**7. Conclusion**

Real-time data acquisition in biomedicine is employed in a lot of different applications, both *in vitro* and *in vivo*. Examples are given in monitoring of chemical reactions (Shutes and Der, 2005), gene expression (Gubern et al., 2009), and drug release (Chouhan and Bajpai, 2009). Concerning living animals, the real-time acquisition is usually based on non-invasive imaging techniques (Ohtani et al., 2010; Li et al., 2010; Voyvodic et al., 2011).

The common issue in both real-time *in vitro* and *in vivo* investigations for biomedicine is that the experimental acquisition of physiological data is performed simultaneously with the correlated event. This is also the case of bioelectromagnetic investigations.

Focus of this chapter was a review of the exposure systems used in real-time biological experiments, i.e. in those investigations where bio-chemical or bio-physical data are acquired from the sample simultaneously with the exposure to the EM field. Real-time investigation is widely spreading, especially in the study of the interaction between nervous system and RF EM fields through *in vitro* electrophysiological techniques.

Although real-time investigations have been gaining increasing interest in the last ten years, a complete and systematic framework on specific requirements of RF exposure systems when applied to real-time data acquisition is still lacking.

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Aim of this chapter was to merge the well-assessed design procedure of RF exposure systems (Kuster & Schönborn, 2000; Paffi et al., 2010) with the requirements emerging from real-time investigations, thus providing a reference work on this segment of knowledge.

The exposure system, defined as the complex structure used for allocating the biological samples (cell cultures for the *in vitro* experiments, animals for the *in vivo* ones) during the exposure phase of a biological experiment, is a fundamental device in the whole experimental setup. Indeed, a well-designed and characterized exposure system is a prerequisite for obtaining reproducible and scientifically meaningful results useful in the process of health risk assessment. Therefore, moving from the analysis of both biological and EM requirements (Kuster et al., 2000), a standardized procedure for the design of the system should be used, as proposed in (Paffi et al., 2010).

Due to the great variety of biological protocols and exposure parameters (dose, duration, frequency and waveform of the EM signal), different exposure systems can be found in the literature, based on radiating (antennas), propagating (waveguides), and resonant (resonant cavities) structures. From an accurate review of them, it emerges that real-time systems, in almost all cases, were designed for *in vitro* investigations on the electrophysiological activity of excitable cells. Such systems generally require modifications of standard RF structures to allow the continuous monitoring of the sample while avoiding RF coupling and interference with the recording apparatus (Paffi et al., 2010). Different solutions can be found in the literature, almost all based on propagating structures. They are mostly open planar structures or semi-open and closed structures modified with holes to allow the access to the sample for the data acquisition. The proposed systems, tailored for the particular biological endpoint and protocol, often result from the trade-off between the two conflicting requirements: the easy access to the sample and the avoidance of interference with the laboratory equipment. Therefore, in these cases, guidelines to design the optimal and most efficient system are particularly significant.
