We report cellular nanosponges as an effective medical countermeasure to the SARS-CoV-2 virus. Two types of cellular nanosponges are made of the plasma membranes derived from human lung epithelial type II cells or human macrophages. These nanosponges display the same protein receptors, both identified and unidentified, required by SARS-CoV-2 for cellular entry. It is shown that, following incubation with the nanosponges, SARS-CoV-2 is neutralized and unable to infect cells. Crucially, the nanosponge platform is agnostic to viral mutations and potentially viral species, as well. As long as the target of the virus remains the identified host cell, the nanosponges will be able to neutralize the virus.