Suncoast yellow fluorescent polymer nanospheres

Suncoast yellow fluorescent polymer nanospheres (excitation/emission maxima 540/600 nm) of nominal size (0.19 μm; 2.653 × 10¹² nanspheres ml⁻¹) were purchased from Bangs Laboratories, Inc. (Fishers, IN, USA). The nanospheres were diluted with 10 mM TRIS buffer (pH 8) to a concentration of 1.5 × 10⁶.
ColE₁ (6 kbp) and Charomid (42 kbp) DNA were purchased from Nippon Gene (Tokyo, Japan). The restriction enzyme SmaI (New England Biolabs (UK)) was used to prepare the linear form, and Topoisomerase I (New England Biolabs) was used to prepare the relaxed form. The DNA molecules were labelled with YOYO-I (Molecular Probes, Carlsbad, CA) (dye molecules to base pair ratio of 1:5) as described in ref. 32 (link).

Supercoiled ColE₁ (6.6 kbp) DNA was obtained from Nippon Gene (Toyama, Japan) whereas the lambda phage DNA was obtained from New England Biolabs (Hitchin, UK). The restriction enzyme SmaI and the digestion buffer were obtained from New England Biolabs and were used to prepare the linear form of the ColE₁ DNA. The DNA molecules were covalently labelled with Cy5 using a Label IT Cy 5 labelling kit obtained from Mirus Bio (Madison, WI, USA).
Suncoast yellow fluorescent polymer nanospheres (excitation/emission maxima 540/600 nm) of nominal size (0.19 μm; 2.653 × 10¹² nanospheres ml⁻¹) were purchased from Bangs Laboratories, Inc. (Fishers, IN, USA). The nanospheres were diluted with 70% glycerol in 10 mM TRIS buffer (pH 8) to yield a concentration of 1.5 × 10⁶ nanospheres ml⁻¹.