Effects of intracellular treatment with 5- or 40-nm AuNPs on spontaneous firing and excitatory synaptic transmission.

(A) The representative traces of spontaneous firing from AuNP-treated and non-treated (No AuNPs) hippocampal CA1 neurons. (B) AuNPs of both sizes significantly increased the rate of spontaneous firing. (C) Neurons treated with 5-nm AuNP showed similar mEPSC frequency and amplitude to non-treated neurons. **p<0.01, Student's t-test, No AuNPs vs. 40-nm AuNPs; ^##p<0.01, Student's t-test, No AuNPs vs. 5-nm AuNPs; N.S., no significance.