Particle Size and Vesicle Formation
Lowell
Short, Nicole Heldt , Yuzhuo Li
Department
of Chemistry
Center
for Advanced Materials Processing
Clarkson
University
Potsdam,
NY 13676
yuzhuoli@clarkson.edu
Phase diagrams were used in order
to produce vesicles by constructing the micellar (L1) phase region
and the liquid laminar crystal (LLC) region of the phase diagram. The three components of the phase diagram
were 0.9% sodium chloride solution, sodium xylenesulfonate (SXS), and
1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Vesicles can be spontaneously formed by diluting a micellar
mixture with an equal mass of 0.9% sodium chloride medium. The standard dilution used was a 50:50
dilution of micellar mixture, however other dilutions were also tested. The results from these other dilutions were
consistent with those of the 50:50 dilution as shown in Fig. 1.
Fig. 1. Phase diagram prepared from DPPC and SXS.
Average particle size of the vesicles was determined using dynamic light scattering (DLS). A direct correlation between particle size and amount of hydrotrope (SXS) was found, where particle size increased with increasing ratios of DPPC / SXS. Various mass ratios of SXS / DPPC were used in conjunction with 0.9% sodium chloride solution to form the vesicles (Fig. 2).
Fig. 2 Particle size dependency on
DPPC/SXS ratio.
The LLC region is presently being investigated in order to distinguish the border between the LLC region and a two phase region. It is necessary to locate the boundary between the L1 and the LLC regions because the vesicles that are formed by the dilution represent samples that show characteristics of both L1 and LLC regions.
Copyright 2000, Lowell Short