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The present development of electroanalysis has produced rapid, convenient, and reliable decentralized monitoring of trace metals. Disposable screen-printed electrodes are promising alternatives to conventional bulky electrodes that provide portable detection instrumentation. In this mini-review, current developments in the design and fabrication of screen-printed sensors are described along with their applications in the stripping determination of trace heavy metals. Starting with a description of the preparation procedures of screen-printed electrodes and an introduction of their fundamental features, this article summarizes the applications of bare and modified screen-printed carbon electrodes in determining trace metals. Special attention is placed on highlighting developing trends of detecting heavy metals with the help of the electrochemical stripping strategy. [ABSTRACT FROM PUBLISHER]

The investigation of highly efficient catalysts for the electrochemical oxidation of glucose is the most critical challenge to commercialize nonenzymatic glucose sensors, which display a few attractive superiorities including the sufficient stability of their properties and the desired reproducibility of results over enzyme electrodes. Herein we propose a new and very promising catalyst: Pt cubes well-dispersed on the porous Cu foam, for the the electrochemical oxidation reaction of glucose in neutral media. The catalyst is fabricated in situ on a homemade screen-printed carbon electrode (SPCE) substrate through initially synthesizing the three-dimensional (3D) porous Cu foam using a hydrogen evolution assisted electrodeposition strategy, followed by electrochemically reducing the platinic precursor simply and conveniently. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) proofs demonstrate that Pt cubes, with an average size (the distance of opposite faces) of 185.1 nm, highly dispersed on the macro/nanopore integrated Cu foam support can be reproducibly obtained. The results of electrochemical tests indicate that the cubic Pt-based catalyst exhibits significant enhancement on the catalytic activity towards the electrooxidation of glucose in the presence of chloride ions, providing a specific activity 6.7 times and a mass activity 5.3 times those of commercial Pt/C catalysts at −0.4 V (vs. Ag/AgCl). In addition, the proposed catalyst shows excellent stability of performance, with only a 2.8 % loss of electrocatalytic activity after 100 repetitive measurements. [ABSTRACT FROM AUTHOR]

Abstract: The sluggish kinetic-controlled glucose oxidation reaction on Pt electrodes is well recognized as the most critical issue that blocks the development and commercialization of enzyme-free glucose sensors, and increasing attention is being focused on improving the analytical performances of these nonenzymatic sensors through exploring new Pt-based catalysts. In the present research, we synthesized novel Pt–Pd nanoflakes (Pt–Pd NFs) with three-dimensional architectures on a homemade screen-printed gold film electrode (SPGFE) substrate using a facile electrochemical deposition without any template, and further investigated the properties of the as-fabricated Pt–Pd NFs/SPGFE for enzymeless glucose detection. The results reveal that the proposed Pt–Pd nanostructure can provide preeminent electrocatalytic activity and excellent selectivity for enzyme-free glucose sensing under simulative physiological conditions, mainly attributing to its attractive structure, large active surface and appropriate applied potential. The resulting Pt–Pd NFs/SPGFE offers linear current responses for glucose with the concentration upper limit to 16mM. The obtained sensitivity is calculated to be as high as 48.0μAcm−2 mM−1 in the presence of 0.15M chlorides ions, and practical applications for blood sample analysis are also demonstrated. The proposed Pt–Pd structure is considered as a great potential building block for the fabrication of nonenzymatic electrochemical glucose sensors. [Copyright &y& Elsevier]

Novel smart materials can be synthesized and designed at the molecular level by attaching well characterized and tailored functionalities to be used in in vitro and in vivo oximetry. A series of porphyrins and metalloporphyrins were synthesized and their EPR and UV–vis spectra studied. The steric hindrance and electronic effects of the substituted groups and the characteristics of different metal ions were the major contributors in influencing the properties of the compounds. As a result, their EPR and UV–vis spectra changed. Through studying the EPR spectroscopic properties of these compounds, we hope that novel EPR oximetry materials can be found and this will help to extend the applications of EPR oximetry in vivo. [Copyright &y& Elsevier]

Abstract: Langmuir–Blodgett (LB) films of mixtures of 3,4,9,10-perylenetetracarboxylic diimide (PTCDI), merocyanine dye (DO) and arachidic acid (C20) with different molecular ratios, were prepared on Cd2+-containing and pure-water subphases. The characterization of mixed Langmuir and LB films were performed by using, respectively, surface pressure–molecular area isothermetry and UV–Vis–IR absorption spectroscopy. The analysis indicates that interaction between the two dyes modifies their arrangements and electronic states in their mixed Langmuir films spread upon the Cd2+-containing subphase. However, the mixed LB films with the pure-water subphase are showed to be simple physical mixtures. The difference in the mixing effect observed for the Langmuir films upon the Cd-containing and pure-water subphases may be caused by the formation of metal chelation with the former subphase. [Copyright &y& Elsevier]

Abstract: Head-to-tail molecular arrangements of J-aggregates modify not only the excited state, but also the ground state of the dye chromophore therein. To clarify such modification of the ground state, which is related with the aggregation mechanism, infrared absorption spectroscopy has been applied to J-aggregates of two alkylated merocyanine dyes, 6MeDS and DO, formed in their pure or mutually mixed Langmuir–Blodgett films. Some vibrational modes have been found to be softened upon the J-aggregation. The nature of these vibrational modes has been determined by density functional calculations. Then, it has been concluded that the J-aggregation induces an enhancement of intramolecular charge transfer both in the 6MeDS and DO cases, although these two dyes are largely different in their tendency to form J-aggregates. [Copyright &y& Elsevier]

UV-visible absorption spectrum of pure 2-methyl-5-octadecyl-N,N[sup ′]-dicyanoquinonediimine (C[sub 18]MeDCNQI) Langmuir films and that of C[sub 18]MeDCNQI-CuI mixed Langmuir films indicated the occurrence of charge-transfer (CT) reactions at the air-water interface in the latter case. These Langmuir films were deposited onto solid substrates as Langmuir-Blodgett (LB) films by the horizontal lifting method. Polarized UV-visible-IR absorption spectra and x-ray diffraction patterns recorded for the obtained LB films revealed a drastic structural change induced by the CT reactions: An interdigitated bilayer structure was suggested for the pure films, while a monolayer structure for the CT films. Furthermore, the CT degree of the major component of the mixed LB films was estimated at -1, unlike in the case of Cu-DCNQI crystals, for which the CT degree is -2/3. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

AbstractSerum homocysteine (Hcy) is considered to be a reliable biomarker of cardiovascular, cerebrovascular and neurological diseases. Therefore, rapid, specific and sensitive measurement of homocysteine is crucial for prevention and diagnosis. Electrochemical methods, which benefit from simplicity, low-cost and quick response, have been widely utilized in the determination of targeted biomolecules. In this work, based upon a portable mini-potentiostat, a homocysteine electrochemical biosensor has been successfully developed combined with the modification of gold and manganese (IV) nanomaterials on multiwalled carbon nanotubes (MWCNTs) (denoted as Au@MnO2/MWCNTs) on screen-printed electrodes (SPEs). Due to the excellent electrochemical activity and catalytic capability of Au@MnO2/MWCNTs, the proposed electrochemical biosensor exhibited wide-linear range (5–125 μmol L−1), high sensitivity (0.01110 μA (μmol L−1)−1) and low detection limit (0.6173 μmol L−1) for homocysteine, requiring only 400 s to complete detection. It was effectively applied in the determination of serum homocysteine, and the results were consistent with those of an automated clinical chemistry analyzer. Furthermore, the simple and portable electrochemical device offers a promising manner for on-site analysis and home health monitoring. [ABSTRACT FROM AUTHOR]

The tumor microenvironment is a barrier to breast cancer therapy. Cancer-associated fibroblast cells (CAFs) can support tumor proliferation, metastasis, and drug resistance by secreting various cytokines and growth factors. Abnormal angiogenesis provides sufficient nutrients for tumor proliferation. Considering that CAFs express the sigma receptor (which recognizes anisamide, AA), we developed a CAFs and breast cancer cells dual-targeting nano drug delivery system to transport the LightOn gene express system, a spatiotemporal controlled gene expression consisting of a light-sensitive transcription factor and a specific minimal promoter. We adopted RGD (Arg-Gly-Asp) to selectively bind to the αvβ3 integrin on activated vascular endothelial cells and tumor cells. After the LightOn system has reached the tumor site, LightOn gene express system can spatiotemporal controllably express toxic Pseudomonas exotoxin An under blue light irradiation. The LightOn gene express system, combined with multifunctional nanoparticles, achieved high targeting delivery efficiency both in vitro and in vivo. It also displayed strong tumor and CAFs inhibition, anti-angiogenesis ability and anti-metastasis ability, with good safety. Moreover, it improved survival rate, survival time, and lung metastasis rate in a mouse breast cancer model. This study proves the efficacy of combining the LightOn system with targeted multifunctional nanoparticles in tumor and anti-metastatic therapy and provides new insights into tumor microenvironment regulation. [Display omitted] • pPEA@mNP is a multi-functional gene delivery system, with high targetability and sensitive release profile • pPEA@mNP can spatiotemporally inhibits tumor cells, cancer associated fibroblasts and tumor angiogenesis • pPEA@mNP can eliminate breast cancer and regulate tumor microenvironment, providing a novel anti-metastatic therapy strategy [ABSTRACT FROM AUTHOR]

Hydrophilic interaction liquid chromatography (HILIC) has inherent advantages in the separation of hydrophilic or strongly polar substances (e.g., saccharides, glycopeptides, metabolites, etc.) due to strong hydrophilic interactions, which represents an attractive complementary approach to the mainstreamed reversed phase LC. Significant improvement in sensitivity, analyte coverage, throughput, analysis speed, and resolution of HILIC largely promote the development of bio-separation and bio-analytical chemistry. Based on the theoretical guidance, a lot of functional hydrophilic materials have emerged, what follows is that people are more concerned about their innovations and breakthroughs. Meanwhile, the combination of HILIC with various separation and characterization techniques (such as HILIC MS, multidimensional LC) present high separation efficiency towards complex samples in the fields of proteomics, metabolomics, food, and medicine industry. In this review the latest progress in HILIC in the past five years are summarized in order to provide a reliable and perfect guidance for future research in bio-separation. • HILIC has been playing an irreplaceable role in many separation fields and shown unlimited development potential. • Recent developments in the advanced applications of HILIC are discussed emphatically. • A lot of modified functional hydrophilic materials have emerged and their future possibilities are discussed. • This review will provide a reliable and perfect guidance for future research in bio-separation. [ABSTRACT FROM AUTHOR]

The encrustation and induced infection severely impact on the therapeutic effectiveness and service life of urinary stents due to the fast formation of conditioning film on urinary stents after implantation. The composition and properties of conditioning film have great influence on antifouling properties of stent materials. In our previous work, we modified polyurethane films by chondroitin sulfate (PU-CS) with different CS grafting densities to verify its anti-fouling properties. To obtain the in-depth understanding of encrustation on urinary stents, we investigated the impact of the composition and properties of conditioning film on the following inorganic salt deposition and bacteria adhesion in urine. The results showed that quantity of proteins and polysaccharides in conditioning films, and the roughness, water contact angle and zeta potential of PU-CSs covered with corresponding conditioning film decreased with the increase of CS grafting density on PU films.PU-CS(3) with highest CS grafting density (3.70 g/cm 2 ) had the highest bacteria inhibition rate and least inorganic salt deposition among the PU-CSs in artificial urine. Moreover, inorganic salts depositing on the PU-CS(3) were less and smaller than those on other films. Bacteria were not detectable until day 21 in real urine. Meanwhile, the pH value was elevated. The results suggested that the component of conditioning films was more important than other surface properties such as hydrophilicity, zeta potential and roughness for inorganic salt deposition and bacteria adhesion. Moreover, the anti-encrustation properties of the surface was promoted by proteins and inhibited by polysaccharides. [ABSTRACT FROM AUTHOR]

Individualized immunotherapy has attracted great attention due to its high specificity, effectiveness, and safety. We used an exogenous antigen to label tumor cells with MHC I molecules, which allowed neoantigen-specific T cells to recognize and kill tumor cells. A neoantigen vaccine alone cannot achieve complete tumor clearance due to a tumor immunosuppressive microenvironment. The LightOn system was developed to effectively eliminate tumor cells through the spatiotemporally controllable expression of diphtheria toxin A fragment, leading to antigen release in the tumor region. These antigens stimulated and enhanced immunological function and thus, recruited neoantigen-specific T cells to infiltrate tumor tissue. Using the nanoparticle delivery system, neoantigens produced higher delivery efficiency to lymph nodes and improved tumor targeting ability for tumor cell labelling. Good tumor inhibition and prolonged survival were achieved, while eliciting a strong immune response. The combination of a spatiotemporally controllable transgene system with tumor neoantigen labeling has great potential for tumor immunotherapy. [Display omitted] [ABSTRACT FROM AUTHOR]

Methanol, a high-energy substance, is widely used for green fuel cells. However, the sluggish electrochemical methanol oxidation reaction (MOR) on state-of-the-art catalysts still requires for exploring high-performance and low-cost materials to further promote the reaction kinetics at low overpotentials. Here we carried out the first electrocatalytic comparison study of two Ni foam-supported Pd nanomaterials (Pd-2-Ni and Pd-4-Ni, respectively), obtained through the spontaneous galvanic replacement of Ni with different palladic precursors ([PdCl 4 ] 2- and [PdCl 6 ] 2− , respectively), toward MOR. With replacement, Pd deposits with discrepant arrangements and coverages were grown on the porous Ni support. Compared to commercial Pd/C, both Pd-2-Ni and Pd-4-Ni exhibited better mass activity and catalytic durability for MOR in alkaline media. More interestingly, different palladic precursors made a significant effect on the catalytic performance of the Ni foam-supported Pd deposits. In Pd-4-Ni, the 2:1 stoichiometric replacement of Ni with [PdCl 6 ] 2− enabled the incompact arrangement of Pd structures, with more exposure of Ni atoms adjoined to Pd atoms on the catalytic interface compared to Pd-2-Ni. As a result, with the favorable Ni-neighbor-Pd regime and the higher utilization efficiency of Pd atoms, the synthesized Pd-4-Ni catalyst provided a mass activity of approximately 1.5 times higher than Pd-2-Ni toward MOR. [ABSTRACT FROM AUTHOR]

A new surface-enhanced Raman scattering (SERS) screen-printed electrode was prepared by simultaneously reducing Ag+and H+at a high potential. The Na2S2O3, which has a large cumulative formation constant with Ag+, was introduced to remove the background Raman interference of Ag2SO4from the electrolyte. Scanning electron micrographs showed that the SERS electrode presented porous and dendritic nanostructures using 0.01 M Ag2SO4and 0.6 M H2SO4, a current density of 0.425 A/cm2, and a deposition time of 30 s. The porous (roughness factor of 78.66) and dendritic structure contributed to the SERS enhancement factor of 3.36 × 104. The electrochemistry of pyridine was characterized on the SERS electrode and in-situ detection was demonstrated. [ABSTRACT FROM PUBLISHER]

• Octahedral Au@Cu-C bimetallic composite derived from Cu-MOF was synthesized. • An electrochemical aptasensor was constructed by Au@Cu-C alloy and MB as indicator. • The proposed aptasensor realized the detection of homocysteine in the human serum. • The detection was conducted by portable potentiostat, enabling on-site application. Homocysteine (Hcy), a metabolic intermediate of methionine, is a biomarker for neurological, cardiovascular and cerebrovascular diseases. Timely measurement of Hcy acts as a significant role in disease prevention and diagnosis. Given the fast response of the electrochemical sensing method, herein, a sensitive electrochemical aptasensor was proposed for the detection of Hcy. The aptasensor was constructed by utilizing the MOF-derived bimetallic carbon nanocomposites (Au@Cu-C) plus multi-walled carbon nanotubes (MWCNTs) as electrode modification materials and methylene blue (MB) as the signal marker. The Au@Cu-C was synthesized through hydrothermal methods, calcination and simple galvanic replacement reactions. The prepared Au@Cu-C enhance the electrical signal due to the synergistic effect of bimetallic alloy, while the specific morphology facilitated the immobilization of the aptamer. MB, served as the signal marker, can reflect the current changes of the aptasensor caused by the conformational change of aptamer before and after binding Hcy. As a result, the constructed electrochemical aptasensor exhibited a high sensitivity of 0.415 μA μM−1, a low detection limit of 0.017 μM and an excellent recovery rate in the detection of human serum samples. Besides, the detection was performed on the portable potentiostat which demonstrated the potential application of the aptasensor in medical diagnosis and on-site analysis. [Display omitted] [ABSTRACT FROM AUTHOR]

Electro-oxidizing glucose effectively is well known as the critical point in developing analytical sensors and carbohydrate-based fuel cells. Here we prepared a new electrode material, platinum nanoparticles encapsulated in carbon microspheres (Pt/GSH), to promote the glucose electrocatalytic oxidation reaction in neutral media. The Pt/GSH composite was synthesized by using a simple hydrothermal method, with reduced glutathione (R-GSH) as the capping agent and reductant simultaneously, followed by a calcination process. It was found that the obtained Pt particles with a mean size of 26.8 nm were well dispersed in the interconnected carbon microspheres, providing a stable and efficient catalytic platform for glucose electro-oxidation. As a result, the synthesized catalyst exhibited higher activity for electro-catalyzing glucose compared to commercial Pt black and Pt/C catalysts, with a mass activity of 15.4 μA μg −1 Pt , approximately 13 times of Pt black and 2.1 times of Pt/C. Besides, due to the decreased dissolution and agglomeration of Pt NPs in the carbon-encapsulated structure, the Pt/GSH catalyst kept quite stable activity upon reuse even in the presence of chloride ions. [ABSTRACT FROM AUTHOR]

A SiO2-coumarin nanohybrid was investigated for its Cu(II) sensing performance in aqueous media, and in comparison with the Cu(II)-selective coumarin used alone. Fluorescence of both coumarin itself and the nanohybrid, λex/λem 435/481 nm, was selectively quenched by Cu(II) when tested against a range of multivalent cations. The nanohybrid had enhanced Cu(II) sensing properties when compared to the coumarin including (i) improved limit of detection from μM-level (0.48 μM) of Cu(II) using coumarin alone to nM-level (0.033 μM) and (ii) an extended linear detection range of 0.033–260 μM (0.0005–4.1 mg/mL) Cu(II) compared to 0.48–55 μM for the coumarin itself. The lower limit of detection and extended range were achieved with a smaller amount of coumarin and no traces of organic solvents used to help coumarin dissolution. Characterization suggested that under applied test conditions at pH = 5, SiO2 nanoparticles with negative surface charges adsorbed coumarin and then (when present) Cu(II) ions. The SiO2-coumarin nanohybrid was then applied for the determination of Cu(II) levels in aqueous soil extracts reaching over 94% recovery rates when used against the standard soil analysis method by inductively coupled plasma mass spectrometry (ICP-MS). [ABSTRACT FROM AUTHOR]

[Display omitted] Inflammatory bowel disease (IBD) is a chronic gastrointestinal disorder characterized by immune dysregulation and intestinal inflammation. Rapamycin (Ra), an mTORC1 pathway inhibitor, has shown promise for autophagy induction in IBD therapy but is associated with off-target effects and toxicity. To address these issues, we developed an oral liposome responsive to reactive oxygen species (ROS) using lipids and amphiphilic materials. We combined ketone thiol (TK) for ROS responsive and hyaluronic acid (HA) with high affinity for CD44 receptors to prepare rapamycin-loaded nanoparticle (Ra@TH). Owing to its ROS responsive characteristic, Ra@TH can achieve inflammatory colonic targeting. Additionally, Ra@TH can induce autophagy by inhibiting the mTORC1 pathway, leading to the clearance of damaged organelles, pathogenic microorganisms and oxidative stress products. Simultaneously, it also collaboratively inhibits the NF-κB pathway suppressed by the removal of ROS resulting from TK cleavage, thereby mediating the expression of inflammatory factors. Furthermore, Ra@TH enhances the expression of typical tight junction proteins, synergistically restoring intestinal barrier function. Our research not only expands the understanding of autophagy in IBD treatment but also introduces a promising therapeutic approach for IBD patients. [ABSTRACT FROM AUTHOR]

When an acute myocardial infarction (AMI) occurs, myoglobin (Mb) is the biomarker whose concentration firstly increases, and the high sensitive detection of Mb is critical for early diagnosis of AMI. Herein, a sandwich-type electrochemical aptasensor for the sensitive detection of Mb was constructed by using Pt@Cu 1.33 OCo 0.83 O as the signal marker. On one hand, nano-flower-like Cu 1.33 OCo 0.83 O was synthesized by hydrothermal method and Pt nanoparticles (Pt NPs) were loaded on its surface. Pt@Cu 1.33 OCo 0.83 O could immobilize aptamer 2 (Apt2) successfully by the Pt–S bond. And because of the synergistic effect between Pt and bimetallic oxide, Pt@Cu 1.33 OCo 0.83 O had an excellent catalytic effect on the signal source of hydrogen peroxide (H 2 O 2) to amplify the current signal, which enhance the sensitivity of the aptasensor. On the other hand, the screen-printed gold electrode (SPGE) was used as the sensing base, which had good conductivity and ensured the immobilization of aptamer 1 (Apt1). The quantitative detection of Mb was achieved by specific recognition between Mb and Apt1, Apt2. As a result, the constructed electrochemical aptasensor had a good linear range (1–1500 ng/mL) with a low detection limit (LOD) of 0.128 ng/mL (S/N = 3), and a high sensitivity of 29.47 μA dec−1. The aptasensor also realized the detection of Mb in human serum samples with good accuracy, and the results were consistent with the hospital's biochemical indicators, which demonstrated the potential application of the prepared sensor in the clinical detection of Mb. [Display omitted] • A sandwich-type electrochemical aptasensor was fabricated based on Pt@Cu 1.33 OCo 0.83 O. • The label Pt@Cu 1.33 OCo 0.83 O made the aptasensor reach a high sensitivity of 29.47 μA dec−1. • The constructed aptasensor can detect Mb in human serum samples and is consistent with hospital's biochemical indicators. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, two disposable screen-printed antimony film electrodes (SPSbFEs) modified with multi-walled carbon nanotubes (MWCNTs) and ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4), respectively for electrochemical stripping measurement are introduced. The modified screen-printed electrode substrate was prepared by homogeneously doping the attractive material into the graphite-based printing ink, and then an antimony film was in situ formed by simultaneously electrodepositing the antimony precursor with interesting analytes on the modified substrate. The electroanalytical performance of the modified SPSbFE for heavy metals based on the anodic stripping protocol was intensively evaluated. It was found that stripping voltammetric measurements of mercury (II) and lead (II) at the modified SPSbFEs resulted in good peaks with very low background contribution. In comparison with the bare SPSbFE, the modifications of both MWCNTs and [Bmim]BF4 were demonstrated providing more sensitive responses. The results indicated that the SPSbFE modified with 4wt% [Bmim]BF4 exhibited well linear behavior in the mercury (II) concentration range from 20 to 140μg/L (R 2 =0.998) with a detection limit of 0.36μg/L (S/N=3) under a 120s accumulation, and good repeatability with a relative standard deviation (RSD) of 4.16% (40μg/L, n =12). The proposed electrodes, as new styles of “mercury-free” electrodes, also exhibit encouraging properties for measurements of practical samples. [Copyright &y& Elsevier]

Abstract: Novel ferrocenyl nitroxides 3−6 were prepared as models for studying the linkage structure–activity relationship. Single-crystal X-ray structures of compounds 4 and 5 were determined and comparatively studied. The in vitro antioxidative activities (e.g. scavenging superoxide anion and hydroxide radical) of compounds 3−6 and 4-ferrocenamido-2,2,6,6-tetramethyl-piperidin-oxy (2) were evaluated. Compounds 3 and 5 exhibit high scavenging activities in low concentration. Results from electrochemistry and UV/Vis spectroscopy show that the redox property and antioxidative activity are closely related to the structure of the linkage bridging ferrocene and cyclic nitroxide moieties. The results further indicate that the ferrocene moiety plays a principal role in antioxidation. The modification of linkage was found to be able to decrease the ferrocene/ferrocenium potential and improve the antioxidative activity effectively. [Copyright &y& Elsevier]

Abstract: In order to elucidate the nanoparticle-induced cytotoxicity and its mechanism, the effects of 20 and 50nm silica nanoparticles on cultured human embryonic kidney (HEK293) cells were investigated. Cell viability, mitochondrial function, cell morphology, reactive oxygen species (ROS), glutathione (GSH), thiobarbituric acid reactive substance (TBARS), cell cycle and apoptosis were assessed under control and silica exposed conditions. Exposure to 20 or 50nm SiO2 nanoparticles at dosage levels between 20 and 100μg/ml decreased cell viability in a dose-dependent manner. Median lethal dose (LD50) of 24h exposure was 80.2±6.4 and 140.3±8.6μg/ml for 20 and 50nm SiO2 nanoparticles, respectively. Morphological examination revealed cell shrinkage and nuclear condensation after SiO2 nanoparticle exposure. Increase in intracellular ROS level and reduction in GSH content were also observed in SiO2 nanoparticle-exposed HEK293 cells. Increase in the amount of TBARS suggested an elevated level of lipid peroxidation. Flow cytometric analysis showed that SiO2 nanoparticles can cause G2/M phase arrest and apoptotic sub-G1 population increase in a dose-dependent manner. In summary, exposure to SiO2 nanoparticles resulted in a dose-dependent cytotoxicity in cultured HEK293 cells that was associated with increased oxidative stress. [Copyright &y& Elsevier]

[Display omitted] • A novel strategy for the simultaneous detection of Cd(II) and Pb(II) with high sensitivity is proposed. • Nitrogen-doped carbon-encapsulates Bi nanoparticles were synthesized. • Nitrogen-doped carbon nanosheets can help to improve electronic conductivity. • Uniformly dispersed Bi nanoparticles provide abundant active sites. Cadmium (Cd) and lead (Pb) are two of the most toxic heavy metals, which cause serious pollution to the environment. It is of great significance to develop electrochemical sensing platforms that can be used for the efficient and simultaneous detection of Cd(II) and Pb(II). Herein, bismuth nanoparticles encapsulated in nitrogen-doped carbon nanosheets (Bi@NC) were successfully synthesized. An electrochemical sensor based on Bi@NC was proposed for the high-performance determination of trace Cd(II) and Pb(II). Encapsulated and uniformly distributed Bi nanoparticles with abundant active sites form alloys with Cd(II) and Pb(II), and the conductive nitrogen-doped carbon nanosheet accelerates the electron transport rate, thus the electrochemical signals of Cd(II) and Pb(II) are significantly amplified. Under optimized conditions, Cd(II) and Pb(II) can be simultaneously detected in concentrations ranging from 1 to 150 μg L−1, with sensitivity of 0.48 μA μg−1 L and 0.36 μA μg−1 L, respectively. Meanwhile, the sensor possesses the outstanding advantages of ultra-high sensitivity, excellent selectivity, and storage stability, being able to serve as an electrochemical platform for Cd(II) and Pb(II) sensing in fruit and river water. [ABSTRACT FROM AUTHOR]

N-glycopeptide is considered as one of significant biomarkers which provide guidance for the diagnosis and drug design of diseases. However, the direct analysis of N-glycopeptides is nearly impracticable mainly owing to their extremely low abundance and grave signal suppression from other interfering substances in the bio-samples. In this research, a multiply-mesoporous hydrophilic TiO 2 nanohybrid (mM-TiO 2 @Cys) was synthesized by immobilizing Cys on a TiO 2 substrate with hierarchical mesopores to achieve the highly-performed enrichment of N-glycopeptides. With the advantages of superior hydrophilicity and multiply-mesoporous structure, the obtained material exhibited an excellent selectivity (IgG digests and BSA digests at the molar ratio of 1/500), a high sensitivity (1 fmol μL−1 for IgG digests) and a good size-exclusion ability (IgG digests, IgG and BSA at the molar ratio of 1/500/500) in the enrichment of N-glycopeptides from IgG digests. As a result, 281 N-glycopeptides corresponded with 109 glycoproteins were identified from 2 μL serum digests of the patients with nasopharyngeal carcinoma, and 181 N-glycopeptides corresponded with 78 glycoproteins were identified from 2 μL serum digests of the healthy volunteers, revealing the potential application value of mM-TiO 2 @Cys in glycoproteomics. [Display omitted] • A novel multiply-mesoporous hydrophilic nanohybrid (mM-TiO 2 @Cys) was designed for N-glycopeptide enrichment. • The multiply-mesoporous structure could offer abundant adsorption sites and facilitate the diffusion of N-glycopeptides. • The recommended method was successfully applied to the analysis of N-glycopeptides in human serum by nano-LC-MS. [ABSTRACT FROM AUTHOR]

Mass spectrometry (MS)-based glycoproteomics research requires additional sample pretreatment to improve the effective identification of low-abundance glycopeptides without interference from non-glycoproteins. Herein, an attractive strategy using resorcinol-formaldehyde (RF) resin and zirconium-based coordination polymer (Zr-BCP) was established to prepare one-dimensional porous coordination polymer composites for glycopeptide enrichment before MS analysis. The obtained Fe 3 O 4 @RF@Zr-BCP nanochains feature excellent magnetic response (42.26 emu/g), high hydrophilicity (16.0°), and large specific surface area (140.84 m2/g), which provides abundant affinity sites for specific capture of glycopeptides. The materials exhibit outstanding performance in the enrichment of glycopeptides in terms of sensitivity (15 fmol/μL IgG), selectivity (1:200, molar ratio of IgG/BSA), loading capacity (200 mg/g) and recovery (106.4 ± 3.5%). In addition, the developed method based on Fe 3 O 4 @RF@Zr-BCP has been successfully applied to capture glycopeptides in tryptic digest of mouse teratoma cell extracts. It is worth emphasizing that compared with dispersed nanoparticles, the one-dimensional chain structure brings extraordinary reusability to Fe 3 O 4 @RF@Zr-BCP nanochains, which is conducive to the rapid cyclic enrichment of glycopeptides. This present work provides a potential enrichment platform for comprehensive glycoprotein analysis, and opens a new avenue for the application of oriented-assembly nanochains. [Display omitted] • 1D magnetic nanochain structure was introduced to glycopeptide enrichment. • Resorcinol-formaldehyde resin encapsulation provided excellent hydrophilicity. • Glycopeptides from mouse teratoma cells were enriched and analyzed by nano-LC-MS. [ABSTRACT FROM AUTHOR]

Hexavalent chromium (Cr(VI)) seriously damages the ecological environment and human health. Therefore, it is necessary and significant to develop efficient, fast and sensitive detection techniques for Cr(VI). In this work, an electrochemical sensing platform for the determination of Cr(VI) was successfully constructed based on hollow mesoporous carbon cubes loaded with Au nanoparticles (Au@HMCC), which were prepared through a soft template method. By virtue of the chemical etching of ZIF-8 and the carbonization process after coating with mesoporous polydopamine, the products presented a highly ordered hollow mesoporous structure, which provided a large surface area and abundant catalytic active sites for the electrochemical reduction of Cr(VI). Au nanoparticles (AuNPs) were loaded through electrostatic adsorption to further improve the conductivity and amplify the current signal. Consequently, the as-fabricated sensor showed excellent performance in Cr(VI) detection, including a detection limit of 3.0 μg L−1 and a wide linear range from 0.01 μg mL−1 to 112 μg mL−1. The anti-interference, repeatability and stability of the sensor were also satisfactory. Furthermore, the recovery experiment at different concentration levels in real samples and the consistent test results with ICP AES were expected to expand the application scenarios in quantitative analysis of Cr(VI). [Display omitted] • Au@HMCC with highly ordered hollow mesoporous structure was synthesized. • Au@HMCC provided large surface area and abundant catalytic active sites. • AuNPs further improved the conductivity and amplify the current signal. • Au@HMCC/SPCE was successfully fabricated for quantitative analysis of Cr(VI). • The sensor showed a wide linear range and low detection limit. [ABSTRACT FROM AUTHOR]

A selectively modified porous metal/carbon nanocomposite was fabricated to enhance the enrichment of low-abundance phosphopeptides from biological samples. The carbon matrix derived from the metal-organic framework provides a suitable pore size to allow the diffusion of peptides, while the deliberately modified metal nanoparticles within the pores enhance their interaction with the phosphopeptides. This nanocomposite shows extremely high enrichment selectivity for phosphopeptides in the MALDI-TOF MS detection, even when the molar ratio of α-casein digests versus bovine serum albumin digests was up to about 1:20,000. By combining such nanocomposite with nano-LC-MS/MS, 4556 unique phosphopeptides were identified with high selectivity (95.2%) from HeLa cell extracts. Furthermore, phosphopeptides from prostate tissue digests were also determined. A total of 277 and 1242 phosphopeptides were identified from normal and tumor tissues of a patient with prostate cancer, respectively. This indicates that phosphorylation and prostate cancer can be related to each other. [ABSTRACT FROM AUTHOR]

An enzyme-free, metal-free, and preconcentration-free electrochemical sensor for pentachlorophenol assay has been fabricated. The interface of the sensor is based on a hollow zeolitic imidazolate framework–derived mesoporous carbon material (denoted as HZC/SPCE). The sensor exhibits linear amperometric response upon pentachlorophenol at 0.82 V (vs. Ag/AgCl) in the concentration range 0.001 to 26.8 mg L−1 (3.75 × 10−8~1.006 × 10−4 M) (R2 = 0.997). The sensitivity of HZC/SPCE is 3.53 × 102 μA mM−1 cm−2 with a detection limit of 2.05 × 10−9 M (S/N = 3) for pentachlorophenol. The method has been applied to the determination of pentachlorophenol in spiked food packaging samples with recoveries in the range 92.0 to 107.0%. [ABSTRACT FROM AUTHOR]

Gene therapy with external gene insertion (e. g. a suicide gene) and expression specifically in mutated tumor cells has shown to be a promising strategy in treatment of tumors. However, current tumor gene therapy often suffered from low efficiency in gene expression and off-target effects which may cause damage to normal tissues. To address these issues, in this study, a light-switchable transgene nanoparticle delivery system loaded with a diphtheria toxin A (DTA) segment encoded gene, a suicide gene for tumor cells, was developed. The nanoparticles contained vitamin E succinate-grafted polyethyleneimine core and arginylglycylaspartic acid (RGD)-modified pegylated hyaluronic acid shell for targeted delivery of the loaded gene to tumor cells via receptor-mediated (CD44 and αvβ3) endocytosis. Notably, the expression of target proteins in tumor cells could be conveniently regulated by adjusting the blue light intensity in the Light-On system. In in-vitro studies in cultured B16-F10 cells, the pG-DTA-loaded nano-micelles showed greatly improved inhibitory rate compared with the pG-DTA group. Moreover, in the tumor-bearing C57BL/6 mice model, the pG-DTA-loaded nanoparticle exhibited greatly improved efficacy and reduced systemic toxicity with significantly increased survival rate after 21 days. Significantly suppressed tumor angiogenesis was also identified in the nanoparticle-treated group likely due to the targeting ability of the RGD-modified nanoparticle. All the above results indicated that the combination of a light-switchable transgene system with a nanoparticle-based targeted delivery system have great potentials in gene therapy of malignant tumors with improved precision and efficacy. Unlabelled Image [ABSTRACT FROM AUTHOR]

Here we established a palm‐sized electrochemical sensor for the determination of cell‐released superoxide anions (O2.−) based on a self‐developed portable potentiostat (xenSTAT) which can perform fast analysis with visual real‐time data and customizable parameters. The xenSTAT was equipped with Bluetooth and USB interfaces, thus being able to be connected with both smartphones and computers for electrochemical analysis. A novel Nanozyme based on Mnx(PO4)y monolayer modified porous carbon cubic was synthesized and used as functional material on the surface of working electrode. By using cyclic voltammetry (CV) and chronoamperometry, xenSTAT was demonstrated to exhibit satisfying sensitivity and excellent stability for real‐time monitoring of O2.− released from cancer cells. With decreased cost, customizable development, small size and convenient usage, the xenSTAT described in this work could promote the commercialization and widespread of in‐house built electrochemical sensors for the monitoring of O2.− in the future. [ABSTRACT FROM AUTHOR]

Nanocarriers are employed to deliver photosensitizers for photodynamic therapy (PDT) through the enhanced penetration and retention effect, but disadvantages including the premature leakage and non‐selective release of photosensitizers still exist. Herein, we report a 1O2‐responsive block copolymer (POEGMA‐b‐P(MAA‐co‐VSPpaMA) to enhance PDT via the controllable release of photosensitizers. Once nanoparticles formed by the block copolymer have accumulated in a tumor and have been taken up by cancer cells, pyropheophorbide a (Ppa) could be controllably released by singlet oxygen (1O2) generated by light irradiation, enhancing the photosensitization. This was demonstrated by confocal laser scanning microscopy and in vivo fluorescence imaging. The 1O2‐responsiveness of POEGMA‐b‐P(MAA‐co‐VSPpaMA) block copolymer enabled the realization of self‐amplified photodynamic therapy by the regulation of Ppa release using NIR illumination. This may provide a new insight into the design of precise PDT. [ABSTRACT FROM AUTHOR]

Nanocarriers are employed to deliver photosensitizers for photodynamic therapy (PDT) through the enhanced penetration and retention effect, but disadvantages including the premature leakage and non‐selective release of photosensitizers still exist. Herein, we report a 1O2‐responsive block copolymer (POEGMA‐b‐P(MAA‐co‐VSPpaMA) to enhance PDT via the controllable release of photosensitizers. Once nanoparticles formed by the block copolymer have accumulated in a tumor and have been taken up by cancer cells, pyropheophorbide a (Ppa) could be controllably released by singlet oxygen (1O2) generated by light irradiation, enhancing the photosensitization. This was demonstrated by confocal laser scanning microscopy and in vivo fluorescence imaging. The 1O2‐responsiveness of POEGMA‐b‐P(MAA‐co‐VSPpaMA) block copolymer enabled the realization of self‐amplified photodynamic therapy by the regulation of Ppa release using NIR illumination. This may provide a new insight into the design of precise PDT. [ABSTRACT FROM AUTHOR]

An entirely biodegradable nano-photosensitizer platform (PPE-FP2) was fabricated by conjugating the photosensitizer TFPC to hydrophilic polyphosphoesters (PPEs) for efficiently liberating photosensitizers at the tumor site. The complete biodegradability of PPE-FP2 avoided residual nanoparticles in vivo after therapy, realizing reliable and effective photodynamic therapy. [ABSTRACT FROM AUTHOR]

The key to diagnosing acute myocardial infarction (AMI) lies in the sensitive and accurate analysis of cardiac troponin I (cTnI) content in human blood. Herein, in order to detect the content of cTnI, a novel sandwich-type cTnI electrochemical aptasensor was developed by utilizing dendritic platinum-copper alloy nanoparticles loaded on graphene-like CuO-TiO 2 mesoporous ultrathin nanosheet (PtCu DNs/MUN-CuO-TiO 2) as label material, and AuNPs loaded on polydopamine modified hollow mesoporous carbon spheres (HMCS@PDA@AuNPs) as electrode-modified material. On the one hand, with its advantages of assistance of Au and PDA coating, abundant pore structure, and large specific surface area, the HMCS@PDA@AuNPs exhibited excellent electronic conductivity but with a low catalytic capacity for the reduction of H 2 O 2 , thus enhancing the sensitivity of aptasensor. On the other hand, because of combining the structural and electrochemical performance superiority of MUN-CuO-TiO 2 and PtCu DNs, such as short electron transfer distance and abundant reactive sites, the catalytic performance of obtained PtCu DNs/MUN-CuO-TiO 2 towards H 2 O 2 reduction was enhanced and realized signal amplification. The constructed electrochemical aptasensor for cTnI detection exhibited a satisfactory dynamic range from 0.01 pg/mL to 500.0 ng/mL and a lower detection limit of 2.3 fg/mL. The recommended sensor has been utilized to detect human serum samples with acceptable results, exhibiting potential for clinical application. • A novel sandwich-type electrochemical aptasensor was constructed to detect cTnI. • HMCS@PDA@AuNPs and PtCu DNs/MUN-CuO-TiO 2 were successfully synthesized. • HMCS@PDA@AuNPs as a transducing material to enhance the conductivity. • PtCu DNs/MUN-CuO-TiO 2 as a signal amplification label showed excellent electrocatalytic performance for the reduction of H 2 O 2. • The sensitive aptasensor showed a wide dynamic range and low detection limit for detecting cTnI. [ABSTRACT FROM AUTHOR]

Cellular metabolism involves complex sequences of controlled biochemical reactions and many chemical compounds or metabolites. The quantification of these metabolites will provide information on the dynamic cellular metabolism and the effect of environmental conditions. There have been extensive studies in this field since the last few decades, including the recent developments in microfluidic-based technologies. The article aims to provide a review on the current microfluidic detection techniques for quantifying the levels of main metabolites, including glucose, lactate, pyruvate, dissolved oxygen, pH and reactive oxygen species, with a focus on continuous and/or long-term detections. Most of the current developments are towards single metabolite detection and single-point or short-time detection techniques. There is increasing effort in the detection of multiple metabolites in microfluidics with integrated cell culturing. The future developments should address several major challenges such as cell culturing, long-term and sensitive detection of multiple metabolites in the dynamic cell environment. • Increasing developments of microfluidic devices for cell metabolomic analysis. • Limited developments in sensitive and fast detection for multiple metabolites. • Urgent need for continuous and long-term detection systems. [ABSTRACT FROM AUTHOR]

Abstract In this work, magnetic mesoporous silica microspheres (Mag-MSMs) with ordered radial mesochannels were fabricated by a self-assembly synthesis in chlorobenzene-water mixed system. Then, the obtained Mag-MSMs were modified with polyethyleneimine (PEI), phytic acid (PA) and Ti4+ (denoted as Mag-MSMs@PEI-PA-Ti4+) via layer by layer (LbL) assembly. Due to the excellent hydrophilicity of PEI and PA and the large amount of Ti4+, the Mag-MSMs@PEI-PA-Ti4+ possessed combined properties of hydrophilic interaction liquid chromatography (HILIC)- and immobilized metal ion affinity chromatography (IMAC)-based materials, which could be used as a dual-purpose material for N-glycopeptides or phosphopeptides enrichment. The proposed Mag-MSMs@PEI-PA-Ti4+ exhibited an outstanding performance for N-glycopeptides enrichment (selectivity: IgG/BSA = 1:1000; sensitivity: 0.5 fmol/μL IgG) and phosphopeptides enrichment (selectivity: α-casein/BSA=1:5000; sensitivity: 0.2 fmol/μL α-casein). Furthermore, after enrichment with Mag-MSMs@PEI-PA-Ti4+, a total of 276 N-glycopeptides assigned to 132 glycoproteins were identified from 2 μL human serum and 1645 phosphopeptides corresponding to 704 phosphoproteins were identified from 200 μg HeLa cell extracts. Graphical abstract fx1 Highlights • A dual-purpose affinity material (Mag-MSMs@PEI-PA-Ti4+) with combined properties of HILIC- and IMAC-based materials was fabricated for highly efficient enrichment of glycopeptides/phosphopeptides. • Phytic acid as chelating ligands has a strong affinity for metal ions and excellent hydrophilicity. • Mag-MSMs@PEI-PA-Ti4+ had high selectivity and sensitivity for glycopeptides/phosphopeptides enrichment. [ABSTRACT FROM AUTHOR]

Abstract As pyrophosphate ion (PPi) and pyrophosphatase (PPase) play crucial roles in the pathological process of arthritis, determination of PPi and PPase in biological fluids turns to be of great importance for clinical diagnosis and therapy of arthritic diseases. In this work, we proposed a new fluorescent assay for PPi and PPase activity detection based on the competitive coordination chemistry of Fe3+ between PPi and an in situ formed fluorescent polydopamine (PDA). FeCo layered double hydroxide (FeCo-LDH) was explored as a peroxidase mimic to facilitate the in situ formation of fluorescent PDA from dopamine mediated by low-concentration H 2 O 2 within 30 min; The formed fluorescent PDA could be significantly quenched by Fe3+ through forming a PDA-Fe3+ complex structure; When PPi existed, it coordinated Fe3+ competitively against PDA and inhibited the fluorescence quenching of PDA by Fe3+; When PPi was hydrolyzed under the catalysis of PPase, the Fe3+ ion could quench the fluorescence of the formed PDA again. With these principles, our fluorescent assay was able to detect PPi and PPase activity specifically, providing detection limits down to 54 μM and 0.13 U/L, respectively. Furthermore, accurate determination of PPi and PPase activity in spiked human serum was also demonstrated using the developed assay. Graphical abstract Image 1 Highlights • In situ rapid synthesis of fluorescent PDA catalyzed by FeCo-LDH with low-concentration H 2 O 2. • Fe3+ significantly quenches the fluorescent PDA. • Coordination between PPi and Fe3+ inhibits the fluorescence quenching of PDA. • After PPase hydrolyzes PPi, the Fe3+ ion quenches the fluorescent PDA again. • The fluorescent PDA as a new probe for detection of PPi and PPase activity. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Cancer immunotherapy is considered to be one of the alternatives to traditional chemotherapy. It's known that foreign antigen, such as ovalbumin (OVA), can label tumor cells, leading to neoantigen recognition by cytotoxic T lymphocytes. Herein, a novel multifunctional micelle coated with PEGylated hyaluronic acid (HA) was prepared through self-assembly and electrostatic interaction. The OVA-loaded micelle with uniform size (132.1 ± 0.2 nm in diameter) exhibited favorable stability and sustained release profiles. The HA-coated micelle could target CD44-overexpressed cells and enhance the cellular uptake of OVA by 11.9 fold compared to free OVA. In vitro studies revealed that the cationic polymer, polyethyleneimine, could facilitate endosomal escape of OVA to label a tumor cell. After treatment with the OVA-loaded micelle, tumor growth in mice was significantly inhibited by 70% compared to the group treated with free OVA. All these results suggest the potential application of the immunotherapeutic micellar platform for melanoma treatment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hg2+-stimulated peroxidase-mimicking activity of Cys-Fe 3 O 4. • Almost no enzymatic activity observed in the as-synthesized Cys-Fe 3 O 4. • Hg2+ despoils Cys from the Fe 3 O 4 surface and leads to the exposure of active Fe 3 O 4. • Ultrasensitive sensing of trace Hg2+ in environmental and biological fluids. Abstract In this work, we developed a novel strategy for ultrasensitive Hg2+ detection based on the Hg2+-triggered peroxidase-mimicking activity of a cysteine-decorated ferromagnetic particle (Cys-Fe 3 O 4). The as-synthesized Cys-Fe 3 O 4 exhibited almost no peroxidase-like activity due to the Cys―Fe coordinative interaction and subsequently blocking of active sites on Fe 3 O 4 by the Cys outerwear. In contrast, in the presence of Hg2+, surface Cys could be despoiled from the Cys-Fe 3 O 4 particles by a stronger Cys-Hg2+-Cys coordination, resulting in the exposure of active Fe 3 O 4 that could catalyze the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into blue TMBox. The Cys-Fe 3 O 4 particles were then employed to fabricate a colorimetric Hg2+ nanosensor. We found that the fabricated enzyme-mimicking biosensor enabled to monitor Hg2+ in a linear range of 0.02–90 nM, providing a limit of detection down to 5.9 pM. The enzyme-mimetic nanosensor also exhibited excellent selectivity for Hg2+ sensing against other common metal ions thanks to the strong coordinative interaction between Cys and Hg2+. Further, the nanosensor was applied to determine trace Hg2+ in environmental and biological fluids. Despite the relatively complex components of these samples, the enzyme-like biosensor still showed excellent accuracy, demonstrating its great promise in environmental monitoring and clinical examination. [ABSTRACT FROM AUTHOR]

Abstract Quantification of superoxide anions (O 2 −) is of great significance for the pathological research of many diseases. In this work, a non-enzymatic electrochemical sensor for superoxide sensing was fabricated on the basis of metal-organic frameworks (MOFs)-derived porous carbon matrix loaded with Pt and Co nanoparticles (denoted as Pt-Co-PC). Zeolitic imidazolate framework-67 (ZIF-67) was utilized as the precursor through a one-step calcination under N 2 atmosphere to prepare cobalt nanoparticles-porous carbon composites (denoted as Co-PC). Pt-Co-PC was then obtained by using a facile galvanic replacement procedure with Co-PC and chloroplatinic acid solution. Furthermore, the home-made screen printed gold electrodes (SPGEs) were used to immobilize the as-synthesized materials, constructing Pt-Co-PC modified electrochemical sensors. The recommended Pt-Co-PC/SPGE sensors exhibit excellent electrochemical performance for the detection of O 2 − with an extremely low detection limit of 0.118 μM (S/N = 3) and a high sensitivity of 6.218 × 10−4 mA μM−1 cm−2. Meanwhile, the proposed sensors possess superior reproducibility and stability. More importantly, our sensors have successfully captured the electrochemical signals of O 2 − released from Hela cells, which means the fabricated sensors have potential application of monitoring O 2 − in pathological and biological fields. Highlights • A facile method to fabricate porous carbon matrix loaded with Pt and Co nanoparticles. • A novel non-enzymatic O 2 − sensor was established. • The recommended sensors can successfully capture the electrochemical signals of O 2 − released from Hela cells. [ABSTRACT FROM AUTHOR]

Abstract In this work, we presented a facile elution-free method for ultrasensitive enrichment of glycopeptides using two kinds of novel Ce-metal-organic frameworks (Ce-MOF) post-modified with hyaluronic acid (Ce-MOF@HA) and glutamic acid (Ce-MOF@Glu). Both of the synthesized materials remained stable in the loading buffer to enrich glycopeptides selectively and degrade in the eluent to release captured glycopeptides. Due to the dissolution of materials, the elution step of the enrichment process is omitted, resulting in an extremely high sensitivity (detection limit, 0.5 fmol/μL). Meanwhile, Ce-MOF@HA and Ce-MOF@Glu also possessed excellent selectivity with molar ratios of IgG and BSA digests being 1:1000 and 1:500, respectively. Noticeably, the practical applicability of the obtained materials was inspected by analyzing the glycopeptides enriched from human serum (2 μL) by nano-LC-MS, in which 434 N-glycopeptides from 182 N-glycoproteins (by Ce-MOF@HA) and 328 N-glycopeptides from 135 N-glycoproteins (by Ce-MOF@Glu) were detected, respectively. This work provides a new method to simplify the process of glycopeptides enrichment and also paves a novel way for the enrichment of trace targets from complex matrices. Graphical abstract Image 1 Highlights • A new facile elution-free method was developed for glycopeptides enrichment by utilizing degradable post-modified Ce-MOFs. • The enrichment sensitivity was great because the loss of glycopeptides caused by incomplete elution was avoided. • The recommended method was successfully applied to the detection of glycopeptides enriched from human serum by nano-LC-MS. [ABSTRACT FROM AUTHOR]

Abstract Here we present a new method to fabricate enzyme-mimic metal-free catalysts for electrochemical detection of superoxide anion (O 2 •−) by introducing phosphate groups into graphene-based foam. Through a template-free hydrothermal process, graphene oxide (GO) was treated with different amount of phytic acid (PA) to obtain 3D porous graphene-based foam (PAGF). Characterizations demonstrate that phosphate groups were successfully modified on the surface and inter layer structure of PAGF materials and the defects and disorder degree of PAGF could be controlled by adjusting the addition of PA precursors. Meanwhile, the synthesized PAGF was successfully immobilized on screen printed carbon electrodes (SPCEs) and employed in O 2 •− detection. With PA treated on graphene structure, the resulted PAGF/SPCEs exhibit distinct characteristic redox peaks, showing enzyme-mimic catalytic activity toward O 2 •− dismutation. Also, the amount of modified phosphate groups has caused a considerable variety on the performance of PAGF-based electrodes. Apart from high sensitivity, wide liner range, low detection limit, good selectivity and long-term stability, our sensors also present satisfying performance in the real-time monitoring of drug-induced O 2 •− released from Hela cells. The reliability of the biological measurement was further demonstrated via electron paramagnetic resonance (EPR) to characterize the released O 2 •− from stimulated cells by using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) to trap the transient O 2 •−. The above results indicate that our established sensors hold potential application in the real-time detection of O 2 •− in biological samples. Highlights • A facile method to fabricate carbon-based Nanozyme with SOD-mimic activity. • The recommended sensor exhibit stable current steps toward cell-released O 2 •−. • The electrochemical determination of cell-released O 2 •− was further confirmed by using EPR. [ABSTRACT FROM AUTHOR]

Abstract The detection of superoxide anions (O 2 •−) is widely considered as a potential way for cancer diagnosis and the development of enzyme-mimic catalysts is the main challenge in the establishment of electrochemical sensors for O 2 •− sensing in real samples. Here we present a novel enzyme- and metal-free electrochemical catalyst for superoxide (O 2 •−) sensing based on the widely-used carbon nanotubes (CNT). Through a one-step hydrothermal process induced by phytic acid (PA), CNT-based porous foam (PACNTF) was successfully obtained. Characterizations demonstrated the enhanced defect and disorder degree of PACNTF after PA treatment, which leaded to the increased active sites of PACNTF for electron transfer and the adhesion of O 2 •− during the electrochemical process. As a result, the PACNTF presented higher conductivity and larger current response toward O 2 •− sensing when compared with CNT precursor and CNTF without PA treatment. The sensitivity of PACNTF/SPCE was calculated to be 1230 μA cm-2 mM-1 in the linear range of 0–193.6 μM (R2 = 0.965) and 373 μA cm-2 mM-1 in the linear range of 193.6–1153.6 μM (R2 = 0.995) with a limit of detection of 0.16 μM (S/N = 3). Further, the PACNTF/SPCE presented fast response toward cell-released O 2 •− stimulated by Zymosan A. The above results indicated that the fabricated sensor holds potential usage in biological samples. Graphical abstract Image 1 Highlights • A facile way to fabricate carbon-based porous foam for O 2 •− sensing from widely-used carbon nanotubes. • The improved activity of PACNTF was attributed to the enhanced defect and disorder degree. • The recommended sensor successfully caught the transient signal of cell-released O 2 •−. [ABSTRACT FROM AUTHOR]

Surface charge engineering of nanosized CuS via acidic amino acid modification is proved to be an efficient strategy to realize high peroxidase-mimicking catalytic activity at neutral pH. As a proof-of-concept application, one-pot high-performance colorimetric sensing of glucose by coupling the engineered nanozyme with glucose oxidase is realized. [ABSTRACT FROM AUTHOR]

In this work, we proposed a new and facile strategy for the high-performance colorimetric detection of Ag + based on the tunable peroxidase-like activity of Pd nanoparticles (NPs) mediated by histidine (His). Bare Pd NPs possess intrinsic catalytic ability to trigger the oxidation of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue TMBox in the presence of H 2 O 2 . After being decorated by His, the formed His-Pd nanozyme exhibits significantly improved mimetic activity due to its favorable physicochemical characteristics including smaller size, interactions between Pd and His, and better hydrophilicity, and such that an enhanced TMB color reaction is observed. When Ag + exists, it is able to despoil the His modifier from the His-Pd surface via the specific interaction between Ag + and His, resulting in the bald Pd again with weak activity. With this principle, highly sensitive determination of Ag + in a linear scope of 30–300 nM was achieved with a limit of detection down to 4.7 nM. In addition, the colorimetric sensor based on the tunable enzymatic activity of nanosized Pd adjusted by His could provide excellent selectivity for Ag + sensing against common interferents. Reliability of the strategy for practical detection of Ag + was also demonstrated. [ABSTRACT FROM AUTHOR]

• CeO 2 /Co 3 O 4 materials with porous structure by calcination of ZIF-67. • The CeO 2 /Co 3 O 4 nanocomposites show high electrochemical activity towards DA. • The synergistic effect of CeO 2 /Co 3 O 4 enhances the electrocatalytic properties. • Sensor has excellent selectivity and reproducibility for dopamine in real samples. In the field of biosensing and disease diagnosis, rapid and sensitive detection of dopamine (DA) is essential. In this work, Co 3 O 4 with a porous structure was prepared by temperature-controlled calcination of the precursor template zeolite imidazole framework-67 (ZIF-67), and CeO 2 /Co 3 O 4 composites with a porous framework structure were prepared by hydrothermal methods. The porous structure of the Co 3 O 4 prevented the aggregation of the CeO 2 nanoparticles and allowed them to be dispersed in a uniform manner on the surface. The CeO 2 introduction led to changes in the specific surface area and pore size of the calcined Co 3 O 4 material, and more active sites were exposed, allowing better binding with CeO 2 thus achieving good catalytic performance and excellent synergistic properties. The CeO 2 /Co 3 O 4 modification on the surface of glassy carbon electrodes (GCE) showed good electrocatalytic activity, which was superior to that of pure Co 3 O 4 and CeO 2 , as determined by electrochemical methods, thanks to. The results show that CeO 2 /Co 3 O 4 /GCE has a limit of detection (LOD) of 0.13 μM for DA (S/ N = 3) and a linear range of 0.13 μM-60 μM, as well as good interference resistance and reproducibility. This work provides a new solution for excellent dopamine sensors in Co 3 O 4 and CeO 2 composites, which can be extended to other biosensing applications. Schematic diagram of a glassy carbon electrode based on CeO 2 /Co 3 O 4 nanocomposite for DA determination. [Display omitted] [ABSTRACT FROM AUTHOR]

Association of R848 and targeted ferric oxide nanoparticles coated with polydopamine to mediate photothermal immunotherapy for breast cancer therapy. [Display omitted] Breast cancer, which requires comprehensive multifunctional treatment strategies, is a major threat to the health of women. To develop multifunctional treatment strategies, we combined photothermal therapy (PTT) with immunotherapy in multifunctional nanoparticles for enhancing the anti-tumor efficacy. Fe 3 O 4 nanoparticles coated with the polydopamine shell modified with polyethylene glycol and cyclic arginine-glycyl-aspartic peptide/anisamide (tNP) for loading the immune adjuvant resiquimod (R848) (R848@tNP) were developed in this research. R848@tNP had a round-like morphology with a mean diameter of 174.7 ± 3.8 nm, the zeta potential of −20.9 ± 0.9 mV, the drug loading rate of 9.2 ± 1.1 %, the encapsulation efficiency of 81.7 ± 3.2 %, high photothermal conversion efficiency and excellent magnetic properties in vitro. Furthermore, this research also explored the anticancer efficacy of nanoparticles against the breast cancer under the near-infrared (NIR) light (808 nm) in vitro and in vivo. R848@tNP-based NIR therapy effectively inhibited the proliferation of breast cancer cells. Moreover, R848@tNP mediated PTT significantly enhanced the maturation of dendritic cells in vitro. Additionally, R848@tNP enhances the anti-tumor effect and evoked an immune response under NIR in vivo. Furthermore, the biosafety of R848@tNP was fully investigated in this study. Collectively, these results clearly demonstrate that R848@tNP, with magnetic resonance imaging characteristics, is a potential therapeutic for breast cancer that combines PTT with the immunotherapy. [ABSTRACT FROM AUTHOR]

The determination of cardiac troponin I (cTnI) and myoglobin (Myo) is increasingly significant considering their potential in acute myocardial infarction (AMI) diagnosis. Here, we constructed a sandwich-type electrochemical aptasensor for the simultaneous detection of cTnI and Myo. The polydopamine-Au-metal ions (PDA-Au-Pb2+/Cu2+) were synthesized and used as the labels of second aptamers (TrO6 and S232). The labels displayed different peaks at different potential sites, thus making the simultaneous detection method available. Meanwhile, the synthesized zirconium-based carbon architecture (CC) was well-conductive originating from the annealing process. After the modification of CC on the bare electrode (screen-printed carbon electrode, SPCE), the coralloid Au (CAu) was further decorated on the electrode by electro-deposition, thus forming CAu/CC/SPCE with high conductivity. Hence, the aptasensor proposed here showed admirable simultaneous quantitative analysis performance towards cTnI and Myo with wide linear ranges (1 μg/mL-0.01 pg/mL, 1 μg/mL-0.1 pg/mL) and low detection limits (3.8 fg/mL, 35 fg/mL). These results demonstrated that the aptasensor held the potential application in clinical diagnosis. ● An electrochemical aptasensor was fabricated based on CAu/CC and PDA-Au-Pb2+/Cu2+. ● The CAu/CC exhibited high electronic conductivity, thus improving sensitivity. ● The labels PDA-Au-Pb2+/Cu2+ made the simultaneous detection available. ● The aptasensor showed good performance for the simultaneous detection of cTnI+Myo. ● The portable aptasensor further showed its potential application in on-site analysis. [ABSTRACT FROM AUTHOR]

Quantifying multiple biomarkers with high sensitivity in tiny biological samples is essential to meet the growing demand for point-of-care testing. This paper reports the development of a novel microfluidic device integrated with mass-producible micropillar array electrodes (μAEs) for multiple biomarker detections. The μAE are mass-fabricated by soft lithography and hot embossing technique. Pt–Pd bimetallic nanoclusters (BNC) are modified on the surface of μAEs by constant potential (CP)/multi-potential step (MPS) electrodeposition strategies to improve the electroanalytical performance. The experimental result displays that Pt–Pd BNC/μAEs have good sensitivity enhancement compared with bare planar electrodes and bare μAEs, the enhancement being 56.5 and 9.5 times respectively, from the results of the H 2 O 2 detection. Furthermore, glucose, uric acid and sarcosine were used as model biomarkers to show the biosensing capability with high sensitivity. The linear range and LOD of the glucose, uric acid and sarcosine detection are 0.1 mM–12 mM, 10 μM–800 μM and 2.5 μM–100 μM, 58.5, 3.4 and 0.4 μM, respectively. In particular, biosensing chips show wide linear ranges covering required detection ranges of glucose, uric acid and sarcosine in human serum, indicating the developed device has great potential in self-health management and clinical requirements. [Display omitted] • Mass-producible micropillar array electrodes have been developed. • Pt–Pd nanoclusters were modified to improve performance. • The device performs glucose, uric acid and sarcosine detection. [ABSTRACT FROM AUTHOR]