Biomedical Engineering Reference
In-Depth Information
FIGURE 5.4 Ocean NanoTech Catalog # SHP 10 loaded with dox that was released at pH 2-5.
(For color version of this figure, the reader is referred to the online version of this topic)
potential problems, such as low and weak binding, poor control of the NM-drug
interactions, and the ligands may not be in the desired orientation after binding.
Dagar and coworkers 74 have used vasoactive intestinal peptide (VIP),
a 28-amino acid mammalian neuropeptide, as a targeting moiety to cancer
and inflamed tissues because receptors for vasoactive intestinal peptide are
overexpressed in human breast cancer. They established that VIPs that are
HI attached to liposomes were less able to target and attach to breast can-
cer cells. 74 They used their sterically stabilized liposomes (SSLs) with cova-
lently associated VIP on the surface. This was carried out by conjugating the
VIP to DSPE-PEG 3400 -NHS [1,2-dioleoyl- sn -glycero-3-phosphoethanol-
amine- n -[poly(ethylene glycol)]- N -hydroxy succinamide, PEG M w 3400]
under mild conditions to obtain a 1:1 conjugate of VIP and DSPE-PEG 3400
(DSPE-PEG 3400 -VIP) which was confirmed by sodium dodecyl sulfate-
polyacrylamide gel electrophoresis. 74 This was followed by the insertion of
DSPE-PEG 3400 -VIP into preformed fluorescent cholesterol (BODIPY-Chol)-
labeled SSL by incubation at 37 °C. The breast cancer targeting ability in vitro
was carried out by incubating these, VIP-SSL with MNU-induced rat breast
cancer tissue sections. Compared with fluorescent SSL without VIP or with
noncovalently attached VIP, significantly more of the covalently formed VIP-
SSL were attached to rat breast cancer tissues. This indicated that SSL with
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