Polymers and nanomedicine: considerations on variability and reproducibility when combining complex systems.

Hot topics in polymer science in the recent years and decades included macromolecular engineering enabled by controlled and living polymerization, use of polymers in biomedical applications. Control over polymerization and the structure of polymers increased tremendously. Despite the increased control over various polymerization techniques, polymers are intrinsically statistical in nature leading to a structural variability. As researchers combine polymers and biological systems, we combine two complex systems. Interestingly though, only the study of biological assays is subject to systematic scrutiny with respect to their reproducibility and variability. Here, it is argued that polymer synthesis should also be considered with systematic variability analysis, in particular in connection with downstream processes such as biological assays.