Differentially permeable outer membrane

Figure 1. Block schematic of a hydrogen peroxide-based electroenzjrmatic glucose sensor with a differentially permeable outer membrane layer.

New polymer membrane-based ISEs for nitrate and carbonate exhibit detection limits and selectivities that may be applicable for ocean measurements. In addition, a number of these ISEs can be used as internal transducers for the design of useful potentiometric gas sensors. For example, dissolved C02 can be detected potentiometrically by using either a glass membrane electrode or a polymer-based carbonate ISE, in conjunction with an appropriate reference electrode, behind an outer gas permeable membrane. Novel differential pC02 sensors based on two polymer membrane-type pH sensors have also been developed recently. 

A bilayered composite skin equivalent has been developed with a viable dermis and epidermis. The epidermis is composed from cornified differentiated keratinocytes and a dermal matrix composed of a collagen lattice containing viable fibroblasts. Its cellular components assist with wound closure through stimulation of the wound bed. The outer layer of the differentiated bilayered skin equivalent, the stratum corneum, acts as a specialized vapor permeable membrane and protective outer barrier.f ... 

Hydrolysis of sucrose occurs rapidly within the outer portion of the brush-border, plasma membrane, whereupon most of the monosaccharides released are transported across a permeability barrier located in the inner portion of the same membrane. Some hydrolytic products diffuse backward from the mucosal site of formation, and accumulate in the lumen.5-8 The mucosal site of hydrolysis is identified by the use of fluorescent antibodies against sucrase8 and by differential centrifugation of intestinal preparations.2... 

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