DIY protective mask with activated carbon filter against COVID-19: this is a prototype printed in very soft TPU 80A by Recreus (Spain) without support...s, it can hold an interchangeable filter with activated carbon but above all it can be printed in Copper3D - MD Flex by Formfutura Holland, a surgical filament with the addition of nanoparticles capable of DESTROYING up to 99.99% of viruses, bacteria and microorganisms that come into contact with the material (other than the simple cotton masks) ... Nobody produces masks with this material obviously, but since we are Makers at least let's think about it.
The combination of a highly antibacterial material (used for prostheses) and an activated carbon filter makes this nice object an interesting scientific experiment ... Obviously is Open Source: we publish all the files on Thingiverse, if anyone wants to develop it, they are welcome, anyone with a printer can do it at home.