Collagen-immobilized cell systems

The primary methods used in cell immobilization are surface adhesion, covalent attachment and entrapment. Surface adhesion involves adsorption of cells to microcarriers such as calcium alginate beads, collagen-coated plastic beads, diatomite silica, and dextrans [68]. Immobilization can be achieved simply by suspending the cells and microcarrier together under slow agitation. Examples of such systems include immobilized bacteria for waste water treatment and adsorbed Azotobacter vinelandii on Cellex E for nitrogen fixation... 

Entrapment provides an alternative to covalent immobilization. IVpically, cells are entrapped in a porous matrix and the cells grow throughout the pores/media to result in high cell densities. Cells may be added to the matrix at the time it is formed, or may be added after matrix formation. Many matrices have been used for entrapment including agarose beads, ceramics and silica, collagen microspheres, polyacrylamide, controlled pore glass, and various membranes [68, 69]. Membrane retention of cells, which has been used for biosensors (table 8.7) is, per se, not an immobilized system since the cells are... 

The properties of spinach chloroplasts adsorbed onto diethylaminoethyl-cellulose have been reported and the immobilized chloroplasts used for the continuous photoreduction of 2,6-dichloroindophenol as an indicator of photosystem II activity in the chloroplasts. The formation of ATP from ADP and orthophosphate via the cyclic photophosphorylation system has been achieved using chloroplasts copolymerized with polyvinylalcohol onto an electrode. Citrobacter freundii cells immobilized by co-casting with collagen have been used in a flow type sensor for cephalosporins. ... 

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