Organic solvent biocompatibility

Poly(iV-vinyl caprolactam) (PVCa) Soluble in water and organic solvents, biocompatible, high absorption ability and LCSTof33°C. 

One of the main obstacles for whole-cell microbial transformation in an organic solvent is its biocompatibility, which has led to screening for organic-solvent-tolerant microorganisms. Numerous organic-solvent-tolerant microorganisms have been found and their tolerance mechanisms have been reviewed [14,33,34]. Two-phase biotransformation systems have been successfully implemented for the production of pharmaceutically relevant metabolites. 

The main advantage is that the entrapment conditions are dictated by the entrapped enzymes, but not the process. This includes such important denaturing factors as the solution pH, the temperature and the organic solvent released in the course of precursor hydrolysis. The immobilization by THEOS is performed at a pH and temperature that are optimal for encapsulated biomaterial [55,56]. The jellification processes are accomplished by the separation of ethylene glycol that possesses improved biocompatibility in comparison with alcohols. 

Fig. 23.5 Aqueous-organic two-liquid-phase system for microbial production of flavour compounds. Here the formation of 2-phenylethanol from L-phenylalanine is exemplarily shown [120]. The organic solvent used for in situ extraction has to be carefully selected on the basis of multiple criteria, such as biocompatibility, non-flammability and legislative regulations. For a more detailed description of flavour production in two-phase systems, see Chap. 24 by Larroche et al.

An illustration of the application of an emulsified liquid bandage is shown in Fig. 2.5. The microscopic view of this film formation shows microscopic spherical particles coalescing to form a continuous film. The advantage of the emulsion is that it is a waterborne and contains no solvents (i.e., organic solvents) which is preferred over organic solvents for the biocompatible property. 

The time has come for the sensors to be taken from the well-controlled environment of the research laboratory and applied to real conditions. This means that the sensors must be robust and able to stand rough conditions in terms of, for example, humidity, temperature, and exposure to organic solvents. When applying the sensors in direct contact with biological fluids biocompatibility will be a major problem. 

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