Precise characterization method of antibody-conjugated magnetic nanoparticles for pathogen detection using stuffer-free multiplex ligation-dependent probe amplification.

Antibody-conjugated magnetic nanoparticles (Ab-MNPs) have potential in pathogen detection because they allow target cells to be easily separated from complex sample matrices. However, the sensitivity and specificity of pathogen capture by Ab-MNPs generally vary according to the types of MNPs, antibodies, and sample matrices, as well as preparation methods, including immobilization. Therefore, achieving a reproducible analysis utilizing Ab-MNPs as a pathogen detection method requires accurate characterization of Ab-MNP capture ability and standardization of all handling processes. In this study, we used high-resolution CE-single strand conformational polymorphism coupled with a stuffer-free multiplex ligation-dependent probe amplification system to characterize Ab-MNPs. The capture ability of Ab-MNPs targeting Salmonella enteritidis and nine pathogens, including S. enteritidis, was analyzed in phosphate buffer and milk. The effect of storage conditions on the stability of Ab-MNPs was also assessed. The results showed that the stuffer-free multiplex ligation-dependent probe amplification system has the potential to serve as a standard characterization method for Ab-MNPs. Moreover, the precise characterization of Ab-MNPs facilitated robust pathogen detection in various applications.