Correlation with flow cytometry and microscopy showed that ThromboLUX is well suited to measure PMP concentration and size distribution in PLT concentrate samples. In combination with noninvasive sampling, ThromboLUX could provide routine microparticle enumeration of PLT-containing samples.

Bacterial contamination of platelet concentrates represents the greatest post‐transfusion infectious risk. Biofilm formation in this environment resulting from platelet–bacteria interactions can lead to non‐uniform contaminant distribution and thus missed detection. As formation of platelet–bacteria aggregates is largely based on receptor–ligand interactions, we examined whether shielding these events would result in reduced biofilm formation by contaminant bacteria. We introduced methoxypoly(ethylene glycol) to covalently modify the platelet surface using a process termed ‘PEGylation’. In the first study of its kind, we demonstrate that PEGylated platelet concentrates inoculated with Staphylococcus epidermidis display a significant reduction in bacterial binding and biofilm formation.

Unlike red blood cells (RBC) which are stored at 4°C, platelets are stored at 22-24°C (room temperature) due to biophysical and biochemical changes induced by cold temperatures aggregately known as the 'cold storage lesion' (CSL). However, 22°C storage greatly increases the risk of microbial growth, thus limiting the safe storage of platelets to only 5-7 days (versus 42 days for RBC). Consequent to the short shelf life of platelets, blood services face chronic shortages of these life-saving cells. To overcome both the risk of microbial contamination and the constrained supplies of platelets, renewed research into attenuating the CSL and/or determining where cold stored platelets are clinically suitable are ongoing. In this chapter, we show that the covalent grafting of methoxypolyethylene glycol (mPEG), a biocompatible polymer, to the membrane of platelets attenuates the CSL. Moreover, the grafted mPEG serves as a potent cryoprotectant allowing platelets to be stored at 4°C, or frozen at −20°C, while retaining normal platelet counts and biologic function. The successful development of platelet PEGylation may provide a means by which the cold storage of platelets can be achieved with a minimal loss of platelet quality while improving both platelet microbial safety and inventory.