Selective Detection of Shiga-like Toxin 1 from Complex Samples Using Pigeon Ovalbumin Functionalized Gold Nanoparticles as Affinity Probes

Abstract

Escherichia coli 0151:H7 is a foodborne pathogen. This bacterial strain can generate Shiga-like toxins (SLTs), which can cause serious sickness and even death. Thus, it is important to develop effective and sensitive methods that can be used to rapidly identify the presence of SLTs from complex samples. Pigeon egg white (PEW) contains abundant glycoproteins, including pigeon ovalbumin (POA) (similar to 60%). POA possesses Gal-alpha(1 -> 4)-Gal-beta(1 -> 4)-GlcNAc termini,. which can recognize the B subunits in SLT type 1 (SLT-1B). Thus, POA is a suitable probe for trapping SLT-1B. In this work, we used PEW proteins as starting materials to react with aqueous tetrachloroauric acid for generation of PEW-protein-immobilized gold nanoparticles (AuNPs@PEW) via one-pot reactions. We demonstrated that the generated AuNPs@PEW were mainly dominated by POA-immobilized Au NPs. The as-prepared AuNPs@PEW were used as affinity probes to selectively probe SLT-1B from complex cell lysates derived from E. coli 0157:H7. The selective trapping step can be completed within similar to 90 s under microwave heating (power = 450 W) to enrich sufficient SLT-1B for Matrix-assisted laser desorption/ionization (MALDI) mass spectrometric analysis. Furthermore; this approach:can be used to detect SLT-1B at a concentration as low as similar to 40 pM. The feasibility of using the proposed method to selectively detect SLT-1B from ham contaminated by E. coli 0157:H7 was also demonstrated.