Measuring Biotin Concentrations for Quantitative Magnetic Immunoassay Using a Femtosecond Laser

Magnetic immunoassay (MIA), a medical application that utilizes magnetic nanoparticles (MNPs), is characterized by its ability to provide quantitative evaluation of antigen levels in a short time with high accuracy, without requiring a washing process. However, a challenge with this technique is that the magnetic signal can decrease due to the aggregation of the MNPs. In this study, we attempted to redisperse the aggregates by irradiating the sample with a laser. The results showed that laser irradiation produced a significantly greater change in signal change compared to the case without laser irradiation. Therefore, it was suggested that laser irradiation can suppress the magnetic signal decrease due to aggregation and enable accurate estimation of the antigen content in the sample.