Bioresponsive polymers for the detection of bacterial contaminations in platelet concentrates

Bacterial contamination of platelet concentrates (PCs) can lead to fatal transfusion transmitted diseases and is the most abundant infectious risk in transfusion medicine. The storage conditions of PCs provide a good environment for bacterial growth. The detection of these contaminations at an early stage is therefore important to avoid the transfusion of contaminated samples. In this study, bioresponsive polymer (BRP) systems were used for the detection of microorganisms in PCs. The backbone of the polymer consisted of labelled protein (casein), which was demonstrated to be degraded by pure proteases as models and by extracellular enzymes released by contaminating microorganisms. The concomitant colour change was easily visible to the naked eye. To enhance stability, the protein was cross-linked with glycidyl methacrylate (GMA). The cross-linked polymer was easier to handle but was less sensitive than the non-cross-linked material. A contamination of a PC with 10CFU/mL S. aureus was detectable after 24 hours. The visible colour reaction was quantified as a ΔE value according to the CIELab concept. A ΔE value of 21.8 was already reached after 24 hours. Hence, this simple but effective system could prevent transfusion of a contaminated PC.