Surface plasmon resonance biosensor based on Au nanoparticle in titania sol–gel membrane

A novel surface plasmon resonance (SPR) biosensor for the determination of human IgG was introduced. The biosensor was prepared with three layers of titania sol–gel membrane by vapor deposition. The colloid Au nanoparticle (AuNP) was immobilized in the second layer of titania membrane and the AuNP coupled with rabbit anti-human IgG was encapsulated in the third layer. The AuNP in the second layer of titania membrane was proved to be effective in the sensitivity enhancement of SPR biosensor. The lowest concentration that could be detected obtained by the biosensor with AuNP is about eight times lower than that obtained without AuNP. In addition, the titania sol–gel is a porous homogeneous material that permits analytes to access the encapsulated biomolecule and can provide a controlled environment for the study of biomolecular recognition. The titania sol–gel was also confirmed to be benefit for biomolecule to keep bioactivity, which could offer a good waterish microenvironment. As a result, the modified biosensor exhibits a satisfactory response for human IgG in the concentration range of 0.30–40.00 μg mL−1 and shows favorable bioactivity for a long time.