A less invasive treatment for age-related macular degeneration
Age-related macular degeneration, or AMD, is the leading cause of irreversible blindness in Australia and affects around one in seven Australians over 50.
There are a number of effective biomacromolecule therapeutics available to treat patients with AMD, but due to their susceptibility to biodegradation these drugs are required to be administered at regular intervals via monthly intravitreal injections targeting the jelly-like substance inside the eye. This invasive procedure can be unpleasant for the patient, and lead to detrimental side effects.
Using gold nanoparticles to solve the problem
Our scientists, together with researchers from Beijing University of Chemical Technology and Wenzhou Medical University, have developed a drug depot that can control the release of drugs by exposing them to light. The method can potentially reduce the number of intravitreal injections required by shining a light into the patient's eye, triggering the release of a small dose of the drug from the depot.
Gold is the magic ingredient for making this work.
The team discovered that hydrogel infused with gold nanoparticles could, when exposed to light, release pre-loaded therapeutics. This is because gold absorbs light at specific wavelengths before releasing it as heat, enabling the polymer matrix encapsulating a pre-loaded drug to soften and accelerate the drug diffusion. The process is reversible, so when the light is turned off, the polymer cools down and hardens, effectively turning off the drug release.
Importantly the drug doesn't need to be modified in any way and it retains very high biological activity after release.
This unique drug delivery system is highly versatile and can deliver a variety of drugs ranging from small molecules to proteins and antibodies. The gold nanoparticles can also be customised to different light wavelengths so the method can be used for applications other than treating retinas. Infrared light, for instance, could release drugs used in deep tissue solid tumour therapy.
This novel method could potentially play a role in fighting cancer, while possible personal care and agricultural applications are also being investigated.
The scientists' research has been published in the international edition of Angewandte Chemie.