Amplified stretch of bottlebrush-coated DNA in nanofluidic channels.

The effect of a cationic-neutral diblock polypeptide on the conformation of single DNA molecules confined in rectangular nanochannels is investigated with fluorescence microscopy. An enhanced stretch along the channel is observed with increased binding of the cationic block of the polypeptide to DNA. A maximum stretch of 85% of the contour length can be achieved inside a channel with a cross-sectional diameter of 200 nm and at a 2-fold excess of polypeptide with respect to DNA charge.

Nanouidic compaction of DNA by like-charged protein.

The effects of the like-charged proteins bovine serum albumin and hemoglobin on the conformation and compaction of single DNA molecules confined in rectangular nanochannels were investigated with fluorescence microscopy. The channels have lengths of 50 μm and cross-sectional diameters in the range of 80-300 nm. In the wider channels, the DNA molecules are compressed and eventually condense into a compact form with increasing concentration of protein.