Sensing hydration and behavior of pyrene in POPC and POPC/cholesterol bilayers: A molecular dynamics study

► Pyrene was simulated in POPC bilayers with variable amounts of cholesterol (Chol). ► Effects of pyrene on the bilayer structure and dynamics are globally small. ► Pyrene locates in the upper acyl chain region, and orders acyl chains in pure POPC. ► However, pyrene locally disorders Chol-rich bilayers, opposing the effect of Chol. ► The bilayer polarity sensed by the pyrene Ham effect is more precise than expected.