On thingiverse I am always looking for science-related projects, and I stumbled on this very very nice DNA filament by chylld.
I decided to give it a go without any support, just adding a fan on front of the Replicator to cool it down faster.
Just some minor cleaning up on the corners where it made some threads, but no overhangs.
Sliced with Makerware (2.0, just found out there is a 2.1 released today!)
infill 5%, number of shells 3, layer height 0.1
speed 80 (extruding) 150 (traveling) (Default settings for high quality)
light blue PLA, from Reprap world