Immune System: Nanobots, Implants & Defenses

[donkeyhide]

hi, I'm new here. i was hoping someone could answer my question about the immune system.

you hear talk sometimes about the possibility of medical nanobots on the horizon. if such nanoscale medical robots were ever to be developed, would the body attack them? i know that the immune system recognizes foreign invaders by their protein coat and/or lipid shell. and I've seen talk about the possibility of these hypothetical medical bots posessing an 'inert surface' as a way past the defensive lines. or that, possibly they could practice biomimicy, and be coated themselves with a protein that the body recognizes, thereby preventing attack by B-cells.

but what constitutes an 'inert surface' as far the immune system is concerned? just metal or a carbon composite? people get implants, after all, and the body doesn't seem to attack artificial hips or cochlear devices.

so. does the immune system recognize tiny little bots as invaders? if so, why and how? and what would happen to them? what might be some strategies be for protecting the bots? and finally, if a protein coat is the answer, what type of coat would be universally accepted by all human bodies?

thanks!

 

[donkeyhide]

maybe it's a dumb question, but i thought someone might take a crack at it.

 

[Monique]

No, it is a very good question: immune responses can be elicited by any foreign object: also metals. You can even feed a macrophage plastic spheres. I'll have to reply later.

 

[donkeyhide]

is this a board full of professionals or are there more laypeople here? perhaps I've come to these boards with questions that are too elementary for anyone to bother with? don't want to bring the level of discussion down. if I'm in the wrong place, i'll go to an easier forum somewhere.

 

[Moonbear]

You just need a little more patience. You asked a really good question, so it might be that people here don't have easy answers on hand. I've only been on this board a short time and don't really know who all is here, but I get the sense it's a mix of science professionals, students of all ages, and others who are just curious about science. I could be wrong.

I'm not sure exactly "what" makes something inert in the body, but as you pointed out, there are biocompatible polymers available. I have a friend who is a biomedical engineer, and I know she works on stuff like that, but I've never asked her directly whether there is a characteristic of a material that predicts it will be biocompatible. I think some of what they used to do was coat medical devices with substances like teflon that just prevented anything in the body from sticking to it...not sure if they still do it.

Theoretically, silicone is an inert substance in the body, but we all know from the many stories about breast implants that it didn't quite work out that way. It may not trigger a full immune reaction, but the body does still seem to recognize a foreign body and try to sequester it with an encapsulation of connective tissue. Maybe that happens with all implants and that's why physical therapy to maintain mobility is so important...to keep that connective tissue encapsulation from hindering movement and function of a joint replacement, for example. But I don't really know, I'm just speculating on this.

 

[donkeyhide]

thanks. yah, patience is good. but if i don't refresh these, they slide to the bottom and get overlooked.

 

[Jikx]

Many people are "allergic" to nickel.. but I'm not sure if its the immune system which causes the inflamation. Nickel might not even be inert ..

The best i could find is how certain metals are adversely effect the immune system.

http://www.hc-sc.gc.ca/hecs-sesc/tsri/research/tsri_44.htm
http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=11811932&dopt=Abstract

But nothing is intirely inert... all it takes is for it to mimick another metal, or deform a protein slightly and its all over!