Trapping biological molecules such as proteins and enzymes or even whole cells in rigid structures makes them easier to use for a whole range of industrial and medical applications. But combining fragile biological molecules with tough materials is difficult to do without damaging the molecules and destroying their biological activity.
As well as keeping the molecules intact, the framework must allow nutrients to reach the cells to keep them alive and enable the cells to interact physically with the chemicals they are being used to detect.
The new sol-gel technique developed by Professor Jaques Livage of the University of Paris uses porous glass made from silicates which enables biosensors to be made at room temperature.
The research is reported today in the UK's Institute of Physics journal, Journal of Physics: Condensed Matter.
"In the past, the high temperatures needed to process glass destroyed the fragile biomolecules and so bio-encapsulation was restricted to organic polymers, but this is no longer true. The sol-gel process means it is now possible to introduce and retain biological activity within silica glasses," Professor Livage said.
Mixing water with chemicals called alkoxides produces a sticky silica solution, trapping the biomolecules within a silica network, a bit like cherries in a cake. When the solution thickens, it can be shaped into films, rods and fibers.
As the sol-gel technique creates these hybrid silica glasses in water and at room temperature, the biological activity of the molecule or cell is not destroyed, meaning that it can still act as a biosensor or probe.
(Reference: Journal of Physics: Condensed Matter, Vol 13, Number 33, 20 August 2001)
[Contact: Professor Jacques Livage]
02-Aug-2001
