A Nanosensor Interface Based on Delta-Sigma Arrays

An emerging area of biosensors is based on the use of structures provided by recent advances of Nanotechnology such as nanowires, nanotubes and nanopores. Among them, the integration of natural nanopores such as ion channels with electronics is a promising approach to develop rapid, sensitive and reliable biosensors able to detect low concentration of target molecules or DNA sequencing. This paper presents a compact and low-cost system able to readout, process and record current in the pA range, provided by biological or synthetic nanopores. The approach is based on the idea that by processing the outputs of a large amount of single-molecule nanosensors would result in a significant increase of resolution and signal-to-noise ratio. The approach consists of an electronic interface able to detect current-based array of nanosensors, where the management of very large amount of data is critical for the readout process. As working example, we acquired the single molecule signals derived from non-covalent bindings between single alpha-hemolysin pores, embedded into an artificial lipid bilayer, and beta-cyclodextrin molecules. The system embeds the electronic readout with the microfluidic where is placed the nanosensor array. The electronic interface is a 0.5mm(2) current amplifier based on an array of Sigma Delta converters. Then the high rate data streams are processed and downsampled by a DSP that communicates with a PC via a USB interface for data processing and storage.