Formation and colloidal stability of DMPC supported lipid bilayers on SiO2 nanobeads.
Supported lipid bilayers (SLBs) of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were formed on 20-100 nm silica (SiO(2)) nanobeads, and the formation was accompanied by an 8 nm increase in diameter of the SiO(2), consistent with single nanobeads surrounded by a DMPC bilayer. Complete SLBs were formed when the nominal surface areas of the DMPC matched that of the silica, SA(DMPC)/SA(SiO2) = 1, and required increasing ionic strength and time to form on smaller size nanobeads, as shown by a combination of nano-differential scanning calorimetry (nano-DSC), dynamic light scattering (DLS), and zeta potential (zeta) measurements. For 5 nm SiO(2), where the nanoparticle and DMPC dimensions were comparable, DMPC fused and formed SLBs on the nanobeads, but it did not form single bilayers around them. Instead, stable agglomerates of 150-1000 nm were formed over a wide surface ratio range (0.25 < or = SA(DMPC)/SA(SiO2) < 2) in 0.75 mM NaCl. At ionic strengths > 1 mM NaCl, charge shielding, as measured by zeta potential measurements (zeta --> 0), resulted in precipitation of the SLBs.
Savarala
Sushma
S
Department of Chemistry, College of Science and Technology, Temple University, 1901 North 13th Street, Philadelphia, Pennsylvania 19122, USA.
Ahmed
Selver
S
Ilies
Marc A
MA
Wunder
Stephanie L
SL
D002151:Calorimetry; D003102:Colloids; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D005782:Gels; D008027:Light; D008051:Lipid Bilayers / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D009994:Osmolar Concentration; D010316:Particle Size; D044367:Phase Transition; D012542:Scattering, Radiation; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
D003102:Colloids; D005782:Gels; D008051:Lipid Bilayers; D012822:Silicon Dioxide; D004134:Dimyristoylphosphatidylcholine