Search

Discrimination of glycoproteins and cell types is a significant but difficult issue. Herein, we presented a novel fluorescence sensor array for the detection and identification of glycoproteins and cancer cells based on the specific affinity between boronic acid-containing carbon dots (BA-CDs) and cis-diol residues of polysaccharides. The differential binding affinity of three BA-CDs to various glycoproteins resulted in a different fluorescence turn-on signal pattern caused by aggregation-enhanced emission (AEE), along with negligible response from other proteins. Therefore, BA-CDs encompassing sensing elements and signal indicator into one can enable a fast and accurate discrimination of glycoproteins with simple and easy operation. Seven glycoproteins could be well discriminated at a very low concentration of 10 nmol/L. The discriminating capability of glycoproteins is not sacrificed in both human urine and serum. Notably, different glycoprotein compositions of cancer cells provide more recognizable features for identification of cancer cells, comparing to the total protein. Five cell types could be identified in 15 min at a low concentration of 1000 cells/mL. This method is fast, accurate, and easy operation, and has a potential application in cancer diagnosis.

Chromium plays an irreplaceable role in the life system. The exploration of chromium is beneficial to reveal its physiological or pathological processes. In this study, a novel method was established for determination of chromium in gels by matrix-matched external standard method-laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The relative standard deviation of chromium signal intensity during ablation standard were less than 16% (n = 300), the correlation coefficient (R2) of LA-ICP-MS quantitative calibration curve was 0.9805, and the detection limit was 2.22 µg/g. The MCF-7 cells were used as an in vitro cell model, and two kinds of polyacrylamide gel electrophoresis (PAGE) method were used to separate the protein extract after chromium incubation. And then, the electrophoresis bands obtained by two electrophoresis methods were ablated respectively by LA-ICP-MS with line scan mode, and the weak chromium-containing protein bands were obtained in electrophoresis band. Finally, the LA-ICP-MS was used to measure and image the chromium in individual cell, and it was found that the cell element distribution map overlapped well with the cell contour map under the laser microscope.

The influence of various water soluble cations (K+, Na+, Ca2+, Mg2+) on the hydration of calcined flue gas desulphurization gypsum was investigated. The results show that all cations but Ca2+ can accelerate the hydration of bassanite. The final crystal size is not largely influenced by different salts, except for Na+, where the giant crystal with length of >130 µm is observed. Current study clarifies the influence of different ions on the hydration of bassanite, which could provide sufficient guide for the pre-treatment of original flue gas desulphurization gypsum before actual application.

Spaser nanoparticles, with ultranarrow spectral line width, small size and good biocompatibility, offer a bright prospect as potential biological probes. Sadly, over ten years since the first demon...

Flow injection chromatography (FIC) or sequential injection chromatography (SIC) is a low-pressure liquid chromatography technique that uses flow injection or sequential injection hardware. Due to the constraints of this hardware, the separation resolution is low; often no more than 3–5 components are resolved. We have recently demonstrated the excellent resolving power of narrow open tubular (OT) columns for various biomolecules, and only moderate elution pressures are needed to carry out these separations. In this paper, we incorporate a narrow OT column with FIC and construct an FIC system using a pressure chamber and two injection valves to implement gradient elution. The resultant system not only improves the resolution but also reduces the system cost. When we use the system to separate peptides from trypsin-digested cytochrome C, we can resolve dozens of peptides (with resolutions of 0.5 or greater) at a speed of 12 samples per hour. When we use this system to separate a mixture containing 3 amino acids, we can base-line resolve these compounds at a speed of 1800 sample per hour.

Phosphate (Pi) plays important roles in various physiological processes. Its quantification in biological fluids is highly crucial for timely warning of Pi accumulation. Herein, an europium (Eu)-based coordination polymer nanoprobe (Eu/DPA/Ade) is prepared by coordinating 2,6-pyridinedicarboxylic acid (2,6-DPA) and adenine (Ade) with Eu3+. Eu/DPA/Ade exhibits light-up fluorescence response to Pi. The strong coordinating interaction between Eu3+ and O atoms in the Pi group not only shortens the Eu3+-ligand distance to improve the energy transfer from 2,6-DPA to Eu3+ but also attenuates the fluorescence quenching from water molecules in the coordinating sphere of Eu3+. Eu/DPA/Ade produces red emission at λem 618 nm via the "antenna effect". The coligand Ade further promotes the fluorescent emission. The selective recognition of Pi within 10-60 μM is achieved with a detection limit of 4.65 μM. In addition, a certain level of Pi (100-170 μM) causes an exponential increment on the fluorescence of Eu/DPA/Ade and makes it feasible for visual estimation of Pi under irradiation by an ultraviolet lamp at 254 nm. The quantitative detection and visual estimation of Pi in human urine and saliva have been demonstrated.

It is still a high challenge to develop a simple, sensitive and portable approach for bioassay in strong scattering medium. Herein, a photoacoustic (PA) device is developed for the detection of alkaline phosphatase (ALP) in serum with silver nanoparticles (AgNPs) as signal probe, without any requirements for expensive equipment, professional operation and pre-processing of real samples. ALP as an important disease marker could catalyze the breakdown of sodium L-ascorbyl-2-phosphate (AAP) into ascorbic acid (AA), thereby reducing Ag+ to AgNPs. AgNPs could generate strong PA signal under the irradiation of modulated 638-nm laser due to their localized plasmon resonance, and detected by the self-made portable PA device. Under the optimized experimental conditions, the present PA device exhibits excellent photostability and reproducibility with the relative standard deviation (RSD) of 2.2% at the concentration of 25 U L−1 ALP. Linear calibration graph is obtained within 5–70 U L−1 for ALP, along with a detection limit of 1.1 U L−1. This portable PA device is applied to detect ALP in serum samples, providing satisfactory spiking recoveries and competitive analytical performances with the current techniques. The PA-based analytical strategy obviously opens up a new avenue to the detection of disease-correlated biomarker in practice.

Most hydrodynamic problems in ship and ocean engineering are complex and highly coupled. Under the trend of intelligent and digital design for ships and ocean engineering structures, comprehensive performance evaluation and optimization are of vital importance during design. In this process, various coupling effects need to be accurately predicted. With the significant progress of computational fluid dynamics (CFD), many advanced numerical models were proposed to simulate the complex coupling hydrodynamic problems in ship and ocean engineering field. In this paper, five key coupling hydrodynamic problems are introduced, which are hull-propeller-rudder coupling, wave-floating structure coupling, aerodynamic-hydrodynamic coupling, fluid structure coupling and fluid-noise coupling, respectively. The paper focuses on the numerical simulation techniques corresponding to each coupling problem, including the theories and the applications. Future directions and conclusions are provided finally.

Al–Si alloy was modified with Al–3P master alloy at 740 °C. The effects of Si content (7, 8, 9, 10 and 11 wt.%) and adding amount of alterant Al–3P (0, 0.1, 0.3, 0.6, 1.0 and 1.5 wt.%) on microstructures and tensile properties of the alloy were investigated with optical microscope (OP), Image Pro Plus 6.0, scanning electron microscope (SEM) and universal testing machine. When the content of Al–3P is 0.6 wt.%, the area fraction of primary α(Al) in the Al–Si alloy increases more compared to the unmodified alloy with an increase in Si content, which could be explained by the movement of non-equilibrium eutectic point. When the Si content is constant (Al–10Si), with the increase of Al–3P content, the increased rate in area fraction of primary α(Al) phase in the Al–10Si alloy increases first and then decreases. And when 0.6 wt.% Al–3P is added, the increase in area fraction of primary α(Al) phase is the largest. Compared to the unmodified Al–10Si alloy, the tensile strength and elongation of Al–10Si alloy increase by 2.3% and 47.0%, respectively, after being modified with 0.6 wt.% Al–3P alloy. The fracture mode of the modified Al–10Si alloy is ductile fracture.

A novel hybrid drug nanocarrier is developed with CuCo2S4 nanoparticles as the core to be encapsulated by poly(ionic liquid) (PIL), that is, poly(tetrabutylphosphonium styrenesulfonate) (P[P4,4,4,4][SS]), as the shell. Doxorubicin (DOX) is loaded onto the PIL shell via electrostatic attraction involving amine in DOX and styrenesulfonate in PIL. pH- and thermal-responsive characteristics of P[P4,4,4,4][SS] endow the multifunctional hybrid nanocarrier system DOX-CuCo2S4@PIL with sensitive dual-stimuli-triggered drug release behaviors. The CuCo2S4 core converts near-infrared (NIR) irradiation into thermal energy to trigger the shrinkage of the PIL shell, which subsequently promotes drug release, and the pH-responsive release of DOX involves pH-sensitive electrostatic interaction of the PIL shell with DOX. A favorable controlled release of 90.5% is achieved under pH/thermo dual stimuli. In vitro experiments with MCF-7 cells well demonstrated that the drug release is controlled by the acidic intracellular environment with NIR irradiation. The CuCo2S4 core also serves as a photoacoustic (PA) imaging contrast agent, as demonstrated by in vivo treatment of the MCF-7-carrying mice.

Regulating the fluorescence of carbon dots (CDs) is important but highly challenging. Here, carbon dots with tunable dual emissions were facilely fabricated via modulating the polymerization and carbonization processes of o-phenylenediamine (OPD) with lysine (Lys) as the co-precursor and modulator, respectively. The self-polymerization/carbonization of the OPD molecules contributed to the blue/green emission of the OPD-derived CDs. The introduction of Lys in the CD fabrication process efficiently suppressed the carbonization of the OPD polymer chains and enhanced the self-polymerization of the OPD molecules. Meanwhile, the formed OPD-Lys co-polymer chains endowed the final CD product with a new green emission center. The dual-emissive CDs were distinctly sensitive to polarity fluctuations, providing a ratiometric fluorescence response towards solution polarity. Due to their specific distribution in the endoplasmic reticulum (ER), the as-prepared dual-emissive CDs successfully distinguished the polarity variations in ER under stress, which offers a new approach for the early diagnosis of cell injury.

Mercury speciation is of significant importance in environmental and biological analysis because its toxicity and metabolic behavior in the human body differ among species. Nanomaterial-assisted optical sensors are widely used for mercury ion detection but rarely applied in mercury speciation analysis. In this work, we develop a novel colorimetric sensing strategy for mercury speciation based on mercury-stimulated peroxidase mimetic activity of gold nanoparticles with the assistance of different reductants. In the presence of a weak reductant, only inorganic mercury can be reduced to Hg0, whereas both inorganic mercury and organic mercury can be reduced to Hg0 in the presence of a strong reductant. Due to the high affinity between Hg and Au, Hg0 deposits on the AuNP surface in the form of a Au-Hg amalgam, leading to a remarkable enhancement of peroxidase mimetic activity of gold nanoparticles. On the basis of this effect, inorganic mercury and total mercury can be detected by using 3,3',5,5'-tetramethylbenzidine (TMB) as the substrate. The limits of detection for inorganic mercury and total mercury are 1.9 and 0.9 nM within 5-100 nM, respectively. The selectivity of this sensing system is high due to the specificity of Au-Hg interaction. Its practical applications are further demonstrated by organic mercury analysis in a fish sample and mercury speciation in a human hair sample.

Carbon dots (CDs) were prepared by a solvent-involved molecular fusion strategy using o-phenylenediamine (OPD) as the carbon source and formamide as the reaction solvent. The CDs possessed not only the functional groups inherited from the carbon source and the reaction solvent, but also numerous C=N groups in the structure, resulting from the Schiff base reaction between -NH2 of OPD and C=O of formamide. These functional groups endowed the final CDs with a favorable soft-base property, leading to the high tolerance level toward hard-acid type metal ions and prominent detection selectivity toward Ag+. Moreover, the obtained CDs displayed outstanding biocompatibility and low cytotoxicity, and demonstrated potential as an effective photoluminescence probe for intercellular Ag+ and Cys imaging, preventing the interference of autofluorescence from living tissues. This study focused on the solvent-involved molecular fusion strategy could provide new insights into the design of novel carbon-based nanostructures and optimization of the structure-property relationship of CDs.

The solidification microstructure, fracture morphologies, and mechanical properties of an Al-18Si alloy and alloys modified with Al-5Ti and Al-3P master alloys were investigated using an optical microscope, scanning electron microscope, and an electronic universal testing machine. The results show that additions of Al-5Ti and Al-3P have significant effects on the size and area fraction of the primary Si and the mechanical properties of the Al-18Si alloy. Compared to the Al-18Si alloy modified with 0.6 wt% Al-5Ti at 850 °C, when the Al-18Si alloy was modified with 0.3 wt% Al-5Ti and 0.5 wt% Al-3P at the same temperature, the average size of the primary Si decreased from 39 to 14 μm and the area fraction increased from 9.5% to 11.6%. The biggest influencing factor on the tensile strength and elongation of the Al-18Si alloy is the addition of Al-3P, followed by the modification temperature and the addition of Al-5Ti. At a modification temperature of 850 °C, the tensile strength and elongation of the Al-18Si alloy modified with 0.3 wt% Al-5Ti+0.5 wt% Al-3P increased by 19.6% and 88.6%, respectively compared to that of the Al-18Si alloy modified with 0.6 wt% Al-5Ti.

A novel dimercaptosuccinic acid-functionalized mesoporous alumina (DMSA–MA) is synthesized by the dicarboxylic acid groups of dimercaptosuccinic acid molecules coordinating to the Al3+ ions located...

It is of great importance to elucidate the fate of drugs, e.g., their cellular uptake, transport and metabolism/excretion at single cell level. In the present work, cellular uptake and excretion of curcumin in HepG2 and MCF-7 cells were investigated by measuring 59Co in a curcumin cobalt complex ([Co(tpa)(cur)](ClO4)2) with inductively coupled plasma mass spectrometry (ICPMS). The uptake and distribution pattern of the metal drug complex in single cells were thoroughly studied, demonstrating extremely large discrepancy of uptake behavior among individual cells. The complex concentration-dependent uptake and excretion behavior is observed for both HepG2 and MCF-7 cells. The uptake of ([Co(tpa)(cur)](ClO4)2) by HepG2 cells is firstly increased with the concentration of the complex followed by level-off at certain level. On the other hand, however, the uptake by MCF-7 cells increases exponentially with the complex concentration within a same concentration range. The present study provides important information on the transport process of the metal drug complex at single cell level, it may be promising for further applications in the elucidation of metal drug effectiveness in vivo.

Long-term and multipoint monitoring is very important to evaluate the safety of water environment. Atomic fluorescence spectrometer (AFS) is generally used for analyzing metals or metalloids in water quality monitoring. In the present work, for the first time, AFS is employed for sensitive monitoring of nitrogen nutrients, i.e., NO2−, NO3− and NH4+, with nitric oxide (NO) vapor generation. By taking advantage of the different vapor generation conditions for NO2−, NO3− and NH4+, a unit integrating with sampling, heating, cooling, gas-liquid separation and moisture removal is employed for controlling the vapor generation process, by reacting with either iodide or titanium (III). An antimony hollow cathode lamp is used for the excitation of NO to produce fluorescence emission at 193–320 nm. Linear calibration graphs are obtained within 0.02–2, 0.1–20, 0.2–1 mg L−1 for NO2−, NO3− and NH4+, along with detection limits of 0.006, 0.03, 0.06 mg L−1, respectively. The new analytical strategy obviously broadens the application of AFS, and it is well demonstrated by the determination of NO2−, NO3− and NH4+ in certified reference materials as well as various real water samples, providing competitive sensitivity with the current techniques for nutrient monitoring in environmental water.

Highly sensitive metal ion discrimination and detection are of great value in environmental monitoring. However, it is still a challenge to obtain multidimensional information from a single material by applying various transduction principles to realize high-order sensing. Herein, a kind of yellow luminescent sub-10 nm carbon-based nanoparticles (CNPs) was prepared by chemically oxidative polymerization. The synthesis process involves only mixing the o-phenylenediamine (o-PD) and ammonium persulphate (APS) aqueous solutions together and allowing to stand at room temperature for 24 h without any external heating or additional energy input. Due to the rich aromatic diamine groups, these room-temperature carbon-based nanoparticles (RT-CNPs) can chelate various metal ions, leading to the changes in absorption and fluorescence as well as further change of fluorescence with the addition of 3,3′,5,5′-tetramethylbenzidine (TMB). Base on this phenomenon, a lab-on-RT-CNPs sensing platform for discrimination of metal ions has been developed. In both the triple-channel and double-channel modes, eight metal ions, including Cr3+, Cu2+, Fe3+, Hg2+, Cd2+, Pb2+, Co2+, and Ni2+, can be discriminated at a low concentration of 0.5 μM. In addition, the sensing platform was also validated by 100% accurate identification of 48 unknown samples and spiked Lake waters.

Metal nanoclusters (NCs) have been in focus received attention due to their superior optical properties, whereas their biomedical applications are limited by the relatively low quantum yield and poor cellular uptaking behaviors. In the present study, a pomegranate-type architecture with densely packed AuAg NCs is constructed, where the aminoterminated dendritic silica spheres (dNSiO

This paper presents finite element model (FEM) based virtual load rating method for accurately and efficiently evaluating the bearing capacity of taxiway bridge in the field under aircraft taxiing. A dynamic load coefficient of aircraft loading was first developed considering deck pavement roughness and aircraft lift force. The in situ responses of taxiway bridges under 10 aircraft were collected using instrumentation system with acceleration sensor, strain sensor, and inclinometer. The modal frequency, strain influence lines, and deflections of taxiway bridge were obtained from FE analysis and in situ test. An optimization objective function in terms of fundamental frequency and strain influence lines was formulated to ensure convergence and effectiveness in the model updating process, wherein the bending stiffness, density and boundary conditions of the structures are selected as the design variables. The weighted-average method of model updating parameters was proposed considering the differences in the obtained parameters under different loading conditions. The analysis results of updated FE model were validated using static loading test conducted on taxiway bridge. Finally, the proposed virtual load rating method was applied to Taxiway Bridge V in Guangzhou Baiyun International Airport (CAN).

Responses of a substructure adjacent to deep excavations are complex, especially when the substructure is connected to the supporting systems of the excavations. In this study, a three-dimensional (3D) numerical model is developed by finite difference (FD) software, FLAC3D v5.0, to examine the responses of a metro line to deep excavations through a case history in Shanghai, China. The developed numerical model includes four deep excavations, which were located at two sides of the metro line and were connected to the structures of the metro station. These deep excavations were constructed in stages and the construction processes are simulated in accordance with the practical execution. Responses of the rails to the deep excavations are illustrated and the numerical results are compared to the measured data to validate the developed numerical model and input parameters. Moreover, 3D structural responses of the metro station and shield tunnels to the deep excavations are presented and analyzed. Numerical results indicate that (i) the walls of the station move upward during the excavations and the slabs are uplifted by the walls; (ii) The station heaves significantly whereas the shield tunnels settle slightly. (iii) The station will be distorted if the unloading is asymmetric.

In general, copper nanoclusters (CuNCs) possess very low or even virtually no bactericidal effect. Herein, we report a novel CuNCs possessing significantly high antibacterial activity, that is tannic acid (TA) capped CuNCs (TA-CuNCs). TA-CuNCs exhibit strong absorption and excitation-dependent fluorescence within pH 2–12, resulting from the functional groups of TA-CuNCs due to two prototropic equilibria, phenol ↔ phenolate and carboxylic ↔ carboxylate. There exists synergistic effect of TA and copper nanoclusters which endows TA-CuNCs remarkable antibacterial capability as a microbicide, as characterized by the effective inhibition on the growth of gram-positive bacteria by damaging the cell membrane. By incubating 1 × 107 CFU/mL of gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with 30 μg/mL of TA-CuNCs for 10 min, the bacteria are completely inhibited, while under same conditions the viabilities of gram-negative bacteria Escherichia coli O157:H7 and Pseudomonas aeruginosa remain 85.0%, 72.0%, respectively. In addition, TA-CuNCs exhibit low cytotoxicity and favorable biocompatibility demonstrated by standard methyl thiazolyl tetrazolium (MTT) assay with HepG2 and 293 T cells, giving rise to cell viability of 94.2% for HepG2 and 96.7% for 293 T by incubating 106 cell/mL with 200 μg/mL of TA-CuNCs for 24 h. These results make TA-CuNCs a potential alternative as bactericide for infection treatment caused by gram-positive bacteria.

Nitrogen and sulfur co-doped graphene oxide nanosheets (N,S-GO) were prepared via a facile one-step solvent-free approach using citric acid as a precursor and cysteine as a dopant. First, the graphene nucleus was formed via intermolecular dehydration of citric acid; N and S were then incorporated into the graphene structure by attacking the margin of the graphene nucleus. Crosslinking among the graphene nucleus via intermolecular condensation led to the final N,S-GO. The latter exhibited favorable photoluminescence behaviors, such as a high fluorescent quantum yield of 56.0%, excellent photoluminescence stability within the pH range 5–12, and high tolerance to external ionic strength ≤1.0 mol L−1 NaCl. The fluorescence energy transfer between AgNPs and N,S-GO could induce efficient quenching of N,S-GO fluorescence, and the presence of biothiols in the system restored fluorescence effectively, so a fluorescence “off–on” procedure was developed for quantitative detection of biothiols. Under optimal conditions, the limit of detection for cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) was 11.8, 4.9, and 7.3 nmol L−1, respectively. This sensing platform exhibited good selectivity toward biothiols in the presence of other amino acids. The practicability of this sensing platform was well demonstrated by determining biothiol content in human plasma samples, which revealed spiking recoveries of 97.10–101.50% with Cys.

Over the past few years, artificial enzymes have attracted enormous attention due to their high stabilities and cost-effective productions. In this work, metal-organic framework-derived SiW12@Co3O4 was synthesized in large quantities by stirring the mixture at ambient temperature and calcination. The obtained SiW12@Co3O4 exhibited a highly inherent peroxidase-like activity and excellent stability. Kinetic studies demonstrated that the synthesized SiW12@Co3O4 had a strong binding affinity to 3,3',5,5'-tetramethylbenzidine (TMB), stronger than HRP had. Specifically, the peroxidase-like activity of SiW12@Co3O4 in an aqueous solution was well maintained after incubation at an elevated temperature, at an extreme pH and for a long time. A SiW12@Co3O4-based method was further developed for H2O2 and one-pot glucose detection with good sensitivity and reliability. The facile synthesis approach is expected to facilitate the practical use of metal-organic frameworks and their derivatives as enzyme mimics in the future.

Fundamental understanding of microRNA (miRNA) regulated cellular processes requires smart tools capable of imaging the expression and distribution of miRNAs in living cells. However, the low-expression of miRNA and a complex intracellular environment bring great challenges for intracellular miRNA imaging. We found that boron doped g-C3N4 nanosheets (BCNNS) are capable of binding copper nanocluster (CuNC)-labeled hairpin DNA and quench the fluorescence of CuNCs. A turn-on fluorescent sensor for the detection of miR-582-3p in living cells is thus developed based on the affinity change of BCNNS and DNA probes upon their recognition to the target. Ratiometric fluorescence measurement is achieved by taking advantage of the inherent fluorescence emission of BCNNS as the cell interior label. By combining the hybridization chain reaction (HCR) amplification and inherent sensitivity of a turn-on fluorescence sensing strategy, this approach gives rise to a limit of detection (LOD) of 49 fmol L-1 for miR-582-3p, within a linear range of 0.2-1 pmol L-1. The LOD is further improved to 12 fmol L-1 with a correlation to ICP-MS by measuring the 63Cu isotope. With the merits of high sensitivity and selectivity of the HCR and the anti-interfering capability of the ratiometric fluorescent probe, the single cell miR-582-3p expression levels are successfully detected, which indicated that this assay provides a sensitive and enzyme-free approach for miRNA imaging in living cells.

The emerging chemodynamic therapy (CDT) has received an extensive attention in recent years. However, the efficiency of CDT is influenced due to the limitation of H2O2 in tumor. In this study, we designed and synthesized a novel core-shell nanostructure, Cu-metal organic framework (Cu-MOF)/glucose oxidase (GOD)@hyaluronic acid (HA) (Cu-MOF/GOD@HA) for the purpose of improving CDT efficacy by increasing H2O2 concentration and cancer cell targeting. In this design, Cu-MOF act as a CDT agent and GOD carrier. Cu(II) in Cu-MOF are reduced to Cu(I) by GSH to obtain Cu(I)-MOF while GSH is depleted. The depletion of GSH reinforces the concentration of H2O2 in tumor to improve the efficiency of CDT. The resultant Cu(I)-MOF catalyze H2O2 to generate hydroxyl radicals (·OH) for CDT. GOD can catalyze glucose (Glu) to supply H2O2 for CDT enhancement. HA act as a targeting molecule to improve the targeting ability of Cu-MOF/GOD@HA to the tumor cells. In addition, after loading with GOD and coating with HA, the proportion of Cu(I) in Cu-MOF/GOD@HA is increased compared with the proportion of Cu(I) in Cu-MOF. This phenomenon may shorten the reactive time from Cu-MOF to Cu(I)-MOF. The CDT enhancement as a result of GOD and HA effects in Cu-MOF/GOD@HA was evidenced by in vitro cell and in vivo animal studies.

Understanding the dynamic behavior of charged particles driven by flow and electric field in nanochannels/pores is highly important for both fundamental study and practical applications. While a great breakthrough has been made in understanding the translocation dynamics of charged particles within the nanochannels/pores, studies on the dynamics of particles at the orifice of nanochannels/pores are scarcely reported. Here, we study particle motion at a smaller-sized orifice of a nanopipette by combining experimentally observed current transients with simulated force conditions. The theoretical force analysis reveals that dielectrophoretic force plays an equally important role as electrophoretic force and electroosmotic force, although it has often been neglected in understanding the particle translocation dynamics within the nanopipette. Under the combined action of these forces, it thus becomes difficult for particles to physically collide with the orifice of the nanopipette, resulting in a relatively low decrease in the current transients, which coincides with experimental results. We then regulate the dynamic behavior by altering experimental conditions (i.e., bias potential, nanopipette surface charge, and particle size), and the results further validate the presence and influence of forces being considered. This study improves the understanding of the relationship between particle properties and observed current transients, providing more possibilities for accurate single-particle analysis and single-entity regulation.

Robust and sensitive cell-based enzyme-linked immunosorbent assay (CELISA) is of great significance in the diagnosis and screening of cancer. However, the method is limited by the high rate of negative results attributed to the instability of horseradish peroxidase (HRP), H2O2, and antibody. Here, we construct a folic acid-functionalized in situ-grown MnO2 nanosheet/graphene oxide hybrid (FA-MnO2/GO) with oxidase-like activity instead of the anti-folate receptor antibody in traditional CELISA to resist the possible negative interference arising from unstable HRP, H2O2, and antibodies for more robust colorimetric detection of cancer cells. The functionalization of FA enables the selective binding between hybrid and cancer cells through the over-expressed folate receptor, and then the binding events are converted into quantitative colorimetric signals though the oxidation of the chromogenic substrate TMB catalyzed by MnO2, allowing the detection of cancer cells with colorimetric method. Moreover, the construction of MnO2/GO hybrid can synergistically enhance the oxidase-like activity of MnO2 and promote its dispersion in water, further ensuring the accuracy and sensitivity of the detection. A detection limit of 20 cancer cells is obtained by a plate reader, which is lower than those obtained by most reported CELISA methods for cancer cell detection, and as few as 75 cancer cells can be identified by the naked eye. This study not only provides a multifunctional sensing platform for robust and sensitive cancer cell detection, but also offers a promising oxidase-like mimic in the field of bioanalysis.

The bacteria redox balance between oxidizing and reducing species plays a critical role in bacterial activities, and the disruption of this homeostasis offers a flexible antibacterial strategy to combat bacterial multidrug resistance. Here, the ligand exchange strategy of Au NCs was first developed to construct an oxidative stress amplifier. We cleverly utilized the reactive oxygen species (ROS) generation ability of histidine (His)-stabilized Au NCs. Cinnamaldehyde (CA) was modified on the surface of Au NCs through an aldimine condensation reaction, and the modification of CA on the surface of Au NCs further accelerated ROS generation. Meanwhile, the strong Au-S interaction between CA-Au NCs and thiols facilitated the ligand exchange of surface histidine-cinnamaldehyde (His-CA) with thiol molecules, causing the consumption of thiols in bacteria and the release of His-CA, which thus finally resulted in efficient bacterial cell death. CA-Au NCs showed excellent antibacterial effects on methicillin-resistant Staphylococcus aureus (MRSA), including 48-h biofilm removal and the treatment of a pig skin wound infection model, representing a promising antibacterial agent for clinical applications.

The study of silver species and their distribution/transformation in cell interior is of high significance for the elucidation of toxicology of silver nanoparticles (AgNPs). The intracellular speciation of dissolved Ag(I) and AgNPs was reported. The analytical platform integrated capillary electrophoresis (CE) to inductively coupled plasma-mass spectrometry (ICP-MS) incorporating a high efficiency interface and a high performance spiral flow spray chamber (SFSC). The interface and the SFSC provide a favorable detection limit of 87 ng L−1 for the dissolved Ag(I). Total silver content was quantified by ICP-MS subject to digestion of the cell lysate, and quantification of AgNPs was carried out by subtraction. The speciation of dissolved Ag(I) and AgNPs in culture medium and HepG2 cells was performed, with RSDs of

Regulating the fluorescence of carbon dots (CDs) is important but highly challenging. Here, carbon dots with tunable dual emissions were facilely fabricated via modulating the polymerization and carbonization processes of o-phenylenediamine (OPD) with lysine (Lys) as the co-precursor and modulator, respectively. The self-polymerization/carbonization of the OPD molecules contributed to the blue/green emission of the OPD-derived CDs. The introduction of Lys in the CD fabrication process efficiently suppressed the carbonization of the OPD polymer chains and enhanced the self-polymerization of the OPD molecules. Meanwhile, the formed OPD-Lys co-polymer chains endowed the final CD product with a new green emission center. The dual-emissive CDs were distinctly sensitive to polarity fluctuations, providing a ratiometric fluorescence response towards solution polarity. Due to their specific distribution in the endoplasmic reticulum (ER), the as-prepared dual-emissive CDs successfully distinguished the polarity variations in ER under stress, which offers a new approach for the early diagnosis of cell injury.

A novel core-shell nanostructure, hollow copper sulfide nanosphere-doxorubicin (DOX)/graphene oxide (GO) (CuS-DOX/GO), is constructed for the purpose of controlled drug delivery and improved photothermo-chemo therapeutic effect. The CuS-DOX/GO nanocomposite is configured by employing dual photothermal agents, where the core, hollow CuS nanoparticle, acts as delivery-carrier for doxorubicin, and the shell, PEGylated GO nanosheet, prohibits the leakage of drug. DOX can be efficiently loaded onto the hollow CuS nanoparticles, and its subsequent release from CuS-DOX/GO nanocomposite is triggered in a pH- and near-infrared light-dependent manner. Moreover, the integration of the two photothermal agents significantly improves the photothermal performance of this system. Ultimately, the combination of phototherapy and chemotherapy based on this system results in a much higher HeLa cell killing efficacy with respect to that for single chemotherapy mode, as demonstrated by in vitro cytotoxicity tests.

In recent years, α-glucosidase inhibitors (AGIs) have played a significant role in the treatment of type II diabetes (T2D), so it is necessary to develop a reliable and sensitive method to find new AGIs. Herein, we establish a novel method based on fluorescent carbon nitride nanoparticles (CNNPs) for the sensitive detection of the activity of α-glucosidase (α-glu) and the screening of its inhibitors. A CNNP-based fluorescent probe is synthesized from green raw materials, urea and lysine, by a one-pot method. In the presence of α-glu, the substrate 4-nitrophenyl-α-D-glucopyranoside (pNPG) is hydrolyzed to generate 4-nitrophenol (pNP), leading to the fluorescence (FL) quenching of CNNPs due to the inner filter effect (IFE). On the other hand, the activity of α-glu is inhibited after the addition of AGIs, which turns on the FL of CNNPs. In this way, the detection of α-glu activity and the screening of AGIs are achieved. The linear range is 1.25–10.00 U L−1 with a limit of detection as low as 0.17 U L−1 and the IC50 values of two typical inhibitors (gallic acid and acarbose) are 813 μM and 465 μM, respectively. The CNNP probe is further applied for the determination of α-glu activity in human serum samples with satisfactory results.

Porous polymeric microspheres, poly(styrene-divinyl benzene, PSDVB)-poly(ethylene glycol monoallyl ether, PEGMAE), termed as PSDVB-PEGMAE, are prepared via double emulsion interfacial polymerization strategy. PSDVB-PEGMAE microspheres exhibit a mean diameter of 2.98 μm, and possess heterogeneous porous structure with a pore volume of 0.354 cm3 g−1 and a pore size of 34.3 nm. PEGMAE moiety is identified on the external surface of the microspheres, while both PSDVB and PEGMAE moieties are found in the interior pores. The PSDVB-PEGMAE microspheres possess favorable selectivity towards the adsorption of conalbumin (ConA) through hydrogen-bonding and hydrophobic interactions, via surface and inter-pore adsorption. At pH 6, an adsorption capacity of 171.9 mg g−1 is achieved for ConA. The captured ConA may be readily recovered by stripping with a cetane trimethyl ammonium bromide (CTAB) solution (0.1%, m/v). The microspheres are further used for the isolation of ConA from egg white, deriving high purity ConA as demonstrated by SDS-PAGE assay.

Zr-based metal-organic framework, UiO-66-NH2, provides favorable adsorption capacity to phosphoproteins, however, it exhibits obvious nonspecific adsorption to other proteins. In the present work, we report a facile strategy to reduce the nonspecific adsorption of nonphosphoproteins by modifying UiO-66-NH2 with imidazolium ionic liquids (ILs). With respect to bare UiO-66-NH2, the modified counterpart, UiO@IL, exhibits much improved selectivity to phosphoproteins while maintains comparable adsorption performance. The surface of UiO@IL presents a strong hydrophilicity due to the modification of ILs. Hydrophobic and electrostatic interaction between the absorbent and nonphosphoprotein is significantly reduced. In addition, the interaction between imidazole group of ILs moiety and phosphate group in phosphoprotein ensures the favorable adsorption capacity of UiO@IL for phosphoproteins. Anionic moieties of ILs, i.e., Cl−, Br−, BF4−, CF3SO3−, play negligible effect in the adsorption process. As a representative, phosphoprotein β-casein (β-ca) is selectively enriched at a mass ratio of BSA:β-ca = 100:1. UiO@IL was further applied for the selective enrichment of phosphoprotein in milk.

Copper transporter 1 (CTR1) is a transport protein involved in copper and cisplatin uptake. The visualization of cellular CTR1 migration and its redistribution is highly important in copper/cisplatin exposure/transport. However, to the best of our knowledge, this is a highly challenging task. Herein, a dual-mode imaging strategy for CTR1 is developed by hyphenating confocal laser scanning microscopy (CLSM) and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) with a fluorescent/elemental bifunctional tag conjugated with anti-CTR1 antibody. The tag consists of rhodamine B and zirconium metal-organic frameworks (Zr-MOF) for CLSM fluorescence imaging and LA-ICPMS element imaging for a same group of HepG2 cells in a designated visual zone. This dual-mode imaging strategy facilitates visualization of CTR1 migration and meanwhile provides information of CTR1 redistribution in HepG2 cells by uptake of divalent copper or cisplatin. The present dual-mode imaging strategy provides in-depth information for the elucidation of CTR1 involved biological processes. Graphical abstract.

The number and arrangement of arginine (Arg) residues in protein chains contribute greatly to the selective capturing of proteins on a designed adsorbent consisting of organic phosphate functionalized fibrous SiO2 microspheres, and the efficient depletion of high abundance Arg-rich protein species from human plasma is achieved.

Rankine pressure involves the special case of active earth pressure and merely considers the influence of the internal friction angle; however, the analytical solution for the general case...

A new type of boric acid derivative-modified molybdenum disulfide nanosheet was prepared by amination and sulfur chemical grafting, where lipoic acid, lysine, and 5-carboxybenzoboroxole were used as reactants. The two-dimensional composite, abbreviated as MoS2-Lys-CBX, is an ultrathin nanosheet with a minimum unit of single or few layers. Compared with the original molybdenum disulfide, the nonspecific adhesion of interfering proteins on the surface was reduced, and the adsorption capacity of glycoproteins was enhanced, which was 1682.2 mg g-1 represented by IgG. The adsorbed IgG can be easily eluted with 0.3 wt % CTAB with an elution efficiency of 94.1%. Circular dichroism spectra indicate no obvious conformation change of IgG during the purification process by the MoS2-Lys-CBX nanosheets. The as-prepared MoS2-Lys-CBX nanosheets were then employed for the isolation of IgG from human serum sample, obtaining high-purity light and heavy chains of IgG, as demonstrated by SDS-PAGE assays.

Developing new methods and techniques for the size analysis of particles in a solution is highly desirable not only for the industrial screening of particles but also for single biological entity analysis (e.g., single cells or single vesicles). Herein, we report a new technique for sizing single particles in a solution with a nanopipette. The rationale is essentially based on ion-current blockage when the particles approach the proximity of a nanopipette orifice. By rationally controlling the geometry of the nanopipette and the applied potential, the spike-type ion current transient generated from the motion of particles in the process of "collision and departure" is employed for sizing single particles. The results show that both the relative ion-current change (ΔI/I0) and the dwell time (Δt) of spike-type transient are dependent on particle size. Differently, Δt is also related to an externally applied voltage. Statistical analysis shows that ΔI/I0 is proportional to the particle diameter, and this linear relationship is further understood by finite-element simulations. This study not only provides a new principle for sizing single particles in a solution but also is helpful to understand the motion of a particle near the orifice of the nanopipette.

Circular single-stranded DNA (ssDNA) viruses are widely distributed globally, infecting diverse hosts ranging from bacteria, archaea, and eukaryotes. Among these, the genome of Banana bunchy top virus (BBTV) comprises at least six circular, ssDNA components that are ∼1 kb in length. Its genome is usually amplified and obtained at the DNA level. However, RNA-based techniques to obtain the genome sequence of such multi-component viruses have not been reported. In this study, transcriptome sequencing analysis showed that the full-length of BBTV each genomic component was transcribed into viral mRNA (vmRNA). Accordingly, the near-complete genome of BBTV B2 isolate was assembled using transcriptome sequencing data from virus-infected banana leaves. Assembly analysis of BBTV-derived reads indicated that the full-length sequences were obtained for DNA-R, DNA-U3, DNA-S, DNA-M, DNA-N, NewS2, and Sat4 components, while two gaps (73 and 25 nt) missing in the DNA-C component which was further filled by reverse transcription-PCR (RT-PCR). The RT-qPCR analysis indicated that the vmRNA levels of coding regions were 3.19–103.53 folds higher than those of non-coding regions, implying that the integrity of genome assembly depended on the transcription level of non-coding region. In conclusion, this study proposes a new approach to obtain the genome of nanovirids, and provides insights for studying the transcriptional mechanism of the family Nanoviridae, Genomoviridae, and Geminiviridae.

A novel polyoxometalate (POM)-based hybrid is prepared for the selective adsorption of acidic and/or basic proteins. The solidification of the POM moiety P8W48 is firstly achieved through dehydration condensation between the –OH group on the P8W48 surface and the Si–OH of aminopropyltriethoxysilane (APTS), and thereafter further condensation of the P8W48O184–APTS intermediate with poly(acrylic acid) (PAA) produces a hybrid, by linking carboxyl groups in PAA with –NH2 groups in P8W48O184–APTS via the formation of an amide bond. The P8W48–APTS–PAA hybrid surface is negatively charged due to abundant COO− groups from PAA, which provides electrostatic interactions with positively charged proteins by varying pHs. Meanwhile, the d–p π bond in P8W48 offers strong affinity to other proteins via π–π stacking interaction. The hybrid thus offers potential for achieving selective adsorption of either acidic or basic proteins by simply controlling the adsorption conditions, i.e., pH value or ionic strength of the adsorption medium. With ovalbumin (Ova) and lysozyme (Lys) as the models of acidic and basic proteins, their adsorption behaviors fit the Langmuir model, with adsorption capacities of 367.0 mg g−1 and 74.0 mg g−1, respectively. The retained proteins are readily recovered with 0.01 mol L−1 CTAB, providing recoveries of 89.0% for Ova and 93.0% for Lys. The P8W48–APTS–PAA hybrid is further applied for the isolation of Ova and Lys from real biological samples, egg white.

Carbon dots are prepared using a green hydrothermal approach with dehydrated shiitake mushroom as the sole carbon source without any additives (these carbon dots are shortly termed as MCDs). Carbonization, surface functionalization and nitrogen doping are involved in the hydrothermal treatment and no further modification or surface passivation is necessary. The derived MCDs are nitrogen-doped, oxygen-rich with hydroxyl, carboxyl and amine groups, with a diameter of ca. 4.2 nm. MCDs exhibit cell permeable properties and a distinct pH-sensitive/excitation-dependent photoluminescence emission feature within pH 4.0–8.0, providing an optical probe for intracellular pH sensing and multicolor imaging of live HeLa cells. MCDs also show a strong fluorescence response to hemin, which facilitates sensitive fluorescent sensing of hemin with a detection limit of 120 nmol L−1.

Carbon dots (CDs) with a high quantum yield have been synthesized by a facile and green one-pot approach under microwaves with silkworm chrysalis (SC) as the natural carbon source, without using any other chemicals/reagents. The morphology and optical properties of the resultant CDs are characterized by TEM, XRD, FT-IR, XPS, UV-vis and photoluminescence (PL). The SC-CDs have an average size of 19 nm, and contain C, O and N with relative contents of ca. 71.32%, 22.96% and 5.72%, respectively. A significant emission at 420 nm at an excitation wavelength of 350 nm is recorded, resulting in a quantum yield of 46% with quinine sulfate (quantum yield 54%) as a reference. In addition to excellent solubility and stability in aqueous medium, the SC-CDs exhibit excitation-dependent photoluminescence with a large Stokes shift of 70 nm. It is further demonstrated that the SC-CDs exhibit a low cytotoxicity at a higher concentration of 15 mg mL−1 and they are able to display bright blue, green and red colors under an inverted fluorescence microscope during cell imaging experiments, showing their vast potential in bioimaging.

Tryptophan (Trp) modified aminated mesoporous silica nanoparticles (AMSNs), shortened to Trp-AMSNs, are prepared via covalent binding. The obtained Trp-AMSNs exhibit a uniform size of ca. 83 nm, a mesopore diameter of ca. 2.6 nm, along with a pore volume of 0.439 cm3 g−1. It is demonstrated that Trp-AMSNs selectively adsorb ovalbumin (Ova) from complex biological matrices. At pH 5.0, 1.0 mg of Trp-AMSNs produces an adsorption efficiency of 96% for 100 mg L−1 Ova in 1.0 mL of solution. An adsorption capacity of 1240.3 mg g−1 is derived for Ova, which is much improved with respect to that of the native AMSNs. The retained Ova could be readily recovered by a sodium dodecyl sulfate (SDS) solution (0.5%, m/v), providing a recovery of 71.2%. Trp-AMSNs are further applied for the isolation of Ova from a protein mixture (with a molar ratio of ovalbumin/lysozyme of 1 : 10) and an egg-white sample. High-purity Ova is obtained, as demonstrated by SDS-PAGE assay results.

Due to their low toxicity, excellent biocompatibility and attractive optical properties, graphene quantum dots (GQDs) have attracted significant attention in the analytical and biological fields. The controllable intrinsic nature of graphene nano-sheets, e.g., size, layer, edge state or shape, offer the chance to fabricate GQDs with tunable photoluminescence behaviors. Carboxylic moieties on the surface and edges of GQDs can provide efficient reactive sites for interaction with various polymeric, organic, inorganic and biological species. This not only provides the chance to tune the optical properties of GQDs via facile chemical approaches such as surface modulation and doping, but also makes GQDs eco-friendly alternatives to replace the traditional fluorescent probes in biological assays. This review highlights new insights into the various strategies for tuning the optical features of GQDs, and their employment as attractive and powerful probes for bio-sensing/imaging. The challenges and future perspectives in the related fields are discussed.

Due to the large cellular heterogeneity, the strategies for the isolation and manipulation of single cells have been pronounced indispensable in the fields of disease diagnostics, drug delivery, and cancer biology at the single-cell resolution. Herein, an overview of the up-to-date techniques for precise manipulation/separation and analysis of single-cell is accomplished, these include the various approaches for the isolation and detection of individual cells in flow cytometry, microfluidic systems, micromodule systems, and others. In addition, the advanced application of these protocols is discussed. In particular, a few designs are highlighted for visualization, non-invasion, and intelligentization in single cell analysis, i.e., imaging flow cytometry, label-free microfluidic platform, single-cell capillary probe, and other related techniques. At the present, the main barriers in the various schemes for single cell manipulation which limited their practical applications are their cumbersome construction and single-functionality. The future opportunities and outstanding challenges in the isolation/manipulation of single cells are depicted.

In an effort to achieve high sensitivity analysis methods for ultra-trace levels of heavy metals, numerous new nanomaterials are explored for the application in preconcentration processes and sensing systems. Nanomaterial-based methods have proven to be effective for selective analysis and speciation of heavy metals in combination with spectrometric techniques. This review outlined the different types of nanomaterials applied in the field of heavy metal analysis, and concentrated on the latest developments in various new materials. In particular, the functionalization of traditional materials and the exploitation of bio-functional materials could increase the specificity to target metals. The hybridization of multiple materials could improve material properties, to build novel sensor system or achieve detection-removal integration. Finally, we discussed the future perspectives of nanomaterials in the heavy metal preconcentration and sensor design, as well as their respective advantages and challenges. Despite impressive progress and widespread attention, the development of new nanomaterials and nanotechnology is still hampered by numerous challenges, particularly in the specificity to the target and the anti-interference performance in complex matrices.

A porphyrin structure carbon dots (CDs) with red fluorescence is prepared by the reaction of terephthalaldehyde with pyrrole under the trifluoroacetic acid catalyst. The CDs with an average particle size of 5.70 nm are red-emission with a maximum fluorescent wavelength at 650 nm due to the large conjugate structure of the porphyrin ring, giving rise to a quantum yield of 14%. The aldehyde groups in CDs make self-aggregation possible, and promote the effective coating of CDs around Transferrin (Trf) via the Schiff base reaction, forming CDs@Trf nanocomposites with a particle size of 19.7 nm. Trf can specifically target cells with Trf receptors on the surface of cell membrane. CDs@Trf exhibits stable red-emission in low polarity solvents, and are able to generate singlet oxygen (1O2), which facilitates cell imaging and photodynamic therapy. In vitro cell experiments demonstrate that CDs@Trf greatly inhibits the growth of tumor cells under laser irradiation at 635 nm. After incubation of 3 mg mL−1 CDs@Trf with Bend.3 cells, the survival rate of the cells is only 26% under laser irradiation of 4.78 mW cm−2 for 5 min.

We constructed a carbon-based polymer dot (CPD) sensor to detect breast cancer based on the differences of peripheral blood cells, providing a new minimally invasive method for cancer diagnosis. This simple and extensible system exhibits clinically relevant accuracy in terms of cancer identification, making it an attractive strategy for diagnosis and prognosis.