BackgroundDue to the high transfer ability of cancer cell, cancer has been regarded as a world-wide high mortality disease. Quantitative analysis of circulating tumor cells (CTCs) can provide some valuable clinical information that is particularly critical for cancer diagnosis and treatment. Along with the rapid development of micro-/nano-fabrication technique, the three-dimensional (3D) bionic interface-based analysis method has become a hot research topic in the area of nanotechnology and life science. Micro-/nano-structure-based devices have been identified as being one of the easiest and most effective techniques for CTCs capture applications.MethodsWe demonstrated an electrospun nanofibers-deposited nickel (Ni) micropillars-based cytosensor for electrochemical detection of CTCs. Breast cancer cell line with rich EpCAM expression (MCF7) were selected as model CTCs. The ultra-long poly (lactic-co-glycolic acid) (PLGA) nanofibers were firstly-crosswise stacked onto the surface of Ni micropillars by electrospinning to construct a 3D bionic interface for capturing EpCAM-expressing CTCs, following immuno-recognition with quantum dots functionalized anti-EpCAM antibody (QDs-Ab) and forming immunocomplexes on the micro-/nano-chip.ResultsThe Ni micropillars in the longitudinal direction not only play a certain electrical conductivity in the electrochemical detection, but also its special structure improves the efficiency of cell capture. The cross-aligned nanofibers could simulate the extracellular matrix to provide a good microenvironment which is better for cell adhesion and physiological functions. Bioprobe containing quantum dots will release Cd2+ in the process of acid dissolution, resulting in a change in current. Beneath favourable conditions, the suggested 3D cytosensor demonstrated high sensitivity with a broad range of 101–105 cells mL−1 and a detection limit of 8 cells mL−1.ConclusionsWe constructed a novel 3D electrochemical cytosensor based on Ni micropillars, PLGA electrospun nanofibers and quantum dots bioprobe, which could be used to highly sensitive and selective analysis of CTCs. More significantly, the 3D cytosensor can efficiently identify CTCs from whole blood, which suggested the potential applications of our technique for the clinical diagnosis and therapeutic monitoring of cancers.

To enhance the photocatalytic activity of TiO 2 nanotubes, tetracycline hydrochloride (TC) molecularly imprinted titania modified TiO 2 nanotubes (MIP-TiO 2 ) was prepared by liquid phase deposition, which improved the molecular recognition ability of the photocatalyst toward template molecules. This MIP-TiO 2 photocatalyst was characterized by ESEM and XRD, which showed that the imprinted titania was deposited on the nanotube uniformly and was of well-crystalized anatase-type. In the adsorption experiments, MIP-TiO 2 exhibited a high adsorption capacity (about 1.6 times higher than that of TiO 2 nanotubes) for TC mainly because of its imprinted sites and high surface area. Under UV irradiation MIP-TiO 2 showed enhanced photocatalytic activity with an apparent first-order rate constant 1.9-fold that of TiO 2 nanotubes. liquid phase deposition (LPD), photocatalytic, molecularly imprinting, tetracycline hydrochloride Citation:Wang H T, Wu X, Zhao H M, et al. Enhanced photocatalytic degradation of tetracycline hydrochloride by molecular imprinted film modified TiO 2

Label selection is an essential procedure for improving the sensitivity of fluorescence immunochromatography assays (FICAs). Under optimum conditions, time-resolved fluorescent nanobeads (TRFN), quantum dots nanobeads (QB) and quantum dots (QD)-based immunochromatography assays (TRFN-FICA, QB-FICA and QD-FICA) were systematically and comprehensively compared for the quantitative detection of aflatoxin B 1 (AFB 1 ) in six grains (corn, soybeans, sorghum, wheat, rice and oat). All three FICAs can be applied as rapid, cost-effective and convenient qualitative tools for onsite screening of AFB 1 ; TRFN-FICA exhibits the best performance with the least immune reagent consumption, shortest immunoassay duration and lowest limit of detection (LOD). The LODs for TRFN-FICA, QB-FICA and QD-FICA are 0.04, 0.30 and 0.80 µg kg −1 in six grains, respectively. Recoveries range from 83.64% to 125.61% at fortified concentrations of LOD, 2LOD and 4LOD, with the coefficient of variation less than 10.0%. Analysis of 60 field grain samples by three FICAs is in accordance with that of LC-MS/MS, and TRFN-FICA obtained the best fit. In conclusion, TRFN-FICA is more suitable for quantitative detection of AFB 1 in grains when the above factors are taken into consideration.Biomolecules 2020, 10, 575 2 of 12 To better monitor the threat of AFB 1 contamination, various methods have been developed in the past few decades [9][10][11][12]. Although the results are reliable and accurate, instrumental techniques [13] need expensive equipment and complicated sample pretreatment. Biosensors based on the antibody immunoprobes such as enzyme-linked immunosorbent assay (ELISA) [14] and fluorescence-linked immunosorbent assay (FLISA) [15,16] can achieve quantitative detection with good performance of specificity, sensitivity and simplicity, but the heterogeneous immunoassays require multiwashing procedures and long analysis times. To address the above issues, lateral flow immunochromatography assays have been considered as a promising method for onsite screening of mycotoxins [17][18][19]. Moreover, immunochromatography assays based on fluorescent markers (time-resolved fluorescent nanobeads (TRFN), quantum dot nanobeads (QB) and quantum dots (QD), etc.) have gradually become a popular research field in recent years for their advantages of sensitivity, accuracy, automated detection, shorter detection time, and so on [20][21][22]. Several fluorescence immunochromatography assays for highly sensitive detection of AFB 1 have been reported [20,21,[23][24][25].

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air is a kind of hydrogen-sensitive material and can change its color when exposed to hydrogen. This hydrogen gasochromic phenomenon provides a visualized and safer method without electrical signals to detect hydrogen.As a versatile material, WO 3 film can be directly used for photocatalysis and electrochromism without catalyst. Researchers have done a lot of work in these fields. [1,2] However, catalyst loading is essential to observe hydrogen gasochromism of WO 3 film at room temperature. Currently, although many issues regarding the mechanism of WO 3 hydrogen gasochromism have not been fully understood, the processes of adsorption and decomposition of H 2 or O 2 on the surface of the catalyst and the diffusion of H or O atoms between catalyst and WO 3 are widely recognized in different models. The commonly used catalyst materials are Pt and Pd. [3,4] Meanwhile, some researchers also use PdO, PtO x or Pd-Pt alloy as catalysts. [5,6] Usually, there are two ways to load catalyst. One is to prepare WO 3 film first, then load the catalyst on it. [4,6,7] The other is to merge the preparation of WO 3 film and the loading of catalyst into one step. [8,9] Many methods have been used to prepare WO 3 films, such as PVD, [10][11][12] CVD, [13,14] sol-gel method, [15,16] hydrothermal/ solvothermal method, [17][18][19][20] electrodeposition and anodic oxidation. [21][22][23][24] The hydrothermal/solvothermal method can be used to prepare nanostructured film with simple experimental conditions and low cost. Compared with dense film, nanostructured porous film with the high specific surface area often has better catalysis and reaction performance, so the hydrothermal/ solvothermal method is a promising method to prepare nanostructured porous WO 3 film. Before hydrothermal/solvothermal synthesis, many researchers prepare seed layer on the substrate firstly for the consideration of the provision of nucleation sites and good adhesion between substrate and film. A typical process of preparing seed layer includes synthesis of WO 3 sol, spin coating, and annealing. To guarantee the quality of the seed layer, this process has to be repeated several times. As a result, the time-consuming and laborious heat treatment is indispensable for preparing seed layer in the solvothermal synthesis of The time-consuming and laborious heat treatment is indispensable for preparing seed layer in solvothermal synthesis of WO 3 film. Herein, WO 3 film is prepared composed of single crystal WO 3 nanowires on indium tin oxide (ITO) glass assisted with simple and energy-saving electrodeposited seed layer for the first time. The catalyst Pt is sputtered on it for 30 s after WO 3 film is synthesized to form the hydrogen gasochromic film. The film structure is redesigned to improve its hydrogen gasochromic properties further. Before WO 3 film is solvothermally synthesized, Pt is sputtered on seed layer for 15 s, then it is sputtered for 15 s again after WO 3 film is prepared. The Pt sputtered on seed layer greatly changes the morphology of nanowires, makin...