Molecules 2018, 23, 1833
Rolling circle amplification (RCA) is a robust way to generate DNA constructs, which are
promising materials for biomedical applications including drug delivery because of their high
biocompatibility. To be employed as a drug delivery platform, however, the DNA materials produced
by RCA need to be shaped into nanoparticles that display both high cellular uptake efficiency and
nuclease resistance. Here, we showed that the DNA nanoparticles (DNPs) can be prepared with RCA
and modified nucleotides that have side-chains appended on the nucleobase are capable of interacting
with the DNA strands of the resulting RCA products. The incorporation of the modified nucleotides
improved cellular uptake efficiency and nuclease resistance of the DNPs. We also demonstrated that
these DNPs could be employed as carriers for the delivery of a photosensitizer into cancer cells to
achieve photodynamic therapy upon irradiation at both the in vitro and in vivo levels.