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Vehicle platooning is a key application in the realm of smart connected vehicles and autonomous driving technologies, holding significant potential to enhance road utilization and save energy consumption. Simultaneously, within intelligent transportation systems, the limited computing resources of vehicle users themselves fail to meet the computational demands of various new applications. Therefore, addressing the ever-increasing computational demands of vehicles is an urgent problem that needs resolution. Unmanned Aerial Vehicle (UAV) equipped with edge computing servers leverage their advantages of flexible deployment and high maneuverability to promptly alleviate issues such as high latency and narrow bandwidth associated with processing remote data in cloud computing. This paper focuses on the scenario of UAV-assisted vehicle platooning, conducting research on task offloading and resource allocation mechanisms within UAV-assisted vehicle platooning systems. We construct a joint optimization problem for decision-making on task offloading, transmission power allocation, and CPU computing frequency allocation in UAV-assisted vehicle platooning systems. The objective is to minimize system energy consumption while ensuring the stability of the task computation queue. Since the formulated joint optimization problem is a mixed-integer nonlinear programming problem, we decompose it into two sub-problems and simultaneously transform them into Markov decision processes. Subsequently, we proposed a continuous optimization algorithm based on Block Coordinate Descent (BCD) and deep deterministic policy gradient(DDPG). Simulation results validate the effectiveness of this method, demonstrating comparatively low energy consumption under different network environments and parameter settings.

High-frequency link matrix converters (HFLMCs) can transfer dc to ac with only one power conversion stage and without intermediate energy storage components. However, the space vector modulation (SVM) strategies and control methods in conventional HFLMCs produce excessive harmonics in the three-phase output currents and high current stress in the primary side of the isolated high-frequency transformers (HFTs). This article proposes a new optimal vector distribution SVM strategy, which maintains low switching action and reduces output current harmonic. The HFLMC's transmission power and the HFT's current stress with the proposed SVM strategy are analyzed, and a coordinated control method coupled with the modulation index and phase shift angle is determined. The proposed SVM strategy and the coordinated control can realize smaller total harmonic distortion (THD) of three-phase currents and lower HFT's current stress than the conventional SVM strategy. The simulation and experiment results confirm a low THD of 3.71% in the output current and a remarkable decrease of the current stress (2.5 to 3 A) in the HFT.

High-frequency link matrix converter (HFLMC) can directly realize dc/ac conversion without intermediate energy storage components, reduce the power conversion stage, and improve efficiency and power density. With the conventional space vector modulation strategy, the secondary-side voltage of the high-frequency transformer presents an asymmetric trapezoidal wave, which leads to the dc magnetic bias phenomenon and increases the current stress in secondary-side switches. This article proposes a novel space vector modulation strategy for HFLMC. It optimizes the space vector distribution, makes secondary-side voltage periodic and symmetric, and reduces the switching actions. The current stress is reduced, and the converter's efficiency is improved. Simulation and experiment results verify the advantages of the proposed modulation strategy.

Benefiting from our discovery that β-cyclodextrin (β-CD) could enhance the catalytic activity of invertase through hydrogen bonding to improve detection sensitivity, a highly sensitive and convenient biosensor for the detection of miR-21 was proposed, which is based on the simplicity of reading signals from a personal glucose meter (PGM), combined with self-assembled signal amplification probes and the performance of β-CD as an enhancer. In the presence of miR-21, magnetic nanoparticle coupled capture DNA (MNPs-cDNA) could capture it and then connect assist DNA/H1-invertase (aDNA/H1) and self-assembled signal amplification probes (H1/H2) in turn. As a result, a “super sandwich” structure was formed. The invertase on MNPs-cDNA could catalyze the hydrolysis of sucrose to glucose and this catalytic process could be enhanced by β-CD. The PGM signal exhibited a linear correlation with miR-21 concentration within the range of 25 pmol L−1to 3 nmol L−1, and the detection limit was as low as 5 pmol L−1with high specificity. Moreover, the recoveries were 103.82–124.65% and RSD was 2.59–6.43%. Furthermore, the biosensor was validated for the detection of miR-21 in serum, and the results showed that miR-21 levels in serum samples from patients with Diffuse Large B-Cell Lymphoma (DLBCL) (n= 12) were significantly higher than those from healthy controls (n= 12) (P< 0.001). Therefore, the ingenious combination of PGM-based signal reading, self-assembled signal amplification probes and β-CD as an enhancer successfully constructed a convenient, sensitive and specific biosensing method, which is expected to be applied to clinical diagnosis.

This article proposes a novel rotor side brushless controller (RSBC) with bidirectional wireless power transmission (WPT) for a doubly-fed motor (DFM), which can realize the brushless DFM without changing the stator and rotor structures. The WPT-RSBC consists of a grid side converter, a series–series compensated resonant converter, and a rotor side converter. According to the operational characteristics of DFMs, the design requirements of the WPT-RSBC are given in this article. The systematic selection method for four-quadrant operations of the DFM is introduced, and the variable bus voltage control strategy is proposed to improve its transmission efficiency. The mathematical model and small-signal model of each subsystem in the WPT-RSBC are given, and the stability of the primary and secondary dc bus is analyzed. An experimental platform is implemented to verify the feasibility of the WPT-RSBC. For the prototype, the air-gap length is 1 mm, and the RSBC's transmission efficiency can be up to 92%.

This article proposes a novel variable frequency isolated bidirectional CLLC resonant converter with voltage-controlled variable capacitors (VCVCs) and auxiliary clamp circuits (ACCs). By employing the class II ceramic capacitors as VCVCs, the converter's modes in one switching cycle and the transient process to set up the dc voltage bias on VCVCs are analyzed in detail to explain the fundamental principles and lossless characteristics of ACCs in the steady state. Suitable ranges of capacitor voltage stress and current stress and gain characteristics of the converter are also given to design the resonant parameters. The converter's soft-switching characteristics, fast transient process, and high efficiency are well demonstrated by the experimental results obtained on a 500 W prototype. The high-efficiency range of the proposed converter with the VCVCs is 20%–100%, which is at least 10% wider than the others without VCVCs.

A triple-amplified and ratiometric electrochemical aptasensor for CA125 was designed based on hemin–graphene/SH-β-cyclodextrin@PdPt nanoflower (H-Gr/SH-β-CD@PdPtNF) composites and an exonuclease I (Exo I)-assisted strategy. In the nanocomposite, hemin acts as an internal reference signal owing to the reversible heminox/heminredpair. PdPtNFs can significantly improve the electron transfer rate. SH-β-CD can efficiently enrich quercetin probes through host–guest recognition and increase the second indicator signal. In the presence of CA125, due to the specific binding between the aptamer and CA125, the conformational change of dsDNA (designed by the CA125 aptamer and its complementary DNA) results in the release of quercetin embedded in dsDNA. Subsequently, the free quercetin and DNA fragments are enriched on the H-Gr/SH-β-CD@PdPtNF-modified electrode. Thus, an enhanced oxidation peak from quercetin (IQ) and a reduced peak from hemin (Ihemin) can indicate the same biological identification event. In addition, the recycling amplification of CA125 by Exo I can effectively assist the increase of the quercetin signal. The value of IQ/Iheminis linear with the concentration of CA125 in the range from 6.0 × 10–4to 1.0 × 103ng/mL, and the limit of detection is 1.4 × 10–4ng/mL. The recovery of CA125 in human blood serum samples was from 99.2 to 104.4%. The proposed sensor is sensitive and reliable, which provides an avenue for the development of triple amplification and ratiometric signal strategies for detecting tumor markers in clinical diagnostics.

It has generally been believed that the interaction between nitrogen dioxide (NO2) and Au can occur only under ultralow temperature (<200 K) and vacuum conditions. The evolution process of NO2on the Au surface and its products are still seriously controversial. Here, the molecular evolution of NO2on a nanostructured Au surface in the atmosphere is studied by time-dependent in situsurface-enhanced Raman spectroscopy. According to the spectral measurements and density functional theory-based simulations, it has been found that when NO2contacts the Au surface in the air with enough relative humidity (≳20%), chemisorbed NO2species would be produced quickly, and after a short induction period (about 1 min), would evolve into NO[Au(NO3)4], which subsequently decomposes into O2and NO, and/or deliquesce into the adsorbed NO2and −OH as well as HNO3, depending on the temperature and the relative humidity. Further experiments show that the presence of O2and H2O molecules is crucial to such molecular evolution of NO2on the Au surface in the atmosphere. Finally, a H2O and O2-assisted reaction mechanism is proposed and nicely describes the molecular evolution of NO2on the Au surface. This work provides sufficient spectral evidences for the molecular evolution of NO2on the Au surface in the atmosphere, and offers a new insight into the interaction between NO2and the Au surface.

Nowadays, due to the increasing threat of heavy metal ion pollution faced by the environment and living systems, the development of rapid and highly selective methods for the detection of chromium ions (Cr3+) has aroused increasing interest. In this study, copper ferrite nanoparticles (CuFe2O4) immobilized on reduced graphene oxide (CuFe2O4/rGO) were successfully fabricated by a simple co-precipitation method. The catalyst exhibits high peroxidase-like activity with 3,3′,5,5′-tetramethylbenzidine (TMB) as a chromogenic matrix due to its large specific surface area, adsorption performance and abundant catalytic active sites. Based on the excellent peroxidase-like activity of CuFe2O4/rGO and its Cr3+-mediated inhibition controllability, a novel colorimetric assay for the heavy metal Cr3+was created for the first time. Under optimal experimental conditions, CuFe2O4/rGO can be used as a peroxidase-like nanozyme to achieve the excellent detection of Cr3+in the range of 0.1–25 μM, and the detection limit is 35 nM. The peroxidase-like CuFe2O4/rGO can provide a general catalytic platform for the application of biomimetic enzymatic catalytic systems and colorimetry, and a new approach has been established for the specific determination of the heavy metal Cr3+.

During environmental testing, it is an urgent problem for scientists to develop and design a new type of electrochemical sensor electrode with distinguished stability, high activity and cost-effectiveness. In our research, a novel and simple electroanalytical method for the simultaneous determination of acetaminophen (AC) and levofloxacin (LEV) in environmental water was proposed based on an ultrathin graphitic carbon nitride nanosheet-doped graphene oxide (CNNS/GO). The physicochemical properties of as-synthesized nanocomposite materials were characterized in detail by various spectroscopic and analytical techniques. Meanwhile, the electrochemical characterisation of the modified GCE was carried out by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The CNNS/GO electrochemical ultra-sensitive strategy was established for detecting AC and LEV in linear concentration ranges of 5 × 10−7–3.0 × 10−5and 5 × 10−7–1.5 × 10−5mol L−1with low detection limits of 1.7 × 10−8and 7.9 × 10−8mol L−1toward AC and LEV, respectively. The sensor was provided with lower cost, excellent accuracy, satisfactory sensitivity and simple fabrication. The fabricated electrochemical sensor was further successfully expanded to determine AC and LEV in river water samples with recoveries between 95.6% and 111.8% and good correspondence with the HPLC method.

Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), the representative reaction of modern “click chemistry”, has been broadly employed in organic synthesis, bio-labeling, and surface functionalization. Nevertheless, it has limitations such as posing a dilemma of either using high concentrations of Cu(I) catalyst or suffering from slow kinetics. Herein, we demonstrate that a newly selected DNAzyme (CLICK-17; a 79-nucleotide, catalytic DNA single strand) can rapidly catalyze CuAAC to tether redox functionalities onto an electrode surface using low concentrations of either Cu(I) or Cu (II). Particularly, the CLICK-17 DNAzyme, at μM concentrations, facilitated the covalent immobilization of ethynylferrocene (Fc-C≡CH) onto 1-azido-11-undecanethiolate self-assembled monolayers on gold (N3C11S-Au SAMs); as low as 50 μM Cu(I) together with 4 μM DNAzyme was able to complete the coupling reaction within 30 min and the pseudo first-order reaction rate constant is 7 times higher than that using the Cu(I) catalyst alone. It was also remarkable that the CLICK-17 DNAzyme is functional with Cu(II) in the absence of an explicit reductant for the catalyzed surface immobilization of Fc-C≡CH on N3C11S-Au SAMs.

Pd–Pt bimetallic nanocrystals have become appealing in the electrocatalytic field by virtue of their synergy effects derived from the electronic coupling between two metals. Herein, a facile seed-mediated growth approach is reported for synthesis of Pt-on-Pd dendritic nanosheets (DNSs) through the growth of Pt branches on ultrathin Pd nanosheets (NSs). The as-obtained Pt-on-Pd DNSs exhibit superior catalytic activity toward both oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR), with mass activities (MAs) 2.2 times higher for ORR and 3.4 times higher for MOR than commercial Pt/C catalysts. Moreover, these spatially separated Pt branches supported on 2D NSs also endow the Pt-on-Pd DNSs with impressive durability for ORR with only 18.9% loss in MA, whereas the Pt/C catalyst loses 50.0% after 10,000-cycle accelerated durability tests. This 2D DNS architecture can be extended to other 2D metallic NS substrates for constructing Pt-based electrocatalysts with excellent electrocatalytic performance.

We report on the use of visible light to conduct carbene-transfer reactions of donor/acceptor diazoalkanes with cyclooctatetraene and polyunsaturated carbocycles to give the corresponding cyclopropanes in excellent yields with excellent stereoselectivities. This photochemical protocol proved to be superior to conventional metal-catalyzed cyclopropanation reactions and now provides platform chemicals containing a cyclic conjugated all-cis triene. The cyclopropane is an important structural feature to prevent 6π electrocyclization. Instead, the triene moiety can now be selectively functionalized in cycloaddition reactions.

A nitrogen-doped carbon quantum dots (NCDs)-decorated Mg-Al layered double hydroxide (MgAl-LDH)-supported gold nanoparticle (NP) was employed in the aerobic oxidation of benzyl alcohol under solvent-free and base-free conditions. Comprehensive characterizations revealed that the decoration of NCDs improved surface basicity of NCD/MgAl-LDH and was beneficial to the stabilization of gold NPs. Compared with MgAl-LDH-supported gold catalyst, Au/NCD/MgAl-LDH showed much better catalytic activity, along with a turnover frequency of about 20 175 h–1for benzyl alcohol conversion. The promoted catalytic efficiency of the NCD/MgAl-LDH-supported Au catalyst was mainly correlated with unique cooperation between surface hydroxyl arrays at the brucite-like lattice of MgAl-LDH matrix and highly dispersed NCDs, thereby favoring the adsorption and activation of alcohol hydroxyls. Furthermore, compared with Au/MgAl-LDH, Au/NCD/MgAl-LDH showed better structural stability due to the strong Au–NCDs interactions. The primary finding opens a promising approach to develop other highly efficient metal-based catalysts applied in various base-catalyzed heterogeneous reactions.

Cyclopropanation reactions of carbenes with arenes provide a straightforward pathway to norcaradienes or cycloheptatrienes. This reaction normally requires harsh reaction conditions or transition-metal catalysts. In this report, we describe the metal-free visible-light photolysis of aryl diazoacetates in aromatic solvents, which provides access to the norcaradiene ring system in a highly regio- and stereoselective manner. The mild reaction conditions of this approach also allow chemoselective cyclopropanation of substituted arenes without competing C–H functionalization reactions.

Quinoxalin-2(1H)-ones are unique nitrogen-containing organic compounds with wide applications in the agrochemical, pharmaceutical, and chemical industries as well as in material science. During the last decades, visible-light-promoted photoredox catalysis has emerged as a versatile platform for constructing quinoxalin-2(1H)-one scaffolds under exceptionally mild conditions. In this review, we provide an overview of recent advances in photocatalytic direct C(3)–H functionalization of quinoxaline-2(1H)-ones, including the construction of C(3)–C bonds and C(3)–RF/C/O/N/Cl/S/D bonds, as well as the related reaction mechanisms. We aim to enhance the methods for the reaction of quinoxalin-2(1H)-ones at the C–3 position, which have extensive applications in organic synthesis and medicinal chemistry.

Nitrene, as an important and intriguing versatile synthon, is widely utilized for the formation of diverse nitrogenous skeletons under thermal or photochemical conditions. Typically, the N-sulfonyl nitrenes could be smoothly generated from iminoiodinanes at relatively low reaction temperatures to generate N-sulfonyl nitrenes. Herein, we described the direct immidation reaction of iminoiodinanes with sulfoxides through a blue-light-induced nitrenes transfer process. This strategy offers an efficient and gentle pathway for directly obtaining sulfoximines within a reaction time of only 10 minutes. Moreover, the reaction conditions do not necessitate the exclusion of moisture or air, rendering this photocatalytic amination reaction highly practical. A broad range of iminoiodinanes were well tolerated and reacted with sulfoxides smoothly to give the corresponding products in moderate to good yields, which provides a practical and green protocol to access N-sulfonyl architectures.

Two discrete octahedral metallo-supramolecular cages were designed and constructed by using truxene-based pyridine Lwith enPd(NO3)2or enPt(NO3)2, followed by detailed NMR, MS, UV absorption, and fluorescence spectroscopy. Owing to the determined cavity size and excellent optical performance of cages, the resulting supramolecular cages were confirmed to be the light-harvesting system based on Föster resonance energy-transfer (FRET). The developed cages display good water solubilities and can act as nanoreactors and light-harvesting systems to catalyze the difluoromethylation of quinoxalin-2(1H)-ones with sodium difluoromethanesulfinate under the irradiation of sunlight. Compared with eosin Y alone, this system displayed enhanced catalytic activity in catalyzing the difluoromethylation, which realizes the simulation of the photosynthesis process.

Large yellow croaker roe phospholipid (LYCRPLs) is a potential antioxidant. In this study, the inhibition of LYCRPLs on fish oil (FO) oxidation was systematically investigated by evaluating peroxide value, acid value, p-anisidine value, thiobarbituric acid value, and volatile compounds in the accelerated oxidation reaction. The results showed that LYCRPLs presented remarkable antioxidant activity and extended FO shelf-life compared with soybean phospholipids. The analysis of volatile compounds elucidated that LYCRPLs mainly inhibited the formation of aldehyde volatile compounds and thus improved the oxidative stability of FO. Moreover, LYCRPLs could effectively improve the thermal stability of FO. This research provides new insights into LYCRPLs as a promising natural antioxidant in the food industry.

We demonstrate herein that hemin–graphene hybrid nanosheets (H–GNs) can differentiate hemin-binding DNA aptamers (i.e., guanine-rich DNA sequences that form G-quadruplex structures upon binding hemin) and nonspecific single-stranded oligonucleotides colorimetrically. By exploiting the tendency of the H–GNS to aggregate under high ionic strength and their inherent catalytic activities, excess H–GNS were removed and the amount of H–GNs remaining in the supernatant was quantified. Subsequently, the binding affinity of hemin-binding DNA aptamers to the H–GNS was determined upon titration with the DNA. With the conformity of the experimental data to the Langmuir adsorption isotherm, hemin is hypothesized to be sandwiched between the G-quadruplex DNA and graphene forming a ternary complex as a result of the specific binding of the aptamer with the H–GNS. The binding affinity of the aptamer is not as strong as that of hemin/G-quadruplex in solution, which is attributed to electronic effects imparted by the graphene surface. The catalytic activity of the resulting complex, however, was confirmed to be higher than that of H–GNs alone.

In this article, we demonstrated a facile electrochemical aptasensing platform based on a polydopamine@graphene (PDA@Gr) composite using thrombin as a model. In the sensing process, PDA@Gr was obtained by depositing PDA on the surface of graphene nanosheets viaself-polymerization under alkaline conditions. The composite was used as a matrix for immobilizing the aptamer due to the powerful adhesion properties of PDA to immobilize biomolecules. It also played a critical role in signal amplification. Upon binding of thrombin to the surface of the electrode due to the affinity between thrombin and its aptamer, the electron transfer rate was greatly reduced, resulting in the electrochemical signal decrease of [Fe(CN)6]3−/4−. The peak current changes increased with the increase of thrombin concentration. Based on this, a facile strategy for selective and sensitive detection of thrombin was developed. Under the optimal conditions, a dynamic response range from 1.0 × 10−16to 1.0 × 10−13mol L−1with a detection limit of 1.0 × 10−16mol L−1(S/N = 3) was obtained. Also, the method can detect thrombin in diluted human blood serum with satisfactory results. More importantly, the strategy of this assay can be easily extended to immobilize other aptamers for detecting a wide range of targets in accordance with the demand.

Delayed graft function (DGF) is a major adverse complication of deceased donor kidney transplantation. Intravenous fluids are routinely given to patients receiving a transplant to maintain intravascular volume and optimise graft function. Saline (0·9% sodium chloride) is widely used but might increase the risk of DGF due to its high chloride content. We aimed to test our hypothesis that using a balanced low-chloride crystalloid solution (Plasma-Lyte 148) instead of saline would reduce the incidence of DGF.

Significantly increasing the photothermal conversion of plasmonic nanostructured particles (PNPs) is a common goal for all applications of thermoplasmonics, but it is still in challenge, especially for PNPs with the morphology and composition required for a specific photothermal application. Here, we present a concept of defect-induced damping-enhanced photothermal conversion, which favors PNP intrinsic properties. A model of a defect-damped harmonic oscillator is established to depict photothermal conversion correlation with the structure of PNPs and is capable of accurately reproducing the optical performance of the PNPs with the local surface plasmon resonance far from the interband transition. The theoretical model analyses demonstrate that the defect-induced damping can significantly suppress the light scattering of the PNPs and effectively improve their photothermal conversion efficiency. Especially for the PNPs with a sufficiently large size (larger than ∼100 nm for Au and Ag), we show that defect-induced damping can significantly enhance their light absorption and photothermal performances. These are experimentally confirmed. Typically, defect-enriched Au nanostars with ∼100–150 nm profile size were fabricated and showed much higher photothermal performance and a big increment by 23% in photothermal conversion efficiency, compared with the normal (or defect-impoverished) counterpart. Furthermore, the in vitroand in vivobiological experiments demonstrate that this defect-enriched PNP can indeed exhibit significantly higher photothermal performance than the normal counterpart in cells and mouse tumors, which confirms the validity of the presented strategy in typical practical applications. This work provides a strategy to intrinsically and significantly enhance plasmonic photothermal conversion of PNPs with a sufficiently large size, which is not only suitable for PNPs with the morphology and composition required for specific applications but also can be combined with existing strategies to further increase their photothermal performance.

Bisphenol A (BPA) is an important and widely used industrial chemical that is harmful to both the environment and human health. Graphene/platinum nanoparticles (Gr/PtNPs) functionalized with heptakis-(2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CD) were successfully synthesized using a simple wet chemistry strategy. The new nanocomposite had both the excellent properties of the Gr/PtNPs (large surface area, high conductivity and excellent electrocatalytic activity) and the cyclodextrin (host–guest supramolecular recognition and enrichment capability). It had a remarkable synergistic effect on the electrochemical reaction of BPA and a highly sensitive electrochemical sensor was developed to detect BPA. The oxidation peak current of BPA was greatly enhanced at the TM-β-CD-Gr/PtNPs modified glassy carbon electrode (GCE) compared with the Gr/PtNPs/GCE and the TM-β-CD-Gr/GCE. Under the optimum condition, the peak current for BPA increased linearly with concentration in the range 5.0 × 10−8to 8.0 × 10−5mol L−1. The detection limit was 1.5 × 10−8mol L−1(S/N = 3). This sensor is cost-effective and convenient and shows great potential for the detection of trace amounts of phenol compounds in environmental pollutants.

In this work, an electrochemical sensor based on a cyclodextrin‐graphene hybrid nanosheets modified glassy carbon electrode (CD‐GNs/GCE) was proposed for the ultrasensitive determination of doxorubicin and methotrexate. The peak currents of doxorubicin and methotrexate on the CD‐GNs/GCE increased 26.5 and 23.7 fold, respectively, compared to the results obtained on the bare GCE. Under optimized conditions, the linear response ranges for doxorubicin and methotrexate are 10 nM–0.2 µM and 0.1 µM–1.0 µM, with detection limits of 0.1 nM and 20 nM, respectively. The sensor showed the advantages of simple preparation, low cost, high sensitivity, good stability and reproducibility. These properties make the prepared sensor a promising tool for the determination of trace amounts of doxorubicin and methotrexate in biological, clinical and pharmaceutical fields.

This paper demonstrated for the first time a simple wet-chemical strategy for synthesizing hemin−graphene hybrid nanosheets (H-GNs) through the π−πinteractions. Significantly, this new material possesses the advantages of both hemin and graphene and exhibits three interesting properties. First, H-GNs have intrinsic peroxidase-like activity, which can catalyze the reaction of peroxidase substrate, due to the existence of hemin on the graphene surface. Second, their dispersion follow the 2D Schulze−Hardy rule, that is to say, the coagulation of H-GNs in electrolyte solution results from the interplay between van der Waals attraction and electric double-layer repulsion. Third, H-GNs exhibit the ability to differentiate ss- and ds-DNA in optimum electrolyte concentration, owing to the different affinities of ss- and ds-DNA to the H-GNs. On the basis of these unique properties of the as-prepared H-GNs, we have developed a label-free colorimetric detection system for single-nucleotide polymorphisms (SNPs) in disease-associated DNA. To our knowledge, this is the first report concerning on SNPs detection using functionalized graphene nanosheets. Owing to its easy operation and high specificity, it was expected that the proposed procedure might hold great promise in the pathogenic diagnosis and genetic diseases.

Cyclodextrins (CDs) are oligosaccharides composed of six, seven, or eight glucose units (α-, β-, or γ-CD, respectively), which are toroidal in shape with a hydrophobic inner cavity and a hydrophilic exterior. These interesting characteristics can enable them to bind selectively various organic, inorganic and biological guest molecules into their cavities to form stable host−guest inclusion complexes or nanostructured supramolecular assemblies in their hydrophobic cavity. On the other hand graphene nanosheet (GN), a rising-star material, holds great promise for potential applications in many technological fields due to its high surface areas, low cost, and high conductivity. If GNs are modified with CDs, it is possible to obtain new materials simultaneously possessing unique properties of GNs and cyclodextrins through combining their individual obvious advantages. In this article, we demonstrate for the first time a simple wet-chemical strategy for the preparation of CD−graphene organic−inorganic hybrid nanosheets (CD−GNs), which exhibited high solubility and stability in polar solvent. The obtained CD−GNs were characterized by UV−vis spectroscopy, static contact angle measurement, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, atomic force microscopy, transmission electron microscopy, and electrochemical impedance spectroscopy, which confirmed that CD had been effectively functionalized on the surface of GNs. Furthermore, the formation mechanism of CD−GNs was also discussed. Interestingly, GNs here could load a number of CD molecules, which was very important for greatly enhancing the supramolecular function of CDs. Electrochemical results obviously reveal that CD−graphene organic−inorganic hybrid nanosheets could exhibit very high supramolecular recognition and enrichment capability and show much higher electrochemical response toward eight probe molecules (biomolecules and drugs) than unmodified GNs and carbon nanotubes, which is probably caused by the synergetic effects from GNs (high conductivity and high surface area) and CD molecules (host−guest recognition and enrichment).