Functional bioassays methods

Fig. 5.17 Demonstration of MS-based bioassay functionality using a plant extract. MS instrument Ion-trap mass spectrometer (LCQ Deca, Thermo Electron), (a) MS analysis of pure extract by direct injection onto restricted-access column 2 in the absence of affinity protein, (b) Analysis of the same natural extract spiked with digoxin using the label-free MS assay method as shown in Fig. 5.15.

Concentration techniques, applied to assign priority pollutants, function as an interface between the environment, chemical analysis, and bioassays. The transition of harmful pollutants in an environmental system to multicomponent concentrates derived from that system is the principal challenge of concentration techniques aimed at the assignment of organic priority pollutants. A compatible combination of chemical and biological methods must be used. These methods can vary from the development of analytical procedures based on the observed biological activity of fractions of an environmental concentrate to the toxicological... 

Methods to determine the potential biological activity of products obtained through recombinant DNA techniques are of fundamental importance. Despite the existence of numerous physicochemical techniques to characterize the protein product structure and the presence of contaminants, they provide little, if any, information about its biological potency. A bioassay is defined as a functional test, and no physicochemical test can measure the function. However, for some peptide hormones, which are less complex in structure than most cytokines, well defined physicochemical tests may be used to estimate biological activity for instance, the capillary electrophoresis analysis of a protein s isoform content if the specific activity of each one is known. 

A bioassay is an analytical procedure that uses a responsive biological system (biological function) to measure the biological potency of a product (Mire-Sluis et al., 1996). The most appropriate method to determine it is by comparing the biological activity of a sample with a well-characterized reference standard. 

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