Use of Graphene Oxide for Concentration of Human Norovirus

Introduction: Graphene and its derivative graphene oxide (GO) are promising molecules for a variety of biotechnology uses, with features such as fluorescence quenching, ssDNA adsorption, ability to protect biomolecules from enzymatic cleavage, and antimicrobial properties.  The impact of GO on noroviruses (NoV) has not yet been studied.

Purpose: The purpose of this work was to investigate the utility of GO for concentration/removal of NoV.

Methods: A representative GII.4 human NoV outbreak strain was inoculated into various concentrations of GO (50 - 1000 µg suspended in 1X PBS), incubated, and pelleted by centrifugation at 10,000 x g. Virus and viral RNA recovery from the GO precipitate and the associated supernatant was determined using RT-qPCR combined with various sample pre-treatments. 

Results: Norovirus adsorbed to GO without virus or viral RNA degradation, as determined by preceding RT-qPCR with RNase treatment. The efficiency of virus capture with GO was concentration-dependent, with recovery efficiencies ranging from 60 to 70% at GO concentrations of 400 to 1000 µg, respectively. Both NoV and viral RNA could be efficiently released from GO by traditional elution methods (e.g., glycine-saline buffer, pH 9.0) with recovery efficiencies of 45 to 87% at GO concentrations in the range of 50 to 1000 µg. Norovirus RNA was protected from RNase treatment after desorption from GO, which suggests that the NoV capsid remained intact.

Significance: Both human NoV and NoV RNA adsorb effectively to GO without inactivation or degradation.  This inexpensive compound shows promise for use in NoV concentration and purification as is necessary for food and environmental detection protocols.