Figure 1

Scheme of the experimental setup. The suspension containing the beads and ssDNA was incubated in a square microcell. The temperature can be controlled within $10°\mathrm{C}–80°\mathrm{C}$ using a thermoelectric cooler (TEC) mounted on the aluminum piece that holds the square capillary. A temperature sensor follows the temperature close to the capillary channel.Reuse & Permissions

Figure 2

(Color) Stretching curves of several ssDNA single molecules. (a) Extension curves starting at $25°\mathrm{C}$ (green), $30°\mathrm{C}$, $35°\mathrm{C}$, $42°\mathrm{C}$, and $45°\mathrm{C}$ (left to right) as the force was increased in PBS. (b) Extension curves in glyoxal (green and orange) at $25°\mathrm{C}$ and $40°\mathrm{C}$ as the force was increased (solid lines) and then decreased (dashed lines) for the same bead at each temperature; the solid blue line was calculated using Eq. (1). (c) The temperature was increased from $25°\mathrm{C}\text{to}50°\mathrm{C}$: green and red circles, respectively; the dashed lines are the theoretical predictions using the mFJC model described by Eq. (1). The green and red solid lines correspond to the fits done with the theory including hairpins (see text). The error bars in (a) and (b) are not shown for clarity but are similar to those shown in (c).Reuse & Permissions

Figure 3

(Color) Extension vs temperature for several beads at constant force. (a) Extension data at several forces and increasing temperature in PBS $p\mathrm{H}$ 7.4 from bottom to top: 2, 3, 6, 10, and $12.5\mathrm{pN}$ (black solid symbols); 2 and $6\mathrm{pN}$ and decreasing temperature (black empty triangles); $3\mathrm{pN}$ and increasing temperature in $0.75\mathrm{M}$ NaCl- phosphate buffer $p\mathrm{H}$ 7.4 (purple squares); theoretical predictions are shown with dotted gray lines for Eq. (1) and blue (PBS) and red ($0.75\mathrm{M}$ NaCl) dashed lines correspond to the fits that include hairpins in the theoretical calculations.Reuse & Permissions