Ultra-sensitive detection of tumor necrosis factor alpha based on silver-coated gold core shell and magnetically separated recognition of SERS aptamer sensors.

A highly sensitive tumor necrosis factor α (TNF-α) detection method based on a surface-enhanced Raman scattering (SERS) magnetic patch sensor is reported. Magnetic beads (MNPs) and core shells were used as the capture matrix and signaling probe, respectively. For this purpose, antibodies were immobilized on the surface of magnetic beads, and then Au@4-MBN@Ag core-shell structures coupled with aptamers and TNF-α antigen were added sequentially to form a sandwich immune complex. Quantitative analysis was performed by monitoring changes in the characteristic SERS signal intensity of the Raman reporter molecule 4-MBN. The results showed that the limit of detection (LOD) of the proposed method was 4.37 × 10-15 mg·mL-1 with good linearity (R2 = 0.9918) over the concentration range 10-12 to 10-5 mg·mL-1. Excellent assay accuracy was also demonstrated, with recoveries in the range 102% to 114%. Since all reactions occur in solution and are separated by magnetic adsorption of magnetic beads, this SERS-based immunoassay technique solves the kinetic problems of limited diffusion and difficult separation on solid substrates. The method is therefore expected to be a good clinical tool for the diagnosis of the inflammatory biomarker THF-α and in vivo inflammation screening.

Effects of Halogenation on the Benzotriazole Unit of Non-Fullerene Acceptors in Organic Solar Cells with High Voltages.

Non-fullerene acceptors (NFAs) can be simply divided into three categories: A-D-A, A-DA'D-A, and A2-A1-D-A1-A2 according to their chemical structures. Benefiting from the easily modified 1,1-dicyanomethylene-3-indanone end groups, the halogenation on the first two types of materials has been proved to be very effective to modulate their optoelectronic properties and improve their photovoltaic performance. Hence, in this work, we systematically investigate the effect of halogenation on the classic NFA molecule of BTA3, which has the linear A2-A1-D-A1-A2-type backbone. After fluorination and chlorination, F-BTA3 and Cl-BTA3 have similar optical band gaps but lower energy levels than BTA3. When blending with a linear copolymer PE25 composed of benzodifuran and chlorinated benzotriazole (BTA) according to "Same-A-Strategy", the corresponding VOC of the halogenated NFAs gradually decreases (1.13 V for F-BTA3 and 1.09 V for Cl-BTA3), compared with that of the BTA3-based device (VOC = 1.22 V). This tendency mainly comes from the lower lowest unoccupied molecular orbital energy levels due to the strong electron-withdrawing ability of halogen atoms and the larger nonradiative energy loss. However, the power conversion efficiencies of the halogenated materials are slightly improved, from 9.08% for PE25: BTA3 to 10.45% for PE25: F-BTA3 and 10.75% for PE25: Cl-BTA, with the nonhalogenated solvent tetrahydrofuran as the processing solvent. The improved photovoltaic performance of F-BTA3 and Cl-BTA3 should come from the higher carrier mobility, weaker bimolecular recombination, and higher fluorescence quenching rate. This study illustrates that halogenation on the A1 unit is a promising strategy for developing novel and effective A2-A1-D-A1-A2-type NFAs.