Effect of electrical stimulation on HIV-1 infectivity. HIV-1LAI or HIV-1KMT was incubated for 3 h at 37°C on PLL-coated ITO electrodes and then stimulated by a constant d.c. potential of 1.0 V (vs. Ag/AgCl) for 2 to 10 min. MAGIC-5 cells were then seeded onto the electrically stimulated virus. After culturing for 3 days at 37°C, HIV-1-infected cells were examined using a MAGI assay. More than 3,000 cells were counted under a microscope. The rates of HIV-1LAI and HIV-1KMT infection were defined as the number of stained cells divided by the total number of cells, as shown in the bar graph. The rates of HIV-1LAI and HIV-1KMT inhibition were derived from the infection rate of electrically stimulated and unstimulated virus, as shown in the polygonal line graph. Data represent the geometric mean ± standard deviation of duplicate determinations.