Numerical analysis of magnetic field distribution of magnetic micro-barcodes for suspension assay technology

In this study, we have investigated real-time decoding feasibility of magnetic micro-barcodes in a microfluidic channel by using numerical analysis of magnetic field distribution of the micro-barcodes. The vector potential model based on a molecular current has been used to obtain magnetic stray field distribution of ferromagnetic bars which consisting of the micro-barcodes. It reveals that the stray field distribution of the micro-barcodes strongly depends on the geometries of the ferromagnetic bar. Interestingly enough, we have found that one can avoide the miniaturization process of a magnetic sensor device needed to increase the sensitivity by optimizing the geometries of micro-barcodes. We also estimate a magnetic sensor response depending on flying height and lateral misalignment of the micro-barcodes over the sensor position and found that control of the flying height is crucial factor to enhance the detection sensitivity and reproducibility of a magnetic sensor signal in the suspension assay technology.