Detection of Aflatoxin B_1 by SPR Biosensor Using Fusion Proteins as a Linker

摘要

It is essential to monitor the level of aflatoxin B_1 (AFB_1) in a variety of foods. HPLC and ELISA methods require skilled personnel and expensive equipments to detect AFB_1. Therefore, simple and sensitive devices are required for detection of AFB_1 in the fields. One of the main issues in the development of SPR immunosensors is efficient immobilization of antibodies. Conventional methods, such as self-assembled monolayers (SAMs) of alkanethiols are cumbersome and cause antibodies to be random oriented. In this work, a novel fusion protein was constructed by genetically fusing gold binding polypeptides (GBP) to protein A (ProA). The resulting GBP-ProA protein was directly self-immobilized onto SPR gold chip surfaces via the GBP portion, followed by the oriented binding of anti-AFB_1 antibodies onto the ProA domain and AFB_1 in series. Consequently, a low detection limit (10 ng/mL) has been achieved for mycotoxin SPR immunosensor by using GBP-ProA fusion proteins as a crosslinker.