Au-nanoshells modified surface field enhanced LRSPR biosensor with low LOD for highly sensitive hIgG sensing

Abstract

A high sensitivity side polished fiber long-range surface plasmon resonance (LRSPR) biosensor with electronic field enhanced through surface modified with Au-nanoshells is proposed to detect human immunoglobulin G (hIgG). LRSPR which has high penetration depth and long propagation distance can effectively detect biomacromolecules. The plasmon coupling effect between the Au-nanoshells and Au-film can enhance the electric field intensity on the surface of the sensor, which makes the proposed sensor structure have a lower limit of detection (LOD) and higher sensitivity. The experimental results show that the sensitivity as well as LOD of side-polished-fiber (SPF)/dielectric-matching-layer (DML)/Au-film/Au-nanoshells sensor is 1.84 nm/(µg/mL) and 0.20 µg/mL, which indicates better responses to hIgG with a concentration range of 1–40 µg/ml compared with the SPF/DML/Au-film sensor. The LRSPR sensor modified by Au-nanoshells was used to detect chicken serum samples and the calculated recovery is 107.62%, showing good practicality and superior self-referenced function. The biosensor has the advantages of small volume, high sensitivity and long-distance detection, and has good practicability in the field of biochemical sensing.