Beilstein Journal of Nanotechnology最新文献

The preparation of multimodal nanoparticles by capping magnetic iron oxide nanoparticles (IONPs) with functional organic molecules is a major area of research for biomedical applications. Conjugation reactions, such as carbodiimide coupling and the highly selective class of reactions known as "click chemistry", have been instrumental in tailoring the ligand layers of IONPs to produce functional biomedical nanomaterials. However, few studies report the controls performed to determine if the loading of molecules onto IONPs is due to the proposed coupling reaction(s) employed, or some other unknown interaction with the IONP surface. Herein, we use 3,4-dihydroxybenzoic acid-functionalized IONPs (IONP-3,4-DHBA) as a platform upon which carbodiimide coupling can be used to conjugate clickable small molecules for further functionalization using two common click reactions, namely, the copper-catalyzed azide-alkyne cycloaddition (CuAAC), and the thiol-maleimide Michael addition reactions. Through the judicious use of controls, we demonstrate significant cross-reactivities of amines, thiols, maleimides, and common disulfide reducing agents with surface Fe of IONPs and show how these unwanted interactions can produce false positive results. Without proper controls, these can lead to erroneous conclusions about the efficacy of conjugation reactions, which can have detrimental impacts on the functionality and safety of IONPs in biomedical applications.

Nanoparticles in their pure colloidal form synthesized by laser-assisted processes such as laser ablation/fragmentation/irradiation/melting in liquids have attained much interest from the scientific community because of their specialties like facile synthesis, ultra-high purity, biocompatibility, colloidal stability in addition to other benefits like tunable size and morphology, crystalline phases, new compounds and alloys, and defect engineering. These nanocolloids are useful for fabricating different devices mainly with applications in optoelectronics, catalysis, sensors, photodetectors, surface-enhanced Raman spectroscopy (SERS) substrates, and solar cells. In this review article, we describe different methods of nanocolloidal synthesis using laser-assisted processes and corresponding thin film fabrication methods, particularly those utilized for device fabrication and characterization. The four sections start with an introduction to the common laser-assisted synthesis for nanocolloids and different methods of thin film fabrication using these nanocolloids followed by devices fabricated and characterized for applications including photovoltaics, photodetectors, catalysis, photocatalysis, electrochemical/photoelectrochemical sensors, hydrogen/oxygen evolution, SERS sensors and other types of devices reported so far. The last section explains the challenges and further scope of these devices from laser-generated nanocolloids.

Silver nanoprisms (AgNPrs) are promising candidates for surface-enhanced Raman scattering (SERS) due to their strong localized surface plasmon resonance and sharp tip geometry. In this study, AgNPrs were synthesized through a photochemical method by irradiating spherical silver nanoparticle seeds with 10 W green light-emitting diodes (LEDs; 520 ± 20 nm) for various periods of time up to 72 h. The growth mechanism was investigated through ultraviolet-visible spectroscopy, field-emission scanning electron microscopy, X-ray diffraction, and transmission electron microscopy analyses, confirming the gradual transformation of spherical seeds into AgNPrs. Optimal conversion was observed after 72 h of irradiation, producing well-defined AgNPrs with an average size of 78 nm. The SERS activity of the AgNPrs was evaluated using 4-mercaptobenzoic acid as a probe molecule. Compared to spherical AgNPs, AgNPrs exhibited a significantly higher SERS enhancement factor of 1.15 × 10⁶, enabling detection limits down to 10^-9 M. These findings demonstrate that green LED-mediated synthesis provides a simple, environmentally friendly route to fabricate high-yield AgNPrs with superior SERS capabilities, suitable for ultrasensitive chemical and biological sensing applications.

This study employs a bibliometric analysis using CiteSpace to explore research trends on the impact of biochar on microplastics (MPs) in soil and water environments. In agricultural soils, MPs reduce crop yield, alter soil properties, and disrupt microbial diversity and nutrient cycling. Biochar, a stable and eco-friendly material, has demonstrated effectiveness in mitigating these effects by restoring soil chemistry, enhancing microbial diversity and improving crop productivity. Recent studies report that biochar increases crop yields by 30-81%, even under high MP contamination levels (up to five times that of biochar-modified bacteria). Additionally, biochar enhances Olsen-P availability by 46.6%, increases soil organic carbon in microaggregates by 35.7%, and reduces antibiotic resistance genes by promoting beneficial microbes such as Subgroup 10, Bacillus, and Pseudomonas. In aquatic systems, biochar serves as an efficient adsorbent, particularly for MPs larger than 10 µm, including polystyrene. Studies suggest that fixed-column models achieve superior removal efficiency (95.31% ± 5.26%) compared to batch systems (93.36% ± 4.92%). Specifically, for MPs ≥10 µm, fixed columns reach 99% efficiency, while magnetically modified biochar captures 96.2% of MPs as small as 1 µm. These efficiencies stem from biochar's integration of physical and chemical mechanisms that enhance MP retention, particularly for MPs smaller than 10 µm, positioning it as a promising solution for nanoplastic remediation.

Nanoscale biosensors have gained attention in recent years due to their unique characteristics and size. Manufacturing steps, cost, and other shortcomings limit the widespread use and commercialization of nanoscale electrodes. In this work, a nano-size electrode fabricated by directed electrochemical nanowire assembly and parylene-C insulation is introduced. Results show that the diameter of the platinum nanowire and electrode tip length can be tuned down to 120 nm and 1.2 µm, respectively, where the exposed nanowires on the electrode tips are chemically active and their surfaces can be modified for specific biosensing applications. The biosensing testing with glucose and dopamine demonstrate limits of detection of 30 nM and 0.01 mM, respectively. The R-squared values for peak current versus concentration are 0.985 and 0.994, indicating strong linear correlations. These nanoscale electrodes hold great promise for single-cell biosensing applications due to their compact size, biocompatibility, and rapid fabrication.

To address the issue of biological pollution in cellulose triacetate (CTA) membranes during seawater desalination, silver (Ag) nanoparticles were incorporated onto the CTA surface using polydopamine (PDA). PDA, which contains phenolic and amino groups, exhibits excellent adhesiveness and provides active sites for the attachment and reduction for Ag nanoparticles. Various characterizations confirm the successful introduction of Ag nanoparticles onto the surface of the PDA-modified CTA (PCTA) membrane and the preservation of CTA microstructures. Antibacterial testing demonstrates that the Ag@PCTA membrane exhibited excellent antibacterial properties. Antibacterial ring experiments revealed significant bactericidal activity against five different bacterial strains, namely, Bacillus cereus, Bacillus thuringiensis, Lysinibacillus xylanilyticus, Lysinibacillus lparviboronicapiens and Burkholderia ambifaria. Moreover, water flux and salt rejection rates of the Ag@PCTA membrane were comparable to those of the parent CTA membrane.

Atomic resolution scanning probe microscopy, and in particular scanning tunnelling microscopy (STM) allows for high-spatial-resolution imaging and also spectroscopic analysis of small organic molecules. However, preparation and characterisation of the probe apex in situ by a human operator is one of the major barriers to high-throughput experimentation and to reproducibility between experiments. Characterisation of the probe apex is usually accomplished via assessment of the imaging quality on the target molecule and also the characteristics of the scanning tunnelling spectra (STS) on clean metal surfaces. Critically for spectroscopic experiments, assessment of the spatial resolution of the image is not sufficient to ensure a high-quality tip for spectroscopic measurements. The ability to automate this process is a key aim in development of high resolution scanning probe materials characterisation. In this paper, we assess the feasibility of automating the assessment of imaging quality, and spectroscopic tip quality, via both machine learning (ML) and deterministic methods (DM) using a prototypical tin phthalocyanine on Au(111) system at 4.7 K. We find that both ML and DM are able to classify images and spectra with high accuracy, with only a small amount of prior surface knowledge. We highlight the practical advantage of DM not requiring large training datasets to implement on new systems and demonstrate a proof-of-principle automated experiment that is able to repeatedly prepare the tip, identify molecules of interest, and perform site-specific STS experiments using DM, in order to produce large numbers of spectra with different tips suitable for statistical analysis. Deterministic methods can be easily implemented to classify the imaging and spectroscopic quality of a STM tip for the purposes of high-resolution STM and STS on small organic molecules. Via automated classification of the tip state, we demonstrate an automated experiment that can collect a high number of spectra on multiple molecules without human intervention. The technique can be easily extended to most metal-adsorbate systems and is promising for the development of automated, high-throughput, STM characterisation of small adsorbate systems.

The rapid spread of antibiotic resistance has intensified the need for novel therapeutic strategies against multidrug-resistant bacterial infections. Metalloantibiotics present a promising alternative in combating resistant pathogens. However, the clinical application of metalloantibiotics is limited by their potential toxicity, instability, and lack of target specificity. Encapsulating metalloantibiotics in drug delivery systems, such as liposomes, nanoparticles, and polymeric carriers, could mitigate these challenges, enhancing their therapeutic index and enabling their precise, localized release. Recent reviews have outlined the key design parameters and clinical translation challenges associated with nanocarrier-based antimicrobial therapies, underscoring their relevance in overcoming bacterial resistance mechanisms [Xie, Y.; Liu, H.; Teng, Z.; Ma, J.; Liu, G. Nanoscale 2025, 17, 5605-5628. https://doi.org/10.1039%2FD4NR04774E ]. This review explores the potential of encapsulated metalloantibiotics as a new frontier in antimicrobial therapy. We address the mechanisms by which drug delivery systems can stabilize and direct metalloantibiotics to their biological targets, discuss current advancements in encapsulation methods, and examine the efficacy of encapsulated metalloantibiotics. Finally, we consider the challenges and future directions for the integration of metalloantibiotic-loaded carriers in the fight against antibiotic-resistant infections.

Ferroptosis has shown potential therapeutic effects in tumor therapy as an iron-dependent programmed cell death. The induction of ferroptosis is based on lipid peroxidation, the accumulation of iron and reactive oxygen species, and the depletion of glutathione. Nowadays, various nanoparticles are reported for ferroptosis-based therapy. Among them, engineered liposomes have received more attention due to their biocompatibility, low immunogenicity, and flexibility in chemical and structural modifications. The present review focuses on the mechanisms of ferroptosis and its induction by engineered liposomes to improve tumor therapy. It also highlights the fascinating outcome of liposome-mediated ferroptosis in overcoming the obstacles to cancer therapy, along with the limitations and possible future directions.