The application of the inexpensive and synthetically simple electrocatalyst CuFe-MoC@NG in immunosensors.

In this study, we used inexpensive and synthetically simple electrocatalysts as replacements for conventional precious metal materials to reduce hydrogen peroxide (H2O2). We for the first time developed N-doped graphene-coated CuFe@MoC using one-step calcination of binary Prussian blue analogues (PBAs) with Mo6+ cationic grafting precursors. The synergistic interaction of CuFe PBA and MoC increased the catalytically active sites for H2O2 reduction. The catalyst was optimized in terms of the ratio of CuFe PBA to Mo6+, PVP content, and calcination temperature to improve its catalytic activity. When it was used to construct an electrochemical immunosensor for carcinoembryonic antigen (CEA) detection, polydopamine (CuFe-MoC@NG@PDA) was coated on its outer surface to increase the antibody loading and MoS2-Au NPs were used as substrates to improve Ab1 immobilization and accelerate electron transfer at the electrode interface, thereby improving the response signal of the immunosensor. Its concentration was linearly related to the response signal from 10 fg mL-1 to 80 ng mL-1, and the lowest limit of detection was 3 fg mL-1. In addition, the immunosensor has acceptable selectivity and high stability. All data indicate that nanocomposites have electrocatalytic applications.

Differences in Performance of Immunosensors Constructed Based on CeO2-Simulating Auxiliary Enzymes.

The morphology effect of cerium oxide (CeO2) has always been the focus of catalysis research. Few people have reported the relationship between the morphology of CeO2 and electrochemical performance in sensors. In this paper, a polyaniline (PANI) matrix is used as the dispersant and stabilizer, ultrafine Au nanoparticles (NPs) (Au@PANI) are uniformly embedded in the PANI matrix, and Au NPs@PANI is fixed on the surface of CeO2 with different morphologies and sizes (Spindle CeO2:(SCe), octahedron CeO2 (OCe)). The morphology and crystal structure of CeO2 were adjusted under different ratios of ethanol and water, and the effect of CeO2 was evaluated. The synthesized CeO2-Au@PANI has different morphologies, sizes, and electrochemical properties. The electrochemical catalytic behavior of CeO2-Au@PANI was studied by using hydrogen peroxide (H2O2) as the reaction substrate. The instantaneous current method (I-T) was used to further study the electrochemical amplification effect, and the best performance was obtained.

Ultrasensitive electrochemical immunosensor based on the signal amplification strategy of the competitive reaction of Zn2+ and ATP ions to construct a "signal on" mode GOx-HRP enzyme cascade reaction.

A GOx/HRP@ZIF-90 nanomaterial is proposed by coating GOx and HRP in ZIF-90 using a bio-simulated mineralization method to improve the tolerance of the enzyme to the external environment. In the detection process, the ZIF-90 is turned on under mild conditions by the competitive reaction of ATP with Zn2+ and imidazole-2-carboxaldehyde (2-ICA), and the electrical signal of the system is amplified by the enzyme cascade reaction of GOx and HRP. Finally, based on the signal amplification strategy of the competitive reaction between Zn2+ and ATP to construct a "signal on" mode, electrochemical immunosensor of GOx-HRP enzyme-linked cascade reaction was prepared. The proposed electrochemical immunosensor shows an excellent analytical performance when detecting CA-125, with good selectivity and stability, with a detection range of 0.1 pg mL-1-40 ng mL-1 and a detection limit of 0.05 pg mL-1. The test has been performed using chronoamperometry under a constant voltage of -0.4 V. The immunosensor also shows an excellent performance when analysing human blood samples. The recovery of the immunosensor is 97.94-101.8%, with a relative standard deviation of 3.7-6.1%. The proposed sensor provides a novel idea for clinical use of GOx and HRP enzymes and a new method for the clinical detection of tumor markers.

Bimetallic PtCu nanoparticles supported on molybdenum disulfide-functionalized graphitic carbon nitride for the detection of carcinoembryonic antigen.

A molybdenum disulfide based graphite phase carbon nitride (MoS2/g-C3N4) which is supported by a platinum-copper nanoparticle (PtCu) Z-type catalyst was created in this study. The catalyst exploits optoelectronic synergistic effect with large surface area, good catalysis, and biocompatibility to amplify the signal. The electrode impedance of the synthesized MoS2/g-C3N4-PtCu was reduced five times in visible light compared with dark conditions, thereby improving the detection of carcinoembryonic antigen (CEA). At a voltage of - 0.4 V, the immunoprobe constructed with this material is used for CEA detection. A linear relationship between 100 fg mL-1 and 80 ng mL-1 concentrations was achieved with a minimum detection limit of 33 fg mL-1 (S/N = 3). The recovery rate was 103-104%, and the relative standard deviation was 2.9-3.8%. This implies that the sandwich immunosensors have good reproducibility, selectivity, and stability and can be used in various applications. Graphical Abstract.

A sandwich-type electrochemical immunosensor for ultrasensitive detection of multiple tumor markers using an electrical signal difference strategy.

Traditional sandwich-type electrochemical immunosensors can only detect single tumor markers because signal interference occurs when detecting multiple tumor markers. In this work, an electrical signal difference strategy was proposed for the accurate detection of multiple tumor markers. We labeled PdAgCeO2 mesoporous nanospheres with a carcinoembryonic antigen (CEA) secondary antibody and MnO2 nanosheets labeled with an alpha-fetoprotein (AFP) secondary antibody. The two electrical signal tags were mixed and incubated on a prepared immunosensor to catalyze H2O2 and generate an electrical signal I1 (i-t ampere curve). When 2.5 mM ascorbic acid solution (AA) was added to 20 mL of PBS solution at pH = 6.5 for 180 s, an electrical signal I2 was generated. I2 was the current response of the CEA antigen concentration, and the electrical signal difference ΔI = I1-I2 was the current response of the AFP antigen. Thus, the immunosensor accurately detected the AFP and CEA tumor markers. This method was called the electrical signal difference strategy. The proposed single-use immunosensor detected CEA antigens in a range of 0.001 ng/mL-40 ng/mL, and the detection limit was 0.5 pg/mL; the detection range of the AFP antigen was 0.005 ng/mL-100 ng/mL, and the detection limit was 1 pg/mL. Therefore, this study provides new ideas and strategies for accurate clinical detection of multiple tumor markers.

A sandwich-type electrochemical immunosensor for detecting CEA based on CeO2-MoS2 absorbed Pb2.

A sandwich-type immunosensor for detecting the concentration of carcinoembryonic antigen (CEA) was prepared. In this work, gold nanoparticles (Au NPs) were used as platform to attach more primary antibody (Ab1) due to excellent electrical conductivity and good biocompatibility. Molybdenum disulfide-Cerium oxide (CeO2-MoS2) nanohybrid was used as a carrier to absorb lead ions (Pb2+) and the second antibody (Ab2). CeO2-MoS2-Pb2+-Ab2 was used as a nanoprobe to detect CEA antigen. Under optimal conditions, square wave voltammetry (SWV) successfully displayed the electrical signal of Pb2+. The designed electrochemical immunosensor has excellent analytical performance. In addition, the detection range was 0.001-80 ng/mL and the minimum detection limit was 0.3 pg/mL (S/N = 3), which had good selectivity and stability. Finally, the proposed immunosensor successfully detected the concentration of CEA in the serum of the sample, which provided a feasible method for CEA testing.

Sensitive detection of carcinoembryonic antigen (CEA) by a sandwich-type electrochemical immunosensor using MOF-Ce@HA/Ag-HRP-Ab2 as a nanoprobe.

Sandwich-type electrochemical immunosensor was one of the main methods for detecting carcinoembryonic antigen (CEA). In this work, using Ce-MoF as the skeleton precursor, hyaluronic acid (HA) was coated on the surface of Ce-metal organic framework (Ce-MoF), which loaded with silver nanoparticles (Ag NPs) and horseradish peroxidase (HRP) to catalyze H2O2 and double amplified the current signal. Thus, a sensitive sandwich-type electrochemical immunosensor (Ce-MoF@ HA/Ag-HRP) was designed to detect carcinoembryonic antigen (CEA). The designed immunosensor used Au NPs to enhance the ability of attach more the first antibody (Ab1). This was due to Au NPs had good electrical conductivity and biocompatibility to accelerate electron transfer on the surface of the electrode. HA was riched in -COOH, -OH and had excellent biocompatibility, which can carry more Ag NPs to catalyze H2O2. Finally, the prepared sandwich-type electrochemical immunosensor had excellent biocompatibility and great catalytic performance. The immunosensor can be tested within 30 min and the logarithm of the current signal and CEA concentration showed a broad linear response range of 1 pg ml-1-80 ng ml-1, and the detection limit of CEA was 0.2 pg ml-1. More importantly, the proposed immunosensor had good reproducibility, selectivity, stability and without matrix effect. This confirmed that the proposed immunosensor had broad prospects in early clinical trials.

Sandwich-type electrochemical immunosensor constructed using three-dimensional lamellar stacked CoS2@C hollow nanotubes prepared by template-free method to detect carcinoembryonic antigen.

Effective treatment of cancer depends on early detection of tumor markers. In this paper, an effective template-free method was used to prepare CoS2@C three-dimensional hollow sheet nanotubes as the matrix of the immunosensor. The unique three-dimensional hybrid hollow tubular nanostructure provides greater contact area and enhanced detection limit. The CoS2@C-NH2-HRP nanomaterial was synthesized as a marker and had a high specific surface area, which can effectively improve the electrocatalytic ability of hydrogen peroxide (H2O2) reduction while increasing the amount of capture-fixed carcinoembryonic antigen antibody (anti-CEA). In addition, the co-bonded horseradish peroxidase (HRP) can further promote the redox of H2O2 and amplify the electrical signal. Carcinoembryonic antigen (CEA) was quantified by immediate current response (i-t), and the prepared immunosensor had good analytical performance under optimized conditions. The current signal and the concentration of CEA were linear in the range of 0.001-80 ng/mL, and the detection limit was 0.33 pg/mL (S/N = 3). The designed immunosensor has good selectivity, repeatability and stability, and the detection of human serum samples shows good performance. Furthermore, electrochemical immunosensor has broad application prospects in the clinical diagnosis of CEA.

[Anaplastic lymphoma kinase-positive adenocarcinoma of lung: a cytopathologic analysis].

OBJECTIVE: To study the cytomorphologic features of anaplastic lymphoma kinase (ALK)-rearranged pulmonary adenocarcinoma. METHODS: The morphologic features in 153 pulmonary adenocarcinoma cytology specimens encountered during the period from September, 2011 to April, 2015 in Shanghai Cancer Hospital were retrospectively reviewed. Fluorescence in-situ hybridization (FISH) and/or immunohistochemistry (Ventana D5F3) for ALK gene rearrangement were carried out. The samples studied included 34 pleural effusion specimens, 40 endobronchial ultrasound-guided transbronchial needle aspirates (EBUS-TBNA) and 79 fine needle aspirates of palpable masses on body surface. RESULTS: Thirty-nine cases (25.5%) of ALK-rearranged samples were identified by FISH and/or immunohistochemistry, including 3 cases diagnosed by FISH and 36 cases by both technologies. The median age of the ALK-positive group was 50 years, significantly younger than that of the ALK-negative group (60 years old, P = 0.002). Only 4 of the ALK-positive patients were smokers, which was significantly less than that of the ALK-negative group (P < 0.01). In ALK-positive group, 3 cases showed cribriform pattern with prominent nucleoli, 3 cases showed cribriform pattern with mucin-rich cells and 8 cases showed extracellular mucus with mucin-rich cells. The above cytomorphologic patterns were significantly less common in ALK-negative tumors (P < 0.01). CONCLUSIONS: ALK-rearranged lung adenocarcinoma is associated with certain distinctive morphologic patterns, including cribriform architecture, presence of prominent nucleoli, mucin-rich cells and extracellular mucus, which can be observed in cytology specimens (including conventional smears and cell block sections). These findings, when combined with clinical features, may give clues to detection of ALK-positive cases.

[Cytogenetic analysis of childhood acute lymphoblastic leukemia].

OBJECTIVE: To characterize the genetic aberrations in pediatric acute lymphoblastic leukemia (ALL). METHODS: Ninety ALL cases were enrolled in the study from January 2009 to November 2011. Chromosome banding analysis and fluorescence in situ hybridization (FISH) were used to detect genetic aberrations. RESULTS: (1) Chromosome analysis: 35 (53.0%) of 66 cases who had metaphase were abnormal, and 24 cases had no metaphase. (2) FISH analysis: among the 31 cases who had normal karyotypes and 24 who had no metaphase detected by chromosome banding technique, 7 (22.6%) and 14 (58.3%) cases were abnormal detected by FISH, respectively. There were no statistically significant differences compared with chromosome analysis (P = 0.655). Among these 55 ALL cases TEL/AML1, bcr-abl and MLL fusion genes were observed in 16 (29.1%), 3(5.5%) and 2(3.6%) cases, respectively. (3) Cytogenetic aberration was observed in 56 of total 90 ALL cases (62.2%). CONCLUSIONS: Cytogenetic changes are common in childhood ALL. Conventional cytogenetic study could reliably detected chromosomal abnormalities for ALL with assessable metaphase. FISH should be used as a complementary method for ALL patients who have poor chromosomal morphology or no metaphase cells, and combination of both methods can improve the detection rate of genetic abnormalities in childhood leukemia.

Osmotic stabilizer-coupled suppression of NDR defects is dependent on the calcium-calcineurin signaling cascade in Aspergillus nidulans.

Establishment and maintenance of cell polarity are coordinated by signaling pathways such as NDR (nuclear Dbf2-related) protein-kinase signaling and calcium signaling pathway. The NDR family of kinase is structurally related to the human myotonic dystrophy kinase, which, when impaired, confers a disease that involves changes in cytoarchitecture and ion homeostasis. CotA kinase, a member of the NDR protein kinase family, forms a complex with MobB to regulate cell polarized growth in Aspergillus nidulans. Our previous study demonstrated that mobB/cotA defects could be suppressed by the osmotic stress in the presence of external calcium. In this study, via the genetic and molecular approach, we further demonstrated that Ca(2+)-permeable stretch-activated nonselective cation channel-MidA, calcium/calmodulin-dependent protein phosphatase catalatic subunit-CnaA and external calcium, but not voltage-gated calcium channel homolog-CchA, were required for the osmotic stabilizer-coupled suppression. The up-regulation of calcium/calcineurin signaling pathway induced by osmotic stress might be the reason for bypassing the requirements of NDR kinase complex, which is otherwise necessary for polar morphogenesis. Our results suggest that calcium-calcineurin signaling pathway coordinates with MobB/CotA kinase complex in regulating polarity growth via maintaining cellular calcium homeostasis. However, CchA may act differently as other components in calcium signaling pathway in Aspergillus nidulans. These findings provide an excellent opportunity to identify the potential pathway linking NDR protein-kinase network to calcium signaling pathway.

Localization and function of calmodulin in live-cells of Aspergillus nidulans.

Calmodulin (CaM) is a small, eukaryotic protein that reversibly binds Ca(2+). Study of CaM localization in genetically tractable organisms has yielded many insights into CaM function. Here, we described the dynamic localization of Aspergillus nidulans CaM (AnCaM) in live-cells by using recombination strains with homologous, single cross-over insertions at the target gene which placed the GFP fused copy under the inducible alcA promoter and the RFP-CaM integration under the native cam promoter. We found that the localization of CaM fusion was quite dynamic throughout the hypha and was concentrated to the active growing sites during germination, hyphal growth, cytokinesis and conidiation. The depletion of CaM by alcA promoter repression induced the explicit abnormalities of germlings with the swollen germ tubes. In addition, the position of highly concentrated GFP-CaM in the extreme apex seemed to determine the hyphal orientation. These data collectively suggest that CaM is constantly required for new hyphal growth. In contrast to this constant accumulation at the apex, GFP-CaM was only transiently localized at septum sites during cytokinesis. Notably, depletion of CaM caused the defect of septation with a completely blocked septum formation indicating that the transient CaM accumulation at the septum site is essential for septation. Moreover, the normal localization of CaM at a hyphal tip required the presence of the functional actin cytoskeleton and the motor protein KipA, which is indispensable for positioning Spitzenkörper. This is the first report of CaM localization and function in live-cells by the site-specific homologous integration in filamentous fungi.