Could silk cocoons help to restore lost sight?

15 Jan, 2021

QEI researchers are currently investigating the role of a protein called sericin (taken from silk cocoons), as an antioxidant agent to hinder the harmful activity of unstable molecules in the eye.

QEI Chief Scientist Professor Traian Chirila, Senior Research Officer Dr Shuko Suzuki  and Research Assistant Dr Onur Sakiragaoglu are a part of the first team of researchers to assess and report on the biological and clinical responses of various cells of the eye to the two proteins that make up the silk thread (fibroin and sericin). After much investigation, the researchers demonstrated that sericin is a more effective surface for the growth of the corneal and retinal cells.

Free radicals are unstable molecules that are extremely reactive and have the ability to chemically damage other molecules in the body. They are produced during the normal metabolism of cells in our body, however can be generated in excess due to exposure to harmful factors or when the body is suffering from disease.

A balance between free radicals and antioxidants is essential for a normal, healthy life. When the balance is disrupted, a condition called “oxidative stress” occurs, and the body can no longer control the damaging effects of the free radicals. Oxidative stress and the presence of free radical molecules have been associated with major degenerative eye diseases such as age-related macular degeneration (AMD), glaucoma and diabetic retinopathy.

AMD is one of the leading causes of blindness in the developed world. In Australia alone, one in seven people over the age of 50 show signs of early macular degeneration. Current treatments are aimed at slowing vision loss. However, there is no treatment available to reverse the toxic effects caused by oxidative stress on the retina and photoreceptor cells, and no current treatments are able to restore their function. Retinal cell transplants have thus far proven to be of limited value to patients, as the healthy cells are eventually exposed to the same high levels of oxidative stress once they are transplanted.

QEIF researchers discovered that solutions of sericin isolated from silk cocoons and added to cells grown in the laboratory had a significant antioxidative effect.

With this evidence, the QEIF research team are able to continue investigations using sericin produced by a mutant silkworm, created by Japanese scientists. The mutant silkworm produces cocoons that contain only sericin, which means no extraction or purification steps are needed.

Currently, work is in progress to further monitor and assess the antioxidative effect of these membranes on the growth of retinal photoreceptor cells.


Silk cocoons (left) and a 5 micrometers thick membrane of silk protein (right)