Biomedical Engineering Reference
In-Depth Information
synergistic effect of multiple strands, possibly due to distinct linear charge density, strand
flexibility and hydrophobicity (Costa et al. 2007). DNA crosslinked polymeric hydrogel
exhibited thermal reversibility and sol-gel transition, which is correlated to the thermal
stability of the DNA base-pairing. As a result, in these gels DNA sequence has to be
designed for desired melting temperature (Tm) by adjusting length of the strand, GC
content, and/or thermal dynamics(Cheng et al. 2009, Lin et al. 2004a). It is noted that the
critical temperature for the DNA based bulk material may be different from that of the
involved DNA strands (Sun et al. 2005, Topuz & Okay 2008).
Fig. 9. Study of cellular behavior using DNA based macromaterials. (
A
) CHO cells in a
DNA-only gel. Stained CHO cell encapsulated inside the gel (A1) and the majority of the
cells were viable (A2). Extracted from (Um et al. 2006b) with publisher's permission. (
B
)
L929 fibroblasts growth on dynamic substrates based on a DNA crosslinked hydrogel.
(Upper panel) Typical morphology of L929 fibroblasts grown on DNA crosslinked
hydrogels at Day 4, two days following DNA delivery. Scale bar is 100 mm. (Lower panel)
Projection area and aspect ratio of L929 fibroblasts on DNA crosslinked hydrogels on Day 4.
Extracted from (Jiang et al. 2010c) with publisher's permission.
Gels consisting of physically entangled DNA strands display resistance to DNase digestion
(Lee et al. 2008). The hybrid between DNA strands and other polymer (such as SP-PPV
(Tang et al. 2009)) also possess resistance to enzyme or heat. Thus, physical interactions
between DNA strands and composite between DNA and other polymer may provide shield
against enzymatic action.
