Properties, Synthesis and Emerging Applications of Graphdiyne: A Journey Through Recent Advancements.

Graphdiyne (GDY) is a new variant of nano-carbon material with excellent chemical, physical and electronic properties. It has attracted wide attention from researchers and industrialists for its extensive role in the fields of optics, electronics, bio-medics and energy. The unique arrangement of sp-sp2 carbon atoms, linear acetylenic linkages, uniform pores and highly conjugated structure offer numerous potentials for further exploration of GDY materials. However, since the material is at its infancy, not much understanding is available regarding its properties, growth mechanism and future applications. Therefore, in this review, readers are guided through a brief discussion on GDY's properties, different synthesis procedures with a special focus on surface functionalization and a list of applications for GDY. The review also critically analyses the advantages and disadvantages of each synthesis route and emphasizes the future scope of the material.

Green Carbon Nanostructures for Functional Composite Materials.

Carbon nanostructures are widely used as fillers to tailor the mechanical, thermal, barrier, and electrical properties of polymeric matrices employed for a wide range of applications. Reduced graphene oxide (rGO), a carbon nanostructure from the graphene derivatives family, has been incorporated in composite materials due to its remarkable electrical conductivity, mechanical strength capacity, and low cost. Graphene oxide (GO) is typically synthesized by the improved Hummers' method and then chemically reduced to obtain rGO. However, the chemical reduction commonly uses toxic reducing agents, such as hydrazine, being environmentally unfriendly and limiting the final application of composites. Therefore, green chemical reducing agents and synthesis methods of carbon nanostructures should be employed. This paper reviews the state of the art regarding the green chemical reduction of graphene oxide reported in the last 3 years. Moreover, alternative graphitic nanostructures, such as carbons derived from biomass and carbon nanostructures supported on clays, are pointed as eco-friendly and sustainable carbonaceous additives to engineering polymer properties in composites. Finally, the application of these carbon nanostructures in polymer composites is briefly overviewed.

Lignin-based fluorescence-switchable graphene quantum dots for Fe3+ and ascorbic acid detection.

The synthesis of lignin-based graphene quantum dots (GQDs) with excellent fluorescence stability, quantum yield, and biocompatibility for sensitive and selective detection of Fe3+ and ascorbic acid (AA) has remained a challenging endeavor. Using an acidolysis process with 17.5% nitric acid followed by hydrothermal treatment at 200 °C, this study provided an improved synthesis route for the production of high-quality GQDs from alkali lignin. The nitrogen-doped GQDs exhibit remarkable fluorescence stability under a wide range of pH (3-10), duration (1-12 h), and [NaCl] (0-1000 mM) conditions, and have a high quantum yield of 28%. The GQDs or GQDs/Fe3+ sensing systems ([GQDs] at 50 mg L-1, [Fe3+] at 500 µmol L-1, and UV excitation at 370 nm) for fluorescence sensing of Fe3+ or AA have excellent sensitivity, selectivity, and reproducibility. For Fe3+ and AA, the limit of detection is 1.49 and 1.62 µmol L-1, respectively. Mechanism investigation shows that photoluminescence quenching is caused by the formation of GQDs-Fe3+ complexes, whereas fluorescence recovery is due to Fe3+ reduction by AA.

Facile one pot microbe-mediatedin situsynthesis and antibacterial activity of reduced graphene oxide-silver nanocomposite.

The present research deals with the development of a novel bioinspiredin situfabrication of reduced graphene oxide (rGO)-silver nanoparticle (AgNPs) nanocomposite (rGO@AgNCs) using microbes namelyPseudomonas aeruginosa(PA) andStaphylococcus aureus(SA). The fabricated rGO@AgNCs were characterized using Ultraviolet-visible (UV-Vis) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), particle size analysis, polydispersity index (PDI), zeta potential analysis, energy dispersive x-ray analysis (EDAX), Raman spectroscopy, powder x-ray diffraction (PXRD), high-resolution transmission electron microscopy (HR-TEM) analysis, etc. Furthermore, the rGO@AgNCs-PA and rGO@AgNCs-SA interaction with serum protein, pH stability study, andin vitrodissolution of AgNPs were also performed. The research findings of the proposed study demonstrated the simultaneous reduction of graphene oxide (GO) and AgNPs and the formation of rGO@AgNCs in the presence of microbes. Thein vitrodissolution studies of rGO@AgNCs composites showed better AgNPs dissolution with controlled release and offered remarkable matrix integrity throughout the dissolution period. The size and stability of rGO@AgNCs-PA and rGO@AgNCs-SA had no significant changes at physiological pH 7.4. A minimal decrease in the zeta potential of rGO@AgNCs was observed, which may be due to the weak interaction of nanocomposites and albumin. The antibacterial application of the synthesized nanocomposite was evaluated against a pathogenic mastitis-forming bacterium. The obtained results suggested an admirable antibacterial activity of synthesized nanocomposites against the tested microbes. This knowledge will assist the scientific fraternity in designing novel antibacterial agents with enhanced antibacterial activity against various veterinary pathogens in near future.

Synthesis of Si/Fe2O3-Anchored rGO Frameworks as High-Performance Anodes for Li-Ion Batteries.

By virtue of the high theoretical capacity of Si, Si-related materials have been developed as promising anode candidates for high-energy-density batteries. During repeated charge/discharge cycling, however, severe volumetric variation induces the pulverization and peeling of active components, causing rapid capacity decay and even development stagnation in high-capacity batteries. In this study, the Si/Fe2O3-anchored rGO framework was prepared by introducing ball milling into a melt spinning and dealloying process. As the Li-ion battery (LIB) anode, it presents a high reversible capacity of 1744.5 mAh g-1 at 200 mA g-1 after 200 cycles and 889.4 mAh g-1 at 5 A g-1 after 500 cycles. The outstanding electrochemical performance is due to the three-dimensional cross-linked porous framework with a high specific surface area, which is helpful to the transmission of ions and electrons. Moreover, with the cooperation of rGO, the volume expansion of Si is effectively alleviated, thus improving cycling stability. The work provides insights for the design and preparation of Si-based materials for high-performance LIB applications.

Graphene oxide-based fluorescent biosensors and their biomedical applications in diagnosis and drug discovery.

Graphene oxide (GO), an oxidized derivative of graphene, has received much attention for developing novel fluorescent bioanalytic platforms due to its remarkable optical properties and biocompatibility. The reliable performance and robustness of GO-based biosensors have enabled various applications in the biomedical field including diagnosis and drug discovery. Here, recent advances in the development of GO-based fluorescent biosensors are overviewed, particularly nucleic acid detection and enzyme activity assay. In addition, practical applications in biomarker detection and high-throughput screening are also examined. Lastly, basic design principles and remaining challenges of these types of biosensors are discussed for further progress.

Synthesis of Highly Near-Infrared Fluorescent Graphene Quantum Dots Using Biomass-Derived Materials for In Vitro Cell Imaging and Metal Ion Detection.

Graphene quantum dots (GQDs) are a subset of fluorescent nanomaterials that have gained recent interest due to their photoluminescence properties and low toxicity and biocompatibility features for bioanalysis and bioimaging. However, it is still a challenge to prepare highly near-infrared (NIR) fluorescent GQDs using a facile pathway. In this study, NIR GQDs were synthesized from the biomass-derived organic molecule cis-cyclobutane-1,2-dicarboxylic acid via one-step pyrolysis. The resulting GQDs were then characterized by various analytical methods such as UV-Vis absorption spectroscopy, fluorescence spectroscopy, dynamic light scattering, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Moreover, the photostability and stability over a wide pH range were also investigated, which indicated the excellent stability of the prepared GQDs. Most importantly, two peaks were found in the fluorescence emission spectra of the GQDs, one of which was located in the NIR region of about 860 nm. Finally, the GQDs were applied for cell imaging with human breast cancer cell line, MCF-7, and cytotoxicity analysis with mouse macrophage cell line, RAW 246.7. The results showed that the GQDs entered the cells through endocytosis on the fluorescence images and were not toxic to the cells up to a concentration of 200 µg/mL. Thus, the developed GQDs could be a potential effective fluorescent bioimaging agent. Finally, the GQDs depicted fluorescence quenching when treated with mercury metal ions, indicating that the GQDs could be used for mercury detection in biological samples as well.

GO-based antibacterial composites: Application and design strategies.

Graphene oxide (GO), for its unique structure with high biocompatibility and designability, is widely used in the antibacterial field. Various strategies have been designed to fabricate GO-based composites with antibacterial properties. This review summarized these strategies, divided them into three types and interpreted their antibacterial mechanisms: (i) "GO*/non-GO" type in which GO acts as the single antibacterial core, (ii) "GO*/non-GO*" type in which GO and non-GO components function synergistically as dual antibacterial cores, (iii) "GO/non-GO*" type in which non-GO acts as the single antibacterial core, while GO component plays a supportive, not a dominant role in antibiosis. Besides, the fields suiting their applications and factors influencing their antibacterial properties were analyzed. Finally, the limitations and prospects in the current researches were discussed. In summary, GO-based composites have revolutionized antibacterial strategies. This review may serve as a reference to inspire further research on GO-based antibacterial composites.

Synthesis, characterization, cytotoxicity studies, theoretical approach of adsorptive removal and molecular calculations of four new phosphoramide derivatives and related graphene oxide.

In this study, four novel phosphoramide ligands (L1-L4) are synthesized and characterized by 31PNMR, 1HNMR, MASS, and FT-IR spectroscopies. In vitro cell growth inhibition is studied by the MTT assay to evaluate the cytotoxicity of ligands against MCF-7 cell line; the result of the assay demonstrates that all ligands significantly suppress the proliferation of breast cancer cells in a concentration-dependent manner. The calculated IC50 values are in the range of 3.6-10.77 µg ml-1, of which the lowest value is attributed to L1. Then a facile approach was developed to functionalize graphene oxide (GO) surface by L1. The data which are obtained by XRD, FT-IR, and EDX analysis confirmed the deposition of phosphoramide on the surface of GO. The cell viability of GO-L1 compound at different concentrations is investigated in 24 h experiment. Excellent synergistic antitumor effects of GO and L1 lead to a decrease in IC50 value up to 2.13 µg ml-1. The Quantum calculations of compounds are used to study energies and HOMO and LUMO values, dipole moments (µ), global hardness (η), global softness (σ), and electrophilicity index (ω) using DMol3 module in Material studio2017. The docking calculations are performed to describe the mode of the binding to DNA and DNA polymerase IIα. Adsorption calculations of ligands (L1-L4) on GO sheet in the presence of water showed that L1 and L2 were located on GO via π electrons of anisole ring. While, L3 and L4 were located on GO by π - π interactions of aniline ring.

Biomedical application of graphitic carbon nitrides: tissue depositionin vivo, induction of reactive oxygen species (ROS) and cell viability in tumor cells.

The urgency for new materials in oncology is immediate. In this study we have developed the g-C3N4, a graphitic-like structure formed by periodically linked tris-s-triazine units. The g-C3N4has been synthesized by a simple and fast thermal process. XRD has shown the formation of the crystalline sheet with a compacted structure. The graphite-like structure and the functional groups have been shown by Raman and FTIR spectroscopy. TEM image and AFM revealed the porous composed of five or six C-N layers stacked. DRS and Photoluminescence analyses confirmed the structure with band gap of 2.87 eV and emission band at 448 nm in different wavelengths excitation conditions. The biological results showed inhibitory effect on cancer cell lines and non-toxic effect in normal cell lines. To the best of our knowledge, this is the first work demonstrating the cytotoxic effects of 2D g-C3N4in a cancer cell line, without any external or synergistic influence. The biodistribution/tissue accumulation showed that g-C3N4present a tendency to accumulation on the lung in the first 2 h, but after 24 h the profile of the biodistribution change and it is found mainly in the liver. Thus, 2D-g-C3N4showed great potential for the treatment of several cancer types.

Synthesis of magnetic chitosan biopolymeric spheres and their adsorption performances for PFOA and PFOS from aqueous environment.

Due to numerous applications and excellent environmental stability, long-chain perfluorinated chemicals (PFCs) are ubiquitous in water across the world and adversely affect the living organisms. Thus, this study focused on the mitigation of the most frequently used long-chain PFCs namely perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) from water using reduced graphene oxide modified zinc ferrite immobilized chitosan beads (rGO-ZF@CB) as an adsorbent. The results from the adsorption isotherm and kinetic studies revealed that the adsorption data fitted well to the Langmuir and the pseudo-second-order models. According to the Langmuir isotherm, the rGO-ZF@CB possessed the maximum adsorption capacity of 16.07 mg/g for PFOA and 21.64 mg/g for PFOS. Both the electrostatic attractions and hydrophobic interactions have driven the removal of PFOA and PFOS by prepared rGO-ZF@CB. Eventually, the rGO-ZF@CB could be considered as an efficient adsorbent for the effective removal of PFOA and PFOS molecules from the aqueous environment.

An electrochemical biosensing platform for progesterone hormone detection using magnetic graphene oxide.

In recent times, graphene and its derivatives have turned out to be emerging nanomaterials as transducers to promote electron transport in the field of biosensing using electrochemical techniques. In electrochemical biosensing strategies, key factors such as signal amplification, stability, and sensitivity are necessary for attaining improved sensor performance. In the present work, we synthesized magnetic nanocomposites of graphene oxide and employed them as an electrode material for the loading of bio receptors. The increased surface area with high electric conductance enhanced the sensor's response. The immobilization of progesterone (PGN) antibodies on the modified electrode-sensing surface led to a hindered electron transport that decreased the current response. The developed electrochemical immunosensor assembled successfully in a stepwise process using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) studies along with the electrochemical impedance spectroscopy (EIS) analysis. The current response decreased linearly with the increased progesterone (PGN) concentration range of 0.01 pM-1000 nM with excellent detection limits of 0.15 pM (DPV) and 0.17 pM (CV) under optimal experimental conditions. The label-free electrochemical immunosensor has shown a promising platform for rapid and direct analysis of PGN due to its high sensitivity, selectivity, stability, and repeatability in water samples.

Design and synthesis of amine grafted graphene oxide encapsulated chitosan hybrid beads for defluoridation of water.

The promising adsorbent like graphene oxide (GO), chitosan (CS) and amine functionalized graphene oxide (AGO) decorated chitosan (CS) namely AGO@CS composite beads was efficiently prepared for defluoridation studies. The prepared AGO@CS composite beads possess enriched defluoridation capacity (DC) of 4650 mgF- kg-1. Batch method was used to optimize the maximum DC of AGO@CS composite beads. The physicochemical properties of AGO@CS composite beads were explored by numerous instrumental techniques viz., FTIR, Raman, XPS, SEM and TGA investigation. The experimental values of AGO@CS composite beads for fluoride removal at various temperature conditions were assessed with adsorption isotherms, kinetic and thermodynamic studies. The possible defluoridation mechanism of AGO@CS beads was mostly proposed that electrostatic attraction. The reusability and field investigation results of AGO@CS beads shows they are regenerable and applicable at field circumstances.

Microscopic Visualization of Porous Nanographenes Synthesized through a Combination of Solution and On-Surface Chemistry.

On-surface synthesis has recently been regarded as a promising approach for the generation of new molecular structures. It has been particularly successful in the synthesis of graphene nanoribbons, nanographenes and intrinsically reactive and instable, yet attractive species. It is based on the combination of solution chemistry aimed at preparation of appropriate molecular precursors for further ultra-high vacuum surface assisted transformations. This approach also owes its success to an incredible development of characterization techniques, such as scanning tunneling/atomic force microscopy and related methods, which allow detailed, local characterization at atomic scale. While the surface-assisted synthesis can provide molecular nanostructures with outstanding precision, down to single atoms, it suffers from basing on metallic surfaces and often limited yield. Therefore, the extension of the approach away from metals and the struggle to increase productivity seem to be significant challenges toward wider applications. Herein, we demonstrate the on-surface synthesis approach for generation of non-planar nanographenes, which are synthesized through a combination of solution chemistry and sequential surface-assisted processes, together with the detailed characterization by scanning probe microscopy methods.

Ti3C2TxMXene/nitrogen-doped reduced graphene oxide composite: a high-performance electrochemical sensing platform for adrenaline detection.

Herein, Ti3C2TxMXene/N-doped reduced graphene oxide (MXene/N-rGO) composite was employed as the electrocatalyst to construct a new electrochemical sensing platform for the determination of adrenaline (AD). The MXene/N-rGO was synthesized via a facile one-step hydrothermal method, where ethylenediamine acted as a reducing agent and N source. The doped N in rGO served as a bridge between MXene and rGO through tight hydrogen bonds. Scanning electron microscopy showed that large numbers of MXenes with accordion-like morphology were distributed on the surface of the N-rGO. The MXene/N-rGO composite displayed a synergetic catalytic effect for oxidizing AD, originating from the unique catalytic activity of N-rGO and the large surface area and satisfactory conductivity of MXene. These characteristics of composite material led to a remarkable effect on signal amplification for the detection of AD, with a wide linear range from 10.0 nM to 90.0µM and a low detection limit of 3.0 nM based on a signal to noise ratio of 3. Moreover, the MXene/N-rGO electrode displayed good stability, repeatability, and reproducibility. Additionally, the proposed sensor was successfully applied for voltammetric sensing of AD in urine with recoveries from 97.75% to 103.0%.

Synthesis of zinc hydroxystannate/reduced graphene oxide composites using chitosan to improve poly(vinyl chloride) performance.

Chitosan-modified zinc hydroxystannate (ZHS-CS) was synthesized using the cations of the biomaterial chitosan (CS) and ion replacement strategy. A ZHS-CS and reduced graphene oxide (rGO) hybrid flame retardant (ZHS-CS/rGO) was synthesized for use in flexible poly (vinyl chloride) (PVC). Scanning electron microscopy images indicated that ZHS-CS and rGO were evenly dispersed in ZHS-CS/rGO without agglomeration. Fourier transform infrared spectroscopy results showed that rGO was fully reduced. The flame-retardant and mechanical properties of PVC composites were investigated using the limiting oxygen index (LOI), a cone calorimeter, and mechanical equipment. By replacing one-fifth of the zinc ions in ZHS by chitosan cations to obtain Sn-4Zn-1CS/rGO, the ZHS-CS/rGO was found to improve PVC composite performance. The total heat release and total smoke release of PVC/Sn-4Zn-1CS/rGO were reduced by 24.2 and 40.0 %, respectively, from those of pure PVC.

SnO2-Doped ZnO/Reduced Graphene Oxide Nanocomposites: Synthesis, Characterization, and Improved Anticancer Activity via Oxidative Stress Pathway.

BACKGROUND: Therapeutic selectivity and drug resistance are critical issues in cancer therapy. Currently, zinc oxide nanoparticles (ZnO NPs) hold considerable promise to tackle this problem due to their tunable physicochemical properties. This work was designed to prepare SnO2-doped ZnO NPs/reduced graphene oxide nanocomposites (SnO2-ZnO/rGO NCs) with enhanced anticancer activity and better biocompatibility than those of pure ZnO NPs. MATERIALS AND METHODS: Pure ZnO NPs, SnO2-doped ZnO (SnO2-ZnO) NPs, and SnO2-ZnO/rGO NCs were prepared via a facile hydrothermal method. Prepared samples were characterized by field emission transmission electron microscopy (FETEM), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), ultraviolet-visible (UV-VIS) spectrometer, and dynamic light scattering (DLS) techniques. Selectivity and anticancer activity of prepared samples were assessed in human breast cancer (MCF-7) and human normal breast epithelial (MCF10A) cells. Possible mechanisms of anticancer activity of prepared samples were explored through oxidative stress pathway. RESULTS: XRD spectra of SnO2-ZnO/rGO NCs confirmed the formation of single-phase of hexagonal wurtzite ZnO. High resolution TEM and SEM mapping showed homogenous distribution of SnO2 and rGO in ZnO NPs with high quality lattice fringes without any distortion. Band gap energy of SnO2-ZnO/rGO NCs was lower compared to SnO2-ZnO NPs and pure ZnO NPs. The SnO2-ZnO/rGO NCs exhibited significantly higher anticancer activity against MCF-7 cancer cells than those of SnO2-ZnO NPs and ZnO NPs. The SnO2-ZnO/rGO NCs induced apoptotic response through the upregulation of caspase-3 gene and depletion of mitochondrial membrane potential. Mechanistic study indicated that SnO2-ZnO/rGO NCs kill cancer cells through oxidative stress pathway. Moreover, biocompatibility of SnO2-ZnO/rGO NCs was also higher against normal breast epithelial (MCF10A cells) in comparison to SnO2-ZnO NPs and ZnO NPs. CONCLUSION: SnO2-ZnO/rGO NCs showed enhanced anticancer activity and better biocompatibility than SnO2-ZnO NPs and pure ZnO NPs. This work suggested a new approach to improve the selectivity and anticancer activity of ZnO NPs. Studies on antitumor activity of SnO2-ZnO/rGO NCs in animal models are further warranted.

In situ reduced graphene-based aerogels embedded with gold nanoparticles for real-time humidity sensing and toxic dyes elimination.

Hybrid aerogels are promising candidates for energy storage, biosensing, and medical applications, but the conventional fabrication methods, being time-consuming and complex, limit their widespread utilization. The critical issues affecting their functionality include the un-controllable particle dispersity, loading of active materials, and the porosity. We report a simple and efficient method to synthesize in situ reduced Au nanoparticles@graphene (Au@graphene) hybrid aerogel using near-infrared radiation (NIR), resulting the uniform loading of well-dispersed Au nanoparticles (Au-NPs) as well as in situ reduction of graphene oxide (GO) with enhanced conductivity. The concentration of iso-propylacrylamide and GO can be adjusted to control the aerogel pore size during the freeze-drying process. Reduction of HAuCl4 and GO to high extent under NIR light was confirmed with advanced characterization techniques. Density functional theory based calculations with generalized gradient-corrected functional (GGA/PW91) in the hybrid aerogel system, and dnd basis sets are used for the confirmation of possible interactions between the GO, Au-NPs, and the polymer. The as-designed highly porous and conductive aerogel shows an excellent humidity response (30-97%) and successfully removes the methylene blue pollutant from the aqueous solution to a high extent (90%). Therefore, Au@graphene hybrid aerogel is potentially an exciting candidate for a wide range of applications in the humidity sensing and biomedical disease detection.

Gas phase formation of carbon cluster (fullerenes and graphenes)/prebiotic sugar complexes.

Among the constituent molecular classes of proteins and nucleic acids, the presence of Ribose and deoxy-Ribose in space remains unclear. Here, we provide experimental evidence of astronomically related sugar derivatives - carbon cluster (fullerenes and graphenes)/prebiotic sugar complexes - and study their formation processes in the gas phase. The results show that, with PAH cations (dicoronylene, DC, C48H20+)/(2-deoxy-d-Ribose, dR, C5H10O4, and dehydrated 2-deoxy-d-Ribose, DedR, C5H8O3) and fullerene cations (C60+)/(dR and DedR) as the initial molecular precursors, two series of graphene-prebiotic sugar cluster cations (graphene/dR and graphene/DedR, e.g., (dR)Cn+ and (DedR)Cn+) and two series of fullerene-prebiotic sugar cluster cations (fullerene/dR and fullerene/DedR, e.g., (dR)(DedR)2Cn+, (DedR)3Cn+, and (dR)2(DedR)Cn+) are formed through an ion-molecule reaction pathway under the influence of a strong radiation field. The structures of the newly formed complexes and the binding energies of these formation reactions are initially theoretically calculated. These laboratory studies attest to the importance of ion-molecule reaction synthesis routes for the chemical complexity in space, demonstrating that the gas phase interstellar materials could directly lead to the formation of large and complex sugar derivatives in a bottom-up growth process. The chemical evolution in space in which single molecules are transformed into complex molecules produces a wide variety of organic compounds (e.g., carbon cluster (fullerenes and graphenes)/prebiotic sugar complexes). For their astrobiological implications, this opens up aromatic based biogenic chemistry that is available to the parent of PAHs or fullerenes in the interstellar environments.

Electrochemiluminescence immunosensor based on the quenching effect of CuO@GO on m-CNNS for cTnI detection.

A sandwich-type electrochemiluminescence (ECL) immunosensor based on the resonance energy transfer (RET) was proposed for ultrasensitive detection of cardiac troponin I (cTnI). The RET behavior could be generated between graphite carbon nitride nanosheets (m-CNNS) as donor and copper oxide@graphene oxide (CuO@GO) as acceptor, achieving the quenching effect of CuO@GO on m-CNNS for cTnI detection. The m-CNNS synthesized by mechanical grinding of the graphite carbon nitride (CN) not only has better dispersion and higher specific surface area, but also has high luminous efficiency and stable chemical properties. Therefore, m-CNNS was used as the matrix material and luminophore. As the acceptor, CuO@GO prepared by in-situ chemical synthesis of CuO NPs onto GO sheets also has a high specific surface area, which could be used as a label of secondary antibody (Ab2). Under optimal conditions, cTnI could be determined within the linear range of 0.1 pg mL-1 to 100 ng mL-1 and had a low detection limit (0.028 pg mL-1, S/N = 3). Meanwhile, the prepared ECL immunosensor possessed great stability, specificity and reproducibility, providing a new method for detecting cTnI and other biomarkers.