Beilstein Journal of Nanotechnology最新文献

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.

Leishmaniasis, caused by protozoa of the genus Leishmania spp., is a neglected tropical disease that poses a significant challenge to the public health in tropical and subtropical regions, affecting mainly low-income individuals. Current therapies are limited due to severe adverse reactions to currently available drugs, high cost, low patient adherence, and even the emergence of resistant strains. Examining safer and more effective alternatives, natural compounds such as phytol - a diterpene derived from chlorophyll - have attracted attention due to their broad biological activities. To increase their solubility, stability, and cell delivery, nanotechnology-based systems, such as nanoemulsions (NEs), represent a promising approach. In this study, soybean oil nanoemulsions loaded with phytol (PHYT-NE) were developed using the phase inversion composition (PIC) method, and then characterized and evaluated. The PHYT-NE had a mean droplet diameter close to 200 nm, a polydispersity index of less than 0.2, spherical shape, and a pH value compatible with cutaneous application. The formulation showed high colloidal stability for at least 30 days of storage and at least 15 days even under stress conditions, with no signs of macroscopic instability or changes in droplet size. The cytocompatibility of NEs was confirmed in 3T3 fibroblasts at the concentrations tested, indicating potential safety for in vivo trials. Notably, PHYT-NE exhibited significant time-dependent leishmanicidal activity against Leishmania amazonensis promastigotes, with lower IC₅₀ values (up to five times lower at 48 hours) and up to 75% parasite death after 48 hours, showing greater antiparasitic activity compared to that of free phytol. Although the use of promastigotes represents a limitation, this model was used as a proof-of-concept, with promising evidence of the potential of PHYT-NE. Future studies in macrophage models infected with intracellular amastigotes will be essential to confirm the observed efficacy and validate the potential of PHYT-NE as a safe and effective topical therapy for cutaneous leishmaniasis.

The widespread use of plastic has led to microplastics (MPs) being released in many water sources. MP contamination in water supply systems is a global concern due to their persistence and ability to adsorb toxic pollutants. Despite having effectiveness, conventional water treatment processes still have limited efficiency in removing MPs, especially smaller particles. Thus, it requires researchers to develop effective and sustainable strategies to deal with this matter. Many studies have shown that adsorbent nanomaterials have potential for the removal of MPs from water. This review evaluates the current status of using adsorbent nanomaterials in removing MPs from water supply systems. It discusses the occurrences and removal efficiency of MPs in water supply systems, as well as the mechanisms and performance when applying these materials for treatment. In addition, the related risk of adsorbent nanomaterials is also considered. Microplastics from land-based sources and wastewater plants persist in water supplies, with conventional treatments removing only 40-70%, especially struggling with smaller particles. Based mainly on mechanisms like electrostatic interactions, hydrophobic interactions, pore filling, hydrogen bonding, π-π stacking, and surface complexation, adsorbent nanomaterials achieve over 90% removal of MPs and can recovery. Their effectiveness depends on material properties and environmental factors, but challenges remain in scale-up and related risks. Adsorbent nanomaterials show promising potential to enhance MP removal through specific properties. Although some related risks are discussed, these materials provide a foundation for developing sustainable, effective solutions to mitigate MPs pollution in the water supply system.

Recent research in alternate sources of energy such as piezoelectric energy conversion devices has positioned layered double hydroxides (LDHs) as promising candidates among the other two-dimensional materials. With their unique flexible layered structure, LDHs hold great potential for piezocatalysis and powering smart wearable electronics. Despite their promise, this area of study is still in its infancy and this review explores its recent advances. The discussion encompasses LDH-based piezoelectric nanogenerators, piezocatalytic and piezo-photocatalytic properties of LDHs, and composite material synergies that enhance the overall electroactive performance. Looking to the future, systematic research into the effects of LDHs' composition and structure on piezoelectric properties will be crucial to unlock their full potential. This mini-review aims to inspire the audience with valuable ideas for the development of new LDH-based piezoelectric materials, thereby contributing to the development of next-generation high-performance piezoelectric devices.

It was recently shown that small bundles of linear carbon chains (LCC) encapsulated by double- and multi-wall carbon nanotubes (LCC@DWCNT and LCC@MWCNT, respectively) behave as Debye's materials for temperatures as high as 293 K with an estimate that such materials could still withstand such characteristics for even higher temperatures (≈700 K). Using the Debye model, thermodynamic observables (internal energy, coefficient of linear thermal expansion, specific heat, thermal strain, and Grüneisen parameter at constant pressure) were empirically determined for the first time in the range of temperatures 70 < T < 293 K. These observables were all correlated with the C-band frequency (ω_LCC) dependence on the temperature (T) and its first and second derivatives with relation to T, dω_LCC/dT, and d²ω_LCC/dT ². The C-band is a Raman spectroscopic signature for LCC, which is not only temperature-dependent but also dependent on the number of carbon atoms (N) constituting the LCC. In this present study, we extend these findings to temperatures ranging from 13 < T < 293 K, which provide more accurate values for both dω_LCC/dT and d²ω_LCC/dT ². The corrected values of these derivatives affect the Grüneisen parameters associated with the LCC, even though the other associated thermodynamic parameters remain essentially unchanged. Our measurements were performed in both isolated and small bundles of LCC@MWCNT, which allowed us to demonstrate that small bundles or isolated environments do not seem to influence the vibrational and thermodynamic properties measured.

Precise control of electrical conductivity, humidity sensitivity, and photocatalytic activity in polymeric and carbon-based materials is essential for advancing technologies in environmental sensing, flexible electronics, and photocatalytic systems. Conventional chemical modification methods often lack spatial precision, introduce impurities, and risk structural degradation. Ion implantation provides a controllable alternative for tuning surface properties at the nanoscale, enabling the targeted introduction of functional species without chemical reagents. This work investigates the effects of low-energy (20 keV) and medium-energy (1.5 MeV) Ag⁺ ion implantation on the electrical, sensory, and photocatalytic properties of graphene oxide (GO) and polyimide (PI). Implantations were carried out with fluences ranging from 3.75 × 10¹² cm^-2 to 1 × 10¹⁶ cm^-2. Silver ions offer excellent electrical, catalytic, and plasmonic characteristics, making them ideal for multifunctional enhancement of GO and PI. Elemental and structural changes induced by implantation were analyzed using Rutherford backscattering spectroscopy, elastic recoil detection analysis, Raman spectroscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Surface morphology was assessed via atomic force microscopy. Electrical properties as a function of air humidity were evaluated using a two-point method, and photocatalytic activity was tested by monitoring the UV-induced decomposition of rhodamine B. The results demonstrate that ion implantation significantly reduces surface resistivity and enhances both the photocatalytic activity and humidity sensitivity of GO and PI. The most pronounced improvements occurred at higher fluences, where defect generation and partial deoxygenation contributed to optimal performance. Ion implantation thus represents an effective approach for tuning the multifunctional behavior of polymer systems.

Polymers play a pivotal role in various drug delivery systems due to their versatility, with polymeric nanoparticles showing significant potential to overcome physiological barriers associated with oral administration. This review examines the current advancements in the application of polymers as oral nanocarriers, emphasizing key natural and synthetic polymers that enhance stability, bioavailability, and release. The physicochemical properties, biodegradability, and chemical modifications of these polymers, which promote mucoadhesion and epithelial permeability, critical factors for effective oral drug delivery, are discussed in detail. Furthermore, nanoparticle synthesis methods that enable controlled release profiles, optimized biodistribution, and improved therapeutic efficacy are also explored. Thus, polymers represent a dynamic platform for developing diverse nanocarriers for oral applications, and this review provides a valuable theoretical foundation for understanding the strategies currently employed in this field.

Esophageal cancer (EC) is a common malignant tumor of the digestive tract with poor prognosis and high mortality. The early diagnosis of EC mainly depends on endoscopic diagnosis, which not only needs to bear certain economic pressure, but also needs patients to recognize the high risk factors of EC. Most EC patients are diagnosed at intermediate or late stages, often due to a lack of awareness regarding early symptoms and lifestyle-related risk factors. However, the discovery of aptamers and the development of nanocarriers bring great benefits to the diagnosis, treatment, and targeted drug delivery of EC. Aptamers or peptide aptamers as biosensors or therapeutic agents for the diagnosis or treatment of EC, aptamer-drug conjugates and aptamer-functionalized drug nanocarriers for targeted drug delivery in esophageal cancer are reviewed in this paper. In addition, we expect investigators to pay special attention to improving aptamer permeability and stability to accelerate aptamer clinical transformation. In conclusion, leveraging the high target specificity of well-selected aptamers may bring new breakthroughs in the diagnosis, treatment and drug delivery of EC.