Poloxamer 188 (P188), a poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) triblock copolymer, protects cell membranes against various external stresses, whereas poly(ethylene oxide) (PEO; 8600 g/mol) homopolymer lacks protection efficacy. As part of a comprehensive effort to elucidate the protection mechanism, we used surface plasmon resonance (SPR) to obtain direct evidence of binding of the polymers onto supported lipid bilayers. Binding kinetics and coverage of P188 and PEO were examined and compared. Most notably, PEO exhibited membrane association comparable to that of P188, evidenced by comparable association rate constants and coverage. This result highlights the need for additional mechanistic understanding beyond simple membrane association to explain the differential efficacy of P188 in therapeutic applications.
Bibliographical noteFunding Information:
This work was supported by a grant from the National Institutes of Health (R01 HL122323) to F.S.B. M.V., C.T.E., and S.-H.O. acknowledge support from the Minnesota Partnership for Biotechnology and Medical Genomics. SPR chips were fabricated in the Minnesota Nano Center (MNC) cleanroom, which receives partial support from the National Science Foundation (NSF) through the National Nanotechnology Coordinated Infrastructure (NNCI).
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