Tetraether Archaeal Liposomes: Remarkable Stability against Surfactants Parkson L. Chong, Temple University, DMR 0706410

• We have studied the effect of surfactant n-tetradecyl-β-d-maltoside (TDM, see below) on liposomes composed of the polar lipid fraction E (PLFE, one kind of archaeal bipolar tetraether lipids) and 1-palmitoyl-2-oleoyl-L-a-phosphatidylcholine (POPC, a monopolar diester lipid).

• Dynamic light scattering was used to monitor the changes in particle size as the concentration of TDM was increased (top graph, right panel; not all the data are shown). Experimental temperature = 25 oC

• For a given liposome, the particle size drops abruptly at a specific TDM concentration (top graph). The TMD concentration where the vesicle size is reduced to half its original value is designated as C1/2. There is a dramatic increase in C1/2 as the content of PLFE increases to >70 mol% (bottom graph).

• According to the C1/2 values, bipolar tetraether (e.g., PLFE) liposomes are ~14 times more stable against the surfactant TDM than monopolar diester (e.g., POPC) liposomes.

TDM structure

Broader Impacts

· Undergraduate training (this current academic year):o Aldo Fafaj, a senior undergraduate student majoring in

chemistry, is the first author of the work described in this highlight. He was a 2010 Temple University Summer Undergraduate Research Program intern. A full manuscript for this experimental work is in preparation.

o The other undergraduate students who participated in this project are: Leeandrew Taylor, Nam Tran, Thida Tran, Jenny Lam, Rachel Youjin Lee, Elizabeth Zellhart, Michael Bellano, Chelsea Little, Annie Kavulich, Anna Versage, Kara Thompson, Nicole Haloupek, James Hwang, Vinoth Birabaharan ( 2 out of 14 are minority students and 10 are women).

• Technological applications:o The extraordinary stability of PLFE liposomes against

surfactants demonstrates that archaeal tetraether liposomes hold great promise for technological applications such as orally administered drug carriers (left panel).

Tetraether Archaeal Liposomes: Remarkable Stability against Surfactants Parkson L. Chong, Temple University School, DMR 0706410

SmallIntestine

PLFE Liposome

Drug

bs

bsTG

bs: Bile salts (surfactants)TG: Triglycerides

Diagram (not to scale) showing the drug carrying PLFE liposomes inside the small intestine where they are exposed to bile salts (surfactants).