Simultaneous Quantitative Detection of IL-6 and PCT Using SERS magnetic immunoassay with sandwich structure

Abstract

Sepsis is a systemic inflammatory response syndrome caused by infection. The mortality rate is as high as 30%−50%. Early diagnosis and treatment can significantly improve the mortality of patients with sepsis. Therefore, we have developed a SERS-based magnetic immunoassay method that uses the principle of sandwich method to quantitatively detect Interleukin 6 (IL-6) and Procalcitonin (PCT). In this article, two different Raman reporter molecules are embedded in the middle of the Au@Ag shell and coupled with the tracer antibody to form a SERS immunoprobe. Biotin was coupled with capture antibody to form a sandwich structure when participating in the immune response. Streptavidin and biotin systems have extremely high binding affinity. The sandwich structure is quickly captured by SA magnetic beads and then applied with a magnetic field to enrich the magnetic beads. Finally, simultaneous quantitative detection is achieved by the intensity of the two Raman reporter characteristic peaks on the solution magnetic beads. IL-6 and PCT showed a good relationship between 0−1000 pg ml−1 and 0−20 ng ml−1, respectively, and the limits of detection were 0.54 pg ml−1 and 0.042 ng ml−1, respectively. The recovery rate was between 89.8% and 104.2%, both intra-assay and inter-assay CV were ≤20%. No cross-reaction with C-reactive protein (100 μg ml−1), showing good specificity. This method provides a new technical reference for the clinical detection of sepsis biomarkers.

Design of Raman reporter-embedded magnetic/plasmonic hybrid nanostirrers for reliable microfluidic SERS biosensors

“…In particular in acute inflammation, elevated IL-6 levels are often used to determine the inflammatory response triggered by bacterial infection. 44,45 Thus, it is urgently required to develop a more advanced, reliable and rapid technique to detect IL-6 in complex biological systems. Here in our experiment, IL-6 was used as a model target analyte.…”

Dual-enhancement and dual-tag design for SERS-based sandwich immunoassays: evaluation of a metal–metal effect in 3D architecture

“…Indeed, a few works demonstrated the improvement of the IL-6 detection level up to ca. 4 pg⋅mL −1 in microfluidic and magnetic devices [19,[30][31][32]. From the other side, our results cannot be directly compared with these works because of different analytical parameters and methods used, e.g., lowest detectable concentration instead of LOD, signal-to-noise (S/N) method, without excluding the false-negative signal.…”

Reduced Graphene Oxide‐Gold Nanoparticle Nanohybrid Modified Cost‐Effective Paper‐Based Biosensor for Procalcitonin Detection

“…[2] The most commonly used techniques include enzyme-linked immunosorbent assay, [3] lateral flow, [4] electro chemiluminescent, [5] chemiluminescence, [6] and surface-enhanced Raman spectroscopy. [7][8][9] However, these procedures are efficient, precise, and specific, but they are often cost-effective for large samples as they require complex devices and highly skilled operators. The limitations may be overcome by developing a simpler, more selective, and sensitive device for detecting PCT in the human body.…”