2023 Volume 47 Issue 3 Pages 66-69
A novel method for the rapid detection of bacteria in the liquid phase for point-of-care testing was developed using magnetic nanoparticles (MNPs) conjugated with antibodies. We utilized the magnetic characteristic that the magnetic susceptibility decreases when the magnetism of MNP aggregate changes from ferromagnetism to superparamagnetism after bacteria bind to MNPs through an antigen-antibody reaction (Nanomag-D, 500 nmφ, 0.2 μl/sample). The magnetic susceptibility of Fusobacterium nucleatum samples was measured using a lab-made detection setup. We found that the susceptibility depends on the concentration of Fusobacterium nucleatum with optical density (OD) values ranging from 10-4 to 1 (i.e. 8 × 104 ~ 8 × 108 CFU/ml). In addition, the detection time was only about 49 seconds, which shows promise for point-of-care testing.
