The room temperature electrical characteristics of biopolymer-gold nanoparticle complexes show threshold behavior, periodic conductance features, and current-voltage scaling that together indicate the nonlinear transport is associated with single electron charging. Repeated measurements over a period of up to 80 h showed the characteristics change with time. The current-voltage scaling behavior is found to be time independent, while the position of the conductance features shifted randomly over

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... periods of many hours. We show that the time dependence is consistent with a fluctuating background charge distribution and can be understood within the framework of the orthodox model of single electron transport that is modified to account for the relatively large self-capacitance of the nanoparticles.