Chemistry Reference
In-Depth Information
Figure 12.8 (a) Image of diacetylene liposome-embedded agar plate with three E. coli BL
colonies after 18 h of growth. (b) Chromatic sensor concept. (Left) Agar scaffold containing
vesicular nanoparticles composed of phospholipids (green) and PDA (blue). (Right)
Bacterial proliferation (green oval) on the agar surface causes a blue to red transformation
of embedded vesicles due to bacterially secreted compounds that diffuse through the agar.
Reprinted from Silbert et al. (2006). Copyright 2006 American Society for Microbiology.
(See color insert.)
polycation, followed by a polyanion layer of unpolymerized vesicles composed of 1.
Additional rounds of polycation and polyanion deposition were carried out.
Photopolymerization of the slides gave rise to the characteristic blue color of
PDA, which underwent a chromatic transition when the slides were heated to 608C.
Layer-by-layer assembly of already polymerized vesicles has also been reported
(Potisatityuenyong et al. 2006). These slides undergo a chromatic transition in response
to the addition of increasing amounts of ethanol and to changes in pH (Fig. 12.10).
Arrayed PDA liposomes have been prepared via microcontact printing of NHS
ester-containing liposomes onto aminopropyl silane terminated glass surfaces
Figure 12.9 Colorimetric bacterial fingerprinting. The color combination for each bacterium
reflects the chromatic transitions (RCS) recorded 7 h after the start of growth at a bacterial
concentration of 1
10
9
/mL. The RCS color key is shown on the left: (i) 1-a-dioleoylpho-
sphatidylethanolamine (DOPE)/PDA (1: 9 mole ratio), (ii) sphingomyelin/cholesterol/PDA
(7 : 3 : 90), (iii) DMPC/PDA (1: 9), and (iv) 1-palmitoyl-2-oleoyl-sn-glycero-3-[phospho-
rac-(1-glycerol)] (POPG)/PDA (1 : 9). Reprinted from Scindia et al. (2007). Copyright 2007
American Chemical Society. (See color insert.)
