Bioinspired Graphene Oxide-Magnetite Nanocomposite Coatings as Protective Superhydrophobic Antifouling Surfaces.

Antifouling (AF) nanocoatings made of polydimethylsiloxane (PDMS) are more cost-efficient and eco-friendly substitutes for the already outlawed tributyltin-based coatings. Here, a catalytic hydrosilation approach was used to construct a design inspired by composite mosquito eyes from non-toxic PDMS nanocomposites filled with graphene oxide (GO) nanosheets decorated with magnetite nanospheres (GO-Fe3O4 nanospheres). Various GO-Fe3O4 hybrid nanofillers were dispersed into the PDMS resin through a solution casting method to evaluate the structure-property relationship. A simple coprecipitation procedure was used to fabricate magnetite nanospheres with an average diameter of 30-50 nm, a single crystal structure, and a predominant (311) lattice plane. The uniform bioinspired superhydrophobic PDMS/GO-Fe3O4 nanocomposite surface produced had a micro-/nano-roughness, low surface-free energy (SFE), and high fouling release (FR) efficiency. It exhibited several advantages including simplicity, ease of large-area fabrication, and a simultaneous offering of dual micro-/nano-scale structures simply via a one-step solution casting process for a wide variety of materials. The superhydrophobicity, SFE, and rough topology have been studied as surface properties of the unfilled silicone and the bioinspired PDMS/GO-Fe3O4 nanocomposites. The coatings' physical, mechanical, and anticorrosive features were also taken into account. Several microorganisms were employed to examine the fouling resistance of the coated specimens for 1 month. Good dispersion of GO-Fe3O4 hybrid fillers in the PDMS coating until 1 wt % achieved the highest water contact angle (158° ± 2°), the lowest SFE (12.06 mN/m), micro-/nano-roughness, and improved bulk mechanical and anticorrosion properties. The well-distributed PDMS/GO-Fe3O4 (1 wt % nanofillers) bioinspired nanocoating showed the least biodegradability against all the tested microorganisms [Kocuria rhizophila (2.047%), Pseudomonas aeruginosa (1.961%), and Candida albicans (1.924%)]. We successfully developed non-toxic, low-cost, and economical nanostructured superhydrophobic FR composite coatings for long-term ship hull coatings. This study may expand the applications of bio-inspired functional materials because for multiple AF, durability and hydrophobicity are both important features in several industrial applications.

Non-enzymatic electrochemical sensing of dopamine from COVID-19 quarantine person.

The worldwide outbreak of COVID-19 pandemic, is not only a great threat to the victim life but it is leaving invisible devastating negative affect on mental health of quarantined individual because of isolation, depression, bereavement, and loss of income. Therefore, the precise monitoring catecholamine neurotransmitters specifically of dopamine (DA) is of great importance to assess the mental health. Thus, herein we have synthesized Co-based zeolitic imidazolate framework (ZIF-67) through solvothermal method for precise monitoring of DA. To facilitate the fast transportation of ions, highly conductive polymer, poly(3,4-ethylenedioxythiophene; PEDOT) has been integrated on the surface of ZIF-67 which not only provides the smooth pathway for ions/electrons transportation but also saves the electrode from pulverization. The fabricated ZIF-67/PEDOT electrode shows a significant sensing performance towards DA detection in terms of short diffusion pathways by expositing more active sites, over good linear range (15-240 µM) and a low detection limit of (0.04 µM) even in the coexistence of the potentially interfering molecules. The developed ZIF-67/PEDOT sensor was successfully employed for sensitive and selective monitoring of DA from COVID-19 quarantined person blood, thus suggesting reliability of the developed electrode.

Microporous P-doped carbon spheres sensory electrode for voltammetry and amperometry adrenaline screening in human fluids.

An electrochemical sensor-based phosphorus-doped microporous carbon spheroidal structures (P-MCSs) has been designed for selective adrenaline (ADR) signaling in human blood serum. The P-MCS electrode sensor is built with heterogeneous surface alignments including multiple porous sizes with open holes and meso-/macro-grooves, rough surface curvatures, and integral morphology with interconnected and conjugated microspheres. In addition, the P atom-doped graphitic carbon forms highly active centers, increases charge mobility on the electrode surface, creates abundant active centers with facile functionalization, and induces binding to ADR molecules. The designed P-MCS electrode exhibits ultrasensitive monitoring of ADR with a low detection limit of 0.002 µM and high sensitivity of 4330 µA µM-1 cm-2. In addition, two electrochemical techniques, namely, square wave voltammetry (SWV) and chronoamperometry (CA), were used; these techniques achieve high stability, fast response, and a wide linear range from 0.01 to 6 µM. The sensing assays based on P-MCSs provide evidence of the formation of active interfacial surface-to-ADR binding sites, high electron diffusion, and heavy target loads along with/without a plane of spheroids. Thus, P-MCSs can be used for the routine monitoring of ADR in human blood serum, providing a fast response, and requiring highly economical materials at extremely low concentrations. Electrode surface modulation based on P-doped carbon spheres (P-MCS) exhibits high electrochemical activity with fast charge transport, multi-diffusible active centers, high loading of ADR, and facile molecular/electron diffusion at its surface. The P-MCS sensitively and selectively detects the ADR in human fluids and can be used for clinical investigation of some neuronal diseases such as Alzheimer diseases.

Monolithic scaffolds for highly selective ion sensing/removal of Co(II), Cu(II), and Cd(II) ions in water.

High exposure to metals, such as cobalt (Co), copper (Cu) and cadmium (Cd), potentially has adverse effects, and can cause severe health problems, leading to a number of specific diseases. This study primarily aims to monitor, detect, separate, and remove the trace concentrations of Co(II), Cu(II), and Cd(II) ions in water, without a preconcentration process, using aluminosilica optical sensor (ASOS) monoliths. These monolithic scaffolds with advantageous physical features (i.e., large surface area-to-volume ratios of the scaffolds, active acid sites and uniform mesocage cubic pores) can strongly induce H-bonding and dispersive interactions with organic chelating agent, resulting in the formation of stable ASOS. In this engineering process, ASOS offers a simple and one-step sensing/capture procedure for the quantification and visual detection of the target elements from water, without requiring sophisticated instrumentation. The key result in this study is the ion selectivity exhibited by the designed ASOS toward the targets, Co(II), Cu(II), and Cd(II) ions, in environmental and waste disposal samples, as well as its reproducibility over a number of analysis/regeneration cycles. These findings can be useful in the fabrication of ASOS can be tailored to suit various applications.

Controllable synthesis of a hybrid mesoporous sheets-like Fe0.5NiS2@ P, N-doped carbon electrocatalyst for alkaline oxygen evolution reaction.

Owing to the high cost of precious metal catalysts for the oxygen evolution reaction (OER), the production of highly efficient and affordable electrocatalysts is important for generating pollution-free and renewable energy via electrochemical processes. A facile hydrothermal approach was employed to synthesize hybrid mesoporous iron-nickel bimetallic sulfides @ P, N-doped carbon for the OER. The prepared Fe0.5NiS2@C exhibited an overpotential (η) of 250 mV at 10 mA/cm2. This exceeded the overpotentials recently reported for surface-modified P, N-doped carbon-based catalysts for the OER in a 1 M KOH medium. Moreover, the Fe0.5NiS2@C catalyst showed a notable Tafel slope of 90.5 mV/dec with long-dated stability even after 24 h at 10 mA/cm2. The superior OER performance of the Fe0.5NiS2@C catalysts may be due to their large surface area, sheet-like morphology with abundant active sites, fast transfer of mass and electrons, control of the electronic structure by co-treatment with heteroatoms (e.g., P and N), and the synergistic effect of bimetallic sulfides, making them favorable catalysts for the oxygen evolution reaction. Density functional theory (DFT) calculations showed that the Fe0.5NiS2@C catalyst exhibited strong H2O-adsorption energy. The enhanced OER activity of Fe0.5NiS2@C was attributed to its higher surface area, favorable H2O adsorption energy, improved electron transfer efficiency, and lower Gibbs free energy compared to those of the other proposed catalysts.

Ultrasensitive Visual Tracking of Toxic Cyanide Ions in Biological Samples Using Biocompatible Metal-Organic Frameworks Architectures.

The extraordinary accumulation of cyanide ions within biological cells is a severe health risk. Detecting and tracking toxic cyanide ions within these cells by simple and ultrasensitive methodologies are of immense curiosity. Here, continuous tracking of ultimate levels of CN--ions in HeLa cells was reported employing biocompatible branching molecular architectures (BMAs). These BMAs were engineered by decorating colorant-laden dendritic branch within and around the molecular building hollows of the geode-shelled nanorods of organic-inorganic Al-frameworks. Batch-contact methods were utilized to assess the potential of hollow-nest architecture for inhibition/evaluation of toxicant CN--ions within HeLa cells. The nanorod BMAs revealed significant potential capabilities in monitoring and tracking of CN- ions (88 parts per trillion) in biological trials within seconds. These results demonstrated sufficient evidence for the compatibility of BMAs during HeLa cell exposure. Under specific conditions, the BMAs were utilized for in-vitro fluorescence tracking/sensing of CN- in HeLa cells. The cliff swallow nest with massive mouths may have the potential to reduce the health hazards associated with toxicant exposure in biological cells.

Fluorescent sensor/tracker for biocompatible and real-time monitoring of ultra-trace arsenic toxicants in living cells.

Real-time monitoring and tracking of extreme toxins that penetrate into living cells by using biocompatible, low-cost visual detection via fluorescent monitors are vitally essential to reduce health hazards. Herein, we report a simple engineering design of biocompatible and fluorescent sensors/trackers for real-time monitoring and ultra-trace tracking (up to ppb) of extremely toxic substances (such as arsenic species) in living cells. The biocompatible As(V) sensor (BAS) design is fabricated via successful dressing/decoration process of 2-hydroxy 5-methyl isophthalaldehyde fluorescent receptor into hierarchical organic-inorganic carriers that have micro-hollow geodes, swirled caves and nest-shaped cages, and uniform cubic structures. The BAS monitors show evidence for the selective trapping/detecting/tracking of As(V) species in biological cells (i.e., HeLa cells) despite the coexistence of highly competitive and interfered species. Our simple batch-contact sensing assays shows real-space evidence of the continuous monitoring of As(V) species in HeLa cells with ultra-sensitive detection (i.e., with a low detection limit of 0.149 ppb) and rapid recognition (i.e., in the order of seconds). Significantly, the BAS monitors did not affect the cell population and achieved low cytotoxicity and high cell viability during the monitoring/tracking process inside HeLa cells. The high biocompatibility of BAS remarkably allows precise quantification and real-time monitoring/tracking of toxicant targets in living cells.

Tailored portable electrochemical sensor for dopamine detection in human fluids using heteroatom-doped three-dimensional g-C3N4 hornet nest structure.

BACKGROUND: There is widespread interest in the design of portable electrochemical sensors for the selective monitoring of biomolecules. Dopamine (DA) is one of the neurotransmitter molecules that play a key role in the monitoring of some neuronal disorders such as Alzheimer's and Parkinson's diseases. Facile synthesis of the highly active surface interface to design a portable electrochemical sensor for the sensitive and selective monitoring of biomolecules (i.e., DA) in its resources such as human fluids is highly required. RESULTS: The designed sensor is based on a three-dimensional phosphorous and sulfur resembling a g-C3N4 hornet's nest (3D-PS-doped CNHN). The morphological structure of 3D-PS-doped CNHN features multi-open gates and numerous vacant voids, presenting a novel design reminiscent of a hornet's nest. The outer surface exhibits a heterogeneous structure with a wave orientation and rough surface texture. Each gate structure takes on a hexagonal shape with a wall size of approximately 100 nm. These structural characteristics, including high surface area and hierarchical design, facilitate the diffusion of electrolytes and enhance the binding and high loading of DA molecules on both inner and outer surfaces. The multifunctional nature of g-C3N4, incorporating phosphorous and sulfur atoms, contributes to a versatile surface that improves DA binding. Additionally, the phosphate and sulfate groups' functionalities enhance sensing properties, thereby outlining selectivity. The resulting portable 3D-PS-doped CNHN sensor demonstrates high sensitivity with a low limit of detection (7.8 nM) and a broad linear range spanning from 10 to 500 nM. SIGNIFICANCE: The portable DA sensor based on the 3D-PS-doped CNHN/SPCE exhibits excellent recovery of DA molecules in human fluids, such as human serum and urine samples, demonstrating high stability and good reproducibility. The designed portable DA sensor could find utility in the detection of DA in clinical samples, showcasing its potential for practical applications in medical settings.

Enzymeless copper microspheres@carbon sensor design for sensitive and selective acetylcholine screening in human serum.

Follow up of neuronal disorders, such as Alzheimer's and Parkinson's diseases using simple, sensitive, and selective assays is urgently needed in clinical and research investigation. Here, we designed a sensitive and selective enzymeless electrochemical acetylcholine sensor that can be used in human fluid samples. The designed electrode consisted of a micro spherical construction of Cu-metal decorated by a thin layer of carbon (CuMS@C). A simple and one-pot synthesis approach was used for Cu-metal controller formation with a spherical like structures. The spherical like structure was formed with rough outer surface texture, circular build up, homogeneous formation, micrometric spheres size (0.5 -1 µm), and internal hollow structure. The formation of a thin layer of carbon materials on the surface of CuMS sustained the catalytic activity of Cu atoms and enriched negatively charge of the surface. CuMS@C acted as a highly active mediator surface that consisted of Cu metal as a highly active catalyst and carbons as protecting, charge transport, and attractive surface. Therefore, the CuMS@C surface morphology and composition played a key role in various aspects such as facilitated ACh diffusion/loading, increased the interface surface area, and enhanced the catalytic activity. The CuMS@C acted as an electroactive catalyst for ACh electrooxidation and current production, due to the losing of two electrons. The fabricated CuMS@C could be a highly sensitive and selective enzymeless sensor for detecting ACh with a detection limit of 0.1 µM and a wide linear range of 0.01 - 0.8 mM. The designed ACh sensor assay based on CuMS@C exhibited fast sensing property as well as sensitivity, selectivity, stability, and reusability for detecting ACh in human serum samples. This work presents the design of a highly active electrode surface for direct detection of ACh and further clinical investigation of ACh levels.

Nitrogen-doped carbon hollow trunk-like structure as a portable electrochemical sensor for noradrenaline detection in neuronal cells.

To date, the production and development of portable analytical devices for environmental and healthcare applications are rapidly growing. Herein, a portable electrochemical sensor for monitoring of noradrenaline (NA) secreted from living cells using mesoporous carbon-based materials was fabricated. The modification of the interdigitated electrode array (IDA) by nitrogen-doped mesoporous carbon spheres (N-doped MCS) and nitrogen-doped carbon hollow trunk-like structure (N-doped CHT) was used to fabricate the NA sensor. The N-doped CHT surface shows multiple holes distributed with micrometer-sized open holes (1-2 µm) and nanometer-sized thin walls (∼98 nm). The N-doped CHT surface heterogeneity of wrinkled and twisted hollow trunk structures improve the diffusion pathway and the NA molecules loading. The N-doped CHT/IDA showed a highly selective assay for monitoring of NA with high sensitivity (1770 µA/µM × cm2), a low detection limit (0.005 µM), and a wide linear range (0.01-0.3 µM). The N-doped CHT/IDA monitored the NA secreted from PC12 cells under various concentrations of simulation agents (KCl). The designed N-doped CHT/IDA provides a portable NA-sensor assay with facile signaling, good stability, high biocompatibility, in-vitro assay compatibility, and good reproducibility. Therefore, the designed sensor can be used as a portable sensor for NA detection in live cells and can be matched with portable smartphones after further developments.

Vancomycin-Loaded Furriness Amino Magnetic Nanospheres for Rapid Detection of Gram-Positive Water Bacterial Contamination.

Bacterial pathogens pose high threat to public health worldwide. Different types of nanomaterials have been synthesized for the rapid detection and elimination of pathogens from environmental samples. However, the selectivity of these materials remains challenging, because target bacterial pathogens commonly exist in complex samples at ultralow concentrations. In this study, we fabricated novel furry amino magnetic poly-L-ornithine (PLO)/amine-poly(ethylene glycol) (PEG)-COOH/vancomycin (VCM) (AM-PPV) nanospheres with high-loading VCM for vehicle tracking and the highly efficient capture of pathogens. The magnetic core was coated with organosilica and functionalized with cilia. The core consisted of PEG/PLO loaded with VCM conjugated to Gram-positive bacterial cell membranes, forming hydrogen bonds with terminal peptides. The characterization of AM-PPV nanospheres revealed an average particle size of 56 nm. The field-emission scanning electron microscopy (FE-SEM) micrographs showed well-controlled spherical AM-PPV nanospheres with an average size of 56 nm. The nanospheres were relatively rough and contained an additional 12.4 nm hydrodynamic layer of PLO/PEG/VCM, which provided additional stability in the suspension. The furry AM-PPV nanospheres exhibited a significant capture efficiency (>90%) and a high selectivity for detecting Bacillus cereus (employed as a model for Gram-positive bacteria) within 15 min, even in the presence of other biocompatible pathogens. Moreover, AM-PPV nanospheres rapidly and accurately detected B. cereus at levels less than 10 CFU/mL. The furry nano-design can potentially satisfy the increasing demand for the rapid and sensitive detection of pathogens in clinical and environmental samples.

Optical glucose biosensor built-in disposable strips and wearable electronic devices.

On-demand screening, real-time monitoring and rapid diagnosis of ubiquitous diseases, such as diabetes, at early stages are indispensable in personalised treatment. Emerging impacts of nano/microscale materials on optical and portable biosensor strips and devices have become increasingly important in the remarkable development of sensitive visualisation (i.e. visible inspection by the human eye) assays, low-cost analyses and personalised home testing of patients with diabetes. With the increasing public attention regarding the self-monitoring of diabetes, the development of visual readout, easy-to-use and wearable biosensors has gained considerable interest. Our comprehensive review bridges the practical assessment gap between optical bio-visualisation assays, disposable test strips, sensor array designs and full integration into flexible skin-based or contact lens devices with the on-site wireless signal transmission of glucose detection in physiological fluids. To date, the fully modulated integration of nano/microscale optical biosensors into wearable electronic devices, such as smartphones, is critical to prolong periods of indoor and outdoor clinical diagnostics. Focus should be given to the improvements of invasive, wireless and portable sensing technologies to improve the applicability and reliability of screen display, continuous monitoring, dynamic data visualisation, online acquisition and self and in-home healthcare management of patients with diabetes.

Engineering nanoscale hierarchical morphologies and geometrical shapes for microbial inactivation in aqueous solution.

Here, we study the effect of hierarchical and one-dimensional (1D) metal oxide nanorods (H-NRs) such as γ-Al2O3, ß-MnO2, and ZnO as microbial inhibitors on the antimicrobial efficiency in aqueous solution. These microbial inhibitors are fabricated in a diverse range of nanoscale hierarchical morphologies and geometrical shapes that have effective surface exposure, and well-defined 1D orientation. For instance, γ-Al2O3 H-NRs with 20 nm width and ˂0.5 µm length are grown dominantly in the [400] direction. The wurtzite structures of ß-MnO2 H-NRs with 30 nm width and 0.5-1 µm length are preferentially oriented in the [100] direction. Longitudinal H-NRs with a width of 40 nm and length of 1 µm are controlled with ZnO wurtzite structure and grown in [0001] direction. The antimicrobial efficiency of H-NRs was evaluated through experimental assays using a set of microorganisms (Gram-positive Staphylococcus aureus, Bacillus thuriginesis, and Bacillus subtilis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Minimal inhibitory and minimum bactericidal concentrations (MIC and MBC) were determined. These 1D H-NRs exhibited antibacterial activity against all the used strains. The active surface exposure sites of H-NRs play a key role in the strong interaction with the thiol units of vital bacterial enzymes, leading to microbial inactivation. Our finding indicates that the biological effect of the H-NR surface planes on microbial inhibition is decreased in the order of [400]-γ-Al2O3 > [100]-ß-MnO2 > [0001]-ZnO geometrics. The lowest key values including MIC (1.146 and 0.250 µg/mL), MBC (1.146, 0.313 µg/mL), and MIC/MFC (0.375 and 0.375 µg/mL) are achieved for [400]-plane γ-Al2O3 surfaces when tested against Gram-positive and -negative bacteria, respectively. Among the three H-NRs, the smallest diameter size and length, the largest surface area, and the active exposure [400] direction of γ-Al2O3 H-NRs could provide the highest microbial inactivation.

Non-metal sensory electrode design and protocol of DNA-nucleobases in living cells exposed to oxidative stresses.

Sensory protocols for evaluation of DNA distortion due to exposure to various harmful chemicals and environments in living cells are needed for research and clinical investigations. Here, a design of non-metal sensory (NMS) electrode was built by using boron-doped carbon spherules for detection of DNA nucleobases, namely, guanine (Gu), adenine (Ad), and thymine (Th) in living cells. The key-electrode based nanoscale NMS structures lead to voids with a facile diffusion, and strong binding events of the DNA nucleobases. Furthermore, the NMS geometric structures would significantly create electrode surfaces with numerous centrally active sites, curvature topographies, and anisotropic spherules. The NMS shows potential as sensitive protocol for DNA-nucleobases in living cells exposed to oxidative stresses. In one-step signaling assay, NMS shows high signaling transduction of Gu-, Ad-, and Th-DNA nucleobases targets with ultra-sensitive and low detection limits of 3.0, 0.36, and 0.34 nM, respectively, and a wide linear range of up to 1 µM. The NMS design and protocol show evidence of the role of surface construction features and B-atoms incorporated into the graphitic carbon network for creating abundant active sites with facile electron diffusion and heavily target loads along with within-/out-plane circular spheres. Indeed NMS, with spherule-rich interstitial surfaces can be used for sensitive and selective evaluation of damaged-DNA to various dysfunctional metabolism in the human body.

Inorganic-organic mesoporous hybrid segregators for selective and sensitive extraction of precious elements from urban mining.

This study aimed to develop a highly selective extraction protocol for gold (AuIII) ions from electronic urban waste (EUW) using simple, low-cost Inorganic-organic mesoporous hybrid segregators. The unique features of mesoporous hybrid segregator architectures are of particular to ensure effective adsorption system in terms of selective and sensitive recovery of AuIII ions from EUW. The segregator platform featured 3D micrometric, mesocage double-serrated plant-leaf-like γ-Al2O3 sheets with hierarchy surfaces containing tri-modal mesopores interiorly and uniformly arranged toothed edges of ~20-40 and ~15 nm groove width and depth at the exterior surfaces, respectively. Rational incorporation of actively organic chelates into hierarchical γ-Al2O3 sheet platforms leads to the production of a couple of selective segregators 1 and 2 (namely, SC1 and SC2) for AuIII ions at specific conditions by applying batch and fixed-bed columnar techniques. The mesocage SC segregators offer a selective extraction approach of AuIII ions from mixed element contents released from a computer motherboard (CMB). Our finding indicated that the textural and hierarchal features of the mesocage SC segregators played key roles in the selective adsorption/recovery of AuIII ions at pH 2-2.5 with high capacity (136-141 mg/g range) and effective reusability ≫10 consecutive cycles. In general, the developed SCs could be utilized as a real extractor of AuIII recovery from spent CMBs.

Anisotropic alignments of hierarchical Li2SiO3/TiO2 @nano-C anode//LiMnPO4@nano-C cathode architectures for full-cell lithium-ion battery.

We report on low-cost fabrication and high-energy density of full-cell lithium-ion battery (LIB) models. Super-hierarchical electrode architectures of Li2SiO3/TiO2@nano-carbon anode (LSO.TO@nano-C) and high-voltage olivine LiMnPO4@nano-carbon cathode (LMPO@nano-C) are designed for half- and full-system LIB-CR2032 coin cell models. On the basis of primary architecture-power-driven LIB geometrics, the structure keys including three-dimensional (3D) modeling superhierarchy, multiscale micro/nano architectures and anisotropic surface heterogeneity affect the buildup design of anode/cathode LIB electrodes. Such hierarchical electrode surface topologies enable continuous in-/out-flow rates and fast transport pathways of Li+-ions during charge/discharge cycles. The stacked layer configurations of pouch LIB-types lead to excellent charge/discharge rate, and energy density of 237.6 Wh kg-1. As the most promising LIB-configurations, the high specific energy density of hierarchical pouch battery systems may improve energy storage for long-driving range of electric vehicles. Indeed, the anisotropic alignments of hierarchical electrode architectures in the large-scale LIBs provide proof of excellent capacity storage and outstanding durability and cyclability. The full-system LIB-CR2032 coin cell models maintain high specific capacity of ∼89.8% within a long-term life period of 2000 cycles, and average Coulombic efficiency of 99.8% at 1C rate for future configuration of LIB manufacturing and commercialization challenges.

Three-Dimensional Circular Surface Curvature of a Spherule-Based Electrode for Selective Signaling and Dynamic Mobility of Norepinephrine in Living Cells.

A highly sensitive protocol for signaling norepinephrine (NEP) in human fluids and neuronal cell line models should be established for clinical investigation of some neuronal diseases. A metal-free electrode catalyst was designed based on a sulfur-doped carbon spheroidal surface (S-CSN) and employed as a transducing element for selective signaling of NEP in biological samples. The designed electrode of S-CSN features a spherical construct and curvature surface to form a spheroidal nanolayer with an average layer size of <2 nm. S-CSN shows surface topography of a circular surface curvature with a rugged surface texture, ridge ends, and free open spaces between interlayers. The rich-space diversity surfaces offer highly active surface with facile molecular/electron diffusion, multi-diffusive centers, and high target loading along with in-/out-of-plane circular spheres of the S-CSN surface. The active doping of S atoms onto the carbon-based electrode creates an active transducing element with many active sites, strong binding to targeted molecules, facile diffusion of charges/molecules, long-term durability, and dense reactive exposure sites for signaling NEP at ultratrace levels. S-CSN could be a sensitive and selective nanosensor for signaling NEP and establishing a sensing protocol with high stability and reproducibility. The sensory protocol based on S-CSN exhibits high sensitivity and selectivity with a low detection limit of 0.001 µM and a wide linear range of 0.01-0.8 µM. The in vitro sensory protocol for NEP secreted from living cells (neuronal cell line model) under stimulated agents possesses high sensitivity, low cytotoxicity, and high biocompatibility. These results confirm the successful establishment of NEP sensor in human blood samples and neuronal cells for clinical investigation.

Progress in biomimetic leverages for marine antifouling using nanocomposite coatings.

Because of the environmental and economic casualties of biofouling on maritime navigation, modern studies have been devoted toward formulating advanced nanoscale composites in the controlled development of effective marine antifouling self-cleaning surfaces. Natural biomimetic surfaces have the advantages of micro-/nanoroughness and minimized free energy characteristics that can motivate the dynamic fabrication of superhydrophobic antifouling surfaces. This review provides an architectural panorama of the biomimetic antifouling designs and their key leverages to broaden horizons in the controlled fabrication of nanocomposite building blocks as force-driven marine antifouling models. As primary antifouling designs, understanding the key functions of surface geometry, heterogeneity, superhydrophobicity, and complexity of polymer/nanofiller composite building blocks on fouling-resistant systems is crucial. This review also discusses a wide range of fouling release coating systems that satisfy the growing demand in a sustainable future environment. For instance, the integration of block, segmented copolymer-based coatings and inorganic-organic hybrid nanofillers enhanced the model's antifouling properties with mechanical, superhydrophobic, chemically inert, and robust surfaces. These nanoscale antifouling systems offered surfaces with minimized free energy, micro-/nanoroughness, anisotropic heterogeneity, superior hydrophobicity, tunable non-wettability, antibacterial efficiency, and mechanical robustness. The confined fabrication of nanoscale orientation, configuration, arrangement, and direction along the architectural composite building blocks would yield excellent air-entrapping ability along the interfacial surface grooves and interfaces, which optimized the antifouling coating surfaces for long-term durability. This review provides systematic evidence of the effect of structurally folded nanocomposites, nanofiller tectonics, and building blocks on the creation of outstanding superhydrophobicity, self-cleaning surfaces, and potential antifouling coatings. The development of modern research gateways is a candidate for the sustainable future of antifouling coatings.

3D-Ridge Stocked Layers of Nitrogen-Doped Mesoporous Carbon Nanosheets for Ultrasensitive Monitoring of Dopamine Released from PC12 Cells under K+ Stimulation.

3D-ridge nanosheets of N-doped mesoporous carbon (NMCS)-based electrodes are fabricated as ultrasensitive biosensors for in vitro monitoring of dopamine (DA) released from living cells. The large-scale ranges of dense-layered sheets are arranged linearly with a thickness of <10 nm, soft tangled edges, stocked layer arrangements, and tunable mesoporous frameworks with 3D orientations. The intrinsic features of the active interfacial surface of the electrode based on NMCS along with polarized surfaces, dense surface-charged matrices, fast electron transfer, and easy molecular diffusion, are present in the highly active electrode for biosensing applications. The designed electrode based on the NMCS shows high sensitivity and selectivity for DA sensing even in the presence of physiological interference molecules, such as ascorbic acid and/or uric acid, at a low applied potential of 0.25 V versus Ag/AgCl. The large-scale NMCS-based electrode shows low detection limits as low as 10 nmol L-1 , wide linear range up to 0.5 mmol L-1 , long-term stability for more than 15 d (relative standard deviation (RSD)= 5.8%), and a low cytotoxicity with high biocompatibility. The findings demonstrated that the NMCS-based electrode is a reliable modified electrode for ultratrace sensitivity of DA, which is secreted normally from dopaminergic cells (PC12) or under a stimulating agent (K+ ).

One-step selective screening of bioactive molecules in living cells using sulfur-doped microporous carbon.

A metal-free electrode using heteroatom-doped microporous carbon was fabricated for the ultrasensitive monitoring of mono-bioactive molecules and the selective signaling of dopamine (DA) secreted by living cells. The constructed electrode based on sulfur-doped microporous carbon (S-MC) shows a high surface area, a spherical construction, numerous carbon chain defects, and microporous structures, which are the key factors of the interactive signaling transducer, fast response, and active interfacial surfaces. The intrinsic features of S-MC with different %S-doping (S-MC-1, and S-MC-2) through the sp2-carbon chain create abundant catalytic active sites, facilitate molecular diffusion through the microporous structure, promote strong binding with the targeted molecules, and induce interactions at electrolyte-electrode interfaces. The S-MC-1 provides selective signaling in a tertiary mixture of DA, ascorbic acid (AA), and uric acid (UA) with a high sensitivity and a wide linear range of 0.01-5, 10-4000, and 1-2000 µM, respectively. The detection limits were set at 3 nM, 1.26 µM, and 0.23 µM for DA, AA, and UA respectively. The S-MC-1 demonstrated a selective screening of DA released from PC12 cells under a K+ ion- stimulator with high sensitivity and promoted high biocompatibility, low cytotoxicity, high stability, and reliable reproducibility (%RSD ranged from 1 to 2.7). Our findings indicated that the S-MC-1 can be utilized as an in-vitro model for simultaneously monitoring extracellular-DA secreted from living cells and sensing mono-bioactive molecules in biological samples.