Insulin delivery responsive membranes

Fig. 27 Cross-sectional view of a bioresponsive insulin delivery system, a feedback-regulated drug delivery system, showing the glucose oxidase-entrapped hydrogel membrane constructed from amine-containing hydrophilic pol5mier. The mechanism of insulin release, in response to the influx of glucose, is also illustrated. (From Ref. l)...

III.B.5) (184). The rates of Cr(VI) reduction in the cells are probably determined by Cr(VI) diffusion through the cell membranes thus, Cr(III) was the dominant (>90%) oxidation state in the Cr(VI) treated mammalian cells (as shown by microprobe XANES spectroscopy) (89). Therefore, it is unlikely that Cr(VI) as such is responsible for the kinase activation seen in intact Cr(VI) treated cells (295, 626). The role of Cr(VI), which permeates the cell membranes much more easily than Cr(III) (Section III.B.l), is probably its delivery of high intracellular Cr(III) concentrations. Such high intracellular Cr(III) concentrations can then act as an insulin mimetic [while insulin potentiation is observed at lower Cr(III) concentrations] (495). 

---