Integrated Low-Noise Current Amplifier for Glass-Based Nanopore Sensing

Nanopores realized with glass nanopipettes allow the electrical characterization of DNA molecules. A low-noise, custom-designed transimpedance amplifier has been developed to detect the current pulses (hundreds of pA) due to the features of the translocating molecule, while handling large DC currents (up to 100 nA). It is based on a CMOS current preamplifier designed to achieve high resolution with a wide bandwidth, thanks to the low parasitic capacitance of glass nanopipettes. With the aim of reducing the shot noise of the integrated amplifier, an auxiliary feedback network has been implemented. The electronic characterization of the system confirms that fast current pulses modulating a large DC current are detected. Validation experiments with DNA molecules demonstrate the actual resolution improvement with respect to the state-of-the-art.