Rapid, highly sensitive, and high-throughput detection of biomarkers at low concentrations is invaluable for the early diagnosis of various diseases. In many sensitive immunoassays, the protocol is time-consuming and requires a complicated and expensive detection system. Previously, we presented a high-throughput optical modulation biosensing (ht-OMB) system, which enables reading a 96-well plate within 10 minutes. In ht-OMB, to aggregate and immobilize the magnetic beads to one spot, a single cylindrical permanent magnet with a sharp tip is positioned under a 96-well plate. To reduce washing and separation steps, the laser beam is manipulated relative to the fixed magnetic beads. Recently, MagBiosense Inc., which commercializes the ht-OMB technology, provided us with a fully automated OMBi detection system. Here, we show the use of the OMBi system for highly sensitive serological (clinical anti-Zika, anti-DENV, and anti-West Nile IgG) and molecular (SARS-CoV-2) assays. Using the OMBi, to detect 336 RNA extracts from 70 confirmed RT-qPCR SARS-CoV-2-positive patients (Ct≤40) and 236 confirmed RT-qPCR SARS-CoV-2-negative individuals, resulted in 100% specificity and 96% sensitivity.
Rapid, highly sensitive, and high-throughput detection of biomarkers at low concentrations is invaluable for early diagnosis of various diseases. In many sensitive immunoassays the protocol is time consuming and requires a complicated and expensive detection system. Here, we demonstrate a high-throughput optical modulation biosensing (ht-OMB) system, which enables reading a 96-well plate within 10 minutes. Using the system, to detect human Interleukin-8, we demonstrated a limit of detection of 0.14 ng/L and a 4-log dynamic range. Testing 94 RNA extracts from 36 confirmed RT-qPCR SARS-CoV-2-positive patients (C_t≤40) and 58 confirmed RT-qPCR SARS-CoV-2-negative individuals resulted in 100% sensitivity and 100% specificity.
Detection of biomarkers at low concentrations is essential for early diagnosis of numerous diseases. In many sensitive assays, the target molecules are tagged using fluorescently labeled probes and captured using magnetic beads. Current devices rely on quantifying the target molecules by detecting the fluorescent signal from individual beads. Here, we demonstrate a high-throughput optical modulation biosensing (ht-OMB) system Using the ht-OMB system to detect human Interleukin-8, we demonstrated a limit of detection of 0.14 ng/L and a 4-log dynamic range, values which are on par with the most sensitive devices, but are achieved without their bulk and laborious protocols.
Detection of biomarkers at low concentrations is essential for early diagnosis of numerous diseases. In many sensitive assays, the target molecules are tagged using fluorescently labeled probes and captured using magnetic beads. Current devices rely on quantifying the target molecules by detecting the fluorescent signal from individual beads. Here, we propose a compact fluorescence-based magnetically aggregated biosensors (MAB) system. Using the device to detect human Interleukin-8, we demonstrated a 0.1 ng/L limit of detection and a 4-log dynamic range, performance which is on par with the most sensitive devices, but is achieved without their bulk and cost.
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.
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