Virus use their spikes to latch on to cells. Their proteins bind to ones on the target cell walls, their membranes fuse, and viral genetic material can then enter the target cell. Many antiviral drugs use particular proteins that bind to the spikes to disrupt that process at various stages. It takes a great deal of effort and time to find suitable proteins.
A variety of other techniques have been suggested over the years, but I can’t find one on Google that uses a net with custom sized holes that mechanically trap the virus by using the spike as a whole.
Imagine playing with a tennis racket and your ball is adapted to look like a big coronavirus:
If the holes between the strings are the right size, the virus will get trapped, like a fish in a net. You don’t need to be really clever coating the strings with some super-smart goo that sticks to a very specific part of the spike. You just need to make the holes the right size. That opens up a new bunch of trees to bark up. If you can make a membrane with the right sized holes, you could use that in a dialysis process, pass the patient’s blood over it, and many of the viruses will get trapped. Blood cells would go right on by, like tennis balls without the spikes.
That still might not be easy, and even if it were, you’d still need dialysis, but perhaps in early stages, it could prevent viruses from becoming rampant for long enough to allow your own immune system to build immunity. Flattening the curve so to speak.