Surface-enhanced Raman Scattering (SERS) is a sensitive and nondestructive technique that provides fingerprint structural information of molecules. Designing and constructing sensitive and stable ...SERS substrates is of great significance for the application of the technique. In this study, single-layer carbon-based dots (CDs) are used as capping agents to synthesize gold nanoparticles (AuNPs/CDs) and manganese dioxide nanosheets (MnO2/CDs), which are then hybridized through a simple cocentrifugation method. After the hybridization, the monodispersive AuNPs/CDs aggregate obviously into some clusters exhibiting strong SERS activity due to the electromagnetic “hot spots” effect, and the MnO2/CDs also show outstanding SERS activity due to the charge-transfer resonance effect. The obtained nanohybrids (MnO2/CDs/AuNPs) with robust chemical stability combine well with the electromagnetic enhancement of AuNPs/CDs and chemical enhancement of MnO2/CDs, leading to an ultrahigh enhancement factor of 3.9 × 108. Based on the novel SERS substrate, a sensitive and rapid sensing system for the detection of malachite green is developed, with a low detection limit of 1 × 10–9 M. This work provides a valuable model for designing and fabricating high-performance SERS substrates.
•One-pot synthesis of targeting agent functionalized CNQDs likes FA-CNQDs.•Investigation of in vivo biocompatibility of CNQDs and FA-CNQDs.•The penetration capability of FA-CNQDs in multicellular ...spheroids.•Performance of targeted fluorescence imaging of folate overexpressed cancer cells.
Graphitic carbon nitride quantum dots (CNQDs) have been widely used in bioimaging due to the unique structure and optical properties, but only a few works demonstrate targeted imaging. Herein, we report a universal one-pot strategy for preparation of targeting agent functionalized CNQDs by taking folate (FA) as an example through hot-fluid annealing of triazine tectons and derived FA. The FA-CNQDs with size of 3 ∼ 8 nm exhibit bright fluorescence, favorable colloidal stability, and well cytocompatibility and in vivo biocompatibility. The remarkable performance of FA-CNQDs in targeted imaging is demonstrated by incubation study with folate receptor overexpressed cancer cells and the cell derived multicellular spheroids. This convenient strategy would open a new avenue for synthesis of various functionalized CNQDs.
Electrochemiluminescence (ECL) emission of gold nanoparticles (Au NPs) loaded graphitic carbon nitride nanosheets (Au-CNN nanohybrids) can be modulated by the Au content. On the basis, a signal-on ...ECL sensor for detecting cyanide, a widespread toxic chemical, has been developed in this work. The sensor utilizes cyanide-mediated etching of Au NPs to recover the ECL emission of Au-CNN nanohybrids initially inhibited by Fӧrster resonance energy transfer (FRET) from CNNs to Au NPs. The ECL sensor has a sensitive response to cyanide in the range of 50 nM to 1 mM with a detection limit of 50 nM, and shows high specificity due to the high affinity of Au-cyanide complex. The proposed FRET modulated ECL sensor may prove valuable in future environmental monitoring.
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Almost all current electrochemiluminescent reagents require real-time electrochemical stimulation to emit light. Here, we report a novel electrochemiluminescent reagent, nitrogen-deficient graphitic ...carbon nitride (CN x ), that can emit afterglow electrochemiluminescence (ECL) after cessation of electric excitation. CN x obtained by post-thermal treatment of graphitic carbon nitride (CN) with KSCN has a cyanamide group and a nitrogen vacancy, which created defects to trap electrically injected electrons. The trapped electrons can slowly release and react with coreactants to emit light with longevity. The cathodic afterglow ECL lasts for 70 s after pulsing the CN x nanosheet (CN x NS-1.6)-modified glassy carbon electrode at −1.0 V for 20 s in 2.0 M PBS containing 1 mM K2S2O8. The afterglow ECL mechanism is revealed by investigation of its influencing factors and ECL wavelength. The discovery of afterglow ECL may open a new doorway for new significant applications of the ECL technique and provide a deeper understanding of the structure–property relationships of CN.
Biocompatible and water-dispersible electrochemiluminescence (ECL) phosphors with potential/spectrum-resolved ECL emission are highly desired to underpin ECL-based multiplex detection in a spot-free ...format. In this work, we develop a band structure engineered graphitic carbon nitride, CN425-PDI0.5, to achieve potential-resolved wavelength tunable ECL emission. The covalent incorporation of pyromellitic diimide (PDI) with high electron affinity and mobility endows CN425-PDI0.5 with the coexistence of polymeric melem motifs and melem-PDI motifs. The melem-PDI motifs show lower lowest unoccupied molecular orbital energy level and narrower bandgap, as compared to polymeric melem motifs. By pulsing the CN425-PDI0.5 nanosheets modified glassy carbon electrode at the increasing reduction potential in phosphate buffer solution containing S2O82‒ as coreactant, the cathode ECL gradually tunes the maximum emission wavelength from 540 nm to 440 nm. The CN425-PDI0.5 nanosheets with potential-resolved wavelength tunable ECL emission may provide a promising prospect for promoting solid-state ECL-based multiple detection and extending CN application in the sensing fields.
Background:
Recently, some studies have shown that prolonging flush interval is safe and feasible for patients who complete chemotherapy. However, there is no consensus about the optimal flush ...interval for those patients.
Objective:
The purpose of this review was to evaluate whether the flush interval could be prolonged based on monthly interval for regular maintenance and to explore the optimal flush interval.
Data sources:
We searched the following databases for articles published between 1 January 1982 and 21 February 2020: PubMed, Cochrane Library, Web of Science, EMBASE, CINAHL, and Ovid.
Study eligibility criteria:
Randomized controlled trials, retrospective and prospective cohort studies of flush interval less than 4 weeks versus longer than 4 weeks for patients who completed chemotherapy, were included.
Results:
Two reviewers extracted information and assessed the quality of the articles independently. In total, 389 articles were retrieved, and 4 studies including 862 cases fulfilled the inclusion criteria. There was no statistical heterogeneity (I2 = 0, p > 0.05) among the included studies. Hence, the fixed-effects model was used for the meta-analysis. The meta-analysis showed that the total complication rate associated with longer than 4-week interval was higher than that associated with less than 4-week interval. Nevertheless, there was no significant difference between the two groups (7.2% vs 7.6%, p = 0.83). Moreover, the meta-analysis showed that the total complication and catheter occlusion rates associated with the 4-week interval were higher than those associated with the 8-week interval. However, there was no significant difference between the two groups (total complications: 11.4% vs 9.5%, p = 0.68; catheter occlusions: 4.9% vs 4.1%, p = 0.89).
Limitations:
Only four non-randomized controlled studies were included, and the outcomes of the included studies were reported incompletely.
Conclusion:
Extending the flush interval to longer than 4 weeks is safe and feasible. Based on previous studies, extending the flush interval to 8 weeks might not increase the incidence of total complications and catheter occlusions. However, there is no conclusion on whether the flush interval could be extended to 3 months or longer.
UV–Vis spectroelectrochemistry (SEC) was introduced for the first time into the study of electrochemiluminescence (ECL) mechanisms of nitrogen heterocyclic compounds. Uracil and its two derivatives, ...5-fluorouracil and 1-methyl-uracil, were chosen as model molecules in the ECL mechanism study. SEC revealed that the substitution of hydrogen at N(1) and the destruction of conjugate heterocyclic ring were very important for ECL activities of uracils. On the basis, a new ECL mechanism was proposed for the uracils. The successful explanation of ECL mechanism for the model molecules by employing SEC indicates that SEC would play an important role in future ECL mechanism studies.
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•Molecular engineering of graphitic carbon nitride (g-CN) can modulate its ECL emission.•Incorporation of g-CN with phenyl groups enhance its cathodic ECL intensity and stability due ...to the improved electrical conductivity.•Development of a sensitive cTnI immunosensor based on the strong and stable ECL emission of Ph-CNNS.
Graphitic carbon nitride (g-CN) is a semiconductor polymer with strong electrochemiluminescence (ECL) emission. However, the sensing application of g-CN ECL suffers from poor ECL stability due to its low electrical conductivity. In this work, g-CN is molecularly engineered with phenyl groups to improve its electrical conductivity. The prepared Ph-CN nanosheets (Ph-CNNS) show stable and strong cathodic ECL emission benefiting from the synergetic effect of improved conductivity preventing electron over-injection and higher luminescent efficiency of Ph-CNNS as compared to CNNS. Based on the strong and stable ECL emission of Ph-CNNS, a ECL immunosensor with biocatalytic precipitation reaction-mediated signal amplification is developed for the detection of cardiac Troponin I (cTnI), a biomarker of acute myocardium infarction. The ECL immunosensor shows a linear response to cTnI in the concentration range of 1 pg mL−1 ∼ 10 ng mL−1 with a detection limit of 0.5 pg mL−1, and exhibits good specificity, reproducibility and long-term stability. The ECL immunosensor is further used for the detection of cTnI in human serum sample. The good recovery suggests its feasibility in clinical application. This work provides a facile molecular engineering strategy to modulate g-CN ECL property, and would promote g-CN ECL in sensing application.
This work is to construct an electrochemiluminescent (ECL) sensor with improved accuracy for the detection of Cu2+. The improved accuracy is achieved by utilizing a reaction system to realize Cu2+ ...dose-dependent dual suppression of ECL recovery from gold nanoparticle-graphitic carbon nitride nanosheet naonohybrid (Au-CNNS) film. The ECL sensor shows sensitive response to Cu2+ in the concentration range of 5nM to 500nM with an enlarged slope, and high specificity attributed to the high affinity of CNNS-Cu2+ complex and the high catalytic activity of Cu(NH3)62+ to decompose H2O2 in the reaction system. The proposed ECL sensor with improved accuracy may prove valuable in future biomedical applications.
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•Dual suppression of graphitic carbon nitride nanosheets (g-CNNs)-based ECL is reported for the first time.•An ECL sensor with improved accuracy has been constructed for the detection of Cu2+ by the dual suppression of Au-CNNs ECL•The proposed ECL sensor with improved accuracy may prove valuable in future biomedical applications.
A novel permeability gate-based electrochemiluminescent (ECL) aptasensor has been constructed by utilizing target-responsive polyelectrolyte-aptamer film deposited on the solid-state ECL electrode to ...control the rate of diffusion of a coreactant that triggers the ECL.
