Improving the sensitivity of fluorescence-based immunoassays by photobleaching the autofluorescence of magnetic beads

One of the most common capture surfaces is a magnetic bead. However, magnetic beads exhibit strong autofluorescence, which often overlaps with the emission of the reporter fluorescent dyes and limits the analytical sensitivity of the assay. Here, we photobleached several widely used magnetic beads and reduced their autofluorescence to 1% of the initial value. The photobleached beads were stable over time and their surface functionality was retained. In a high sensitivity LX-200TM system using photobleached magnetic beads, human interleukin-8 was detected with a 3-fold improvement in analytical sensitivity and signal to noise ratio over results achievable with non-bleached beads.

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