Cationic Nanocapture for the Concentration of Foodborne Hepatitis A Virus

Introduction: The low amount of viral particles in contaminated foods makes it challenging to develop methods for their detection. Rapid and easy-to-use methods for separating and concentrating viruses from contaminated foods are needed to help enhance the efficiency of virus detection, improve food safety, and reduce foodborne viral diseases.

Purpose: The purpose of this study was to investigate the recovery efficiency of hepatitis A virus (HAV), as a model of foodborne virus capture, using iron oxide magnetic nanoparticles (20-30 nm; MNP) coated with a cationic food protein, protamine.

Methods: Protamine was covalently coated onto the surface of the MNPs using a three-step chemical reaction. Fourier transform infrared spectroscopy, zeta potential, and transmission electron microscopy were employed to confirm the conjugation of protamine to the MNPs. The feasibility of protamine-coated MNPs for the recovery of HAV from 50 ml of viral suspensions (10⁰ 10¹, 10³, or 10⁵ PFU, 0.05 M glycine, 0.2% Tween 20) was tested under different pH (4.5, 6, 7.5 and 9), NaCl concentration (0.14, 0.28, 0.56, and 1M), and MNP concentrations (50, 100, 200, and 300 μL). The recovery efficiency was determined by real-time RT-PCR.

Results: The optimal conditions for HAV recovery from 50 ml of viral suspension using cationic MNPs were pH 9, 0.14 M NaCl, and 50 μl of the MNPs. The recovery rate obtained under these conditions was between 24% and 49% in 70 min, depending on the viral inoculation level. 

Significance: Protamine-coated cationic MNPs were able to recover HAV in a short time. The recovery efficiency of HAV in food matrices is under investigation.