  We summarize and compare recent Molecular Dynamics simulations on the
interactions of dipalmitoylphosphatidylcholine (DPPC) bilayers in the liquid
crystalline phase with a number of small molecules including trehalose, a
disaccharide of glucose, alcohols, and dimethylsulfoxide (DMSO). The sugar
molecules tend to stabilize the structure of the bilayer as they bridge
adjacent lipid headgroups. They do not strongly change the structure of the
bilayer. Alcohols and DMSO destabilize the bilayer as they increase its area
per molecule in the bilayer plane and decrease the order parameter. Alcohols
have a stronger detrimental effect than DMSO. The observables which we compare
are the area per molecule in the plane of the bilayer, the membrane thickness,
and the NMR order parameter of DPPC hydrocarbon tails. The area per molecule
and the order parameter are very well correlated whereas the bilayer thickness
is not necessarily correlated with them.
