Saccharides are found in many plants and animals. They play important role in keeping many organisms active even in extreme life conditions such as complete dehydration as they have ability to prevent headgroup of lipid membrane to pack when water is removed. However, the mechanism of stabilization of lipid membrane in dry state by saccharides is still not well understood due to the lack of effective experimental probes. Sum frequency generation (SFG) spectroscopy is an interface-sensitive technique, based on a second-order nonlinear optical effect, in which a photon is generated at a frequency equal to the sum of the frequencies of the two incident photons, and is effective for the study of interfacial molecular structure. In this work, the role of saccharides for the preservation of DMPC bilayer structure in dry state was studied using SFG spectroscopy, atomic force microscopy (AFM) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy.    Although the DMPC bilayer was stable in D2O, it was broken and formed an ordered monolayer when D2O was removed. The stability of the DMPC bilayer increased when saccharide was introduced. Moreover, the size of the saccharide was found to be an important factor in stabilizing the DMPC bilayer structure in dry state. ATR-FTIR measurements showed hydrogen bond formation between saccharide and phospholipid headgroups was minimal. From these results, we concluded that the volumetric effect play a main role in preserving bilayer structure in dry state.

Important role of saccharides in the preservation of lipid bilayer structure in dehydration probed by sum frequency generation (SFG) spectroscopy

247th National Meeting (2014)

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