A sandwich-type colorimetric magnetophoretic immunoassay (MPI) is introduced to monitor tuberculosis (TB) antigen, CFP-10, in cultures of Mycobacterium tuberculosis (Mtb) using nanoparticle complexes of Au nanoparticles (NPs), magnetic microparticle (MMPs), and TB immuno-moieties. The MPI can monitor the target antigen quantitatively and qualitatively within 10 min in the detection range of 101 ~ 104 pg/mL. Furthermore, the quantitative analysis of the MPI in Mtb culture showed that there was linear relationship between the concentration of the secreted CFP-10 from 106 CFU/ml of Mtb and culture time. From these data, it is suggested that the MPI analysis can carry out TB diagnosis within 3~7 days, based on antigen secretion from Mtb. These data suggest that our MPI kit is able to be applied in early TB diagnosis through detection of TB specific antigen during culture.

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