Figure 6

Calcium imaging of silver wire-treated A549 cells. A. Cells were treated with 6.5 μm (SW 6.5 μm, upper left panel) and 12 μm (SW 12c μm, upper right panel) long silver wires at a concentration of 1 × 10¹⁰ Wrs/ml in 1.2 mM Ca²⁺ buffer and fluorescence intensities were measured at 340 and 380 nm excitation. PVP was used as control (lower left panel) and additional experiments were carried out in low calcium buffer (lower right panel) to investigate whether changes were from extracellular calcium influx or intracellular storage depletion. Arrows indicate the addition and elution of particles/coating agent. Each line represents the response of one single cell. B. False- colour fluorescence images were generated by taking the 340/380 nm ratio pixel by pixel after background subtraction. Images were taken 5, 26, 32 and 47 minutes after the start of the experiment using 6.5 μm wires (SW 6.5 μm) at a concentration of 1 × 10¹⁰ Wrs/ml (left panel) and 4, 26, 30 and 47 minutes after the start of the experiment using 12 μm wires (SW 12c μm) at the same concentration (middle panel). Blue = low calcium levels, red = high calcium levels. Infrared pictures (right panel) were taken immediately before and 25 min after addition of 12 μm (SW 12c μm) long wires. Scale bars represent 50 μm.