Question: How do you know what materials work on which disease?

Jess Smith answered on 11 Mar 2014:

This is a great question.

There are a lot of things that you need to think about. There are two general ways that we use materials to help fight disease:

1. We use them to replace part of a body that has broken, or is diseased.
For example, if we pretend that there is a patient called Janet. Janet has arthritis in her hip. This is a disease where the cartilage has worn away, but not replaced itself. (Cartilage is a special type of hard tissue that sits in joints to prevent the bones rubbing against each other.) With the cartilage gone the bones are rubbing against each other, and this causes a lot of pain, swelling and limited motion. Well to help Janet we need to take this joint out and replace it with an artificial one (a hip implant). To decide what materials are needed, we have to think about what role the hip plays in the body. So we need to chose one that is very strong, that wont bend or snap, and that isn’t too heavy. It also needs to be ‘biocompatible’, which means that it wont harm the body. Quite often we use a combination of materials. For example in hip implants we use a metal, which has a polymer coating.

2. We use them to fight the disease itself.
This is where biomaterials overlaps most strongly with medicine, pharmaceuticals, and biochemistry. In this case, the starting point is the disease itself. Normally medical/ pharmaceuticals/biochemists will work out the drug required to treat a disease. They do this by looking closely at the virus or bacteria and finding its weak spots. They try a lot of different ways to stop it attacking your body. The role of biomaterials is quite often how to get this drug to the right place, and how to carry the drug around the body. Scientists are working on drugs called ‘targeted drugs’. Imagine that you want to target a disease that is in the stomach. But you don’t want the drug to be released anywhere except the stomach as it can have nasty side effects. Well then you can encase the drug in another molecule which is chemically programmed only to detach in the stomach. How do we chemically program it? Well we chose a molecule that will only breakdown (and so release the drug) in the exact conditions of the stomach. In the case of the stomach we would make a drug that breaks down in low PH (acidic) environments.

So in summary, we look at the problem and decide what characteristics our material needs to have in order to fix it.

I hope this helps, feel free to ask again if you want me to clarify anything as I know the answer is quite long!