If there are microbiological invasion within our body

nanobot is like virus.. they r not living thing but exist for a certain 'programmed' goal

how do u attack a virus?

its non living in outside environment which means they're dead outside of the cell.

it is easier to target them as a living organism in the cell

I know we're still in the early stages of this particular technology, but scientists have made predictions that nanotechnolgy will change human lives forever. We'll never be hungry again, we'll never be sick, our wounds grow back in a second, and we'll never get old. If you've ever played the Metal Gear Solid series, you'll have an idea what nanotechnology is, in this case how nanobots produced through nanotechnology can create the ultimate soldier.

"Nanotechnology, shortened to "Nanotech", is the study of the control of matter on an atomic and molecular scale. Generally nanotechnology deals with structures of the size 100 nanometers or smaller, and involves developing materials or devices within that size. Nanotechnology is very diverse, ranging from novel extensions of conventional device physics, to completely new approaches based upon molecular self-assembly, to developing new materials with dimensions on the nanoscale, even to speculation on whether we can directly control matter on the atomic scale."

"With the advent of full-scale nanotechnology in the 2020s we will have the potential to replace biology’s genetic-information repository in the cell nucleus with a nanoengineered system that would maintain the genetic code and simulate the actions of RNA, the ribosome, and other elements of the computer in biology’s assembler. A nano-computer would maintain the genetic code and implement the gene-expression algorithms. A nanobot would then construct the amino-acid sequences for the expressed genes.

There would be significant benefits in adopting such a mechanism. We would eliminate the accumulation of DNA transcription errors, one major source of the aging process. We would also be able to defeat biological pathogens (bacteria, viruses, and cancer cells) by blocking any unwanted replication of genetic information."

"Kurzweil notes earlier in the book how nanobots would do a better job of getting oxygen to cells than the biological solution (red blood cells), and in the following paragraphs, suggests how we could redesign the cells themselves to be mostly immune to pathogens."

The possibilities are endless with such technology. Lets look at some of the issues the world is currently facing that can drastically shorten our lifespan and could be solved by nanotechnology.

Diseases, namely cancer. Nanobots could enter the human body and destroy the cancer one cell at a time.

Hunger. Nanobots could turn a rock into something edible by rearranging it's atomic structure and by introducing some other common elements into it.

Dirty air. Nanobots could peel the Carbon from the C-O2, and we'll have our breathable O2.

Human Flaws. War, anger, evil intentions, etc. Nanobots can trigger or suppress certain parts of your brain to control your emotions and thinking. You'll always be able to control your anger and fear. You'll be a flawless human, somewhat like the people in Gattaca if you've watched that movie.
I believe if we ever get this perfected, I'll be something that will change humans forever. Nanotechnology is at the ladder of science that will branch into infinite possibilities.

If this really comes true and it gets perfected, there will be a problem of living spaces. Cuz, no one can die, and human keeps on reproducing 

Do you know that Nanorobotics is expected to be used in many high-tech areas ranging from medical to environmental sensing to space and military applications? From precise drug delivery to repairing cells and fighting tumor cells, nanobots are expected to revolutionize the medical industry in the future. If you are looking for a nice historical presentation of the nanorobotic concept for medical applications, read Freitas’ book on NanoMedicine.

I'm more concerned about nanopollution. do we have some kind of filter that can used to filter nanoparticles? They can easily get into our body.. if a nanobot or any nanomaterial designed for certain application, say for space or military applications, worn out and break off, how do we stop them from entering our body?