ABSTRACT

Since its original development in the area of immunodiagnostics, optical sensor technology has expanded into a wide variety of biological and medical areas of interest. An obvious choice for signal transduction research, SPR has become a standard tool for the analysis of receptor-ligand interactions [13,14]. The field of chaperonins also discovered the technology early on [15-17]. Beyond mere protein-protein interactions, SPR has found applications in small-molecule screening [18] as well as proteincarbohydrate [19] and protein-nucleic acid interactions [20-22]. Even viral particle binding to cell surface receptors has been analyzed by SPR [23]. At downstream junctures of the drug development process, specialized optical bionsensors are used for bioprocess monitoring and product analysis [24]. In spite of the great diversity of molecules analyzed, SPR studies mainly fall into two categories as far as experimental goal and design are concerned. Screening applications look for the relatively simple answer of an approximate kinetic ranking, basically to see if an analyte is specifically binding to a given ligand or not. Functional studies look at the mechanism of a certain biological interaction by determining quantitative rate constants. Clearly a functional study with the aim of retrieving key mechanistic data requires a different level of insight and experimental premeditation than a simple “quick and dirty” screen. Yet it is crucial to realize that the mimicking of a biological interaction event on a two-dimensional platform is not a trivial endeavor per se. Failure to understand the key biochemical parameters, caveats, and limitations of the system will inevitably lead to the failure of even the simplest of studies.