Artificial cells are one possible line of future biotechnology; devices built to resemble the body's building blocks, essentially nanomachines constructed of proteins. Here researchers take a modest step in that direction, by developing "a novel method of disguising nanoparticles as red blood cells, which will enable them to evade the body's immune system and deliver cancer-fighting drugs straight to a tumor. ... The method involves collecting the membrane from a red blood cell and wrapping it like a powerful camouflaging cloak around a biodegradable polymer nanoparticle stuffed with a cocktail of small molecule drugs. Nanoparticles are less than 100 nanometers in size, about the same size as a virus. ... This is the first work that combines the natural cell membrane with a synthetic nanoparticle for drug delivery applications. This nanoparticle platform will have little risk of immune response. ... Stealth nanoparticles are already used successfully in clinical cancer treatment to deliver chemotherapy drugs. They are coated in a synthetic material such as polyethylene glycol that creates a protection layer to suppress the immune system so that the nanoparticle has time to deliver its payload. ... today's stealth nanoparticle drug delivery vehicles can circulate in the body for hours compared to the minutes a nanoparticle might survive without this special coating. But in [this latest] study, nanoparticles coated in the membranes of red blood cells circulated in the bodies of lab mice for nearly two days. ... one of the next steps is to develop an approach for large-scale manufacturing of these biomimetic nanoparticles for clinical use. ... Researchers will also add a targeting molecule to the membrane that will enable the particle to seek and bind to cancer cells, and integrate the team's technology for loading drugs into the nanoparticle core so that multiple drugs can be delivered at the same time."