Colorimetric Immunosensor Based on Au@g-C3N4-Doped Spongelike 3D Network Cellulose Hydrogels for Detecting α-Fetoprotein.

A colorimetric immunoassay is a powerful tool for detecting tumor markers, with outstanding advantages of visualization and convenience. This study designed a colorimetric immunoassay using the antibody/antigen to control the catalytic activity to be "switched on/off". This system, where Au NPs (18.5 ± 3.9 nm) were loaded on the g-C3N4 nanosheets that were fixed in a three-dimensional porous cellulose hydrogel, was used as a binding site for the antibody/antigen. After being incubated with an antibody of a cancer marker, the turned-off catalytic sites on Au NPs in Au@g-C3N4/microcrystalline cellulose hydrogels would not be "turned on" until the corresponding antigen was added. The number of the recovered Au active sites was related to the amount of the antigen added. The Fourier transform infrared and X-ray photoelectron spectroscopy measurements did not detect the existence of Au-S bonds. Catalyzed by the turned-on Au NPs, 4-nitrophenol was reduced to 4-aminophenol accompanied by a color fading. The color and the absorption spectrum changes in the process were used as the colorimetric quantitative basis for immunoassays. The colorimetric immunoassay showed a linear relationship with the liver cancer marker (α-fetoprotein, AFP) in the range of 0.1-10 000 ng/mL with the detection limit of 0.46 ng/mL. In addition, 4-nitrophenol had a significant color fading when the AFP concentration exceeded the healthy human threshold. The clinical patient's serum test results obtained from the developed colorimetric immunosensor were consistent with those obtained from the commercial enzyme-linked immunosorbent assay. Furthermore, the immunosensor exhibited a good selectivity, repeatability, and stability, which demonstrated its potential for practical diagnostic application.

Asymmetrically coated LAGP/PP/PVDF-HFP composite separator film and its effect on the improvement of NCM battery performance.

Li1.5Al0.5Ge1.5(PO4)3 (LAGP) is an inorganic solid electrolyte with a Na superionic conductor (NASICON) structure that provides a channel for lithium ion transport. We coated LAGP particles on one side of a polypropylene (PP) separator film to improve the ionic conductivity of the separator, and water-dispersed polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) on the other side to reduce the interfacial resistance between the separator and the lithium metal anode. The results show that the LAGP/PP/PVDF-HFP separator has a high ionic conductivity (1.06 mS cm-1) at room temperature (PP separator: 0.70 mS cm-1), and an electrochemical window of 5.2 V (vs. Li+/Li). The capacity retention of a NCM|LAGP/PP/PVDF-HFP|graphite full cell is 81.0% after 300 charge-discharge cycles at 0.2C. When used in a NCM|LAGP/PP/PVDF-HFP|Li half-cell system, the initial discharge capacity is 172.5 mA h g-1 at 0.2C, and the capacity retention is 83.2% after 300 cycles. More significantly, the surface of the Li anode is smooth and flat after 200 cycles. The interface resistance increased from 7 to 109 Ω after 100 cycles at 0.2C. This indicates that the synergistic effect of the asymmetric coated LAGP and PVDF-HFP is beneficial to inhibiting the growth of lithium dendrites in the battery and reduces the interface resistance.

Syntheses of [12]aneN3-oligopeptide conjugates as effective DNA condensation agents.

With the aim to develop effective and low toxicity DNA condensation agents, a series of oligopeptide derived macrocyclic polyamine [12]aneN(3) conjugates 7a-h·3HCl have been designed and synthesized through multi-step amidation reactions. Structure-property study through gel electrophoresis proved that the conjugates containing high hydrophobic ending amino acids exhibited effective condensation ability at concentration of 150-250 µM, which was further confirmed by dynamic light scattering and atomic force microscopy experiments. EB displacement assay, ionic salt effect, and structure-property relationship in gel electrophoresis indicated that DNA condensation resulted from both the electrostatic interaction of [12]aneN(3) unit and hydrogen-bonding/hydrophobic multi-interaction of oligopeptide moiety in the conjugates with DNA. The reversible condensation process and their low cytotoxicity suggest that the new condensing agents are potential for the development of non-viral vectors.

Isolation and characterization of the murine Nanog gene promoter.

Nanog protein is expressed in the interior cells of compacted morulae and maintained till epiblasts but downregulated by implantation stage. It is also expressed in embryonic stem cells, embryonic carcinoma cells and embryonic germ cells but disappeared in differentiated ES cells. In this study, we have isolated, sequenced, and performed the first characterization of the Nanog promoter. The transcription start sites were mapped by primer extension analysis. Two promoter regions were found upstream the transcription start sites and the expression of major Nanog promoter/reporter gene construct is abolished in differentiated F9 EC cells as compared to the undifferentiated counterpart. We also showed that a putative octamer motif (ATGCAAAA) is necessary for the major promoter activity. Gel shift and supershift assays showed that Oct-1, Oct-4 and Oct-6 protein selectively bind to the octamer motif.