FIG 4.

Impact of copper surface exposure on HuNoV VLP receptor binding. One-microliter aliquots (representing 590 ng) of purified HuNoV GII.4 Houston VLPs were placed onto either stainless steel (A) or copper (B) surfaces and eluted at various time points in PBS-EDTA. VLPs were then bound to a 96-well polystyrene plate and blocked, and synthetic biotinylated blood type A HBGA was added to each well. Plates were developed by using the TMB peroxidase substrate system, and receptor binding was determined by measuring the optical density at 450 nm using a microplate reader. Data are presented as percentages of the absorbance of untreated VLPs.