Chemistry Reference
In-Depth Information
Figure 12.6 Colorimetric response (CR) values obtained upon exposure of the liposome
array to lipopolysaccharides from different Gram negative bacteria for (
B
) Trp and (B) Tyr.
All values are the average of at least four experiments. RT, room temperature; [liposome]
0.6 mM, [LPS]
2.2 mg/mL, [SDS] ¼ 2 mM, [EDTA] ¼ 1 mM. See supporting information
for details.
DCR corresponds to the difference between the CR in the presence of the calixarene
in the vesicles and the CR in the absence of the calixarene receptor (to correct for
nonspecific interactions). A plot of DCR for the cationic calixarene versus DCR
for the anionic calixarene gave rise to a unique diagnostic point for each protein
that was examined.
12.2.8. Whole Cells
The propensity of diyne lipids to phase separate from phospholipids has been suc-
cessfully exploited to incorporate PDA patches into whole cells as functioning
sensors. Addition of unpolymerized PDA/phospholipid vesicles to erythrocyte
ghosts (red blood cells that have had their hemoglobin removed) resulted in incorpor-
ation of the vesicle lipids into the erythrocyte cell membrane (Shtelman et al. 2006).
Subsequent UV irradiation of the solution resulted in the formation of the character-
istic blue color of PDA. Addition of membrane binding or disrupting agents resulted
in a chromatic transition to the red form. Moreover, because the red form of PDA
is fluorescent, these chromatic transitions could also be followed by fluorescence
microscopy. A similar set of experiments was carried out using U937 cells, a
human leukemic monocyte lymphoma cell line (Orynbayeva et al. 2005). The viabi-
lity of cells containing these PDA patches remained unchanged soon after treatment
but decreased after 3 h.
