Membrane perturbing properties of sucrose polyesters

Area of Science:

• Lipid-based materials science
• Biophysical chemistry
• Membrane biophysics

Background:

• Sucrose polyesters (SPEs) are utilized in various applications, including as fat substitutes and contrast agents.
• Ingestion of SPEs can lead to depletion of essential lipid-soluble vitamins and molecules.
• The molecular-level interactions between SPEs and lipid membranes require further investigation.

Purpose of the Study:

• To synthesize and characterize labeled and non-labeled SPEs.
• To investigate the effects of SPEs on model lipid membranes (DEPE and DPPC) at varying temperatures, compositions, and concentrations.
• To elucidate the molecular interactions between SPEs and lipid membranes.

Main Methods:

• Synthesis of various SPEs.
• Differential scanning calorimetry (DSC).
• X-ray diffraction.
• 2H and 31P Nuclear Magnetic Resonance (NMR) spectroscopy.
• Order parameter measurements.

Main Results:

• At low concentrations (<1 mol%), SPEs promote the transition to the inverted hexagonal (HII) phase in DEPE and induce cubic phase formation in a composition-dependent manner.
• At low concentrations, SPEs induce non-bilayer phase formation in DPPC.
• SPEs significantly influence the phase behavior of model membranes, with effects dependent on SPE type, concentration, chain length, and saturation.
• At higher concentrations (>=10 mol%), SPEs strongly promote the DEPE bilayer to HII phase transition but lose the ability to form cubic phases.

Conclusions:

• SPEs exert significant influence on the phase behavior of model membrane systems.
• The observed effects are dependent on SPE composition, concentration, and lipid type.
• These findings are critical for optimizing current and future industrial and medical applications of SPEs.