Low LOD and Non-Adsorption Probing of Functionalized Magnetic Beads Using Quartz Crystal Microbalance Under Bimodal Magnetic Field

Abstract

Low limit of detection (LOD) and highly sensitive probing of functional magnetic nanobead labels is the cornerstone of magnetic label molecular detection technology, which is of great significance in analytical chemistry and biomolecular analysis. Here we present a probing technology based on quartz crystal microbalance (QCM) combines bimodal magnetic fields to accurate and rapid probing of magnetic beads. The proposed technique uses QCM to detect the change of viscosity and density of tested solution under a bimodal magnetic field, thereby enabling the quantification of magnetic bead concentration. The experimental findings demonstrate that the technique can detect magnetic beads accurately and rapidly within 0 ng/mL to 100 μg/mL without anchoring magnetic beads on the QCM. Furthermore, when the particle size of magnetic beads is 1 μm and 0.28 μm, the LOD is reached at 4.62 ng/mL and 2.31 ng/mL, respectively. The versatility of the no-modification probing platform yet the wide detection range and low LOD to various magnetic particles, showcase the potential of the proposed technology to enable swift, repeatable, and dependable assays across a broad range of applications, including but not limited to biomolecule analysis, Molecular genetics, pre-symptomatic diagnosis, and biosafety.