Integrated Cu-Au stereo microelectrode arrays and microfluidic channels for the electrochemical detection of glucose.

Noble and transition metal nanomaterials are widely used in glucose sensing. However, the fabrication of these sensors still suffers from complex nanomaterial synthesis process and unstable nanomaterial loading on sensing surfaces. Herein, a Cu-Au bimetallic microelectrode array was prepared via local electrochemical deposition and electrochemical reduction without the need for templates and additional nanomaterial preparation processes. Based on the COMSOL computational fluid study, the obtained microelectrode arrays combined with microfluidic channels allow the continuous and rapid detection of glucose. Large number of active sites on the surface of 3D nano-arrays contributes to excellent sensing performance for glucose, with good linear detection ranges in 10 µM to 4 × 102 µM and 4 × 102 µM to 4 × 105 µM, and a low detection limit of 284 nM. The feasibility of sensor in real sample was verified by detecting glucose in beverages with good recoveries ranging from 95.50% to 104.31%.

Large-scale assembly of geometrically diverse metal nanoparticles-based 3D plasmonic DNA nanostructures for SERS detection of PNK in cancer cells.

The organization of geometrically diverse metal nanoparticles into a core/satellite structure at a large scale is a promising strategy for improve SERS performance due to hot spots localized enrichment and signal increase. However, due to the lack of extensional frames and strong electrostatic repulsion between plasma NPs, the fabrication of such 3D architectures with a high-density periodic hotspot in the focus volume has proven exceedingly difficult. Herein, we demonstrate a facile large-scale assembly of geometrically diverse metal nanoparticles strategy for constructing spatially extended 3D plasmonic nanostructures resembling "signal towers" based on RCA-mediated periodic organization of gold nanospheres (GNS) surrounding gold nanorods (GNRs). Using cancer cell T4 PNK as a model, a padlock probe with 5'- hydroxyl (P-circle) was designed as the T4 PNK substrate. The center Au nanorod was coated with P1 and served as a "pedestal" to allow substantial loading of P-circle after target phosphorylation to initiate the rolling ring amplification reaction (RCA). The resultant DNA nanowire serves as an "antenna" to successively lock numerous Raman reporter P2 (Cy3-P2-SH) through base pairing at regular intervals. Finally, the 3D plasma DNA nanostructures that resemble "signal towers" could be obtained by placing a large number of GNS with a strong affinity for Au-S. The proposed 3D SERS sensor exhibited a sensitivity of LOD as low as 0.274 mU/mL, which was attributed to a substantial electromagnetic field enhancement at the inter-nanoparticle gaps between the adjacent pedestal and antenna. Moreover, by exploiting the synergistic effect of the periodically extended DNA scaffold generated by RCA amplification and the co-assembly of thiol ligand, the loaded GNS can be extended to three-dimensional space, forming a high-density periodic hotspot in the focal volume, thereby ensuring high enhancement and high reproducibility of Raman signals. In addition, this method can be used to quantify T4 PNK in HeLa cells, demonstrating its applicability in diagnosing and estimating PNK-related diseases in complex fluids.

A triple-aptamer tetrahedral DNA nanostructures based carbon-nanotube-array transistor biosensor for rapid virus detection.

Outbreaks of infectious viruses cause enormous challenges to global public health. Recently, the coronavirus disease 2019 (COVID-19) induced by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has severely threatened human health and resulted in the global pandemic. A strategy to detect SARS-CoV-2 with both fast sensing speed and high accuracy is urgently required. Here, rapid detection of SARS-CoV-2 antigen using carbon-nanotube-array-based thin-film transistor (CNT-array-based TFT) biosensors merged with tetrahedral DNA nanostructures (TDNs) and triple aptamers is demonstrated for the first time. Compared with CNT-network-based TFT biosensors and metal-electrode-based CNT-TFT biosensors, the response of CNT-array-based TFT biosensors can be enhanced up to 102% for SARS-CoV-2 receptor-binding domain (RBD) detection, which is supported by its sensing mechanism. By combining TDNs with triple aptamers, the biosensor has realized the wildtype SARS-CoV-2 RBD detection in a broad detection range spanning eight orders of magnitude with a low limit of detection (LOD) of 10 aM (6 copies/µL) owing to the improved protein capture efficiency. Moreover, the triple-aptamer biosensor platform has achieved the detection of SARS-CoV-2 Omicron RBD in a low LOD of 6 aM (3.6 copies/µL). Additionally, the CNT-array-based TFT biosensors have exhibited excellent specificity, enabling identification among SARS-CoV-2 antigen, SARS-CoV antigen and MERS-CoV antigen. The platform of CNT-array-based TFT biosensors combined with TDNs and triple aptamers provides a high-performance and rapid approach for SARS-CoV-2 detection, and its versatility by altering specific aptamers enables the possibility for rapid virus detection.

Paper-based fluorescent materials containing on-demand nanostructured brain-cells-inspired AIE self-assembles for real-time visual monitoring of seafood spoilage.

Biogenic amines containing NH3 are important indicators for conducting full-scale appraisal of food spoilage and disease diagnosis. However, the currently-used detection methods of NH3 have several limitations such as time-consuming high cost, and inability to provide visual real-time monitoring. Therefore, researchers have attempted to explore strategies for quantitative real-time monitoring of NH3 for food spoilage has attracted widespread attentions. Herein, we developed sustainable, fast response, hypersensitized, user-friendly and molecular-level light-emitting biomass-based materials (AFP-FP) containing on-demand nanostructured brain-cells-inspired aggregation-induced-emission (AIE) self-assembles for real-time visual monitoring of seafood spoilage. The 2-hydroxy-5-methyl-isophthalaldehyde-based AIE probe (AFP) was synthesized using a simple "one-step" route. AFP-FP exhibited high selectivity, sensitivity, repeatable and quantitative recognition (y = 7.292×103x + 7.621×104, R = 0.990) of NH3 with a low detection limit (246 ppb) and fast response (<1 s). Furthermore, we integrated AFP-FP into a user-friendly smartphone color recognition app, enabling its practical application in visual, real-time daylight monitoring of food spoilage.

Using Vertically Aligned Carbon Nanofiber Arrays on Rigid or Flexible Substrates for Delivery of Biomolecules and Dyes to Plants.

The delivery of biomolecules and impermeable dyes to intact plants is a major challenge. Nanomaterials are up-and-coming tools for the delivery of DNA to plants. As exciting as these new tools are, they have yet to be widely applied. Nanomaterials fabricated on rigid substrate (backing) are particularly difficult to successfully apply to curved plant structures. This study describes the process for microfabricating vertically aligned carbon nanofiber arrays and transferring them from a rigid to a flexible substrate. We detail and demonstrate how these fibers (on either rigid or flexible substrates) can be used for transient transformation or dye (e.g., fluorescein) delivery to plants. We show how VACNFs can be transferred from rigid silicon substrate to a flexible SU-8 epoxy substrate to form flexible VACNF arrays. To overcome the hydrophobic nature of SU-8, fibers in the flexible film were coated with a thin silicon oxide layer (2-3 nm). To use these fibers for delivery to curved plant organs, we deposit a 1 µL droplet of dye or DNA solution on the fiber side of VACNF films, wait 10 min, place the films on the plant organ and employ a swab with a rolling motion to drive fibers into plant cells. With this method, we have achieved dye and DNA delivery in plant organs with curved surfaces.

Organic Electrochemical Transistor with MoS2 Nanosheets Modified Gate Electrode for Sensitive Glucose Sensing.

An organic electrochemical transistor (OECT) with MoS2 nanosheets modified on the gate electrode was proposed for glucose sensing. MoS2 nanosheets, which had excellent electrocatalytic performance, a large specific surface area, and more active sites, were prepared by liquid phase ultrasonic exfoliation to modify the gate electrode of OECT, resulting in a large improvement in the sensitivity of the glucose sensor. The detection limit of the device modified with MoS2 nanosheets is down to 100 nM, which is 1~2 orders of magnitude better than that of the device without nanomaterial modification. This result manifests not only a sensitive and selective method for the detection of glucose based on OECT but also an extended application of MoS2 nanosheets for other biomolecule sensing with high sensitivity.

Carbon nanotubes: a powerful bridge for conductivity and flexibility in electrochemical glucose sensors.

The utilization of nanomaterials in the biosensor field has garnered substantial attention in recent years. Initially, the emphasis was on enhancing the sensor current rather than material interactions. However, carbon nanotubes (CNTs) have gained prominence in glucose sensors due to their high aspect ratio, remarkable chemical stability, and notable optical and electronic attributes. The diverse nanostructures and metal surface designs of CNTs, coupled with their exceptional physical and chemical properties, have led to diverse applications in electrochemical glucose sensor research. Substantial progress has been achieved, particularly in constructing flexible interfaces based on CNTs. This review focuses on CNT-based sensor design, manufacturing advancements, material synergy effects, and minimally invasive/noninvasive glucose monitoring devices. The review also discusses the trend toward simultaneous detection of multiple markers in glucose sensors and the pivotal role played by CNTs in this trend. Furthermore, the latest applications of CNTs in electrochemical glucose sensors are explored, accompanied by an overview of the current status, challenges, and future prospects of CNT-based sensors and their potential applications.

Synthesis, Characterization and Antimicrobial Activity of Multiple Morphologies of Gold/Platinum Doped Bismuth Oxide Nanostructures.

Bismuth oxides were synthesized from bismuth carbonate using the sol-gel method. Studies have described the formation of Bi2O3, as a precursor of HNO3 dissolution, and intermediate oxides, such as BixOy when using H2SO4 and H3PO4. The average size of the crystallite calculated from Scherrer's formula ranged from 9 to 19 nm, according to X-ray diffraction. The FTIR analysis showed the presence of specific Bi2O3 bands when using HNO3 and of crystalline phases of "bismuth oxide sulphate" when using H2SO4 and "bismuth phosphate" when using H3PO4. The TG curves showed major mass losses and specific thermal effects, delimited in four temperature zones for materials synthesized with HNO3 (with loss of mass between 24% and 50%) and H2SO4 (with loss of mass between 45% and 76%), and in three temperature zones for materials synthesized with H3PO4 (with loss of mass between 13% and 43%). Further, the thermal stability indicates that materials have been improved by the addition of a polymer or polymer and carbon. Confocal laser scanning microscopy showed decreased roughness in the series, [BixOy]N > [BixOy-6% PVA]N > [BixOy-C-6% PVA]N, and increased roughness for materials [BixOy]S, [BixOy-6% PVA]S, [BixOy-C-6% PVA]S, [BixOy]P, [BixOy-6% PVA]P and [BixOy-C-6% PVA]P. The morphological analysis (electronic scanning microscopy) of the synthesized materials showed a wide variety of forms: overlapping nanoplates ([BixOy]N or [BixOy]S), clusters of angular forms ([BixOy-6% PVA]N), pillars ([BixOy-6% PVA]S-Au), needle particles ([BixOy-Au], [BixOy-6% PVA]S-Au, [BixOy-C-6% PVA]S-Au), spherical particles ([BixOy-C-6% PVA]P-Pt), 2D plates ([BixOy]P-Pt) and 3D nanometric plates ([BixOy-C-6% PVA]S-Au). For materials obtained in the first synthesis stage, antimicrobial activity increased in the series [BixOy]N > [BixOy]S > [BixOy]P. For materials synthesized in the second synthesis stage, when polymer (polyvinyl alcohol, PVA) was added, maximum antimicrobial activity, regardless of the microbial species tested, was present in the material [BixOy-6% PVA]S. For the materials synthesized in the third stage, to which graphite and 6% PVA were added, the best antimicrobial activity was in the material [BixOy-C-6% PVA]P. Materials synthesized and doped with metal ions (gold or platinum) showed significant antimicrobial activity for the tested microbial species.

Is a 2D Nanostructured Surface Capable of Changing the Corrosion and Magnetic Properties of an Amorphous Alloy?

In this work, an attempt was made to reveal and explain the influence of the process of formation of 2D nanostructures at the surface of an amorphous alloy (an alloy with the composition Co75Si15Fe5Cr4.5Al0.5 (in at.%) was used for this purpose) on the corrosion and magnetic properties of such an alloy. Two-dimensional nanostructures (nanocells of 100-150 nm in size, which were obtained by anodizing the initial sample in an ionic liquid) are essentially a pattern on the surface of the sample, and they cannot completely cover and block the surface from external effects. It was postulated that the presence of these nanostructures during corrosion and magnetic tests has no significant effect. However, a noticeable inhibition effect was observed during corrosion tests and a less noticeable (but still detectable) effect was observed during magnetic tests. The authors believe that the effect obtained, with a detailed study, can be used to increase the corrosion resistance and to improve the properties of traditional magnetic materials.

Metallic Nanowires Self-Assembled in Quasi-Circular Nanomolds Templated by DNA Origami.

The self-assembly of conducting nanostructures is currently being investigated intensively in order to evaluate the feasibility of creating novel nanoelectronic devices and circuits using such pathways. In particular, methods based on so-called DNA Origami nanostructures have shown great potential in the formation of metallic nanowires. The main challenge of this method is the reproducible generation of very well-connected metallic nanostructures, which may be used as interconnects in future devices. Here, we use a novel design of nanowires with a quasi-circular cross-section as opposed to rectangular or uncontrolled cross-sections in earlier studies. We find indications that the reliability of the fabrication scheme is enhanced and the overall resistance of the wires is comparable to metallic nanostructures generated by electrochemistry or top-down methods. In addition, we observe that some of the nanowires are annealed when passing a current through them, which leads to a clear enhancement for the conductance. We envision that these nanowires provide further steps towards the successful generation of nanoelectronics using self-assembly.

Interaction of Nanomaterials with Cells and Tissues.

Nanomaterials have gained enormous importance in biomedicine in recent years, both in basic and applied sciences [...].

Dynamic crosstalk between silicon nanomaterials and potentially toxic trace elements in plant-soil systems.

Agricultural soil pollution with potentially toxic trace elements (PTEs) has emerged as a significant environmental concern, jeopardizing food safety and human health. Although, conventional remediation approaches have been used for PTEs-contaminated soils treatment; however, these techniques are toxic, expensive, harmful to human health, and can lead to environmental contamination. Nano-enabled agriculture has gained significant attention as a sustainable approach to improve crop production and food security. Silicon nanomaterials (SiNMs) have emerged as a promising alternative for PTEs-contaminated soils remediation. SiNMs have unique characteristics, such as higher chemical reactivity, higher stability, greater surface area to volume ratio and smaller size that make them effective in removing PTEs from the environment. The review discusses the recent advancements and developments in SiNMs for the sustainable remediation of PTEs in agricultural soils. The article covers various synthesis methods, characterization techniques, and the potential mechanisms of SiNMs to alleviate PTEs toxicity in plant-soil systems. Additionally, we highlight the potential benefits and limitations of SiNMs and discusses future directions for research and development. Overall, the use of SiNMs for PTEs remediation offers a sustainable platform for the protection of agricultural soils and the environment.

Fabrication of poly-dopamine-modified magnetic nanomaterial and development of integrated QuEChERS method for 122 pesticides residue analysis in fruits.

A rapid and accurate integrated QuEChERS method was established for the determination of multi-pesticide residues in fruits. Poly-dopamine-modified magnetic nanomaterial (Fe3O4-pDA) was homemade and characterized. The prepared Fe3O4-pDA has the functional group of absorbing the saccharides, and can be used as co-adsorbent with 3-(N, n­diethyl amino) propyl trimethoxy-silane (PSA) in the developed integrated QuEChERS method to purify the fruit matrix, thus achieve the accurate determination of multi-pesticides residue. Grape was used as the representative sample to explore the influence of the salting out agent and each purification adsorbent on the pesticide recoveries. Under the optimized conditions, the proposed method showed good linearity for 92.6% of pesticides in the concentration range of 1-150 µg L-1 with method limit of quantitative (mLOQs) ranged from 10 to 18 µg kg-1. Spiked recoveries experiments were performed on four kinds of grapes and other fruits (apple, watermelon, pear, jujube and peach), in which satisfactory recoveries and precision were obtained for most of the pesticides. Meanwhile, comparison experiments also verified this method was superior to the traditional QuEChERS method in terms of convenient operation, high efficiency and low reagent consumption. The further real sample analysis was performed using this method, and the overall detection rate was 52%, while 2% of samples were exceeding the maximum residue limits. All results confirmed that the proposed method could be used for the rapid, simple, low-costing and effective analyses of trace multi-pesticides residue in fruit samples.

Histidine modulates amyloid-like assembly of peptide nanomaterials and confers enzyme-like activity.

Amyloid-like assembly is not only associated with pathological events, but also leads to the development of novel nanomaterials with unique properties. Herein, using Fmoc diphenylalanine peptide (Fmoc-F-F) as a minimalistic model, we found that histidine can modulate the assembly behavior of Fmoc-F-F and induce enzyme-like catalysis. Specifically, the presence of histidine rearranges the ß structure of Fmoc-F-F to assemble nanofilaments, resulting in the formation of active site to mimic peroxidase-like activity that catalyzes ROS generation. A similar catalytic property is also observed in Aß assembled filaments, which is correlated with the spatial proximity between intermolecular histidine and F-F. Notably, the assembled Aß filaments are able to induce cellular ROS elevation and damage neuron cells, providing an insight into the pathological relationship between Aß aggregation and Alzheimer's disease. These findings highlight the potential of histidine as a modulator in amyloid-like assembly of peptide nanomaterials exerting enzyme-like catalysis.

Green Synthesis of Antimicrobial Peptide-Protected Silver Nanoclusters with Regulated Antibacterial Behavior.

The antibacterial system based on the silver element has been a very promising antibacterial material. However, the antibacterial activity of silver nanomaterials largely depends on their chemical composition and physical properties. Herein, we prepared ultrasmall silver nanoclusters by directly reducing silver ions with antimicrobial peptide in a green way. The positively charged peptide ligands drove the silver nanoclusters binding to bacteria by electrostatic attraction. Contrary to the large-sized silver nanomaterials, the ultrasmall silver nanoclusters were able to rapidly penetrate bacteria membranes via strong hydrophobic association, significantly promoting the generation of reactive oxygen species, and the subsequent high oxidative stress led to bacterial death. Moreover, the silver nanoclusters with antibacterial peptide ligand exhibited good stability, low cytotoxicity, and long-term antibacterial activity. Besides, synergistic enhancement of silver nanoclusters on antibacterial activity was observed. Therefore, the silver nanoclusters conjugated with the antimicrobial peptide can act as a synergistic antibacterial agent, in which their bio-interactions with bacteria have been regulated to achieve a rapid, long-lasting, and broad-spectrum antibacterial effect.

Nanomaterial genotoxicity evaluation using the high-throughput p53-binding protein 1 (53BP1) assay.

Toxicity evaluation of engineered nanomaterials is challenging due to the ever increasing number of materials and because nanomaterials (NMs) frequently interfere with commonly used assays. Hence, there is a need for robust, high-throughput assays with which to assess their hazard potential. The present study aimed at evaluating the applicability of a genotoxicity assay based on the immunostaining and foci counting of the DNA repair protein 53BP1 (p53-binding protein 1), in a high-throughput format, for NM genotoxicity assessment. For benchmarking purposes, we first applied the assay to a set of eight known genotoxic agents, as well as X-ray irradiation (1 Gy). Then, a panel of NMs and nanobiomaterials (NBMs) was evaluated with respect to their impact on cell viability and genotoxicity, and to their potential to induce reactive oxygen species (ROS) production. The genotoxicity recorded using the 53BP1 assay was confirmed using the micronucleus assay, also scored via automated (high-throughput) microscopy. The 53BP1 assay successfully identified genotoxic compounds on the HCT116 human intestinal cell line. None of the tested NMs showed any genotoxicity using the 53BP1 assay, except the positive control consisting in (CoO)(NiO) NMs, while only TiO2 NMs showed positive outcome in the micronucleus assay. Only Fe3O4 NMs caused significant elevation of ROS, not correlated to DNA damage. Therefore, owing to its adequate predictivity of the genotoxicity of most of the tested benchmark substance and its ease of implementation in a high throughput format, the 53BP1 assay could be proposed as a complementary high-throughput screening genotoxicity assay, in the context of the development of New Approach Methodologies.

Reliable and Scalable Piezoresistive Sensors with an MXene/MoS2 Hierarchical Nanostructure for Health Signals Monitoring.

The increased popularity of wearable electronic devices has led to a greater need for advanced sensors. However, fabricating pressure sensors that are flexible, highly sensitive, robust, and compatible with large-scale fabrication technology is challenging. This work investigates a piezoresistive sensor constructed from an MXene/MoS2 hierarchical nanostructure, which is obtained through an easy and inexpensive fabrication process. The sensor exhibits a high sensitivity of 0.42 kPa-1 (0-1.5 kPa), rapid response (∼36 ms), and remarkable mechanical durability (∼10,000 cycles at 13 kPa). The sensor has been demonstrated to be successful in detecting human motion, speech recognition, and physiological signals, particularly in analyzing human pulse. These data can be used to alert and identify irregularities in human health. Additionally, the sensing units are able to construct sensor arrays of various sizes and configurations, enabling pressure distribution imaging in a variety of application scenarios. This research proposes a cost-effective and scalable approach to fabricating piezoresistive sensors and sensor arrays, which can be utilized for monitoring human health and for use in human-machine interfaces.

Functional nanoparticle-enabled non-genetic neuromodulation.

Stimulating ion channels targeting in neuromodulation by external signals with the help of functionalized nanoparticles, which integrates the pioneering achievements in the fields of neurosciences and nanomaterials, has involved into a novel interdisciplinary field. The emerging technique developed in this field enable simple, remote, non-invasive, and spatiotemporally precise nerve regulations and disease therapeutics, beyond traditional treatment methods. In this paper, we define this emerging field as nano-neuromodulation and summarize the most recent developments of non-genetic nano-neuromodulation (non-genetic NNM) over the past decade based on the innovative design concepts of neuromodulation nanoparticle systems. These nanosystems, which feature diverse compositions, structures and synthesis approaches, could absorb certain exogenous stimuli like light, sound, electric or magnetic signals, and subsequently mediate mutual transformations between above signals, or chemical reactions, to regulate stimuli-sensitive ion channels and ion migrations which play vital roles in the nervous system. We will also discuss the obstacles and challenges in the future development of non-genetic NNM, and propose its future developments, to add the further progress of this promising field.

How Combined Macrolide Nanomaterials are Effective Against Resistant Pathogens? A Comprehensive Review of the Literature.

Macrolide drugs are among the broad-spectrum antibiotics that are considered as "miracle drugs" against infectious diseases that lead to higher morbidity and mortality rates. Nevertheless, their effectiveness is currently at risk owing to the presence of devastating, antimicrobial-resistant microbes. In view of this challenge, nanotechnology-driven innovations are currently being anticipated for promising approaches to overcome antimicrobial resistance. Nowadays, various nanostructures are being developed for the delivery of antimicrobials to counter drug-resistant microbial strains through different mechanisms. Metallic nanoparticle-based delivery of macrolides, particularly using silver and gold nanoparticles (AgNPs & AuNPs), demonstrated a promising outcome with worthy stability, oxidation resistance, and biocompatibility. Similarly, macrolide-conjugated magnetic NPs resulted in an augmented antimicrobial activity and reduced bacterial cell viability against resistant microbes. Liposomal delivery of macrolides also showed favorable synergistic antimicrobial activities in vitro against resistant strains. Loading macrolide drugs into various polymeric nanomaterials resulted in an enhanced zone of inhibition. Intercalated nanomaterials also conveyed an outstanding macrolide delivery characteristic with efficient targeting and controlled drug release against infectious microbes. This review abridges several nano-based delivery approaches for macrolide drugs along with their recent achievements, challenges, and future perspectives.

Unique Features of Nanomaterials and their Combination Support Applications in Orthodontics.

Nanotechnology is a rapidly evolving field with numerous biological applications and is becoming increasingly significant due to its immense potential to enhance the properties of orthodontic and biomaterials. It is employed in various emerging areas of orthodontics, focusing on improving the performance of diverse orthodontic appliances and accessories, as well as nanoelectromechanical systems (NEMS) and nanorobots. Nevertheless, the biocompatibility and cytotoxicity of nanomaterials in orthodontic applications require further investigation. This paper reviews the latest applications of nanomaterials in orthodontics, elucidates their unique features and synergistic applications in orthodontics, and outlines prospective developments in the field.