Magnetic field-aligned Fe3O4-coated silver magnetoplasmonic nanochain with enhanced sensitivity for detection of Siglec-15

Noble metal nanoparticles could provide a significant gain in sensitivity of surface plasmon resonance (SPR) sensor by electromagnetic field coupling between the localized plasmon resonance of nanoparticles and gold film. A facile and cost-effective SPR sensor based on magnetic field-aligned Fe3O4-coated silver magnetoplasmonic nanoparticles (Ag@MNPs) nanochain (M-Ag@MNPs) was proposed to improve the sensitivity of the sensor, which gave access to detect clinical targets at low concentration. Optimization experiments proved that 80 ng mL(-1) M-Ag@MNPs-based SPR sensor showed high refractive index sensitivity and increased detection accuracy and quality factor when comparing with those of bare gold. Sialic acid binding Ig like lectins-15 (Siglec-15) was used as proof of concept to verify the sensitivity enhancement performance of M-Ag@MNPs in the actual detection process. SPR angle shifts of M-Ag@MNPs/gold sensor were significantly higher than those of traditional gold sensor under the same concentration of Siglec-15, which was consistent with previous performance analysis. Also, the detection limit of M-Ag@MNPs/gold sensor was calculated to be 1.36 pg mL(-1). All these results had proved that aligning M-Ag@MNPs onto the gold chip could improve the performance of the SPR sensor and achieve sensitive detection of small amounts of clinical biomarkers.

Automated summary

Utilizing noble metal nanoparticles to enhance the sensitivity of surface plasmon resonance sensors, a facile and cost-effective sensor based on magnetic field-aligned Fe3O4-coated silver magnetoplasmonic nanoparticles nanochain was proposed to detect clinical targets at low concentration. Experimental results demonstrated that this sensor showed improved refractive index sensitivity, detection accuracy, and quality factor compared to traditional gold sensors.