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-200™ 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.
Luminex 200 is a flow cytometer that is widely used to detect very small concentrations of biomarkers. For biomarkers detection, fluorescently labeled probes and magnetic beads are attached to target molecules. After several washing and separation steps to remove unbound fluorescent molecules, single magnetic beads pass one by one through a narrow channel and their fluorescent signal is measured. Previously, we presented a novel magnetic modulation biosensing (MMB) system, which provides very high sensitivity in biomarkers detection. Unlike the particle by particle approach of flow cytometry, the MMB system is based on aggregating the magnetic beads and manipulating them in and out of the excitation laser beam. The modulation separates the signal from the background noise without washing steps. Using the MMB platform, we were able to detect Interleukin-8 with a limit of detection of 0.04 ng/L. Here, we provide a head-to-head comparison of the MMB platform and the Luminex 200 instrument. Comparisons were performed by processing identical bead-based tests in both systems. Using Luminex Triple Dye Beads, we showed that the MMB has at least 2x better sensitivity than the Luminex 200. In addition, we used a cardiac Troponin I assay and showed that the MMB has 10x better sensitivity than the Luminex 200. While the Luminex 200 has multiplexing capabilities, the MMB system provides higher sensitivity and a washless protocol that facilitates the use of the platform in point of care applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.