Beilstein Journal of Nanotechnology最新文献

Shape-and size-controlled synthesis of nanomaterials has been a long-term aim and challenge of modern nanotechnology. Despite many synthesis methods are still mainly focused on the production of near-spherical NPs, a number of emerging applications require nanomaterials of nonspherical shape and developed surface, which determine the functional performance of nanostructured devices. Laser ablation in liquids has been demonstrated as a clean, simple, and versatile NP synthesis method. However, the conditions of NP formation and growth are favouring the production of spherical NPs. There are fewer studies of shape control during laser ablation. With that in mind, this perspective article represents a view on the current stage of the development of laser ablation in liquids from the perspective of shape control of the forming nanomaterials. The key parameters influencing the NP shape are highlighted, including the composition of a liquid, laser focusing conditions and introduction of external fields, and the mechanism of their impact on the conditions for anisotropic NP formation and growth. The description of the methods developed for the control over nanomaterial morphology is summarized by the vision of the current challenges and development routes of laser ablation in liquids.

Contact resonance atomic force microscopy (CR-AFM) has been used in many studies to characterize variations in the elastic and viscoelastic constants of materials along a heterogeneous surface. In almost all experimental work, the quantitative modulus of the surface is calculated in reference to a known reference material, rather than calculated directly from the dynamics models of the cantilever. We measured the cantilever displacement with very high sampling frequencies over the course of the experiment and captured its oscillations that result from thermal energy. Using short-term Fourier transformations, it was possible to fit the thermal resonance peak of the normal displacement to track the frequency and Q-factor of the cantilever during an experiment, using a similar process to that used to calibrate the normal bending stiffness of cantilevers. With this quantitative data, we have used the dynamic mechanics models relating the contact stiffness of the tip/cantilever pressing into a surface with the oscillation frequency of the cantilever and show that they did not accurately model the experiment. Several material combinations of tip and sample were examined; tip size and cantilever stiffness demonstrate that existing models cannot capture the physics of this problem. While concrete solutions to use analytical models to interpret CR-AFM data have not been found, a possible solution may include revisiting the analytical model to capture a potentially more complex system than the current model, improved matching the cantilever/sample stiffness to obtain a larger variation in contact stiffness with frequency, or investigating the use of higher-order modes that may achieve this improved match.

The development of modern metal deposition techniques like focused ion/electron beam-induced deposition (FIBID/FEBID) relies heavily on the availability of metal-organic precursors of particular properties. To create a new precursor, extensive testing using specialized gas injection systems is required along with time-consuming and costly chemical analysis typically conducted using scanning electron microscopy (SEM). This process can be quite challenging due to its complexity and expense. Here, the response of new metal-organic precursors, in the form of supported thick layers, to the ion beam irradiation is studied through analysis of the chemical composition and morphology of the resulting structures. This is done using SEM backscattered electron/energy-dispersive X-ray spectroscopy along with machine learning data processing techniques. This approach enables a comprehensive fast examination of precursor decomposition processes during FIB irradiation and provides valuable insights into how the precursor's composition influences the final properties of the metal-rich deposits. Although solid-layer irradiation differs from gas-phase deposition, we think that our method can be employed to optimize pre-screen and score new potential precursors for FIB applications by significantly reducing the time required and conserving valuable resources.

The superconductor-insulator-normal metal-insulator-superconductor (SINIS) tunnel junction structure is the basic building block for various cryogenic devices. Microwave detectors, electron coolers, primary thermometers, and Aharonov-Bohm interferometers have been fabricated by various methods and measured at temperatures down to 100 mK. The manufacturing methods included Dolan-type shadow evaporation, Manhattan-type shadow evaporation, and magnetron sputtering with selective etching of superconducting and normal metal electrodes. Improvement in ultimate sensitivity is achieved by suspending the absorber above the substrate. Best responsivity of up to 30 electrons per photon at a frequency of 350 GHz, or 72000 A/W, and voltage responsivity up to 3.9 × 10⁹ V/W were obtained with a black body radiation source and series of band-pass filters. The specially designed SINIS arrays are intended to detect 90 GHz radiation at the "Big Telescope Alt-azimuthal" (romanized Russian: "Bolshoi Teleskop Alt-azimutalnyi", BTA) with noise equivalent power of less than 10^-16 W·Hz^-1/2. The receiver in a ³He cryostat with an optical window was mounted at the Nasmyth focus of the BTA and tested at a temperature of 260 mK with a IMPATT diode radiation source.

Lipid nanoparticles (LNPs) have become significant vehicles in the delivery of therapeutic substances, particularly for nucleic acid vaccines and gene therapies. A key component in the nanoparticle formulation is polyethylene glycol-modified (i.e., PEGylated) lipids (PEG lipids), which can significantly influence the stability, cell interactions, and overall effectiveness of LNP delivery vehicles. This review collates insights into the role of PEG lipids in LNPs by illustrating how the PEG chains arrange on the nanoparticle surface and the potential impacts on LNPs' physicochemical properties by varying surface PEG density or PEG chemistry. Subsequently, PEG conformations are discussed in terms of their modulation of protein corona formation, cellular uptake, and immunogenic responses, particularly the pathways of anti-PEG antibody production and complement activation. Building on these understandings, functionalized PEG lipids are reviewed for ligand conjugation and targeted LNP delivery function. Promising alternatives to replace the benchmark PEG lipids are also systematically reviewed to address PEGylation associated immunogenicity. By conducting a critical analysis of the recent literature and identifying potent candidates for PEGylation strategies or PEG-free platforms, this review aims to provide insights and support the advancement of LNP mediated delivery.

Mosquitoes of the Aedes genus are responsible for the transmission of arboviruses that seriously affect public health. Given the increasing resistance to traditional insecticides and their negative environmental impacts, the need for safer alternatives arises. In this context, natural produts such as essential oils (EOs) have been studied for their larvicidal and repellent properties against Aedes aegypti, due to the presence of compounds such as terpenoids and phenols. However, the usage of EOs is limited due to some properties such as poor water solubility, high volatility, and intrinsic oxidation sensitivity. Thus, the development of novel formulations to efficiently deliver bioactives represents an innovative approach for Aedes aegypti control. In this context, nanothecnology provides smart formulations with improved drug solubility, controlled release, and protection against degradation. Nanoemulsions are colloidal systems with droplets of 20 to 500 nm, which improve the dispersion of the compounds, protect their active properties, and enhance their efficacy. This review addresses the potential of nanoemulsions as efficient carriers of EOs, and how this approach could emerge as ecological alternatives to synthetic insecticides. Herein, the focus was kept on targeting larvicidal and repellent activities against Ae. aegypti. For that, 23 studies were analyzed, which demonstrated a significant increase in the efficacy of nanoemulsions with EOs compared to that of free EOs, in both activities. However, the repellent activity has been less explored, present in only three of the studies evaluated, in the last 10 years. Correlatingh with this, other aspects such as botanical species of EOs, mechanisms of action, composition, and characteristics of nanoemulsions are discussed. In addition, this review highlights challenges and perspectives on pharmaceutical nanotechnology towards nanoemulsions as safe, effective, and eco-friendly tools for controlling Ae. Aegypti.

We demonstrate the programmable control of kinetic soliton dynamics in all-Josephson-junction (all-JJ) networks through a novel tunable cell design. This cell enables on-demand switching of transmission lines and operates across defined parameter regimes supporting diverse dynamical modes. By introducing a structural asymmetry into a transmission line, we implement a Josephson diode that enforces unidirectional soliton propagation. The programmability of the kinetic inductance then provides a crucial mechanism to selectively enable or disable this diode functionality. By engineering artificial inhomogeneity into the circuit architecture, we enhance robustness in all-JJ logic circuits, 2D transmission line all-JJ lattices, and neuromorphic computing systems.

We demonstrate atomic force microscopy (AFM) imaging with a microcantilever force transducer where an integrated superconducting microwave resonant circuit detects cantilever deflection using the principles of cavity optomechanics. We discuss the detector responsivity and added noise, pointing to its crucial role in the context of force sensitivity. Through analysis of noise measurements we determine the effective temperature of the cantilever eigenmode and we determine the region of detector operation in which the sensor is thermal-noise-limited. Our analysis shows that the force-sensor design is a significant improvement over piezoelectric force sensors commonly used in low-temperature AFM. We discuss the potential for further improvement of the sensor design to achieve optimal detection at the standard quantum limit. We demonstrate AFM operation with surface-tracking feedback in both amplitude-modulation and frequency-modulation modes.

Marine organisms such as barnacles rely on a complex underwater adhesive system, driven by self-assembly and intermolecular associations between cement proteins, for permanent attachment to a variety of surface types. In this study, we investigated the influence of environmental parameters on the self-assembly of recombinant cp19k, a key adhesive protein in Pollicipes pollicipes. Using TEM imaging, a low pH (4.0) and high salt concentration (600 mM NaCl) environment, mimicking P. pollicipes gland conditions, was identified to promote the formation of extended, needle-like fibrils by the cp19k protein. The β-amyloid nature of fibrils formed under these conditions and at high pH/low salt concentration was confirmed by Thioflavin T assay. Non-fibrillar cp19k adhered most effectively to hydrophilic and hydrophobic surfaces under low pH/low salt concentration conditions, while pre-formed fibrils retained their adhesion ability upon switching to a high pH/high salt concentration environment, which was designed to mimic the change in the protein environment upon secretion in vivo. These findings support the hypothesis that fibril formation occurs in the acidic, iso-osmotic gland of the barnacle, with delayed cement curing enabling fibril secretion for sustained adhesion of the organism. The study provides insight into the environmental sensitivity of cp19k structure-function dynamics and may support the design of bioinspired adhesives and biomaterials.

The growing interest in green-synthesized metallic nanoparticles reflects a global shift toward sustainable, eco-friendly technologies in biomedical innovation, particularly in dentistry. This scoping review examines the rising focus on these nanoparticles regarding their antimicrobial, regenerative, and therapeutic potential in dental applications. Among the metals studied, silver and zinc oxide nanoparticles dominate because of their broad-spectrum antimicrobial activity and enhanced biocompatibility, achieved through phytochemically mediated synthesis. Conventional nanoparticle production often relies on toxic reagents and energy-intensive processes, posing environmental and clinical challenges. In contrast, green synthesis, using plant extracts, fungi, or bacteria, offers a sustainable alternative by leveraging natural reducing agents like polyphenols and flavonoids. These bioactive compounds not only facilitate nanoparticle formation but also improve stability and biological efficacy, making them ideal for dental applications such as caries prevention, endodontic disinfection, and periodontal regeneration. Our analysis of 98 studies reveals India as the leading contributor (78.6%), driven by its rich biodiversity and strong research infrastructure. Key plant families including Lamiaceae and Fabaceae were frequently employed due to their high phenolic content. Despite promising results, gaps remain, such as the predominance of in vitro studies (68.7%) and insufficient cytotoxicity assessments (47.8%), underscoring the need for translational research. This review highlights the transformative potential of green-synthesized nanoparticles in dentistry, merging technological advancement with ecological responsibility. Future work should prioritize clinical trials, long-term safety evaluations, and standardized protocols to fully realize their therapeutic benefits.