under solar irradiation. Moreover, 83.5% degradation was achieved when the biochar-supported titanium oxide nanoparticles were used as photocatalysts in comparison with the reference titanium oxide, which only achieved 20% degradation. Full article

Toxic metal wastewater is a challenge for exposed terrestrial and aquatic environments, as well as the recyclability of the water, prompting inputs for the development of promising treatment methods. Consequently, the rGO/ZnONP nanocomposite was synthesized at room temperature for four hours and was tested for the adsorption of cadmium and lead in wastewater. The optimized nanocomposite had the lowest band gap energy (2.69 eV), and functional group interactions were at 516, 1220, 1732, 3009, and 3460 cm⁻¹. The nanocomposite showed good ZnO nanoparticle size distribution and separation on rGO surfaces. The nanocomposite’s D and G band intensities were almost the same, constituting the ZnO presence on rGO from the Raman spectrum. The adsorption equilibrium time for cadmium and lead was reached within 10 and 90 min with efficiencies of ~100%. Sips and Freundlich best fitted the cadmium and lead adsorption data (R² ~ 1); therefore, the adsorption was a multilayer coverage for lead and a mixture of heterogenous and homogenous coverage for cadmium adsorption. Both adsorptions were best fitted by the pseudo-first-order model, suggesting the multilayer coverage dominance. The adsorbent was reused for three and seven times for cadmium and lead. The nanocomposite showed selectivity towards lead (95%) and cadmium (100%) in the interfering wastewater matrix. Conclusively, the nanocomposite may be embedded within upcoming lab-scale treatment plants, which could lead to further upscaling and it serving as an industrial wastewater treatment material. Full article

Nano-encapsulation and conjugation are the main strategies employed for drug delivery. Nanoparticles help improve encapsulation and targeting efficiency, thus optimizing therapeutic efficacy. Through nanoparticle technology, replacement of a defective gene or delivery of a new gene into a patient’s genome has become possible. Lipid nanoparticles (LNPs) loaded with genetic materials are designed to be delivered to specific target sites to enable gene therapy. The lipid shells protect the fragile genetic materials from degradation, then successfully release the payload inside of the cells, where it can integrate into the patient’s genome and subsequently express the protein of interest. This review focuses on the development of LNPs and nano-pharmaceutical techniques for improving the potency of gene therapies, reducing toxicities, targeting specific cells, and releasing genetic materials to achieve therapeutic effects. In addition, we discuss preparation techniques, encapsulation efficiency, and the effects of conjugation on the efficacy of LNPs in delivering nucleic acid materials. Full article

ZnS is a II-VI semiconductor with a wide bandgap. ZnS-based nanomaterials have been produced in a variety of morphologies with unique properties and characteristic features. An extensive collection of research activities is available on various synthetic methodologies to produce such a wide variety of ZnS-based nanomaterials. In this comprehensive review, we thoroughly covered all the different synthetic techniques employed by researchers across the globe to produce zero-dimensional, one-dimensional, two-dimensional, and three-dimensional ZnS-based nanomaterials. Depending on their morphologies and properties, ZnS-based nanomaterials have found many applications, including optoelectronics, sensors, catalysts, batteries, solar cells, and biomedical fields. The properties and applications of ZnS-based nanostructures are described, and the scope of the future direction is highlighted. Full article

The leaves of the Murraya koenigii aromatic plant contain various specific phytochemicals, including lutein, β-carotene, vitamin C, nicotinic acids, and other polyphenols, which act as reducing agents to produce metallic nanoparticles from their respective precursors. In this study, we report the green synthesis of iron–cobalt bimetallic nanoparticles (Fe–Co BMNPs) using natural resources of reducing and capping agents from aqueous extract of Murraya koenigii leaves. The synthesized Fe–Co BMNPs were characterized using SEM, EDS, BET surface area, TGA, XRD, TEM, and VSM techniques, revealing their crystalline structure with a surface area of 83.22 m² g⁻¹ and particle sizes <50 nm. Furthermore, the photocatalytic ability of the synthesized Fe–Co BMNPs was examined concerning methylene blue dye (MBD) aqueous solution. The synthesized Fe–Co BMNPs exhibited promising potential for dye removal from aqueous solution in acidic and basic medium (>97% of 10 mg L⁻¹). Full article

This paper presents the continuation of experimental investigations conducted by the present authors to measure and compare the thermal and fluid dynamic performance of a residential hydronic air coil using nanofluids. The prior experiments were limited to testing only one volumetric concentration (1%) of aluminum oxide (Al₂O₃) nanofluid. They compared it with the base fluid, a 60% ethylene glycol/40% water mixture by mass (60% EG). The original tests revealed some deficiencies in the experimental setup, which was subsequently revised and improved. This paper summarizes the results of experiments from the improved test bed using three concentrations of Al₂O₃ nanofluids: 1, 2, and 3% volumetric concentrations prepared with an average particle size of 45 nm in a 60% EG dispersion. The test bed in these experiments simulates a small air handling system typical of heating, ventilation, and air conditioning (HVAC) applications in cold regions. Entering conditions for the air and liquid were selected to emulate typical commercial air handling systems operating in cold climates. Contrary to previous findings, our test results revealed that nanofluids did not perform as well as expected. Prior predictions from many analytical and numerical studies had promised significant performance gain. The performance of the 1% nanofluid was generally equal to that of the base fluid under identical inlet conditions. However, the performance of the 2% and 3% nanofluids was considerably lower than that of the base fluid. The higher concentration nanofluids exhibited heat rates up to 14.6% lower than the 60% EG and up to 44.3% lower heat transfer coefficient. The 1% Al₂O₃/60% EG exhibited a 100% higher pressure drop across the coil than the base fluid, considering equal heat output. This performance degradation was attributed to the inability to maintain nanofluid dispersion stability, agglomeration, and subsequent decline in the thermophysical properties. Full article

Understanding the role of oxygen vacancies in the phase transformation of metal oxide nanomaterials is fundamental to design more efficient opto-electronic devices for a variety of applications, including sensing, spintronics, photocatalysis, and photo-electrochemistry. However, the structural mechanisms behind the phase transformation in reducible oxides remain poorly described. Here, we compare P25 and black TiO₂ during the thermal anatase-to-rutile transformation using in situ synchrotron powder diffraction. The precise measurement of the phase fractions, unit cell parameters, and Ti-O bond sheds light on the phase transformation dynamics. Notably, we observe distinct temperature-dependent shifts in the relative phase fractions of anatase and rutile in both materials highlighting the role of the oxygen vacancy in promoting the phase transformation. We employ bond valence concepts for structural modeling, revealing unique trends in temperature evolution of Ti-O distances of black rutile, confirming that this TiO₂ phase is preferentially reduced over anatase. These findings not only enhance our understanding of phase transitions in TiO₂ but also open new ways for the design of advanced photocatalytic materials through targeted phase control. Full article

This work presents the green synthesis of iron oxide nanoparticles (IONPs) using Baccharis salicifolia extract and their incorporation in mesoporous silica MCM-41, obtaining an MCM-41@IONP composite. The MCM-41@IONP composite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption and desorption, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The use of the natural reducing agent Baccharis salicifolia resulted in nanoparticles with an average size of 31 nm. Furthermore, we showcase the application of the MCM-41@IONP nanocomposite in a metal–insulator–semiconductor (MIS) diode, which was fabricated at room temperature. The current–voltage and capacitance–voltage curves of the MIS diode were carefully measured and subjected to detailed analysis. The results demonstrate the potential utility of MCM-41@IONP nanocomposite-based MIS diodes, suggesting their applicability in the design of biosensors or as discrete components in electronic devices. Full article

This computational research study will compare the specific charge capacity (SCC) between lithium ions inserted into crystallized silicon (c-Si) nanowires with that of sodium ions inserted into amorphous silicon (a-Si) nanowires. It will be demonstrated that the potential energy V(r) within a lithium–silicon nanowire supports a coherent energy state model with discrete electron particles, while the potential energy of a sodium–silicon nanowire will be discovered to be essentially zero, and, thus, the electron current that travels through a sodiated silicon nanowire will be modeled as a free electron with wave-like characteristics. This is due to the vast differences in the electric fields of lithiated and sodiated silicon nanowires, where the electric fields are of the order of ${10}^{10}$ V/m and ${10}^{-15}$ V/m, respectively. The main reason for the great disparity in electric fields is the presence of optical amplification within lithium ions and the absence of this process within sodium ions. It will be shown that optical amplification develops coherent optical interactions, which is the primary reason for the surge of specific charge capacity in the lithiated silicon nanowire. Conversely, the lack of optical amplification is the reason for the incoherent optical interactions within sodium ions, which is the reason for the low presence of SCC in sodiated silicon nanowires. Full article

Nanoparticles composed of inorganic boron-containing compounds represent a promising candidate as ¹⁰B carriers for BNCT. This study focuses on the synthesis, characterization, and assessment of the biological activity of composite nanomaterials based on boron carbide (B₄C). Boron carbide is a compelling alternative to borated molecules due to its high volumetric B content, prolonged retention in biological systems, and low toxicity. These attributes lead to a substantial accumulation of B in tissues, eliminating the need for isotopically enriched compounds. In our approach, B₄C nanoparticles were included in composite nanostructures with ultrasmall superparamagnetic nanoparticles (SPIONs), coated with poly (acrylic acid), and further functionalized with the fluorophore DiI. The successful internalization of these nanoparticles in HeLa cells was confirmed, and a significant uptake of ¹⁰B was observed. Micro-distribution studies were conducted using intracellular neutron autoradiography, providing valuable insights into the spatial distribution of the nanoparticles within cells. These findings strongly indicate that the developed nanomaterials hold significant promise as effective carriers for ¹⁰B in BNCT, showcasing their potential for advancing cancer treatment methodologies. Full article

Based on the unique properties of optical Fano resonance and plasmonic-waveguide coupling systems, this paper explores a novel refractive index concentration sensor structure. The sensor structure is composed of a metal–insulator–metal (MIM) waveguide and two identically shaped and sized double-tooth ring couplers (DTR). The performance structure of the nanoscale refractive index sensor with DTR cavity was comprehensively assessed using the finite element method (FEM). Due to the impact of various geometric parameters on the sensing characteristics, including the rotation angles, the widths between the double-tooth rings, and the gaps between the cavity and the waveguide, we identified an optimal novel refractive index sensor structure that boasts the best performance indices. Finally, the DTR cavity sensor achieved a sensitivity of 4137 nm/RIU and Figure of merit (FOM) of 59.1. Given the high complexity and sensitivity of the overall structure, this nanoscale refractive index sensor can be applied to the detection of oil concentration in industrial oil–water mixtures, yielding highly precise results. Full article