Platelet activation, polyurethane

L. Salzman, E. W. Merrill, E. W. XPS Analysis of Segmented Polyurethane-ureas Assessment of Surface Activity toward Blood Platelets, in press. 

Polyethylene glycol (PEG) is another well-known molecule used to reduce protein adsorption and/or platelet adhesion. Surface enrichment of a triblock oligomeric PEG containing additive from a polyurethane matrix was reported [54,55]. The authors used PEG as the active groups to suppress protein and platelet adhesion. The authors first synthesized a methylene diphenyl diisocyanate (MDI)-poly (tetramethylene oxide) (PTMO) 1000 prepolymer with a MW of approximately 4750 (PU4750), and then this prepolymer was terminally functionalized with mono amino-polyethylene oxide (PEG) with different MW (PEO550, 2000, or 5000, Table 2.3). This triblock copolymer was mixed with a polyurethane (MDI/ PTMO 1000/ethylene diamine (ED)) at different ratios in dimethylformamide (DMF) and cast into polymer films. The surface compositions of these films were evaluated by XPS. 

Tseng HI, Lin JJ, Ho TT, Tseng SM, Hsu SH. The biocompatibUity and antimicrobial activity of nanocomposites from polyurethane and nano silicate platelets. J Biomed Mater Res Part A 2011 99A(2) 192-202. 

Park KD, Suzuki K, Lee WK, et al. Platelet adhesion and activation on polyethylene glycol modified polyurethane surfaces. Measurement of cytoplasmic calcium. ASAIO J September 1996 42(5) M876-81. 

Among the most used synthetic polymers as cover materials for stent devices within the vasculature we can find polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and polyurethane. PTFE is a synthetic polymer of tetrafluoroethylene (C F ) composed of a carbon chain saturated with fluorine. This polymer has hydrophobic properties conferred by the presence of electronegative fluorine atoms. This characteristic which results in unfavorable reactions that enhance platelet adhesion, activation and thrombus formation [123], consists of ethylene glycol and terephthaHc add. 

---