Nanotechnology in medicine
Nanoengineers in Singapore have invented a contact lens that can release precise amounts of medication to treat glaucoma and other eye diseases.
Developed by researchers at the Government-backed Institute of Bioengineering and Nanotechnology, the new technique for making lenses begins by mixing the drug with a pre-polymer liquid. This mix is then polymerised, creating a transparent contact lens material.
If the drug is water-soluble, it becomes trapped within a matrix of tiny interconnected, water-filled channels in the material. If it's water-insoluble, the drug is trapped within nano-spaces in the polymer network, and slowly leaches out into the channels. When the lens is in place, the contact with the fluid on the eyeball causes these channels to open up and slowly release the drug.
By adapting the water content of the original mix, the team can vary the size of the channels and so control the rate at which the drug is released.
The polymeric nanostructure allows the lenses to be permeable to gases (such as oxygen), salts, nutrients, water and other substances found in eye fluid.
Moreover, with changes to the size, concentration and structure of the polymeric nanoparticles within the lenses, the delivery system can be tailored to dispense various drugs or even produce self-lubricating contact lenses for those with dry eyes.
Most ophthalmic medications are currently delivered through eye drops. The problem with this method is that the drugs often mix with tears and can reach other organs through the bloodstream, potentially causing side effects.