Abstract
Inorganic mercury (Hg2+) and Inorganic Cadmium (Cd2+) are toxic heavy metals linked to the development of cancer, diabetes and neurological dysfunctions. The effect of these metals on the fluidity and phase transition (Tm) of biomimetic and polar extract membranes was investigated using Laurdan Generalized Polarization (GP) and Dynamic Light Scattering (DLS). Hg2+ and Cd2+ electrostatically target and induce rigidity in membranes containing cationic and anionic lipids respectively. Hg2+ also imparts rigidity by acting as a catalyst in the vinyl ether hydrolysis of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) plasmalogens. Cd2+-induced rigidity of anionic membranes results in a stabilization of the gel phase and a suppression of the Tm of membranes composed of phosphatidic acid (PA), cardiolipin (CL), phosphatidylserine (PS), phosphatidylglycerol (PG) and phosphatidylinositol (PI). Cd2+ induces more rigidity in rigid anionic membranes compared to more fluid anionic membranes. These results further our understanding of metal-lipid interactions.
