Portable Diagnostic Platform for Rapid Detection of 2µL Paramagnetic Particles in 5s

With the fast development of Tunneling magnetoresistance (TMR) biosensors, this paper reports a low noise, rapid, lab-on-chip system based on TMR sensors for malaria pigment (hemozoin) detection. A semiconductor circuit is designed to amplify the negligible (approximately 5mV) signal from the TMR sensor and to reduce the high frequency noise from the electronics. The semiconductor circuit is comprised of several Low drop-out (LDO) regulators, an instrumentation amplifier and an 8-order Butterworth ladder lowpass filter. In detail, this instrumentation amplifier reaches 90dB dc gain with 1 nV/$\sqrt{}$Hz low input noise at double ± 5V voltage supply. The cut-off frequency of the lowpass filter is adjustable 0.1Hz to 50kHz, which can obviously reduce the noise from the environment and the electronics. COMSOL Multiphysics® is applied to simulate the infected red blood cell (RBC) as well as the external magnetic field. The simulation results certify the feasibility of the system, which provides a fast response to the hemozoin samples. The designed system can detect the liquid paramagnetic samples in real time.