P2X4 receptor activation facilitates secretion of pulmonary surfactant from secretory vesicles called lamellar bodies in alveolar epithelial cells. Fois et al. reveal that P2X4 receptors on the lamellar body membranes are activated by ATP stored within the vesicles themselves upon vesicle exocytosis.
The reproducible immobilization of enzymes represents a key requirement in developing sensitive and fast‐responding amperometric microbiosensors. A microbiosensor for the respective detection of glucose and adenosine‐5′‐triphosphate (ATP) is presented by using a poly(benzoxazine) derivative for the entrapment of the enzymes glucose oxidase (GOD) and hexokinase (HEX) at platinum (Pt) microelectrodes (MEs). For glucose, a sensitivity of 123.05±10.78 pA/mM (n=5) was obtained, which shows twice as high sensitivity compared to microbiosensors that use electrophoretic paints as the immobilization matrix for the same size ME (radius: 25 μm). For the determination of ATP, a sensitivity of 48.47±5.12 pA/μM and a signal‐to‐noise ratio of 40 at physiological pH values were obtained. Apart from their enhanced sensitivity, a significant improvement of these sensors is related to their improved mechanical stability. The applicability of these poly(benzoxine)‐based microbiosensors for ATP detection was demonstrated with measurements at receptor protein tyrosine phosphatase zeta (PTPRζ) osteoblastic cells during mechanical stimulation.
The Back Cover picture shows a scheme of the improved ATP microbiosensor based on poly(benzoxazine) entrapment of enzymes for the detection of ATP at mechanically stimulated osteoblastic cells. More information can be found in the Article by C. Kranz and co‐workers on page 864 in Issue 4, 2017 (DOI: 10.1002/celc.201600765).
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