Layer encapsulation strategies

Chapter 2, by Ariga, Ji and Hill, presents recent developments on the application of the layer-by-layer technique for encapsulating enzymes. Encapsulation strategies are demonstrated for enzymes in both thin film and particle formats to generate complex enzyme architectures for microreactions. The integration of such systems into advanced biodevices such as microchannels, field effect transistors and flow injection amperometric sensors is also presented. 

In the context of controlled release, the layer-by-layer fabrication procedure offers potential advantages over conventional protein and nucleic acid encapsulation strategies, including the ability to control the order and location of multiple polymer layers with nanometer scale precision, and the ability to define the concentrations of incorporated materials simply by varying the number of polymer layers incorporated [190-192]. Although numerous reports describe the application of these materials to the sustained release of permeable small molecules [193-197], there are few examples of these assemblies designed to release macromolecular components. Several groups have performed... 

Encapsulation of small drugs in M S has also been demonstrated by a similar strategy [68]. In that work, the MS spheres were loaded with ibuprofen and then encapsulated within eight layers of PAH and PSS on the particle surface to cap the mesopore openings [68]. The encapsulated drug molecules were subsequently released from the MS particles under the influence of solution pH and salt concentration. 

In this article we demonstrated our strategy to chemically mimic Hb and a red blood cell. As the model of a red blood cell, usually Hb has been separated from a red blood cell and this membrane-free Hb has been artificially encapsulated with a synthetic polymer or a phospholipid liposome. We also used a liposome as the carrier of the active site but payed attention on the skin layer of the closed vesicle and not on its inside water pha. That is, we utilized the hydrophobic region of the liposome bilayer... 

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