Environmental Engineering Reference
In-Depth Information
Fig. 7.1 Cell immobilization
techniques [65], Reprinted by
permission of the publisher
encapsulation technique wraps the cells inside a shell (matrix) as shown in Fig. 7.1e.
As a result, the two techniques provide more protection to the cells and are some-
times grouped together as a single category of cell immobilization. There are a
number of successful applications of entrapped and encapsulated cells in environ-
mental, pharmaceutical, and food industries. Entrapment matrices are known to be
more durable than encapsulation matrices and therefore are more suitable for field
applications.
7.2.1 General Principles of Cell Entrapment
Cell entrapment procedures normally consist of two steps: (1) mixing of cells and
viscous-liquored matrix and (2) gelation (Fig. 7.2) [38]. The mixing of cells and
matrix is performed by dispersing the cells in the matrix, which can be accomplished
by simple blending techniques such as magnetic stirring and propeller mixing. There
are two common approaches for gelation: droplet and plated gelations. In droplet
gelation, the mixture of cells and matrix is dropped into a gel formation solution to
produce spherical beads using a syringe or a peristaltic pump (Fig. 7.2). In plated
gelation, the mixture of cells and matrix is poured into a tray containing a gel
formation solution and the formed gel is cut into small cubes (Fig. 7.2).
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