Effects of charge density and thermal history on the morphologies of spontaneously formed unilamellar vesicles.
A phospholipid mixture consisting of dimyristoyl phosphatidylcholine (DMPC), dihexanoyl phosphatidylcholine (DHPC), and the negatively charged dimyristoyl phosphatidylglycerol (DMPG) lipid is found to spontaneously form uniform-size unilamellar vesicles (ULVs). Small angle neutron scattering (SANS) is used to examine ULV size as a function of net charge, dilution, and thermal history. It shows that ULVs only exist within a narrow window of charge densities, where larger size ULVs can be obtained at a lower charge density through slow temperature annealing. There is also a 6-fold change in the size of low polydispersity ULVs, confirming a previously proposed model for spontaneously forming ULVs [Nieh, M.-P. et al. Langmuir 2005, 21, 6656]. Finally, the stability of these ULVs was confirmed through a series of high temperature dilution experiments, further making the case that these nanoparticles can be used as carriers for drugs and contrast imaging agents.
Mahabir
Suanne
S
Biomedical Engineering Graduate Program, The University of Western Ontario, London, Ontario, Canada, N6A 5B9.
Wan
Wankei
W
Katsaras
John
J
Nieh
Mu-Ping
MP
D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry; D010316:Particle Size; D010713:Phosphatidylcholines / Q000737:chemistry; D010715:Phosphatidylglycerols / Q000737:chemistry; D053838:Scattering, Small Angle; D013696:Temperature; D053835:Unilamellar Liposomes / Q000737:chemistry*
D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D053835:Unilamellar Liposomes; C032166:1,2-hexanoylphosphatidylcholine; C002773:dimyristoylphosphatidylglycerol; D004134:Dimyristoylphosphatidylcholine