Is the future grow-your-own?
Many people now have their worn joints fixed with metal and plastic substitutes – operations that could be avoided if we were able to regrow bone and cartilage to replace worn-out parts. That is one possible application for stem cells, versatile cells that can be nurtured to develop into different types of tissue. If they are grown in the lab on the right kind of scaffold, bone stem cells can, in theory, generate new bone. At the moment, the cells are grown on donated bone from earlier operations, but the search is on for artificial materials that will do the job.
The aim is to make scaffolds that are as similar to natural bone matrix as possible (ie that are biomimetic). They need to be made of material that will degrade once new tissue has formed and that has the right mechanical and chemical properties. This is a very demanding specification, but the formulation of such materials is gradually improving. Naturally occurring materials can also help: a British company is developing replacements for damaged cartilage, especially in knee joints, using a new material based on spider silk fibres.Lead image:
Wellcome Library, London