One-step green synthesis of a polypyrrole-Au nanocomposite and its application in myoglobin aptasensor

An electrochemical aptasensor was fabricated based on a polypyrrole-Au nanocomposite (PPy-Au NC) and myoglobin-binding aptamer (MBA). The PPy-Au NC was synthesized using a one-step green synthesis method and was characterized by transmission electron microscopy (TEM), UV-vis spectroscopy and a diffuse reflectance spectrum. The studies revealed that the PPy-Au NC provided a mild micro-environment and large surface area for MBA immobilization and facilitated electron transfer. Glassy carbon electrodes (GCEs) surface modified with PPy-Au NC were grafted with MBA, which had excellent binding affinity and selectivity for myoglobin (Mb). The binding of Mb at the modified GCE surface greatly restrained the access of electrons for a redox probe of [Fe(CN)(6)] (3-/4) . Moreover, the aptasensor could be used for the detection of Mb in biochemical assays, with a wide detection range (0.0001 to 0.15 g L-1) and a low detection limit of 30.9 ng mL(-1). The aptasensor had a good anti-interference property towards hemin, glucose oxidase (GOx), cytochrome c and hemoglobin. The idea and method presented herein provide a new approach for the evaluation of the freshness and quality of stored meat.