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.
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.