E.coli outer membrane with autodisplayed Z-domain as a molecular recognition layer of SPR biosensor

Abstract

In this work, Z domain of protein A with IgG-binding activity was expressed on the outer membrane of E.coli as a fusion protein of AIDA-1 by using Autodisplay method, and the outer membrane with autodisplayed Z-domain was applied for the SPR biosensor. The outer membrane of E.coli with Z-domain was coated to the gold surface of SPR biosensor. After anti-hIgG antibodies were immobilized to the Z-domain, hIgG antibodies were measured as a target analyte. The LOD of SPR biosensor with the outer membrane of E.coli with Z-domain and intact E.coli outer membrane was estimated to be 1.6 ng/ml, 316 ng/ml, respectively. This result shows that the outer membrane of E.coli with Z-domain could increased the sensitivity of SPR biosensor through the orientation control of antibodies at the molecular recognition layer.