Electric field control, enzyme

Fig. 9. Upper - Schematic of the electric field controlled enzymatic digestion of DNA in a manifold of microchannels a principal arrangement, b loading of DNA and enzyme, c injection of the digested products, d separation of the fragments.

Electric Field Control of Enzyme Activity. An electric field is expected to be a powerful external source for enzyme activity... 

A renewed interest in this research field may lead to the construction of functional immobilized biocatalysts that surpass the conventional definition, or usually credited advantages, of immobilized biocatalysts with regard to their capabilities as catalysts [22-24], i.e. immobilized enzyme systems in which, for example, an enzymatic process can be controlled by externally applied stimuli such as light, electric fields, pH, temperature, and mechanical force. In such cases, what is crucial in system construction is not to rely on a possible... 

The effects of oscillating electric fields on ion accumulation processes are also explained by SCM calculations (20). The oscillations lead to periodic changes in the ionic concentrations that are functions of the frequency, but the percentage change is greatest in those concentrations with the lowest steady-state values. In particular, sodium on the inner surface and potassium on the outer surface show maximal changes at about 100-200 Hz. These two ionic concentrations normally control the activity of the Na, K-ATPase of cell membranes, and increases could stimulate the enzyme. 

At the simplest level, communication with amino acids, proteins, enzymes, antibodies, DNA, and whole cells is clearly important [158]. It is well known that biological systems can be influenced by the application of electric fields. The ICP provides us with the capability of charge injection or removal at biological interfaces due to its electronic conductivity. More interestingly, though is the redox capability of these polymers, whereby they can function as simple on-o f switches, facilitate controlled release of molecular species of interest, or direct mechanical interaction with the biological interface in the form of actuation. 

Field effect transistor, FET an electronic device in which the conductivity of the semiconductor material is controlled by the electrical field at a particular part of its surface, known as the gate . This electrical field may be varied by attachment (and subsequent reaction) of enzymes (ENZFET) or antibodies (IM-MUNOFET) to the gate. The gate may also be sensitized to specific ions (ISFET) or other chemicals (CHEMFET). 

Protein immobilization is an important issue for biomedical and biotechnological applications, including controlled drug delivery, protein separation, and biosensors. Smart polymers can manage protein immobilization by the manipulation of environmental parameters (temperature, pH, ionic strength, electric field, and light) (Mendes, 2008). SPB are an attractive option for protein or enzyme immobilization (Jain et al., 2009). 

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