Synthesis of sp-hybridized nitrogen doped ultrathin graphdiyne and application to the electrochemical detection for 6,7-dihydroxycoumarin

Advances of functional graphdiyne in separation and detection

Separation and detection technologies are essential tools for ensuring quality, safety and efficiency across various industries. Graphdiyne (GDY), a carbon material made up of alkyne bonds conjugated with benzene rings to form a planar all-carbon network, is increasingly utilized in the fields of separation and detection. GDY is becoming an ideal separation medium due to its adjustable pore sizes, unique alkyne-rich framework, and easy to be functionalized. On the other hand, GDY shows great potential in detection with the advantages of efficient photoelectric effect, high carrier mobility, and large surface areas to provide active sites. This review summarizes the progress of functional GDY in separation and detection from 2011 to 2024. Various synthesis methods were introduced on improving the properties of GDY in separation and detection. Efforts have increasingly focused on the development of functional GDY in separation functionalities such as magnetic and membranous separations. Moreover, the application of functional GDY in detection technologies are discussed such as electrochemical, spectroanalysis, and dual-mode approaches. Finally, the promising research directions and prospects of functional GDY are discussed to explore further applications in both separation and detection.

Modulating the electronic structure of graphdiyne-based nanomaterials for engineering nano-bio interfaces in biomedical applications

Graphdiyne (GDY), a two-dimensional (2D) carbon allotrope featuring a unique electronic structure, has attracted considerable attention due to its outstanding properties and potential applications in various fields, particularly in biomedicine due to its exceptional surface area, tunable electronic structure, and biocompatibility. Although promising, this field is still in the proof-of-concept stage due to incomplete understanding of the effects of structural regulation, particularly electronic structure, of GDY-based nanomaterials on their nano-bio interfaces, which seriously hinders the research of GDY-based nanomaterials in the biomedical field. To provide a comprehensive understanding of the relationship between electronic structures and nano-bio interfaces, this review focuses on the modulation of the electronic structure of GDY-based nanomaterials and its implications for engineering nano-bio interfaces for biomedical applications. Firstly, we delve into the intrinsic electronic properties of GDY, including its bandgap tunability and high carrier mobility, which are critical for its functionality in biomedical applications. We then discuss strategies for modulating these properties through oxidation, nonmetallic doping, covalent modification, and metal loading, aiming to optimize the electronic structure of GDY-based nanomaterials for superior performance in specific biomedical contexts, such as biomedical imaging, surface and interface catalysis, free radical scavenging, and drug delivery. Furthermore, we provide an overview of the methodologies for the investigation of these electronic properties, including theoretical simulation, characterization techniques, and real-time analysis of electron transfer at the nano-bio interfaces, highlighting their roles in advancing our understanding and guiding the design of novel GDY-based materials. Finally, this review provides an outlook on future research directions aimed at further optimizing the design of GDY-based nanomaterials and nano-bio interfaces, emphasizing the need for interdisciplinary collaboration to overcome current challenges and to fully realize the potential of GDY-based nanomaterials in biomedical applications. These principles are anticipated to facilitate the future development and clinical translation of precise, safe, and effective nanomedicines with intelligent theranostic features.

Graphdiyne biomaterials: from characterization to properties and applications

Graphdiyne (GDY), the sole synthetic carbon allotrope with sp-hybridized carbon atoms, has been extensively researched that benefit from its pore structure, fully conjugated surfaces, wide band gaps, and more reactive C≡C bonds. In addition to the intrinsic features of GDY, engineering at the nanoscale, including metal/transition metal ion modification, chemical elemental doping, and other biomolecular modifications, endowed GDY with a broader functionality. This has led to its involvement in biomedical applications, including enzyme catalysis, molecular assays, targeted drug delivery, antitumor, and sensors. These promising research developments have been made possible by the rational design and critical characterization of GDY biomaterials. In contrast to other research areas, GDY biomaterials research has led to the development of characterization techniques and methods with specific patterns and some innovations based on the integration of materials science and biology, which are crucial for the biomedical applications of GDY. The objective of this review is to provide a comprehensive overview of the biomedical applications of GDY and the characterization techniques and methods that are essential in this process. Additionally, a general strategy for the biomedical research of GDY will be proposed, which will be of limited help to researchers in the field of GDY or nanomedicine.

Nanomaterial-Based Sensors for Coumarin Detection

Sensors are widely used owing to their advantages including excellent sensing performance, user-friendliness, portability, rapid response, high sensitivity, and specificity. Sensor technologies have been expanded rapidly in recent years to offer many applications in medicine, pharmaceuticals, the environment, food safety, and national security. Various nanomaterial-based sensors have been developed for their exciting features, such as a powerful absorption band in the visible region, excellent electrical conductivity, and good mechanical properties. Natural and synthetic coumarin derivatives are attracting attention in the development of functional polymers and polymeric networks for their unique biological, optical, and photochemical properties. They are the most abundant organic molecules in medicine because of their biological and pharmacological impacts. Furthermore, coumarin derivatives can modulate signaling pathways that affect various cellular processes. This review covers the discovery of coumarins and their derivatives, the integration of nanomaterial-based sensors, and recent advances in nanomaterial-based sensing for coumarins. This review also explains how sensors work, their types, their pros and cons, and sensor studies for coumarin detection in recent years.

Heparin-stabilized gold nanoparticles embedded in graphene for the electrochemical determination of esculetin

A conductive nanocomposite consisting of heparin-stabilized gold nanoparticles embedded in graphene was prepared and characterized to develop an electrochemical sensor for the determination of esculetin in tea and jam samples. The gold nanoparticles were characterized by spectroscopic and microscopic techniques. The different proportions of graphene in the nanocomposite were evaluated and characterized by electrochemical practices. The heterostructure material on the glassy carbon electrode with esculetin showed π-π stacking interactions with an adsorption-controlled process. The voltammetric profile of esculetin using the proposed nanomaterial presented oxidation and reduction peaks at +0.61 and +0.58 V vs. Ag/AgCl, respectively, facilitating the electron transfer with esculetin through the transfer of two moles of protons and two moles of electrons per mole of esculetin. Using optimized conditions and square wave voltammetry, the calibration curve was obtained with two linear ranges, from 0.1 to 20.5 μmol L-1, with a detection limit of 43.0 nmol L-1. The electrochemical sensor showed satisfactory results for repeatability and stability, although interferences were observed in the presence of high concentrations of ascorbic acid or quercetin. The sensor was successfully applied in the determination of esculetin in samples of mulberry jam, white mulberry leaf tea, and white mulberry powder tea, presenting adequate recovery ranges. This directive provides valuable insights for the development of novel electrochemical sensors using heparin-based conductive nanomaterials with improved sensitivity and sensibility.

La-doped NiWO4 coupled with reduced graphene oxide for effective electrochemical determination of diphenylamine

Diphenylamine (DPA) is a harmful pesticide widely used to control post-harvest scald of fruits. In this study, rapid and sensitive determination of DPA was realized by the development of an effective electrochemical sensor, which was fabricated by coupling La-doped NiWO4 nanoparticles (La/NiWO4) with reduced graphene oxide (rGO), and the obtained rGO/La/NiWO4 nanocomposite was modified on glassy carbon electrodes (GCEs). The morphologies, structures and compositions were well characterized, and the effects of La doping and the introduction of rGO on the crystal structure and electrochemical performance were discussed. The incorporation of both La and rGO was found to enhance the active surface area and improve conductivity, resulting in the enhanced electrocatalytic performance of rGO/La/NiWO4/GCE, including a wide linear range (0.01-500 μM), a low detection limit (0.0058 μM) and high sensitivity (1.778 μA μM-1 cm-2). The fabricated sensor was further used for DPA detection in fresh apple extract to evaluate its practicality and demonstrated excellent recoveries ranging from 99.52 to 104.70%.

In Situ Polymerization Synthesis of Graphdiyne Nanosheets as Electrode Material and Its Application in NMR Spectroelectrochemistry

In situ NMR spectroelectrochemistry is extremely powerful in studying redox reactions in real time and identifying unstable reaction intermediates. In this paper, in situ polymerization synthesis of ultrathin graphdiyne (GDY) nanosheets was realized on the surface of copper nanoflower/copper foam (nano-Cu/Cuf)-based electrode with hexakisbenzene monomers and pyridine. Palladium (Pd) nanoparticles were further deposited onto the GDY nanosheets by the constant potential method. By using this GDY composite as electrode material, a new NMR-electrochemical cell was designed for in situ NMR spectroelectrochemistry measurement. The three-electrode electrochemical system consists of a Pd/GDY/nano-Cu/Cuf electrode as the working electrode, a platinum wire as the counter electrode, and a silver/silver chloride (Ag/AgCl) wire as a quasi-reference electrode, which can be dipped into a specially constructed sample tube and adapted for convenient operation in any commercial high-field, variable-temperature FT NMR spectrometer. The application of this NMR-electrochemical cell is illustrated by monitoring the progressive oxidation of hydroquinone to benzoquinone by controlled-potential electrolysis in aqueous solution.

Electrochemical Characterization of the Antioxidant Properties of Medicinal Plants and Products: A Review

Medicinal plants are an important source of bioactive compounds with a wide spectrum of practically useful properties. Various types of antioxidants synthesized in plants are the reasons for their application in medicine, phytotherapy, and aromatherapy. Therefore, reliable, simple, cost-effective, eco-friendly, and rapid methods for the evaluation of antioxidant properties of medicinal plants and products on their basis are required. Electrochemical methods based on electron transfer reactions are promising tools to solve this problem. Total antioxidant parameters and individual antioxidant quantification can be achieved using suitable electrochemical techniques. The analytical capabilities of constant-current coulometry, potentiometry, various types of voltammetry, and chrono methods in the evaluation of total antioxidant parameters of medicinal plants and plant-derived products are presented. The advantages and limitations of methods in comparison to each other and traditional spectroscopic methods are discussed. The possibility to use electrochemical detection of the antioxidants via reactions with oxidants or radicals (N- and O-centered) in solution, with stable radicals immobilized on the electrode surface, via oxidation of antioxidants on a suitable electrode, allows the study of various mechanisms of antioxidant actions occurring in living systems. Attention is also paid to the individual or simultaneous electrochemical determination of antioxidants in medicinal plants using chemically modified electrodes.

Fabrication of Graphdiyne/Graphene Composite Microsphere with Wrinkled Surface via Ultrasonic Spray Compounding and its Microwave Absorption Properties

Advanced carbon materials are constantly being used in the field of microwave absorption. Herein, in order to enrich the variety and expand the application fields of graphdiyne (GDY), the wrinkled graphene (RGO) nanosheet coated and embedded with GDY porous microspheres (RGO/GDY) are prepared by GDY synthesis, ultrasonic spray, and pyrolysis. The study finds that RGO and GDY have effective synergistic effects. The suitable pores and composition, conductive network formed by overlapping 0D and 2D materials, special surface and internal morphology design, and high-temperature activation process make RGO/GDY exhibit excellent impedance matching and attenuation capabilities. Under the best amount of GDY (20 mg), the particle sizes of the microspheres (≈6 µm), and filler content (27.5%), the minimum reflection loss (RL_min ) is -58 dB@8.3 GHz, and the corresponding matching thickness is 2.7 mm. The effective absorption bandwidth is 4.3 GHz as the thickness is 1.9 mm. By adjusting the thickness, the absorber can completely absorb microwaves of all the C, X, and Ku bands. The microwave absorbing mechanisms are elucidated. GDY materials are first applied to the field of microwave absorption, enhancing the absorption performance of RGO/GDY. It provides a new way to manufacture electromagnetic wave absorbers with satisfactory performance.

Synthesis of carbon dots-based covalent organic nanomaterial as stationary phase for open tubular capillary electrochromatography

The transformation of zero-dimensional carbon dots (CDs) to cross-linked nanomaterials is rare. In this work, a novel carbon dots-based covalent organic nanomaterial (CON CDs-TAPB) consisted of 1,3,5-tris(4-aminophenyl)-benzene (TAPB) and carbon dots (CDs) through facile Schiff-base reaction was synthesized and then employed as a stationary phase for open-tubular capillary electrochromatography (OT-CEC). The CON CDs-TAPB and the CDs-TAPB coated column were characterized through Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), UV-spectra experiments and X-ray photoelectron spectroscopy (XPS). Thanks to CON CDs-TAPB unique structure and abundant accessibility and interaction sites, the prepared column exhibited a satisfactory separation ability towards analytes including parabens, phenolic compounds. Among all analytes, the highest column efficiency was over 1.6 × 10⁵ plates·m^-1. In addition, affording methylbenzene loading capacity of 156.9 pmole, surpassing most of those materials-based OT-CEC reported thus far. Thus, the prepared carbon dots-based covalent organic nanomaterial (CON CDs-TAPB) gave a potential as a stationary phase in the separation science.