The introduction of comprehensive health, related to human living environment and mental state, helps people to improve human health literacy and accept scientific health guidance. The unique structure and properties of black phosphorene (BP) provide potential opportunities for rapid development and versatile applications of high-performance sensors serving comprehensive health. The review begins with the preparation from bulk black phosphorous crystals via transforming requirements of phosphorous allotropes and BP nanosheets via preparative strategies using both “top-down” and “bottom-up” methods. Then the diversified modification of BP and versatile fabrication of diversified bio-/chemo-nanosensors for sensitive detection of analytes are discussed. Besides, the challenges including the preparation of BP, diversified modification, devices for improving performance defects and chemo-/bio-nanosensors for enhancing performance are outlined together with potential opportunities for the BP preparation and applications in comprehensive health from agricultural environments, food safety, personal life, physical and mental life, and finally to medical care.

Coconut cadang-cadang viroid (CCCVd) is an infectious single-stranded RNA (ssRNA) pathogen, which leads directly to the death of a large number of coconut palm trees and heavy economic loss to coconut farmers. Herein, a novel electrochemical impedance RNA genosensor is presented based on highly stable gold nanoparticles (AuNPs) decorated phosphorene (BP) nanohybrid with graphene (Gr) for highly sensitive, low-cost, and label-free detection of CCCVd. BP-AuNPs are environmentally friendly prepared by ultrasonic-assisted liquid-phase exfoliation of black phosphorus, accompanying direct reduction of chloroauric acid. Gr/BP-AuNPs are facilely prepared by the in situ growth of AuNPs onto the BP surface and its nanohybrid with Gr to improve environmental stability of BP. Gr/BP-AuNP-based RNA genosensor is fabricated by immobilizing the thiol-functionalized single-stranded DNA (ssDNA) oligonucleotide probe onto the surface of Gr/BP-AuNP-modified glassy carbon electrode via gold-thiol interactions, which served as an electrochemical genosensing platform for the label-free impedance detection of CCCVd by hybridization between the functionalized ssDNA probe and the complementary CCCVd ssRNA sequence in a wide linear range from 1.0 × 10−11 to 1.0 × 10−7 M with a low limit of detection of 2.8 × 10−12 M. This work supplies an experimental support and theoretical direction for the fabrication of RNA biosensors based on graphene-like materials and potential application for a specific diagnosis of plant RNA viral disease in Arecaceae planting industry.

The label-free immunosensing technique is highly valued for its sensitivity and specificity, and advantages of simple preparation, fast detection (one-step), and rapid signal response. However, the sensitivity, stability, and specificity of this technique not only depend on the performance of antibodies, but also on the immunosensing interface of the bare glassy carbon electrode (GCE). This includes factors such as electrical conductivity, biocompatibility, and antibody loading capacity. In this study, carboxyl multiwalled carbon nanotubesferrosoferric oxide-graphene oxide (COOH-MWCNTs-Fe3O4-GO) was screened as the modified material of GCE to create an ideal immunosensing interface for the biological reaction between antibody-sulfadimidine (antiSM2) and SM2. The structure of both nanomaterials and the immunosensor were characterized. The nanohybrid exhibited a uniform interwoven structure of laminar and tubular components. This unique structure allows for a higher capacity for antibody loading. Based on this, a novel electrochemical immunosensor was constructed using COOH-MWCNTs-Fe3O4-GO/GCE, which exhibited a high anti-SM2 loading capacity and a rapid detection time of 30 min. The immunosensor exhibited a linear detection range of 0.01-100 ng/mL for SM2, with a limit of detection (LOD) of 0.003 ng/mL and a limit of quantification (LOQ) of 0.01 ng/mL. Additionally, satisfactory recoveries ranging from 94.40% to 109.00% were achieved in crayfish samples, with a relative standard deviation (RSD) of 4.97-8.64%. A novel immunosensors for highly sensitive detection of SM2 has been developed, which may provide an alternative idea for determination of SM2 in crayfish and other seafood.

The stability of black phosphorene (BP) and its preparation and modification for developing and applying devices have become a hot topic in the interdisciplinary field. We propose ultrasound-electrochemistry co-assisted liquid-phase exfoliation as an eco-friendly one-step method to prepare gold–silver bimetallic nanoparticles (Au−AgNPs)-decorated BP nanozyme for smartphone-based portable sensing of 4-nitrophenol (4-NP) in different water sources. The structure, morphology, composition, and properties of Au−AgNPs−BP nanozyme are characterized by multiple instrumental analyses. Bimetallic salts are induced to efficiently occupy oxidative sites of BP to form highly stable Au−AgNPs−BP nanozyme and guarantee the integrity of the lamellar BP. The electrochemistry shortens the exfoliation time of the BP nanosheet and contributes to the loading efficiency of bimetallic nanoparticles on the BP nanosheet. Au−AgNPs−BP-modified screen-printed carbon electrode coupled with palm-sized smartphone-controlled wireless electrochemical analyzer as a portable wireless intelligent sensing platform was applied to the determination of 4-NP in a linear range of 0.6−10 μM with a limit of detection of 63 nM. It enables on-site determination of 4-NP content in lake water, river water, and irrigation ditch water. This work will provide a reference for an eco-friendly one-step preparation of bimetallic nanoparticle-decorated graphene-like materials as nanozymes and their smartphone-based portable sensing application outdoors.

It’s very essential to exploit a portable wireless integrated sensing platform for field simultaneous, on-site detection of heavy metal ions pollution that has been exhibited to Serious ecological and health risks even under trace levels, including Cd (II) and Pb (II) ions. In this work, we developed a portable sensing platform, consisting of an integrated screen-printed electrode (SPE) with the calcium/aluminum-layered double hydroxide (CaAl-LDH) nanocomposite based on carboxyl functionalized multi-walled carbon nanotubes (MWCNTs-COOH), a hand-held wireless electrochemical potentiostat and a tablet with a specially designed app, for field simultaneous rapid detection of both Cd (II) and Pb (II) in water environmental sample. The CaAl-LDH was produced through a facilely hydrothermal method, and the CaAl-LDH nanocomposite with MWCNTs-COOH was prepared by a one-step ultrasonic route, which demonstrated superior sensing performance for simultaneous determination of both Cd (II) and Pb (II) with a broad detection range (2–250 μ g L −1 for Cd (II) and 5–250 μ g L −1 Pb (II)) and low limit of detection (LOD) (0.96 μ g L −1 Cd (II) and 0.74 μ g L −1 for Pb (II)).Furthermore, the proposed tablet-operated portable wireless sensing platform was utilized for detection of both Cd (II) and Pb (II) in farmland irrigation canals with acceptable recoveries.

Highly selective and sensitive analysis of bisphenol A (BPA) in many plastic products remains its significance. We explored a simple, highly sensitive, and inexpensive electrochemical sensor based on a self-healing threedimensional nanoarray (3DN) via a single-step electrochemical preparation of both platinum nanoparticles (PtNPs) and reduced graphene oxide (rGO) on a glassy carbon electrode for the portable detection of bisphenol (BPA) in plastic bottled waters. The structure of PtNPs/3DNrGO was confirmed by electron microscope and spectroscopic characterization. Electrochemical characteristics indicated that PtNPs/3DNrGO could decrease the oxidation overpotential due to the self-healing effect of the physical interaction between PtNPs and hydroxyl groups of rGO with an increase in the active surface area. The PtNPs/3DNrGO exhibited remarkably efficient electrocatalytic performance for the oxidation of BPA. The PtNPs/3DNrGO sensor for BPA demonstrated a wide linear range from 0.7 to 20 mu M with a low limit of detection of 6 nM (S/N = 3) and effective performance including high sensitivity, high repeatability, and excellent selectivity. The developed sensor had been effectively implemented to assess BPA in plastic samples with desirable impacts. The interaction mechanism of both PtNPs and rGO was inferred by density functional theory. The proposed electrochemical sensor enabled the development of a portable, low-cost, and user-friendly monitoring of water quality, which will offer theoretical support for environmental monitoring.

The accumulation of heavy metal cadmium (Cd) in the food chain poses a serious threat to human health, necessitating the development of rapid, on-site, and portable detection methods for Cd (II). Herein, we developed a smartphone-based electrochemical sensor for portable determination of Cd (II) in vegetables using a bismuth metal-organic framework (Bi-MOF) nanocomposite. Prismatic rod-like Bi-MOF was hydrothermally synthesized using trimesic acid as organic ligands, and subsequently, carboxyl-functionalized multi-walled carbon nanotubes (COOH-MWCNTs) were incorporated to form Bi-MOF nanocomposite network. The smartphone-based electrochemical sensor enables rapid, sensitive, and portable detection of Cd (II) in vegetable samples using Bi-MOF/ COOH-MWCNTs-modified screen-printed carbon electrodes (SPCE). A comparative analysis of traditional electrochemical sensors coupled with desktop computer for linear voltametric responses for Cd (II) in the range of 0.2-500 ng/mL with a limit of detection (LOD) of 0.07 ng/mL using Bi-MOF/COOH-MWCNTs-modified glassy carbon electrodes (GCE), the portable sensor demonstrated good linear range in 0.7-350 ng/mL with a LOD of 0.22 ng/mL. This work introduces a novel approach for on-site and portable detection of Cd (II) in agricultural products.

The development of high-performance and stable trifunctional electrocatalysts is a pressing challenge for the practical application of water splitting and regenerative Zn-air batteries. Herein, bamboo-like N-doped carbon tubes encapsulated Co2P-Fe2P nano-particles (CoFe-PN/C) was fabricated via a facile template-sacrificial approach by using CoZn-ZIF trapping Fe3+ (CoFeZn/C) as the precursor. The incorporation of Fe3+ was achieved by the one-pot synthesis approach during crystallization of ZIF, which led to the generation of the unique bamboo-like tube structure under the condition of simultaneous phosphating and carbonization. Benefiting from the large surface area, the optimized electronic structure of active sites and the unique bamboo-like nanotube, the resultant CoFe-PN/C can be used as the trifunctional electrocatalyst possessing a small overpotential at 10 mA cm-2 for the HER (178 mV) and OER (300 mV), as well as a high half-wave potential of 0.884 V for ORR (40 mV more positive than that of commercial 20 wt% Pt/C). Moreover, the self-designed CoFe-PN/C||CoFe-PN/C alkaline electrolyzer driving 50 mA cm-2 only need operating potential of 1.84 V and the maximum discharge power density of the CoFePN/C-assembled ZABs could achieve 152.0 mW cm-2, superior to those of Pt/RuO2 couple. This work will facilitate the development and application of trifunctional electrocatalysts based on bi-transition metallic phosphides for energy conversion and storage technology. & COPY; 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

With the assistance of machine learning (ML), black phosphorene (BP) stabilized by silver nanoparticles (AgNPs) is used to modify halloysite nanotube (HNT) to obtain highly conductive nanomaterials, HNT/BP-AgNPs, which are morphologically characterized and elementally analyzed. Artificial neural network (ANN) and least squares support vector machine (LS-SVM) are adopted for the intelligent and rapid analysis of maleic hydrazide (MH). An ultra-portable electrochemical sensor bases on HNT/BP-AgNPs modifying screen-printed carbon electrode (SPCE), smartphone and mini-palm potentiostat for detection of MH in the linear range 0.7-55 mu M with limit of detection (LOD) of 0.3 mu M. For comparison, a traditional electrochemical sensor is fabricated by glass carbon electrode (GCE), desktop computer and large electrochemical potentiostat, and the linear range is 0.3-600 mu M with low LOD of 0.1 mu M. The ultra-portable electrochemical sensor combined with ML for the detection of MH in sweat potato and carrot gain satisfactory recoveries.

Metal ions have great significance for agricultural development, food safety, and human health. In turn, there exists an imperative need for the development of novel, sensitive, and reliable sensing techniques for various metal ions. Agricultural sensors for the diagnosis of both agricultural safety and nutritional health can establish quality and safety traceability systems of both agro-products and food to guarantee human health, even life safety. Metal-organic frameworks (MOFs) are utilized widely for the design of diversified sensors due to their distinctive structural characteristics and extraordinary optical and electrical properties. To serve agricultural sensors better, this review is dedicated to providing a brief overview of the synthesis of MOFs, the modification of MOFs, the fabrication of MOF-based film electrodes, the applications of MOF-based agricultural sensors for metal ions, which are centered on electrochemical sensors and optical sensors, and current challenges of MOF-based agricultural sensors. In addition, this review also provides potential future opportunities for the development and practical application of agricultural sensors.

Machine learning (ML) plays an important role in the electrochemical application of electrode materials. In this work, an emerging machine learning strategy for both electrochemical sensor and supercapacitor using carbonized metal-organic framework (C-ZIF-67) is proposed. The morphology and element analysis of C-ZIF-67 are characterized and further demonstrate the presence of C, N, O, Co elements. The ML model based on artificial neural network (ANN) algorithm as a powerful tool to realize intelligent analysis of niclosamide (NA), the derivative technique as an auxiliary means of voltammogram treatment to reduce personal error from data-reading and improve the sensitivity of electrochemical responses at very low concentrations, and the theoretical calculation is employed for both adsorption and binding energy, optimized structure of the prepared sensing material. The developed sensor displays excellent electrochemical response about 196.6-fold improvement compared with the bare GCE for NA, wider linear ranges of intelligent analysis from 1 nM to 9 mu M with low limit of detection of 0.3 nM, and satisfactory practicability. ML model with ANN algorithm is also employed for predicting the performance of supercapacitor. The supercapacitor shows good performance with capacitance of 336.67 F/g at the current density of 2 A/g and excellent prediction with acceptable errors. This work will provide a new strategy for the development and electrochemical application of bifunctional electrode materials using the ML technique combined with theoretical calculation.

A novel and simple strategy was proposed for the determination of ZEA in breakfast cereal, maize powder and rice flour using an electrochemical nanohybrid sensor based on copper-based metal-organic framework (Cu-MOF)/magnetic Fe3O4-graphene oxide (Fe3O4-GO) modified electrode fabricated by the layer-by-layer assembled technique. The synthesized Cu-MOF with high porosity favorably improved the effective surface area and the analytical performance of nanohybrid sensing electrode. The crafted sensor has large surface area, high electron transfer, and satisfactory efficiency. ZEA was electrochemically detected in a wide linear range from 159.2 to 2865.2 ng mL-1 with LOD of 23.14 ng mL-1 under the optimal conditions. Moreover, the electrocatalytic mechanism of ZEA oxidation was proposed by density functional theory (DFT). A favorable energetic interaction was presented when Cu-MOF adsorbed on Fe3O4-GO, and a small new band appeared on the Fermi level energy (Ef) that facilitated the electron transfer between bands.

It is an urgent need to exploit a potentially green, cost efficient and eco-friendly strategy for the utilization of waste kudzu vine. We developed a one-step green preparation of kudzu vine biochar (BC) decorated graphenelike molybdenum selenide (MoSe2) with the oxidase-like activity as intelligent nanozyme sensing platform for voltametric detection of hesperetin (HP) in orange peel using the in-situ hydrothermal synthesis method. The structure and properties of MoSe2-BC was characterized, and found that BC significantly improved electrochemical cycle stability, electronic conductivity, electrochemical active area, and electrocatalytic activity of MoSe2. The oxidase-like activity of MoSe2-BC was confirmed by the oxidization of the colorless substrate 3,3 ',5,5 '-tetramethylbenzidine (TMB) to form blue products and the change of absorbance intensity of UV-vis absorption spectra. The MoSe2-BC exhibited excellent electrochemical sensing performance for the detection of HP in wide linear ranges from 10 nM to 9.5 mu M with a low limit of detection of 2 nM using differential pulse voltammetric method. An emerging machine learning technique is used to realize the intelligent sensing of HP, and the performance evaluation of regression analysis was selected to evaluate this technique. This work will provide a guidance for the preparation and application of biochar decorated graphene-like nanomaterials with the oxidase-like activity and the development of intelligent nanozyme sensing platform.

Hierarchical structural PEDOT@MoS2 nanocomposite is synthesized via a facile electrochemical co-deposition of the intercalation of PEDOT into flower-like MoS2 microspheres. The SEM, TEM, and other characterization results demonstrate the hierarchical PEDOT@MoS2 composite with an enlarged interlayer spacing of MoS2 to 1.02 nm, in which PEDOT nanoparticles act as intercalation, and flower-like MoS2 microspheres are used as a substrate for growth. The electrochemical characterizations indicate that the PEDOT@MoS2 electrode has an ultrahigh specific capacitance of 4418 mF cm(-2) at 2 mA cm(-2) and remarkable cycling stability, retaining 100% of the initial capacitance at a high current density of 100 mA cm(-2) after 10,000 cycles. The symmetric PEDOT@MoS2 supercapacitor presents a high energy density of 88.3 mWh cm(-2) at 60 mW cm(-2), and outstanding cycling stability (93% after 10,000 cycles). These prominent electrochemical performances are attributed to the expanded interlayer spacing, the synergistic effect between PEDOT and MoS2, the low resistance, along with the PEDOT@MoS2 porous structure, indicating great potential applications of the PEDOT@MoS2 electrode in the energy storage field.

A novel nanozyme sensor based on the electro-synthesized molecularly imprinted conducting poly(3,4ethylenedioxythiophene) (PEDOT) nanocomposite with graphene-like two-dimensional layered molybdenum disulfide (MoS2) was successfully prepared for electrochemical detection and analysis of luteolin in Gnaphalium affine. MoS2-MIPs were prepared facilely by electrochemical polymerization of monomer 3,4-ethylenedioxythiophene in the presence of both modifier MoS2 and template molecule luteolin that can change the morphological structure and specific surface area of PEDOT, enhance electronic conductivity of MoS2, and improve the recognition capability and electrocatalytic capacity of electrode interface. The morphological structure of MoS2MIPs was characterized by SEM, and its electrochemical performance and sensing parameters were investigated by voltammetry. The electrochemical response of luteolin was recorded by MoS2-MIPs in the linear concentration range from 3 & times; 10-7 to 3 & times; 10-5 \M with limit of detection of 0.04 mu\M under the optimal conditions, which was successfully employed for electrochemically detecting luteolin in Gnaphalium affine with acceptable recoveries in comparison with high-performance liquid chromatography. This will provide a new nanozyme sensing platform comprised of electro-synthesized molecularly imprinted conducting polymers and graphene-like twodimensional layered nanomaterials.

Green and sustainable development provides a new idea for solving environmental pollution issues of rural biomass wastes. Amorphous molybdenum sulfide (a-MoSx) nanocomposite based on biochar microsphere (BM) as voltametric sensing platform for smart analysis of baicalin in real sample was facilely prepared. Pomelo peel was employed as the carbon source for improving electronic conductivity and environmental stability and electrocatalytic capacity of a-MoSx. A mixture consisted of the precursor of both a-MoSx and BM were treated by a co-hydrothermal method. The a-MoSx nanocomposite with porous BM was formed by centrifuging, washing, drying, pulverizing, and calcining. The structure and properties of the as-obtained nanocomposite were characterized, and the electrochemical behaviors of baicalin, parametric conditions and performance of the as-prepared sensor were investigated. Peak currents recorded by differential pulse voltammetry is proportional to baicalin concentrations in wide linear ranges from 10 nM to 5 mu M with a low limit of detection of 2 nM. Machine learning algorithms like least squares support vector machine and artificial neural network was built to realize smart analysis and digital output for baicalin. Good cyclic stability, excellent voltammetric response, and satisfactory practicability will provide a promising electrochemical sensing platform for facile preparation of two-dimension nanomaterials functionalized with biochar derived from agroforestry biomass.

Ultrasonic-assisted liquid-phase exfoliation is one of high-efficiency strategies for preparing two-dimensional (2D) materials. Herein, we report a facile and green synthesis of the phosphorene (BP) obtained from bulk black phosphorus crystal in the ionic liquid (IL) 1-ethyl-3-methylimidazoliumtetrafluoroborate ([EMIm]BF4) through ultrasonic-assisted liquid-phase exfoliation under the continuous nitrogen atmosphere. To gain more insight, the morphology and composition of the as-prepared BP were characterized. The prepared BP showed satisfactory stability in ambient condition containing oxygen and water. In the following, single walled carbon nanohorn (SWCNH) was selected to enhance electrocatalytic capacity and endow oxidase-like (nanozyme) characteristics, which was further applied for electrochemical sensing of 5-hydroxytryptamine (5-HT). Derivative techniques were employed for treating voltammograms to obtain sharper and narrower voltammetric peak, transform asymmetric peak into much more symmetrical peak, reduce background interference, eliminate personal error and directly read the accurate value. Machine learning (ML) model based on artificial neural network (ANN) algorithm as an artificial intelligence approach is adopted to establish smart sensing system via the relationship between concentrations and currents in comparison with traditional linear regression model. The BP-IL-SWCNH nanozyme sensor displayed excellent electrocatalytic ability for second-order derivative voltammetric smart analysis of 5-HT range from 0.3 to 115 mu M under optimal conditions.

Luteolin (LUT) is one of the biologically active functional components, which was widely used in pharmacological applications. Thus, development of sensitive analytical methods for LUT determination is highly desired. In this work, Ti3C2-MXene/ZIF-67/CNTs heterostructure was exploited as a new electrochemical sensing platform for the sensitive determination of LUT. For the design of composite, the in-situ growth of ZIF-67 on CNTs surface ensures the stability of their binding and enhances the synergetic catalysis. Conductive MXene as matrix for the loading of ZIF-67/CNTs can promote the catalytic ability of composite. Electrochemical results show that the MXene/ZIF-67/ CNTs modified electrode displays preeminent electrocatalytic activity and enhances electrochemical response to the redox reaction of LUT, ascribing to the synergistic effect of ZIF-67/CNTs and MXene. Upon the optimization of experimental parameters, e.g., pH, enrichment time, the sensor based on MXene/ZIF-67/CNTs composite exhibits excellent performance with wide linear relationship ranging from 0.1?1000 nM and a low limit of detection (LOD) of 0.03 nM (S/N = 3). Besides, MXene/ZIF-67/CNTs electrode performs high selectivity, stability, and acceptable reproducibility. Furthermore, the constructed sensor was successfully utilized to detect LUT in real samples with satisfactory recovery.

An active material electrode with high areal specific capacitance is needed for a high-performance supercapacitor, but it is difficult to achieve this goal for PEDOT-based composites. Here, a novel hierarchical core/shell PEDOT@MoS2 composite was assembled by the electrochemical co-deposition of EDOT and MoS2 submicron spheres. The SEM, TEM images of the as-obtained composite explicitly reveal the core/shell heterostructure of PEDOT@MoS2 with a diameter of about 800 nm. The electrochemical characterizations show that the optimized PEDOT@MoS2 composite possesses a high specific capacitance of 2540 mF cm(-2) at 1 mA cm(-2) and excellent capacitance retention of 98.5% after 5000 cycles at a high current density of 100 mA cm(-2). The assembled P@M-(4)//PEDOT asymmetric supercapacitor shows a high energy density of 937 Wh m(-2) at 6500 W m(-2), and outstanding cycling stability with capacitance retention of 100% after 5000 cycles. It is proposed that the enhanced performances are attributed to the robust hierarchical core/shell structures and the synergic effect between PEDOT and MoS2, which is expected to become a promising candidate for applications in high-performance supercapacitors. (C) 2021 Elsevier Ltd. All rights reserved.

In this report, we have prepared 3D porous graphene flexible nanozyme electrode on polyimide by direct laser writing technology using a home-made computer-controlled laser scribing machine, which is a cost-efficient and one-step mass-production method. This flexible electrode exhibited outstanding mechanical flexibility, distinctive 3D porous structure, expected cycle stability, high conductivity, which was employed as a novel electrochemical nano-sensing platform for intelligent evaluation of fish freshness via simultaneous detection of both xanthine (XT) and hypoxanthine (HX) and smart analysis and digital output using machine learning (ML) model based on artificial neural network (ANN) algorithm. The as-prepared flexible electrode showed an enzyme-like kinetic (nanozyme) characteristic during the detection of XT (0.3-179.9 mu M) and HX (0.3-159.9 mu M) with a limit of detection (LOD) of 0.26 mu M and 0.18 mu M, respectively. The fish freshness was evaluated by voltammetric detection of both XT and HX in fish sample with different storage times, and ML model with ANN algorithm was built to realize smart analysis and digital output for evaluating the fish freshness. This will provide an experimental support for biomimetic flexible nano-sensing platform based on nanozyme flexible electrode via facile and rapid one-step mass production and intelligent nano-sensing platform based on ML model for intelligent operation for smart analysis and intelligent transformation for digital output.