Sigmaplot 9

Current-clamp experiments were carried out using an Axopatch 200A (Axon Instruments, Union City, CA). Data were digitized using a Digidata 1332a (Axon Instruments). Data capture and voltage control were performed using Clampex (pClamp9.0; Axon Instruments). Data were analyzed with Clampfit10.6.2.2 (Molecular Devices, San Jose, CA).
For analyses, mean, SD, SE, and t test calculations were carried out using Excel (Microsoft, Redmond, WA). All calculated data are means ± SE. Plots were constructed using Excel (Microsoft) and SigmaPlot 9 (Systat Software, San Jose, CA).
Capacitance and input resistance were calculated by fitting the discharging phase of voltage traces using the following double-exponential decay equation: $y=a\cdot exp\left(-t/\tau -a\right)+m\cdot exp\left(-t/\tau -m\right),$ where y is membrane potential (V_m), a and m are amplitudes, τ − a and τ − m are decaying time constants, t is time, and τ = RC, where R is membrane resistance and C is cell capacitance.
Double-exponential fit was necessary because discharging voltage traces consist of the access resistance (R_acc, number of transmembrane conductive nanoparticles) and the membrane input resistance (R_m). Contributions of R_acc and R_m were determined as a and m, and contributions of decay time constant were τ − a and τ − m, respectively.

All experiments were repeated at least three times and results were expressed as mean ± SE. One Way analysis of variance (ANOVA) was calculated with SigmaPlot 9 (Systat Software, San Jose, CA). A one-tailed t-test was used to compare any significant difference between control and treated groups. The criterion for statistical significance was p<0.05. For western blotting results, the band intensities were measured by using the ImageJ and normalized with GAPDH.