2.5. Electrophysiology
The electrodes were connected to a patch-clamp amplifier
(Axopatch 200B; Axon Instruments). The currents were filtered with a
low-pass Bessel filter (80 dB/decade) with a corner frequency of 2 kHz
and then digitized with a DigiData 1400 series A/D converter (Axon
Instruments) at a sampling frequency of 5 kHz. The oil reservoir and
amplifying headstage were enclosed in a metal box, which served as a
Faraday cage.
We examined the membrane activity of D9-NBD both in the
presence and absence of HRP (Figure S7). Regardless of the polarity of
the applied potential or the presence of HRP, transient pores formed
in the DIB membrane. Typically, more “pore-forming activity” is observed
in the first half of the trace when compared with the second
half. By 10 min, the conductance of the membrane approaches zero pA.