Airborne particulate matter (PM) have been significantly increasing over the past two decades carrying significant health risks such as premature death, damage to the lungs, heart tissue, and even cancer. PM2.5 is the main concern as it has the most harmful health effects while being more difficult to detect 1. Moreover, these magnetic nanoparticles are readily absorbed into the bloodstream causing neurodegenerative diseases such as Alzheimer’s and cancerous tumors 2. Therefore, it is essential to monitor the magnetic portion of PM and its adverse effects on health 3, 4.
This work focuses on developing, modeling, and simulation of a new kind of magnetic sensor that can count and localize these magnetic nanoparticles. Additionally, we have fabricated a novel low-noise and high-precision readout circuit for tunneling magnetoresistive (TMR) array to evaluate the bio-magnetic measurement platform’s suitability for detecting weak bio-magnetic fields. The proposed sensors could help to prevent these nanoparticles from the polluted environment and undoubtedly reduce their adverse risks to humans. The modeled magnetic system consists of a TMR sensor array, a conducting line, and the detected magnetite nanoparticles as shown in Fig. 1(a). The localization and quantization of these Fe3O4 nanoparticles (characterized in Fig. 1(b)) can be achieved by analyzing total output voltages from the TMR sensor array. The Fe₃O₄ magnetite is injected inside the small closed chamber and they are exerting an external magnetic field that is aligned or opposed to the pinning field, which results in shifting the MTJ curve as seen in Fig. 1(c). After applying a current in the conducting line and creating an external field, the magnetite gets polarized and approaches the MTJ sensors. This technique can detect 50-200 nm magnetic particles compared to existing commercial monitoring solutions that are limited to 1-3µm particles.