Sensitivity and signal complexity as a function of the number of ion channels in a stochastic sensor.

Alternating current, phase-sensitive stochastic detection using between 1 and 26 alpha-hemolysin ion channels reconstituted in a lipid bilayer, suspended over a 160-nm-radius orifice glass nanopore, is reported. As predicted by the binomial distribution, simultaneous analyte detection at large numbers of channels is effectively zero, independent of the number of ion channels. The results indicate that alphaHL channels are noninteracting and that significant gains in sensitivity are possible without sacrificing the simplicity of single-molecule detection strategies.