In this article, we report the structural and optical properties of zirconium oxide (ZrO2) nanoparticles synthesized via chemical co-precipitation method. The effect of calcination temperature on structural and optical properties of ZrO2 nanoparticles is investigated through XRD, FESEM, EDX, FTIR, UV–Vis absorption, fluorescence emission and life time measurements. XRD spectrum reveals the tetragonal phase at calcination temperature 600 °C and crystallinity of samples increases with calcination temperature. At 800 °C the phase transition from tetragonal to tetragonal-monoclinic mixed phase is noticed. The FESEM images show the particles are of irregular shape and highly agglomerated. FTIR spectra also confirm the formation of ZrO2 in crystalline phase. From UV–vis absorption spectra it is found a strong quantization and varying band gap with calcination temperature. The change in emission wavelength and intensity with phase change is observed form fluorescence emission spectra. At higher calcination temperature emission intensity is decreased which may be due to the phase change and the formation of surface defects. The life time measurements also reveal the different trap states and life time with calcination temperature.
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N C Horti et al 2020 Nano Ex. 1 010022
Sonima Mohan et al 2020 Nano Ex. 1 030028
Zinc Oxide (ZnO) nanoparticles were synthesized by hydrothermal method under different conditions and studied various properties. FTIR studies proved the presence of ZnO bonding and purity of the samples. Grain size was found to be decreased with the increase of reaction temperature and increased with reaction time. TEM images show formation of nanorods under same reaction temperature, also nanoflowers and nanospheres for different temperatures. Intensity of luminescence peaks is found to be changed with variation in interplanar spacing. UV–vis spectra helped to identify the increased photon absorption in particles of bigger size. Change in bandgap value is also observed due to the difference in size of nanoparticles.
Rachana Yadwade et al 2021 Nano Ex. 2 022003
The field of nanotechnology is being greatly explored by cosmetic industries in order to improve the efficacy of cosmetic products. The increased use of nanomaterials in the field of cosmetics can have two sides as health-related benefits and detrimental effects. This review mainly seeks the pros and cons of the use of nanomaterials in cosmetics along with some examples of nanomaterials that are widely used in cosmetic industries along with different types of nanotechnology-based cosmetic products. The benefits of nanomaterials in cosmetic formulations are huge. Moreover the study regarding the toxic effects on the health also equally matters. This review gives a brief outline of the advantages as well as disadvantages of nanotechnology in cosmetics.
Md Jahidul Haque et al 2020 Nano Ex. 1 010007
In this work, two different methods (sol-gel and biosynthesis) were adopted for the synthesis of zinc oxide (ZnO) nanoparticles. The leaf extract of Azadirachta Indica (Neem) was utilized in the biosynthesis scheme. Structural, antibacterial, photocatalytic and optical performances of the two variants were analyzed. Both variants demonstrated a wurtzite hexagonal structure. The biosynthesized variant (25.97 nm) exhibited smaller particles than that of the sol-gel variant (33.20 nm). The morphological analysis revealed that most of the particles of the sol-gel variant remained within the range of 15 nm to 68 nm while for the biosynthesized variant the range was 10–70 nm. The antibacterial assessment was redacted by using the agar well diffusion method in which the bacteria medium was Escherichia coli O157: H7. The zone of inhibition of bacterial growth was higher in the biosynthesized variant (14.5 mm). The photocatalytic performances of the nanoparticles were determined through the degradation of methylene blue dye in which the biosynthesized variant provided better performance. The electron spin resonance (EPR) analysis revealed that the free OH · radicals were the primary active species for this degradation phenomenon. The absorption band of the sol-gel and biosynthesized variants were 363 nm and 356 nm respectively. The optical band gap energy of the biosynthesized variant (3.25 eV) was slightly higher than that of the sol-gel variant (3.23 eV). Nevertheless, the improved antibacterial and photocatalytic responses of the biosynthesized variants were obtained due to the higher rate of stabilization mechanism of the nanoparticles by the organic chemicals (terpenoids) present in the Neem leaf extract.
Bharti et al 2021 Nano Ex. 2 022004
Supercapacitors provide remarkable eco-friendly advancement in energy conversion and storage with a huge potential to control the future economy of the entire world. Currently, industries focus on the design and engineering aspects of supercapacitors with high performance (high energy), flexibility (by the use of composite polymer based electrolytes), high voltage (ionic liquid) and low cost. The paper reviews the modelling techniques like Empirical modelling, Dissipation transmission line models, Continuum models, Atomistic models, Quantum models, Simplified analytical models etc. proposed for the theoretical study of Supercapacitors and discusses their limitations in studying all the aspects of Supercapacitors. It also reviews the various software packages available for Supercapacitor (SC) modelling and discusses their advantages and disadvantages. The paper also reviews the Experimental advancements in the field of electric double layer capacitors (EDLCs), pseudo capacitors and hybrid/asymmetric supercapacitors and discusses the commercial progress of supercapacitors as well.
Yamir Islam et al 2020 Nano Ex. 1 012002
With estimated worldwide cost over $1 trillion just for dementia, diseases of the central nervous system pose a major problem to health and healthcare systems, with significant socio-economic implications for sufferers and society at large. In the last two decades, numerous strategies and technologies have been developed and adapted to achieve drug penetration into the brain, evolving alongside our understanding of the physiological barriers between the brain and surrounding tissues. The blood brain barrier (BBB) has been known as the major barrier for drug delivery to the brain. Both invasive and minimally-invasive approaches have been investigated extensively, with the minimally-invasive approaches to drug delivery being more suitable. Peptide based brain targeting has been explored extensively in the last two decades. In this review paper, we focused on self-assembled peptides, shuttle peptides and nanoparticles drug delivery systems decorated/conjugated with peptides for brain penetration.
Sergio Solis Flores et al 2024 Nano Ex. 5 025007
Microalgae cultures have an excellent ability to capture CO2 and produce high, medium, and low valuable biocompounds such as proteins, carbohydrates, lipids, pigments, and polyhydroxyalkanoates; those compounds have shown excellent properties in the pharmaceutical, cosmetic, food, and medical industries. Recently, the supplementation of carbon dots (CDs) in autotrophic microalgae cultures has been explored as a new strategy to increase light capture and improve photoluminescence, which in turn enhances biomass growth and biocompounds production. In this work, we synthesized CDs through a simple carbonization method using orange juice as a natural precursor. The green synthesized CDs were analyzed in detail through characterization techniques such as Fourier-transform infrared spectroscopy (FTIR), UV–visible, fluorescence spectroscopy, and ζ potential analysis. Moreover, CDs were added to Chlorella vulgaris to analyze the response under different photoperiod cycles and CDs dosages. The optimal results were obtained with the addition of 0.5 mg l−1 of CDs under a photoperiod cycle of 16 h:8 h (light:dark). In these conditions, a maximum biomass production of 2.12 g l−1 was observed, which represents an enhancement of 112% and 17% in comparison to the control samples under the photoperiod of 12 h:12 h and 16 h:8 h (light/dark), respectively. Furthermore, the production of lipids, proteins, and carbohydrates was significantly increased to 249 mg g−1, 285 mg g−1, and 217 mg g−1 dry weight, respectively. These results suggest that the addition of CDs enhances cell growth and increases the production of lipids and proteins, being a strategy with great potential for the food and pharmaceutical industries.
Ayan Roy et al 2023 Nano Ex. 4 022002
The swiftly growing global economies remain the root cause of the soaring demand for oil and gas to satisfy their excessive energy demands, thus making the oil and gas sector one of the most important industrial sectors. Though renewable energy technologies are the more sustainable option, technological advances are required to make them more accessible to the common people. Therefore, due to the limitation of renewable energy technologies, oil and gas continue to be a more viable alternative. Extensive research is being conducted on the applications of nanotechnology to make the upstream, midstream, and downstream processes efficient in the oil and gas sector. Nanomaterials make the activities in processing and transportation more economical, efficient, and environment-friendly than their conventional counterparts. In this review, we have highlighted the need for nanomaterials in oil and gas, for example, in crude oil exploration, including drilling and EOR, separation techniques, refining, transportation, and other related activities. Further, this review summarizes novel nanomaterials developed and used in the activities mentioned above, and at the end, we have briefly described the synthesis mechanism of these nanomaterials. Finally, we emphasize the current challenges and future work prospects in this area of study.
Ahmed Haroun et al 2021 Nano Ex. 2 022005
Self-sustainable sensing systems composed of micro/nano sensors and nano-energy harvesters contribute significantly to developing the internet of things (IoT) systems. As one of the most promising IoT applications, smart home relies on implementing wireless sensor networks with miniaturized and multi-functional sensors, and distributed, reliable, and sustainable power sources, namely energy harvesters with a variety of conversion mechanisms. To extend the capabilities of IoT in the smart home, a technology fusion of IoT and artificial intelligence (AI), called the artificial intelligence of things (AIoT), enables the detection, analysis, and decision-making functions with the aids of machine learning assisted algorithms to form a smart home based intelligent system. In this review, we introduce the conventional rigid microelectromechanical system (MEMS) based micro/nano sensors and energy harvesters, followed by presenting the advances in the wearable counterparts for better human interactions. We then discuss the viable integration approaches for micro/nano sensors and energy harvesters to form self-sustainable IoT systems. Whereafter, we emphasize the recent development of AIoT based systems and the corresponding applications enabled by the machine learning algorithms. Smart home based healthcare technology enabled by the integrated multi-functional sensing platform and bioelectronic medicine is also presented as an important future direction, as well as wearable photonics sensing system as a complement to the wearable electronics sensing system.
C Reyes-Damián et al 2024 Nano Ex. 5 025006
ZnO nanostructures have attracted considerable attention because of their physicochemical properties and applications as antibacterial agents, photocatalytic reactions for pollutant removal, and electronics. Hence, efficient production and knowledge of their properties under different synthesis conditions are essential. Biosynthesis has emerged as an excellent growth-directing method for synthesizing nanomaterials, representing a soft and cleaner alternative for their production. In this study, we synthesized different ZnO nanostructures using a soft chemistry method at different growth temperatures, from 200 to 800 °C every 200 °C. The crystalline structure was estudied by x-ray Diffraction (XRD) and High-Resolution Transmission Electron Microscopy (HRTEM). The shape and size were studied by Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM), which revealed a ZnO hexagonal phase with two shapes: nanoparticles (NPs) with irregular shapes and nanorods of different sizes. The optical properties were studied by Raman and UV-visible spectroscopy, and optical absorption measurements showed bandgap tuning of the produced nanostructures. Finally, the magnetic characteristics of the samples demonstrated magnetic anisotropy due to the preference for crystalline formation and the size of the nanoparticles. The magnetic interaction between the two types of NPs increased the diamagnetism associated with the nanorods.
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Aman Sharma et al 2024 Nano Ex. 5 022002
Silver nanoparticles (AgNPs) have received a lot of interest for their several applications, including their remarkable potential as photocatalysts for organic dye degradation. This research thoroughly investigates the efficacy of ecologically friendly, green-synthesized AgNPs in the treatment of synthetic dye-contaminated wastewater. The synthesis of AgNPs from various biological substrates is investigated, emphasizing their economic viability, significant conductivity, and considerable biocompatibility. The improper disposal of synthetic dyes in wastewater poses severe environmental and health risks due to their non-biodegradable nature and persistent chemical features. In response to this challenge, this review paper investigates the capability of AgNPs to serve as effective photocatalysts for degrading a range of organic dyes commonly found in industrial effluents. Specific dyes, including methyl orange, congo red, nitrophenol, methylene blue, and malachite green, are studied in the context of wastewater treatment, providing insights into the efficacy of AgNPs synthesized from diverse biological sources. The review sheds light on the photocatalytic degradation methods used by green-synthesized AgNPs, shedding light on the transition of these synthetic dyes into less hazardous compounds. It also delves into the toxicity aspect of the AgNPs and its possible remediation from the environment. The ecologically friendly synthesis procedures investigated in this work provide an alternative to traditional methods, highlighting the importance of sustainable technologies in solving modern environmental concerns. Furthermore, a comparative examination of various biological substrates for AgNPs synthesis is presented, evaluating their respective dye degradation efficiencies. This not only helps researchers understand the environmental impact of synthetic dyes, but it also directs them in choosing the best substrates for the production of AgNPs with enhanced photocatalytic activities.
Takumu Hirose et al 2024 Nano Ex. 5 025019
Sensing layers with an increased affinity for water molecules are essential for the development of highly sensitive humidity sensors. Graphene possesses superior electrical properties that make it suitable for the fabrication of low-noise miniaturized sensors. However, the enhancement of water affinity by introducing surface defects such as covalently attached hydrophilic groups reduces the electrical conductivity of graphene. In this study, we exploit the wetting transparency of graphene to increase its water affinity without introducing defects. Kinetic measurements using a Kelvin probe with a large-diameter tip showed that the rate constant of water adsorption was higher for graphene deposited on a hydrophilic substrate. These findings suggest that the wetting transparency of graphene can be exploited to reduce defect introduction into the graphene sensing layer, and has potential applications in sensor technologies.
Ineesha Piumali Madhushika et al 2024 Nano Ex. 5 025018
Perishable food post-harvest loss is a major global concern, and research is currently concentrated on creating active packaging materials. This research is focused in multiple antioxidants intercalated Layered Double Hydroxides (LDH) that are combined in one matrix, and their overall effect that defines as synergism, which successfully preserves perishable food by releasing antioxidants slowly. For this purpose, a hybrid LDH material of ascorbic-LDH (AA-LDH), salicylic-LDH (SA-LDH), and citric-LDH (CA-LDH) was synthesized, characterized and incorporate into electrospun nanofiber mat to be used as a potential active packaging material. Antioxidants intercalated Mg/Al LDH was synthesized and successfully characterized by PXRD, FTIR, XPS, Raman, SEM, and EDS. The shifts in the LDHs' peaks in PXRD indicated the successful incorporation of antioxidants into LDH. FTIR, Raman, and XPS data clearly indicated the establishment of metal-oxygen bonds by observing the characteristic peaks. Morphological features and the layered structure were clearly observed by SEM images. Antioxidants were slowly released from the LDHs, and it was evaluated for time intervals up to 24 h. The hybrid LDH material exhibited the highest antioxidant activity with an IC50 value of 132.5 μg ml−1, where 234.1, 354.5, and 402.2 μg ml−1 were reported for ascorbic-LDH, salicylic-LDH, and citric-LDH respectively. The hybrid LDH material incorporated electrospun mats showed the best antibacterial activity against the tested bacteria and clearly evidenced the synergistic activity of the combination of the nanohybrids. It has showed a minimal bacterial growth compared to the other control samples (∼2.41 log CFU/ml). The shelf life of cherry tomatoes was studied at different physiochemical parameters with and without hybrid LDH material incorporated electrospun mats. The fabricated mat showed an extended shelf life of 42 days for cherry tomatoes, whereas the control sample showed a shelf life of 17 days. It is concluded that hybrid LDH material exhibited synergistic performance and the best antioxidant activity when comparing with mono LDH materials.
Vartika Tiwari et al 2024 Nano Ex. 5 025017
Here, we synthesized a MoS2/Si heterojunction device using a scalable approach involving DC sputtering coupled with sulfurization. The observed current–voltage characteristics unequivocally indicate a rectifying behavior at MoS2/Si heterointerface. To quantitatively assess the carrier dynamics, a comprehensive analysis utilizing thermionic emission and Landauer transport formalism model was employed. The spatial variation in current across the MoS2/Si devices suggests a potential influence of MoS2's in-plane series resistance. Furthermore, the electrical behavior of the device is found to be temperature-dependent, with higher temperatures resulting in enhanced conductivity attributed to an increase in thermally generated charge carriers. As temperature rises, the Landauer current model observes an increased ratio of density of states to carrier injection rate, along with other temperature-dependent terms. Meanwhile, the thermionic current model maintains a fixed effective value for its material-dependent term, the Richardson constant, irrespective of temperature changes. Therefore, a comparative analysis between thermionic emission and Landauer transport formalism reveals that the conventional thermionic emission model better aligns with experimentally observed leakage current in reverse bias, showcasing a minimal barrier height at the heterojunction. This comprehensive investigation provides valuable insights into the charge transfer mechanisms at the MoS2/Si interface, opening avenues for its potential innovative applications in electronic devices.
Ritu Nain et al 2024 Nano Ex. 5 025016
Exploring new materials and synthesis recipes are required to enhance the electrochromic performance especially, when used in solid-state devices. Here, polycrystalline gadolinium titanate (Gd2TiO5 or GTO), synthesized using a simple solid-state reaction method, has been used for this purpose by combining it with polythiophene (P3HT). The electrochemical investigation of the Gd2TiO5 doped P3HT electrode has been carried out using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), which reveals the dominance of diffusion-controlled mechanism over charge storage on the electrode surface as compared to the P3HT electrode. The Gd2TiO5 doped P3HT solid-state electrochromic device shows color modulation at 515 nm and 670 nm wavelengths with a color contrast of as high as 79% and 42%, respectively, under an external bias of as low as ±1.4 V. The prepared device switches between maroon to a transparent state in less than a second under the external bias (±1.4 V) with a high coloration efficiency of 346 cm2/C. The device shows improved cycle life over 100 switching cycles at both the wavelengths, which makes it more suitable for real-life applications.
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Aman Sharma et al 2024 Nano Ex. 5 022002
Silver nanoparticles (AgNPs) have received a lot of interest for their several applications, including their remarkable potential as photocatalysts for organic dye degradation. This research thoroughly investigates the efficacy of ecologically friendly, green-synthesized AgNPs in the treatment of synthetic dye-contaminated wastewater. The synthesis of AgNPs from various biological substrates is investigated, emphasizing their economic viability, significant conductivity, and considerable biocompatibility. The improper disposal of synthetic dyes in wastewater poses severe environmental and health risks due to their non-biodegradable nature and persistent chemical features. In response to this challenge, this review paper investigates the capability of AgNPs to serve as effective photocatalysts for degrading a range of organic dyes commonly found in industrial effluents. Specific dyes, including methyl orange, congo red, nitrophenol, methylene blue, and malachite green, are studied in the context of wastewater treatment, providing insights into the efficacy of AgNPs synthesized from diverse biological sources. The review sheds light on the photocatalytic degradation methods used by green-synthesized AgNPs, shedding light on the transition of these synthetic dyes into less hazardous compounds. It also delves into the toxicity aspect of the AgNPs and its possible remediation from the environment. The ecologically friendly synthesis procedures investigated in this work provide an alternative to traditional methods, highlighting the importance of sustainable technologies in solving modern environmental concerns. Furthermore, a comparative examination of various biological substrates for AgNPs synthesis is presented, evaluating their respective dye degradation efficiencies. This not only helps researchers understand the environmental impact of synthetic dyes, but it also directs them in choosing the best substrates for the production of AgNPs with enhanced photocatalytic activities.
Aditi Manna and Nirat Ray 2024 Nano Ex. 5 012005
Colloidal quantum dots (QDs) have emerged as transformative materials with diverse properties, holding tremendous promise for reshaping the landscape of photovoltaics and thermoelectrics. Emphasizing the pivotal role of surface ligands, ranging from extended hydrocarbon chains to intricate metal chalcogenide complexes, halides, and hybrid ligands, we underscore their influence on the electronic behavior of the assembly. The ability to tailor interdot coupling can have profound effects on charge transport, making colloidal QDs a focal point for research aimed at enhancing the efficiency and performance of energy conversion devices. This perspective provides insights into the multifaceted realm of QD solids, starting from fundamentals of charge transport through the coupled assemblies. We delve into recent breakthroughs, spotlighting champion devices across various architectures and elucidating the sequential advancements that have significantly elevated efficiency levels.
Makoto Sakurai 2024 Nano Ex. 5 012004
Emergent functionalities created by applying mechanical stress to flexible devices using SnO2 microrods and Ga2O3/SnO2-core/shell microribbons are reviewed. Dynamic lattice defect engineering through application of mechanical stress and a voltage to the SnO2 microrod device leads to a reversible semiconductor-insulator transition through lattice defect creation and healing, providing an effective and simple solution to the persistent photoconductivity (PPC) problem that has long plagued UV semiconductor photosensors. Here, lattice defects are created near slip planes in a rutile-structured microrod by applying mechanical stress and are healed by Joule heating by applying a voltage to the microrod. Nanoscale amorphous structuring makes the Ga2O3/SnO2-core/shell microribbon with a large SnO2 surface area more sensitive to changes in temperature, while mechanical bending of the wet device improves its sensitivity to adsorbed water molecules. These results illustrate the potential for developing flexible devices with new functionalities by enhancing the intrinsic properties of materials through miniaturization, mechanical stress, and hybridization.
Cuixiu Wu et al 2024 Nano Ex. 5 012003
Zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) are emerging metal–organic framework nanomaterials composed of 2-methylimidazole and zinc ions, which are widely used in biomedical fields due to their distinctive features such as high porosity, bioresponsive degradation, and superior biocompatibility. Especially, the advanced research of ZIF-8 NPs in smart drug delivery systems is providing unique insights into the rational design of versatile nanomedicines for the treatment and diagnosis of serious diseases. This article provides a comprehensive review and outlook on ZIF-8 NPs-based smart drug delivery systems (SDDSs) including the synthesis methods, drug loading strategies, surface modification, and stimuli-responsive release. In particular, we focus on the advantages of ZIF-8 NPs-based drug loading strategies between the metal coordination-based active loading and the physical packaging-based passive loading. Finally, the opportunities and challenges of ZIF-8 NPs as smart drug delivery carriers are discussed.
Shanmuga Priya S and Suseem S R 2024 Nano Ex. 5 012002
Carbon dots are small carbon-based particles with unique properties that make them useful in various applications. Some advantages include low toxicity, bio-compatibility, excellent photo luminescence, high stability, and ease of synthesis. These features make them promising for biomedical imaging, drug delivery, and optoelectronic devices. Carbon dots derived from plants have several advantages, including their low toxicity, biocompatibility, and renewable sources. They also have excellent water solubility and high stability and can be easily synthesized using simple and low-cost methods. These properties make them promising candidates for various biomedicine, sensing, and imaging applications. Plant-based carbon dots have shown great potential in metal sensing and bio-imaging applications. They can act as efficient sensors for detecting heavy metals due to their strong chelation and fluorescence properties. This article showcases plant-based carbon dots, emphasizing their low toxicity, biocompatibility, renewability, and potential in metal sensing and bio-imaging. It aims to illustrate their versatile applications and ongoing research for broader use. The current investigation explores their full potential and develops new synthesis and application methods.
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Goswami et al
Colloidal semiconductor nanocrystals (NCs) or quantum dots (QDs) have shown great potential for solution-processable photodetector due to their exceptional optical and electronic properties. However, broadband and sensitive photodetection from single QDs- based devices is quite challenging. Nano-heterojunction with proper band alignment based on two different materials offers significant advantages for developing broadband photodetector. Herein, we report ultraviolet–visible (UV–Vis) to near-infrared (NIR) light-responsive photodetector based on solution-processed nano-heterojunction of visible light absorber CsPbBr3 perovskite NCs and wide absorption range, environment-friendly Bi2S3 QDs. Our results demonstrate that the CsPbBr3–Bi2S3 nano-heterojunction-based photodetector has higher responsivity (380 μA/W at a wavelength of 532 nm) and higher specific detectivity (1.02×105 Jones), as compared to the individual CsPbBr3 or Bi2S3 QDs based devices. Interestingly, the detection wavelength range of our heterojunction device is further extended to the near-infrared region (1064 nm) due to the broadband absorption range of Bi2S3 QDs, which is not observed in the visible light absorber CsPbBr3 devices. Remarkably, the responsivity of the heterojunction device is 90 μA/W. The enhanced specific detectivity and the broadband response of hybrid devices are attributed to the improved charge carrier generation, efficient charge separation and transfer at the interface between CsPbBr3 and Bi2S3 QDs.
Ayed et al
The escalating issue of antibiotic resistance in bacteria necessitates innovative detection methods to identify resistance mechanisms promptly. In this study, we present a novel approach for detecting resistance in \textit{Pseudomonas aeruginosa}, a bacterium known for its metallo-beta-lactamase production during the development of antibiotic resistance. We have designed an aptasensor employing Förster resonance energy transfer utilising two distinct methodologies. Initially, indium phosphide quantum dots with a zinc sulphide shell, and gold nanoparticles were utilised as the Förster resonance energy transfer donor-acceptor pair. Although this system demonstrated a response, the efficiency was low. Subsequently, optimisation involved relocating the donor and acceptor in close proximity and incorporating two quantum dots with varying emission wavelengths as the acceptor and donor. This optimisation significantly enhanced the Förster resonance efficiency, resulting in a novel method for detecting metallo-$\beta$-lactamase. Förster resonance energy transfer efficiency was increased from 31% to 63% by optimising the distance and donor using a quantum dot-quantum dot pair. Our findings showcase a cheap, rapid and versatile aptasensor with potential applications beyond antibiotic resistance, highlighting its adaptability for diverse scenarios.
Abdullahi et al
In this work, the terbium oxide (Tb4O7) passivation layers were sputtered using radio frequency (RF) sputtering and then post-annealed in oxygen (O2), nitrogen (N2), argon (Ar), and nitrogen-oxygen-nitrogen (NON) environments. Different characterization techniques were utilized to investigate the detailed influence of these different annealing environments. Grazing incidence X-ray diffraction (GIXRD) patterns indicate a cubic crystal structure in all samples investigated. The sample annealed in Ar ambient reached the highest crystallinity close to 48 nm. The morphological analysis showed a distinct surface structure for all the investigated samples when viewed with field emission scanning electron microscopy (FESEM). Atomic force microscopy (AFM) was utilized to study the surface roughness, and it was found that the Tb4O7 passivation layer annealed in an Ar ambient achieved a higher surface roughness at (1.150 nm). The UV-Vis analysis was performed, and absorbance was determined from reflectance data. The direct bandgap (Eg) was estimated by applying the Kubelka-Munk (KM) approach and found to be 3.28, 3.17, 2.37, and 2.27 eV for O2, N2, Ar, and NON ambients, respectively. These findings highlight the importance of post-deposition annealing treatments using different annealing gases and provide insight into the development of optimal Tb4O7 passivation layers.
Jiménez-Ramírez et al
The unique physicochemical properties of metallic and magnetic nanowires, whether obtained in well-ordered arrays or as single, isolated, and free-standing structures from patterned templates, have been extensively studied for various technological applications. These applications include magnetic data storage, sensing, biolabeling, barcoding, among many others. Novel template-assisted methods for the synthesis of metallic nanowires offer an enhancement over the control of their shape and morphology, compositional uniformity, and interconnectivity, allowing them for being applied as new metamaterials for novel multifunctional applications. Within this critical review, an extensive overview focused on the synthesis and characterization of the particular properties exhibited by multilayered and multisegmented metallic nanowires having specifically controlled geometries and compositional graded designs through employing electrochemical techniques based on sacrificial nanoporous alumina template-assisted methods, is presented. We review recent advancements in designing synthesis protocols for fabricating new metallic nanowires with multifunctional applications. These protocols offer competitive fabrication costs compared to conventional laboratory procedures, potentially expanding their use in various research areas. In this review, we also establish the new challenges and suggest the future perspectives and expectations that will be covered by these new metamaterial-based nanowires.
Nguyen et al
In this study, we introduce a synthesis process of bimetallic nanoparticles (BNPs) Fe/Ni and Fe/Cu utilizing concentrated green tea extract that was optimized with a solvent ratio of ethanol/H2O 4/1 (v/v), a metal ratio of 5/1 (w/w), a total polyphenol content (TPC) in the solution of 12.5 g.L-1, pH = 3-4, 25 oC, and the reaction time ranging from 30 min to 50 min. The structural and morphological characteristics of the resulting materials were determined using several techniques, such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The maximum removal efficiency of methylene blue (MB) by Fe/Ni and Fe/Cu materials was found to be 88.60 % and 91.06 %, respectively, at a concentration of MB = 25 mg.L-1 and 25 oC. According to the results of the kinetic modeling study, the adsorption process of MB on the two BNPs materials followed second-order kinetics, with the maximum adsorption capacities of MB on Fe/Ni and Fe/Cu BNPs being 26.94 mg.g-1and 28.00 mg.g-1, respectively.