Biomedical Engineering Reference
In-Depth Information
4.6
DNA-Directed Assembly
4.6.1
Assembly of Liposomes
One of the most straightforward applications of DNA-functionalized liposomes is
to perform DNA-directed assembly. The first example of DNA-directed assembly
was demonstrated by Mirkin and coworkers in 1996 using DNA-functionalized
AuNPs. Upon addition of a linker DNA that is complementary to the DNAs on
AuNPs, AuNP aggregates were formed with a red-to-blue color change (Fig.
4.5
a)
[
39
]. A TEM micrograph of assembled 13-nm AuNPs is shown in Fig.
4.5
c. This
assembly is reversible and heating the AuNPs to remove linker DNA results in
disassembly (Fig.
4.5
b). Interestingly, compared to the melting of free DNA, a
characteristic sharp melting transition is often observed with AuNPs, which is
attributed to the cooperative melting of AuNPs containing multiple DNA linkages
[
40
]. The soft nature of liposomes may allow for additional features. A number
Fig. 4.5
Schematics of DNA-directed assembly of (
a
)AuNPs,
d
) liposomes, and (
g
)
AuNP/liposome hybrids. Photographs of assembled and disassembled (
b
)AuNPs,(
e
) liposomes,
and (
h
) AuNP/liposome hybrids. TEM micrographs of DNA-linked (
c
)AuNPs,(
f
) liposomes, and
(
i
) AuNP/liposome hybrids (Reprinted with permission from Ref. [
36
]. Copyright 2011 American
Chemical Society and from Ref. [
48
] by permission of John Wiley & Sons Ltd)
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