Improving the SERS signals of biomolecules using a stacked biochip containing Fe2O3/Au nanoparticles and a DC magnetic field

Abstract

This study proposes a magnetic biochip that uses surface-enhanced Raman scattering (SERS) for antigen detection. The biochip was a sandwich structure containing alternating layers of gold and magnetic Fe₂O₃ nanoparticles. Both single (Au/Fe₂O₃/Au) and multilayer (Au/Fe₂O₃/Au/Fe₂O₃/Au) chips containing Fe₂O₃ nanoparticles were fabricated to detect bovine serum albumin (BSA). The single-layer chip detected the BSA antigen at a signal-to-noise ratio (SNR) of 5.0. Peaks detected between 1000 and 1500 cm^-1 corresponded to various carbon chains. With more Fe₂O₃ layers, bond resonance was enhanced via the Hall effect. The distribution of electromagnetic field enhancement was determined via SERS. The signal from the single-layer chip containing Au nanoparticles was measured in an external magnetic field. Maximum signal strength was recorded in a field strength of 12.5 gauss. We observed peaks due to other carbon-hydrogen molecules in a 62.5-gauss field. The magnetic field could improve the resolution and selectivity of sample observations.