Superparamagnetic MoS(2)@Fe(3)O(4) nanoflowers for rapid resonance-Raman scattering biodetection

Sensors for rapid and reliable detection of biomolecules are crucial for clinical medical diagnoses. Here, a rapid, ultra-sensitive, magnetic-assisted biosensor based on resonance Raman scattering at MoS(2)@Fe(3)O(4) composite nanoflowers is presented. Raman shifts and X-ray photoelectron spectra indicated that the composite was formed via Fe–S covalent bonds. Convenient magnetic separations could be performed because of the superparamagnetic Fe(3)O(4) nanoparticles. MoS(2) E(1)(2g) and A(1g) Raman peaks were used as probe signals for anti-interference immunoassays. The probe unit of the immunoassay also included goat anti-human IgG molecules that were used as the target analyte. Au substrates coupled with the goat anti-human IgG were used as capture units to form sandwich biosensors. Because of the magnetic enrichment, the detection limit was improved by three orders-of-magnitude and the detection time was reduced from 1.5 h to 1 min. Sandwich biosensors using MoS(2)@Fe(3)O(4) nanoflowers as Raman probes could be very promising sensors for proteins, antigens, and other immunogenic biopolymers, as well as for corpuscular viruses and cells.