Search

The hydraulic permeability of the lipid bilayer membrane of a single cell, a very important parameter in biological and medical fields, has been attracting increasing attention. To date, methods developed to determine this permeability are either operation-complicated or time-consuming. Therefore, we developed a chip for automatically and rapidly determining the permeability of cells that integrates microfluidics and cell impedance analysis. The chip is designed to automatically identify a single cell, capture the cell, and record the volume change in that cell. We confirmed the abilities of single-cell identification and capture with the upper and lower voltage thresholds determined, validated the performance of the differential electrode design for accurate cell volume measurements, deduced the extracellular osmotic pressure change in the presence of a hypertonic solution according to fluorescence intensity, and demonstrated the single-cell volume change recorded by the chip. Then, the accuracy of the permeability determined with the chip was verified using HeLa cells. Finally, the permeability of human-induced pluripotent stem cells (hiPSCs) was determined to be 0.47 ± 0.03 μm/atm/min. Using the chip, the permeability can be determined within 5 min. This study provides insights for the new design of an automatic single-cell identification and capture chip for single cell–related studies. [ABSTRACT FROM AUTHOR]

The investigation of limited hydrolysis combined with Maillard-induced glycation on improving the freeze-thaw stability of soy protein isolate (SPI) was carried out. Soy protein isolate hydrolysate (SPH) was first prepared by trypsin, with a hydrolysis degree of 2% and 5%. Afterwards, SPI and SPH were conjugated with dextran to form a covalent complex macromolecule, which were named SPI-D, SPH2-D and SPH5-D, respectively. Covalent bond was formed between SPI/SPH and dextran molecules via the glycation reaction has been confirmed by fourier transform infrared (FTIR) spectroscopy analysis. Subsequently, the freeze-thaw stability of SPI-D and SPH-D was evaluated. After three freeze-thaw cycles, the characters of SPH-D emulsions exhibited smaller values than those of SPI-D emulsions in terms of oiling off, particle size, flocculation degree (FD) and coalescence degree (CD). In addition, SPH2-D emulsions were more stable after freeze-thaw treatment compared with SPH5-D emulsions. Optical microscopy analysis also supported the results above. [ABSTRACT FROM AUTHOR]

• LC–MS/MS analysis method was developed for arachidonic acid metabolome. • The method was firstly applied for eicosanoids determination in a mouse model of breast cancer. • Significant content differences of arachidonic acid and its metabolites were found. • Eicosanoids may be used as new biomarkers to assist for breast cancer diagnosis. Arachidonic acid (AA) is closely associated with breast cancer. In addition to the two metabolic pathways regulated by cyclooxygenase and lipoxygenase, AA has a third metabolic pathway through which cytochrome P450 (CYP) enzymes produce hydroxyeicosatetraenoic acids (HETEs) and epoxyeicosatrienoic acids (EETs). The targeted CYP-mediated pathway of AA can not only kill cancer cells but also inhibit the interstitial microenvironment around a tumor. Therefore, it makes sense to identify potential biomarkers from the AA metabolome for the diagnosis and treatment of breast cancer. This study established a liquid chromatography-tandem mass spectrometry (LC–MS/MS) method for the analysis of AA and its main metabolites, EETs and HETEs, in MMTV-PyMT mice, a spontaneous breast cancer mouse model. The results showed that there were significant differences in the concentrations of AA, 12-HETE, 19-HETE and 8,9-EET in plasma and tumor tissues between normal and MMTV-PyMT mice. Therefore, the eicosanoids mentioned above may be used as new biomarkers for breast cancer diagnosis. This study provides a new perspective for the recognition and diagnosis of breast cancer. [ABSTRACT FROM AUTHOR]