**6. Conclusion**

The aim of this chapter was to survey the currently used experimental methods for evaluation of polymeric materials in biological systems concerning various methods for biocompatibility, immunological, bioimmunological and immunotoxicological assessment. This covers practical aspects throughout assay development and specific methodology adjustment. Decisive stages in development and application of these methods and practical suggestions are discussed. Such kind of research is essential due to enormous progress in the development of polymeric materials for different biomedical applications.

Among a number of polymers suitable for the use in medicine, poly(2-oxazolines) belong to polymeric materials with a great potential for different biomedical application. Their possible application areas in biological and medicinal contexts were reported. Especially the drug delivery, gene therapy and tissue engineering belong to the principal areas of their applications. Nowadays, several immunobiological and immunotoxicological methods were employed for the assessment of their biocompatibility and bioavailability. *In vitro* cytotoxicity of poly(2-oxazolines) was evaluated mainly by colorimetric MTT assay. However, other laboratory methods, like XTT, TB, SRB or WST assays, can be also used. All published results proved high biocompatibility of poly(2-oxazolines). Additionally, polymers prepared by cationic polymerization of 2-alkyl-2-oxazolines behave as "stealth" materials. This behaviour was confirmed by several independent immunological methods. Selected techniques as flow cytometric evaluation of phagocyte functions, immunocytometric determination of TH1/TH2/TH17 cytokines and ELISpot evaluation of cytokine producing cells comprise novel approaches to characterise immunomodulation of basic functions of immune competent cells targeted with poly(2-oxazolines). Last part of the chapter summarized *in vitro* and *in vivo* visualisation methods.
