A Facile Sensor for Detection of Lysozyme in Egg White Based on AuNPs and Ferrocene Dicarboxylic Acid

Abstract

Lysozyme (Lyz) is found in animal and human bodily fluids, and is frequently utilized as a biomarker for various diseases. Even trace amounts of Lyz in food can potentially trigger adverse immune system reactions in sensitive individuals. Therefore, it is very important to monitor Lyz concentration in foods for safety. In this study, a simple and convenient electrochemical sensor for Lyz detection was prepared by modifying gold nanoparticles (AuNPs) and ferrocene dicarboxylic acid (Fc(COOH)2) on a glass carbon electrode (GCE), which was characterized fully by various electrochemical methods and field emission scanning electron microscope (FESEM). The proposed method utilized Fc(COOH)2 as a probe and AuNPs as an electron transfer medium to improve the sensor’s current response performance. Under optimal conditions, the sensor was used to detect Lyz with a linear range from 0.10~0.70 mmol·L−1 with a sensitivity of 50.55 μA·mM−1·cm−2, and a limit of detection (LOD) of 0.07 mmol·L−1. In the standard addition experiment of food samples (egg white), a total R.S.D. of less than 6.75% and an average recovery between 95.45% and 102.62% were obtained.