Micrometer-sized, 4-cyno-4-pentylbiphenyl (5CB) droplets were developed for glucose detection in an aqueous medium by coating with poly(acrylicacid-b-4-cynobiphenyl-4-oxyundecylacrylate) (PAA-b-LCP) at the 5CB/water interface and covalently immobilizing glucose oxidase (GOx) to the PAA chains. This functionalized liquid-crystal (LC) droplet detected glucose from a radial to bipolar configurational change by polarized optical microscopy under crossed polarizers at concentrations as low as 0.03 mM and response times of ~3 min and showed the selective detection of glucose against galactose. This new and sensitive LC-droplet-based glucose biosensor has the merits of low production cost and easy detection by the naked eye and might be useful for prescreening the glucose level in the human body.

A liquid-crystal (LC)-filled transmission electron microscopy (TEM) grid cell coated with the cationic surfactant dodecyltrimethylammonium bromide (DTAB), to which a single-stranded deoxyribonucleic acid probe (ssDNAprobe) was adsorbed at the LC/aqueous interface (TEMDTAB/DNA), was applied for the highly specific detection of target DNA molecules. The DTAB-coated E7 (used LC mixture) in the TEM grid (TEMDTAB) exhibited a homeotropic orientation, and changed to a planar orientation upon adsorption of the ssDNAprobe. The TEMDTAB/DNA was then exposed to complementary (target) ssDNA, which resulted in a planar-to-homeotropic configurational change of E7 that could be observed through a polarized optical microscope under crossed polarizers. The optimum adsorption density (2 μM) of ssDNAprobe enabled the detection of ≥0.05 nM complementary ssDNA. This TEMDTAB/DNA biosensor could differentiate complementary ssDNA from mismatched ssDNA as well as double-stranded DNA. It also successfully detected the genomic DNAs of the bacterium Erwinia carotovora and the fungi Rhazictonia solani. Owe to the high specificity, sensitivity, and label-free detection, this biosensor may broaden the applications of LC-based biosensors to pathogen detection.

This study describes a novel Dean flow assisted cell ordering system which is connected to an electrospray ionization-mass spectrometer for the detection of lipids in a single-cell. This platform provides a facile method for direct analysis of label-free lipids in single-cells and significantly improves the efficiency of single-cell mass spectrometry.

A transmission electron microscopy (TEM) grid filled with 4-cyno-4-pentylbiphenyl (5CB) on the octadecyltrichloro silane-coated glass in an aqueous medium was developed to construct a glucose biosensor by coating poly(acrylicacid-b-4-cynobiphenyl-4-oxyundecylacrylate) (PAA-b-LCP) at the aqueous/5CB interface and immobilizing glucose oxidase (GOx) covalently to the PAA chains. The glucose was detected from a homeotropic to planar orientational transition of 5CB by polarized optical microscopy under crossed polarizers. The maximum immobilization density of the GOx, 1.3 molecules/nm(2) obtained in this TEM grid cell enabled the detection of glucose at concentrations as low as 0.02 mM with a response time of 10 s. This liquid crystal-based glucose sensor provided a linear response of birefringence of the 5CB to glucose concentrations ranging from 0.05 to 2 mM with a Michaelis-Menten constant (Km) of 0.32 mM. This new and sensitive glucose biosensor has the merits of low production cost and easy detection through the naked eye and might be useful for prescreening the glucose level in the human body.

Single-cell biology provides insights into some of the most fundamental processes in biology and promotes the understanding of life's mysteries. As the technologies to study single-cells expand, they will require sophisticated analytical tools to make sense of various behaviors and components of single-cells as well as their relations in the adherent tissue culture. In this paper, we revealed cell heterogeneity and uncovered the connections between cell adhesion strength and cell viability at single-cell resolution by extracting single adherent cells of interest from a standard tissue culture by using a microfluidic chip-based live single-cell extractor (LSCE). We believe that this method will provide a valuable new tool for single-cell biology.

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Activated MoS2-QDs exhibit a promising capability for the generation of reactive oxygen species.

Three-dimensional (3D) hydrogel microspheres have aroused increasing attention as an in vitro cell culture model. Yet the preservation of cells' original biological properties has been overlooked during model construction.Here we present an integrated microfluidic device to accomplish the overall process including cell-laden microsphere generation, online extraction, and dynamic-culture. The method extends the noninvasive and nonsuppression capabilities of the droplet preparation system and provides a constant microenvironment, which reduces intracellular oxidative stress damage and the accumulation of mitochondria. Compared to the conventional preparation method, the coculture model of tumor-endothelial construction on an integrated platform displays high-level angiogenic protein expression. We believe that this versatile and biocompatible platform will provide a more reliable analysis tool for tissue engineering and cancer therapy.