Janus Carbon Nanotube@poly(butylene adipate-co-terephthalate) Fabric for Stable and Efficient Solar-Driven Interfacial Evaporation

Solar-driven seawater desalination is considered a promising method for alleviating the water crisis worldwide. In recent years, significant efforts have been undertaken to optimize heat management and minimize salt blockage during solar-driven seawater desalination. However, it remains challenging to achieve an efficient and stable seawater evaporator simply and practically. Here, we designed and prepared a novel three-dimensional (3D) water channel evaporator (3D WCE) equipped with a Janus CNT@PBAT fabric (JCPF). The as-prepared Janus CNT@PBAT fabric has broad-band light absorption (∼97.8%), excellent superhydrophobicity (∼162°), and photothermal properties. After optimizing the structure of the thermal insulator, our designed evaporator could realize the equilibrium between enhanced thermal management and sufficient water supply. As a result, the as-prepared evaporator achieved an excellent evaporation rate of 1.576 kg·m–2·h–1 and an energy efficiency of over 92.7% under 1 sun irradiation in 3.5 wt % saline water. Moreover, this evaporator also revealed good salt rejection performance compared to the traditional two-dimensional (2D) water channel evaporator (2D WCE) in high saline water, which could maintain stable evaporation rates under long-term evaporation of 8 h. Our study may develop a simple method for the design and fabrication of a low-cost, effective, and stable solar-driven evaporator for seawater desalination

Magnetic Bead-Sensing-Platform-Based Chemiluminescence Resonance Energy Transfer and Its Immunoassay Application

A competitive immunoassay based on chemiluminescence resonance energy transfer (CRET) on the magnetic beads (MBs) is developed for the detection of human immunoglobulin G (IgG). In this protocol, carboxyl-modified MBs were conjugated with horseradish peroxidase (HRP)-labeled goat antihuman IgG (HRP-anti-IgG) and incubated with a limited amount of fluorescein isothiocyanate (FITC)-labeled human IgG to immobilize the antibody–antigen immune complex on the surface of the MBs, which was further incubated with the target analyte (human IgG) for competitive immunoreaction and separated magnetically to remove the supernatant. The chemiluminescence (CL) buffer (containing luminol and H₂O₂) was then added, and the CRET from donor luminol to acceptor FITC in the immunocomplex on the surface of MBs occured immediately. The present protocol was evaluated for the competitive immunoassay of human IgG, and a linear relationship between CL intensity ratio (<i><i>R</i> = I</i>₄₂₅/<i>I</i>₅₂₅) and human IgG concentration in the range of 0.2–4.0 nM was obtained with a correlation coefficient of 0.9965. The regression equation was expressed as <i>R</i> = 1.9871<i>C</i> + 2.4616, and a detection limit of 2.9 × 10^–11 M was obtained. The present method was successfully applied for the detection of IgG in human serum. The results indicate that the present protocol is quite promising for the application of CRET in immunoassays. It could also be developed for detection of other antigen–antibody immune complexes by using the corresponding antigens and respective antibodies

Silver Nanoparticles/N-Doped Carbon-Dots Nanocomposites Derived from <i>Siraitia Grosvenorii</i> and Its Logic Gate and Surface-Enhanced Raman Scattering Characteristics

Silver/carbon dots (CDs) nanocomposites receive significant attention for diverse applications owing to their unique physical and chemical properties. Herein, a green method is proposed for synthesizing silver nanoparticle/N-doped CDs (AgNPs/N-CDs) nanocomposites, wherein the AgNPs are grown on the surface of reduced N-CDs derived from Siraitia grosvenorii. The N-CDs were used as a reducing agent and stabilizer, no additional reducing agent and stabilizer were necessary. The as-synthesized AgNPs/N-CDs nanocomposites were characterized using ultraviolet–visible spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). An AND logic system based on the obtained N-CDs was proposed, which avoids complicated modifications and chemical labeling. The surface-enhanced Raman scattering (SERS) properties of the prepared AgNPs/N-CDs nanocomposites were also investigated, indicating the potential application for SERS detection

Design of a New Near-Infrared Ratiometric Fluorescent Nanoprobe for Real-Time Imaging of Superoxide Anions and Hydroxyl Radicals in Live Cells and in Situ Tracing of the Inflammation Process in Vivo

The superoxide anion (O₂^•–) and hydroxyl radical (^•OH) are important reactive oxygen species (ROS) used as biomarkers in physiological and pathological processes. ROS generation is closely related to the development of a variety of inflammatory diseases. However, the changes of ROS are difficult to ascertain with in situ tracing of the inflammation process by real-time monitoring, owing to the short half-lives of ROS and high tissue autofluorescence in vivo. Here we developed a new near-infrared (NIR) ratiometric fluorescence imaging approach by using a Förster resonance energy transfer (FRET)-based ratiometric fluorescent nanoprobe for real-time monitoring of O₂^•– and ^•OH generation and also by using in situ tracing of the inflammation process in vivo. The proposed nanoprobe was composed of PEG functionalized GQDs as the energy donor connecting to hydroIR783, serving as both the O₂^•–/^•OH recognizing ligand and the energy acceptor. The nanoprobe not only exhibited a fast response to O₂^•– and ^•OH but also presented good biocomapatibility as well as a high photostability and signal-to-noise ratio. We have demonstrated that the proposed NIR ratiometric fluorescent nanoprobe can monitor the changes of O₂^•– and ^•OH in living RAW 264.7 cells via a drug mediating inflammation model and further realized visual monitoring of the change of O₂^•– and ^•OH in mice for in situ tracing of the inflammation process. Our design may provide a new paradigm for long-term and real-time imaging applications for in vivo tracing of the pathological process related to the inflammatory diseases

Green Preparation of S and N Co-Doped Carbon Dots from <i>Water Chestnut</i> and <i>Onion</i> as Well as Their Use as an Off–On Fluorescent Probe for the Quantification and Imaging of Coenzyme A

Fluorescent carbon dots (CDs) originated from natural biomass have been of great interest in recent years because of their superior optical and chemical properties. However, previously reported CDs used only one natural biomass as precursor, and the fluorescence quantum yield (QY) and long-wavelength emissions are usually weak, which restrict their further applications in biology-relevant fields. Here a green method was demonstrated for the preparation of S and N codoped fluorescent CDs (S,N/CDs) by adopting two natural biomasses (<i>water chestnut</i> and <i>onion</i>) as precursors. The fabrication process is simple and environmentally friendly. By hydrothermal heating of <i>water chestnut</i> and <i>onion</i>, monodispersed, highly fluorescent S,N/CDs (diameter 3.5 nm) were obtained. The carboxyl on the surface of S,N/CDs can bind to Cu­(II) ion, resulting in the luminescence quenching of S,N/CDs. And coenzyme A (CoA) can restore the luminescence of S,N/CDs. Based on the above features of S,N/CDs, an innovative off–on fluorescence probe was presented for high sensitivity determination of CoA. Under optimum conditions, the linear range for CoA detection is 0.03–40 μM with a detection limit of 0.01 μM. The developed off–on nanoprobe was applied for the quantification of CoA in pig liver, and imaging of CoA in living T24 cells

Intermolecular and Intramolecular Quencher Based Quantum Dot Nanoprobes for Multiplexed Detection of Endonuclease Activity and Inhibition

DNA cleavage by endonucleases plays an important role in many biological events such as DNA replication, recombination, and repair and is used as a powerful tool in medicinal chemistry. However, conventional methods for assaying endonuclease activity and inhibition by gel electrophoresis and chromatography techniques are time-consuming, laborious, not sensitive, or costly. Herein, we combine the high specificity of DNA cleavage reactions with the benefits of quantum dots (QDs) and ultrahigh quenching abilities of inter- and intramolecular quenchers to develop highly sensitive and specific nanoprobes for multiplexed detection of endonucleases. The nanoprobe was prepared by conjugating two sets of DNA substrates carrying quenchers onto the surface of aminated QDs through direct assembly and DNA hybridization. With this new design, the background fluorescence was significantly suppressed by introducing inter- and intramolecular quenchers. When these nanoprobes are exposed to the targeted endonucleases, specific DNA cleavages occur and pieces of DNA fragments are released from the QD surface along with the quenchers, resulting in fluorescence recovery. The endonuclease activity was quantified by monitoring the change in the fluorescence intensity. The detection was accomplished with a single excitation light. Multiplexed detection was demonstrated by simultaneously assaying <i>Eco</i>RI and <i>Bam</i>HI (as model analytes) using two different emissions of QDs. The limits of detection were 4.0 × 10^–4 U/mL for <i>Eco</i>RI and 8.0 × 10^–4 U/mL for <i>Bam</i>HI, which were at least 100 times more sensitive than traditional gel electrophoresis and chromatography assays. Moreover, the potential application of the proposed method for screening endonuclease inhibitors has also been demonstrated. The assay protocol presented here proved to be simple, sensitive, effective, and easy to carry out

Nitrogen and Phosphorus Co-Doped Carbon Nanodots as a Novel Fluorescent Probe for Highly Sensitive Detection of Fe³⁺ in Human Serum and Living Cells

Chemical doping with heteroatoms can effectively modulate physicochemical and photochemical properties of carbon dots (CDs). However, the development of multi heteroatoms codoped carbon nanodots is still in its early stage. In this work, a facile hydrothermal synthesis strategy was applied to synthesize multi heteroatoms (nitrogen and phosphorus) codoped carbon nanodots (N,P-CDs) using glucose as carbon source, and ammonia, phosphoric acid as dopant, respectively. Compared with CDs, the multi heteroatoms doped CDs resulted in dramatic improvement in the electronic characteristics and surface chemical activities. Therefore, the N,P-CDs prepared as described above exhibited a strong blue emission and a sensitive response to Fe³⁺. The N,P-CDs based fluorescent sensor was then applied to sensitively determine Fe³⁺ with a detection limit of 1.8 nM. Notably, the prepared N,P-CDs possessed negligible cytotoxicity, excellent biocompatibility, and high photostability. It was also applied for label-free detection of Fe³⁺ in complex biological samples and the fluorescence imaging of intracellular Fe³⁺, which indicated its potential applications in clinical diagnosis and other biologically related study

Label-Free Colorimetric Aptasensor Based on Nicking Enzyme Assisted Signal Amplification and DNAzyme Amplification for Highly Sensitive Detection of Protein

Highly sensitive detection of proteins is essential to biomedical research as well as clinical diagnosis. Here, we develped a novel label-free colorimetric aptasensor based on nicking enzyme assisted signal amplification and DNAzyme amplification for highly sensitive detection of protein. The system consists of a hairpin DNA probe carrying an aptamer sequence for target, a G-riched DNA probe containing two G-riched DNAzyme segments and the recognition sequence as well as cleavage site for nicking enzyme, a blocker DNA, and the nicking enzyme. The hybridization of the G-riched DNA with the blocker DNA prohibits the formation of the activated DNAzymes in the absence of target. Upon addition of target to the system, the hairpin probe is opened by the specific recognition of the target to its aptamer. The open hairpin probe hybridizes with a G-riched DNA and forms a DNA duplex, which triggers the selective cleavage of the G-riched DNA probe by nicking enzyme, leading to the release of the aptamer–target complex and the G-riched DNAzyme segments. The released open hairpin probe then hybridizes with another G-riched DNA probe, and the cycle starts anew, resulting in the continuous cleavage of the G-riched DNA probes, generating a much of G-riched DNAzyme segments. The G-riched DNAzyme segments interact with hemin and generates the activated DNAzyme that can catalyze the H₂O₂-mediated oxidation of 2,2′-azino-bis­(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS^2–) to the colored ABTS^•–, thus providing the amplified colorimetric detection of target. With the use of thrombin (Tb) as a proof-of-principle analyte, this sensing platform can detect Tb specifically with a detection limit as low as 1.5 pM, which is at least 4 orders of magnitude lower over the unamplified colorimetric assay. Moreover, the assay does not involve any chemical modification of DNA, which is simple and low-cost. This sensing platform provides a promising approach for the amplified analysis of target molecules

A Macrophage Membrane-Coated Cu–WO_3–<i>x</i>-Hydro820 Nanoreactor for Treatment and Photoacoustic/Fluorescence Dual-Mode Imaging of Inflamed Liver Tissue

A disease-targeting nanoplatform that integrates imaging with therapeutic activity would facilitate early diagnosis, treatment, and therapeutic monitoring. To this end, a macrophage membrane-coated Cu–WO3–x-Hydro820 (CWHM) nanoreactor was prepared. This reactor was shown to target inflammatory tissues. The reactive oxygen species (ROS) such as H2O2 and ·OH in inflammatory tissues can react with Hydro820 in the reactor to form the NIR fluorophore IR820. This process allowed photoacoustic/fluorescence dual-mode imaging of H2O2 and ·OH, and it is expected to permit visual diagnosis of inflammatory diseases. The Cu–WO3–x nanoparticles within the nanoreactor shown catalase and superoxide enzyme mimetic activity, allowing the nanoreactor to catalyze the decomposition of H2O2 and ·O2– in inflammatory cells of hepatic tissues in a mouse model of liver injury, thus alleviating the oxidative stress of damaged liver tissue. This nanoreactor illustrates a new strategy for the diagnosis and treatment of hepatitis and inflammatory liver injury

Direct Analysis of Biofluids by Mass Spectrometry with Microfluidic Voltage-Assisted Liquid Desorption Electrospray Ionization

Signal suppression by sample matrix in direct electrospray ionization–mass spectrometric (ESI-MS) analysis hampers its clinical and biomedical applications. We report herein the development of a microfluidic voltage-assisted liquid desorption electrospray ionization (VAL-DESI) source to overcome this limitation. Liquid DESI is achieved for the first time in a microfluidic format. Direct analysis of urine, serum, and cell lysate samples by using the proposed microfluidic VAL-DESI-MS/MS method to detect chemical compounds of biomedical interest, including nucleosides, monoamines, amino acids, and peptides is demonstrated. Analyzing a set of urine samples spiked with dihydroxyphenylalanine (DOPA) showed that the assay had a linear calibration curve with <i>r</i>² value of 0.997 and a limit of detection of 0.055 μM DOPA. The method was applied to simultaneous quantification of nucleosides, that is, cytidine, adenosine, uridine, thymidine, and guanosine in cell lysates using 8-bromoadenosine as internal standard. Adenosine was found most abundant at 26.5 ± 0.57 nmol/10⁶ cells, while thymidine was least at 3.1 ± 0.31 nmol/10⁶ cells. Interestingly, the ratio of adenosine to deoxyadenosine varied significantly from human red blood cells (1.07 ± 0.06) to cancerous cells, including lymphoblast TK6 (0.52 ± 0.02), skin melanoma C32 (0.82 ± 0.04), and promyelocytic leukemia NB4 cells (0.38 ± 0.06). These results suggest that the VAL-DESI-MS/MS technique has a good potential in direct analysis of biofluids. Further, because of the simplicity in its design and operation, the proposed microfluidic liquid DESI source can be fabricated as a disposable device for point-of-care measurements