Biomedical Engineering Reference
In-Depth Information
cleavable S-S bond
O
SWCNTs
O
S
P
O
S
n
O
O
O
S
P
O
S
n
PL
si-RNA
O
PEG
2000
44
44
Figure 5.30.
Functionalisation of SWCNTs with phospholipids (PLs), polyethylene
glycol (PEG
2000
) and siRNA through a cleavable S-S bond.
Then RNA was modiied with a thiol group to produce cleavable disulide
bonds, and results showed about 90% of silencing eficiency upon incubation
for 3 days of T cells with the CNT complexes carrying siRNA
CXCR4
. In addition,
since both CD4 receptors and CXCR4 co-receptors are required for HIV
infection of human T cells, the delivery of CD4 siRNA (siRNA
CD4
) into T cells
by SWNTs was investigated as well. Interestingly, the down-regulation of CD4
receptors on T cells by treatment with SWNT-siRNA
CD4
had no non-speciic
effect on the CXCR4 receptors, and vice versa (Fig. 5.31).
Figure 5.31
CD4 and CXCR4 expression levels on cells treated with an SWNT-siRNA
CD4
complex. Reproduced from Kam
et al.
107
with permission.
Another covalent functionalisation of CNTs with siRNA afforded branched
structures made up of polyamidoamine (PAMAM) dendrons linked to the
surface of MWCNTs.
108
The presence of PAMAM dendrons guaranteed the
solubility of the tubes in aqueous media, while the progressive synthetic
pathway provided increasing peripheral primary amino groups, with
the highest number associated with the second generation of dendrons.
Search WWH ::
Custom Search