Reflectometric detection of influenza virus in human saliva using nanoimprint lithography-based flexible two-dimensional photonic crystal biosensor

Protecting the human body from viral infections is extremely important for maintaining human health. To prevent viral infections, early diagnosis is important. Moreover, the diagnosis must also be non-invasive and non-painful. Hence, for development of novel analytical systems for protecting from viral infections, non-invasive biosensing devices with high sensitivity and high throughput are effective analytical systems that can be conveniently used to make a diagnosis. For establishment of novel analytical systems, photonic crystal (PC) can be used to observe nanometer-sized periodic structures, and their structural color can be used to realize on-site non-invasive biosensor. In this study, we have demonstrated the reflectometric detection of influenza virus in human saliva using antibody-immobilized flexible nanoimprint lithography (NIL)-based two-dimensional (2D)-PC biosensor. As a result, using antibody-immobilized 2D-PC biosensor, reflection intensity change which related with influenza virus concentrations could be observed. In addition, we could detect the influenza virions present in human saliva (detection limit: 1 ng mL−1). Our approach provides versatile analytical systems for the establishment of novel rapid diagnostic systems of serious viral diseases.