Encapsulation strategies

Recently, we proposed an alternative process for encapsulating biomacromolecules within PE microcapsules. This approach involves using nanoporous particles as sacrificial templates for both enzyme immobilization and PE multilayer capsule formation (Figure 7.2, route (I)) [66,67]. Unlike previous LbL encapsulation strategies, this approach is not limited to species that undergo crystallization, and is not dependent upon adjustments in electrostatic interactions within PE microcapsules to alter shell permeability characteristics. The salient feature of this method is that it is applicable to a wide range of materials for encapsulation. 

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. 

Beck, J., Angus, R., Madsen, B., Britt, D., Vernon, B. Nguyen, K. T. (2007) Islet encapsulation strategies to enhance islet cell functions. Tissue Eng, 13, 589-99. 

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... 

The crystalline microporosity and well-defined internal surfaces of zeolites, in addition to their great chemical variety, make these materials very attractive hosts for many areas of inclusion chemistry. o A brief overview of encapsulation strategies follows. 

ST-OPVs and, finally, development of an efficient encapsulation strategy and evaluation of the lifetime of ST-OPVs. By overcoming these hurdles, we can expect the commercialization of ST-OPVs in near future. 

---