Biomagnetic glass beads for protein separation and detection based on surface-enhanced Raman scattering

A novel surface-enhanced Raman scattering (SERS)-based detection method for proteins attached to magnetic glass beads have been developed in this study. Silica coated magnetic nanoparticles (Fe3O4) are prepared and aldehyde-functionalized for capturing proteins in solutions by Schiff reaction, which is more biocompatible than previous magnetic nanoparticle and SERS-based detection methods. Target protein and molecule with a specially recognized feature are captured and separated by the magnetic nanoparticles, followed by SERS-based detection. Moreover, these biomagnetic glass beads and detection protocol are found to be useful in protein immunoassay and protein-ligand recognition even in a mixture system (two protein ligands). The proposed magnetic nanoparticles are biocompatible, manipulatable by an external magnetic force and highly sensitive after silver nanoparticles staining, which makes the protocol quite promising for high throughput protein assays.