Tuesday, June 17, 2008 - 1:40 PM
Room 7a (McKimmon Conference Center)
361

Templating Elongated and Helical Liposomes to Form Novel Silica Nanostructures

Peng Xu, Grace Tan, Jibao He, John D. Clements, and Vijay T. John. Tulane University, New Orleans, LA

Since liposomes are typically spherical, the majority of successful examples of liposome templating are of spherical shells. Here, we report the formation of novel elongated and helical liposomes by doping L-a-phosphatidylcholine (which typically forms spherical shaped liposomes) with ceramide VI (a skin ceramide). The liposomes formed from these two lipids are elongated, some of which exhibit helical structures and remain stable for more than two weeks after extrusion. By introducing a silica precursor such as TEOS to the liposome solution, hydrolysis and condensation of the silica precursor takes place at the bilayer of the liposomes and templates the liposomes to form uniquely structured silicas. The hollow helical nanosilicas obtained from templating liposomes typically measure 50 nm in diameter and are less than 800 nm in length. Although some change in morphology is observed after templating, the helical structure of the liposomes can be successfully transcribed to the inorganic silica coating. All the helical nanosilicas follow a left-handed helix conformation. The formation of the silica coating may offer protection of the liposome contents, as well as enable surface functionalization for drug or targeted delivery.