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In this work, we present a Ag@Au nanoprism-metal-organic framework-paper based glucose sensor for rapid, sensitive, single-use and quantitative glucose determination in human serum. To achieve painless measurement of glucose with a non-invasive detection methodology, this biosensor was further tested in human urine. In this approach, a new hybrid-Ag@Au nanoprism loaded in close proximity to micrometer sized coordination polymers as phosphorescent luminophores significantly enhanced the emission intensity due to metal-enhanced phosphorescence and worked as reaction sites to support more dissolved oxygen. Reports of enhanced phosphorescence intensity are relatively rare, especially at room temperature. The true enhancement factor of Ag@Au-phosphorescent metal-organic frameworks on paper was deduced to be 110-fold, making it a better optical type glucose meter. The results demonstrate the validity of the intensity enhancement effect of the excitation of the overlap of the emission band of a luminophore with the surface plasmon resonance band of Ag@Au nanoprisms. Ag@Au nanoprisms were used not only to improve the detection limit of glucose sensing but also to extend the glucose sensing range by enhancing the oxygen oxidation efficiency. The oxidation of glucose as glucose oxidase is accompanied by oxygen consumption, which increases the intensity of the phosphorescence emission. The turn-on type paper-based biosensor exhibits a rapid response (0.5 s), a low detection limit (0.038 mM), and a wide linear range (30 mM to 0.05 mM), as well as good anti-interference, long-term longevity and reproducibility. Finally, the biosensor was successfully applied to the determination of glucose in human serum and urine.

A simple approach to the evaluation of blood coagulation using a microfluidic paper-based lateral flow assay (LFA) device for point-of-care (POC) and self-monitoring screening is reported. The device utilizes whole blood, without the need for prior separation of plasma from red blood cells (RBC). Experiments were performed using animal (rabbit) blood treated with trisodium citrate to prevent coagulation. CaCl2 solutions of varying concentrations are added to citrated blood, producing Ca(2+) ions to re-establish the coagulation cascade and mimic different blood coagulation abilities in vitro. Blood samples are dispensed into a paper-based LFA device consisting of sample pad, analytical membrane and wicking pad. The porous nature of the cellulose membrane separates the aqueous plasma component from the large blood cells. Since the viscosity of blood changes with its coagulation ability, the distance RBCs travel in the membrane in a given time can be related to the blood clotting time. The distance of the RBC front is found to decrease linearly with increasing CaCl2 concentration, with a travel rate decreasing from 3.25 mm min(-1) for no added CaCl2 to 2.2 mm min(-1) for 500 mM solution. Compared to conventional plasma clotting analyzers, the LFA device is much simpler and it provides a significantly larger linear range of measurement. Using the red colour of RBCs as a visible marker, this approach can be utilized to produce a simple and clear indicator of whether the blood condition is within the appropriate range for the patient's condition.

By virtue of the biocompatibility and physical properties of hydrogel, picoliter-sized hydrogel microcapsules have been considered to be a biometric signature containing several features similar to that of encapsulated single cells, including phenotype, viability, and intracellular content. To maximize the experimental potential of encapsulating cells in hydrogel microcapsules, a method that enables efficient hydrogel microcapsule purification from oil is necessary. Current methods based on centrifugation for the conventional stepwise rinsing of oil, are slow and laborious and decrease the monodispersity and yield of the recovered hydrogel microcapsules. To remedy these shortcomings we have developed a simple one-step method to purify alginate microcapsules, containing a single live cell, from oil to aqueous phase. This method employs oil impregnation using a commercially available hydrophobic filter paper without multistep centrifugal purification and complicated microchannel networks. The oil-suspended alginate microcapsules encapsulating single cells from mammalian cancer cell lines (MCF-7, HepG2, and U937) and microorganisms (Chlorella vulgaris) were successfully exchanged to cell culture media by quick (~10 min) depletion of the surrounding oil phase without coalescence of neighboring microcapsules. Cell proliferation and high integrity of the microcapsules were also demonstrated by long-term incubation of microcapsules containing a single live cell. We expect that this method for the simple and rapid purification of encapsulated single-cell microcapsules will attain widespread adoption, assisting cell biologists and clinicians in the development of single-cell experiments.

Nerve ending particles isolated from prenatal and postnatal rats by means of density-gradient centrifugation in a ficoll medium actively incorporated [32P]-orthophosphate into nucleotides, phosphoproteins and phospholipids. This process requires Mg2+; is dependent on malate plus pyruvate but not glucose, and is inhibited by dinitrophenol, gramicidin, oligomycin, azide, p-chloromercuribenzoate, CaCl2 but not iodoacetate. It was concluded that the metabolic energy at the synapse is derived largely from the mitochondria of the synaptic complex rather than from its cytoplasm. Thin-layer chromatography and paper electrophoresis revealed that the metabolically active phospholipids, namely phosphatidic acid, phosphatidyl inositol and the polyphosphoinositides which were found to be tightly bound to the phosphoprotein fraction, contained more than 90% of the total radioactivity but constituted less than 9% of the total phospholipids. The highest phosphoprotein and phospholipid content of the nerve endings (expressed in μmoles P/mg nerve ending protein) as well as maximal 32P-incorporation occurred just prior to and continued into the stage when functional changes are formed. It is suggested that an increase in the amount of enzymatic activity coupled with an increase in the permeability of the synaptosomal membrane to inorganic phosphate and other metabolites could trigger the rapid morpho-biochemical and functional changes observed in rat brain during this period of development. A simple density-gradient withdrawing device for the isolation of the submitochondrial particles after density-gradient centrifugation of the conventional mitochondrial fraction was described.