Negligible risk of surface transmission of SARS-CoV-2 in public transportation.

Background: Exposure to pathogens in public transport systems is a common means of spreading infection, mainly by inhaling aerosol or droplets from infected individuals. Such particles also contaminate surfaces, creating a potential surface-transmission pathway.

Methods: A fast acoustic biosensor with an antifouling nano-coating was introduced to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on exposed surfaces in the Prague Public Transport System.

Biomolecular charges influence the response of surface plasmon resonance biosensors through electronic and ionic mechanisms.

Surface plasmon resonance (SPR) biosensors have become an important label-free optical biomolecular sensing technology and a "gold standard" for retrieving information on the kinetics of biomolecular interactions. Even though biomolecules typically contain an abundance of easily ionizable chemical groups, there is a gap in understanding of whether (and how) the electrostatic charge of a biomolecular system influences the SPR biosensor response. In this work we show that negative static charge present in a biomolecular layer on the surface of an SPR sensor results in significant SPR spectral shifts, and we identify two major mechanisms responsible for such shifts: 1) the formation of an electrical double layer (ionic mechanism), and 2) changes in the electron density at the surface of a metal (electronic mechanism).