Advantages of Sarfus
Vesicles adhesion on lectin surface is studied by Sarfus. For
glycolipid vesicles, contact area on the surface is clearly observed whereas no
contact area is visible for DOPC vesicles. A correlation is done between contact
area and vesicles adhesion.
Surface flow on soft objects submitted to external shear flow is a problem
involved in an increasing number of engineering and biophysical situations:
microfluidics, emulsion processing, biomechanics, blood circulation. Here we
report the deformation and unbinding of weakly adhering vesicles. In this study,
the vesicle adhesion is mediated through a specific recognition: lectin-sugar.
Glycolipid vesicles and lectin-grafted substrates are chosen to mimic cells and
endothelial surface, respectively.
Vesicles are prepared by electroformation by mixing DOPC and glycolipid. Immersion Surfs
(Nanolane) have been firstly cleaned with piranha and UV lighting before
silanisation (mercapto propyltrimethoxysilane). Then, lectin-PEG molecules have
been grafted on mercapto-silane surface. The thickness of the lectin layer is
about 12nm and its density, determined by confocal microscopy, is about 500
Figure 1 shows three glycolipid vesicles (DOPC/glycolipid: 2/3) adsorb on the
surface of the functionalized Immersion
Surfs. On the left, the two vesicles display a contact area whereas the
vesicle on the right shows no surface contact. Figure 2 showing the same area
taken few seconds later, indicates that only the vesicle on the right has moved
Figures 1 and 2. Glycolipid vesicles (DOPC/glycolipid:
2/3) on functionnalized Immersion Surf (t0 and t0+few
The images sequence hereafter (Figure 3) presents the glycolipid vesicle
(DOPC/glycolipid: 2/3) adhesion on the surface vs. time. In the first seconds of
the adhesion process, the vesicle vibrates drastically. But after few seconds,
most of contact area is still fixed tightly on surface.
Figure 3. Image sequence of glycolipid vesicle
(DOPC/glycolipid: 2/3) vibration (0.2 and 0.6s) and vesicle fixation on the
surface (5.0 and 5.6 s).
Figure 4 shows a similar sequence for DOPC vesicle (DOPC/glycolipid: 1/0) for
which no adhesion is expected. Thermal fluctuations of the membrane close to the
Surf are clearly visible.
Figure 4. Image sequence of DOPC vesicle
(DOPC/glycolipid: 1/0) vibration on the surface.
Sarfus has shown that most of glycolipid vesicles are fixed on
the surface. In contrary, DOPC vesicles only interacted though fluctuant contact
area without any surface contact.
Advantages of Sarfus
The advantages of Sarfus include:
- Work in immersion at ambient conditions
- Non-invasive/non contact technique
- No labelling/pretreatment of the sample
- Direct and fast sample analysis (1 image / 200ms)
For more information on this source please visit Nanolane