Ray Kurzweil Flickr/null0 Google's Ray Kurzweil wants to live forever, and he thinks he'll need nanobots to help him get there.

In an interview with Playboy, Kurzweil described a future in which microscopic robots inhabit our bloodstream, helping our immune system fight disease.

"By the 2020s we’ll start using nanobots to complete the job of the immune system," he said. "Our immune system is great, but it evolved thousands of years ago when conditions were different. It was not in the interest of the human species for individuals to live very long, so people typically died in their 20s. The life expectancy was 19."

Although life expectancy was indeed 19 a few thousand years ago (we've come a long way since), Kurzweil isn't wrong to point out the flaws in our immune system. Our immune system is notoriously finicky, which is where we get allergies, autoimmune diseases, and other instances of the immune system on the fritz. The same goes for cancer.

"Your immune system, for example, does a poor job on cancer," he told Playboy. " It thinks cancer is you. It doesn’t treat cancer as an enemy. It also doesn’t work well on retroviruses. It doesn’t work well on things that tend to affect us later in life, because it didn’t select for longevity." Kurzweil's statements about cancer are a bit oversimplified, given how diverse cancer can be even within one person. But the general idea is that cancer cells get good at hiding from the immune system so that they don't die when they are supposed to.

His solution? Nanobots that act as T cells, a type of blood cell that's involved our immune system response. If you can get the T cell to attack the cancer cells, then you have a shot at sending that person into remission. This is an idea researchers are using in certain cancer immunotherapies. Only Kurzweil doesn't want to harness the body's own T cells, but use the nanobots instead.

"They’re the size of a blood cell and are quite intelligent," he told Playboy. "I actually watched one of my T cells attack bacteria on a microscope slide. We could have one programmed to deal with all pathogens and could download new software from the internet if a new type of enemy such as a new biological virus emerged."

It may sound like science fiction — little robots swimming around in our bloodstream fighting disease — but it's not a completely off-the-walls idea. The National Cancer Institute even has an Alliance for Nanotechnology in Cancer that supports work in the nano-area. Some research has been done to investigate how nanobots could help us out, though the results of human clinical trials have not been reported yet.

The goal for nanobots and nanoparticles are mainly to be used in drug delivery. In people with cancer, often the cancer cells get good at recognizing the body's mechanisms that are trying to attack them. By throwing in a non-human element, the hope is to get the nanoparticle into the tumor so it can deliver medicine that will attack the cancer.

Nanobots in our immune system are just one of many ways to approach cancer treatment, and it remains to be seen if this is an effective form of treatment. But perhaps by 2029, when Kurzweil predicts we'll be at a point with medical technology where they'll be able to add on years to life expectancy, we'll see some progress.