Patterned and switchable surfaces for biomaterial applications

Chapter 1 - Introductioninteractions of the DNA base pairs [18, 19], although hydrogen bond formation alsoplays a certain role in DNA surface interactions in aqueous conditions [20]. Unlikesynthetic polyelectrolytes, which generally adopt a loop-train conformation whenadsorbed to a surface due to their flexible ‘thread-like’ nature [21], double-strandedDNA (dsDNA) can be considered as a rigid rod (Figure 1.1B) with a nitrogenouscore and a phosphate and pentose sugar exterior (Figure 1.1A) such that it generallylies flat to a surface upon adsorption [22]. Conversely, although more ordered andrigid than synthetic polyelectrolytes, single-stranded DNA (ssDNA) can beconsidered as a flexible thread, not nearly as rigid as dsDNA, with the nitrogenousbases readily exposed (Figure 1.1C). Thus, hydrophobic interactions play a moresignificant role with the adsorption of ssDNA as compared with dsDNA [22].1-6