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Updated: Jun 17, 2026

High Resolution Physical Characterization of Single Metallic Nanoparticles
Published on: June 28, 2019
Attofarad resolution potentiostat for electrochemical measurements on nanoscale biomolecular interfacial systems
Marco Carminati1, Giorgio Ferrari, Marco Sampietro
1Dipartimento di Elettronica e Informazione, Unità IIT Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
Abstract:
We present an instrument that enables electrochemical measurements (cyclic voltammetry, impedance tracking, and impedance spectroscopy) on submicrometric samples. The system features a frequency range from dc to 1 MHz and a current resolution of 10 fA for a measurement time of 1 s, giving a sensitivity of few attofarads in terms of measurable capacitance with an applied voltage of only 100 mV. These performances are obtained using a low-noise wide-bandwidth integrator/differentiator stage to sense the input current and a modular approach to minimize the effect of input stray capacitances. A digitally implemented lock-in filter optimally extracts the impedance of the sample, providing time tracking and spectroscopy operating modes. This computer-based and flexible instrument is well suited for characterizing and tracking the electrical properties of biomolecules kept in the physiological solution down to the nanoscale.
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