Multi-Sensor Low-Noise Modular Magnetic Flow Cytometer for Bacteria Detection

This work proposes an ultra-low-noise modular multichannel signal acquisition platform for interfacing magnetoresistive sensors employed in a magnetic flow cytometer (MFC). The MFC is portable and powered by batteries featuring an input-referred noise of 7.2 nV/root Hz at 10 kHz and an integrated noise of 2.1 mu V-rms over a bandwidth of 100 kHz. The modularity is achieved by designing a stackable board comprising two analog front-ends. The proposed work is based on a low-noise current mirror and low-noise amplification states. Spin-valve magnetic sensors are combined with microfluidic channels to allow biological detection. A custom-made application was developed to enable continuous data acquisition and storage with a total sampling rate of 200 kSps per sensor. The system capability to detect Klebsiella pneumoniae bacteria in patient samples is successfully demonstrated.