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Fast and sensitive detection of E.coli O157: H7 is significantly essential for clinical management as well as for transmission prevention during disease outbreaks. Though many types of detection strategies have been implemented for measuring E.coli O157: H7, most of them still rely on complex instruments or tedious/laborious setups, which restrict their applications in resource-limited scenarios. Herein, we introduce an eye-based microfluidic aptasensor (EA-Sensor) for fast detection of E.coli O157: H7 without the assist of any instruments. We demonstrate the perfect coupling of aptamer sensing, hybridization chain reaction (HCR)-amplification and a distance-based visualized readout to quantitatively determine the pathogen concentration. We first used gel-electrophoresis assay to evaluate the system and the results proved that E.coli O157: H7 was well recognized by the aptamer and HCR could increase the signal by about 100 folds. In addition, the Aptamer specificity and signal-amplification ability were verified on the EA-Sensor for sensing E.coli O157: H7 by naked eyes. Furthermore, we demonstrated that E.coli O157: H7 in milk could be accurately and conveniently measured with good performance. With the benefits of operation integration and strategy integration, our EA-Sensor shows advantages of high specificity, easy operation, efficient amplification and visualized readout, which offers a favorable point-of-care tool for E.coli O157: H7 or other pathogen detection in resource-constrained settings. Image 1 • An eye-based aptasensor (EA-Sensor) is developed for point-of-care detection of E.coli O157:H7. • Integration of aptamer recognition, HCR amplification and a visualized readout is firstly realized for pathogen detection. • On-chip measurement of E.coli O157:H7 in milk samples was successfully achieved. [ABSTRACT FROM AUTHOR]

A protein gel electrophoresis procedure using 0.05% w/v sarkosyl, is reported. The method called 05SAR-PAGE can be used to identify the native masses, dimeric states and modification states of proteins, and also be suitable for pursuing native electroblotting and immunodetection. It has been demonstrated by NMR spectroscopy that 0.05% w/v SAR is much milder than SDS, so it has subtle effects on the native structure of proteins. Therefore, the non-covalent dimerization of PhoB N and PhoR cp can be identified by 05SAR-PAGE which cannot be observed by SDS-PAGE. It has also been demonstrated that 05SAR-PAGE can be used to identify the phosphorylated or methylated proteins. Besides, 05SAR-PAGE shows the advantages of simple operation and low cost, and can be easily adapted to diverse applications. Image 1 • Determination of the dimerization states of PhoB N and PhoR cp by 05SAR-PAGE. • Mild effect of SAR on protein structure. • Western-blot of monomer and dimer states in vivo by 05SAR-PAGE. • Identification of different modification states of proteins by 05SAR-PAGE. [ABSTRACT FROM AUTHOR]

The number of chemical species is crucial in analyzing pulsed field gradient nuclear magnetic resonance spectral data. Any method to determine the number must handle the obstacles of collinearity and noise. Collinearity in pulsed field gradient NMR data poses a serious challenge to and fails many existing methods. A novel method is proposed by taking advantage of the two obstacles instead of eliminating them. In the proposed method, the determination is based on discriminating decay-profile-dominant eigenvectors from noise-dominant ones, and the discrimination is implemented with a novel low- and high-frequency energy ratio (LHFER). Its performance is validated with both simulated and experimental data. The method is mathematically rigorous, computationally efficient, and readily automated. It also has the potential to be applied to other types of data in which collinearity is fairly severe. [ABSTRACT FROM AUTHOR]