Patients with dry eye syndrome could be relieved. Biotribologists are testing a better raw material for artificial tears

Dry eye syndrome is one of the most common diseases that bring patients to the ophthalmologist's office. In addition, the number of patients is still growing. For milder forms of the disease, doctors prescribe the so-called artificial tears in the form of eye drops. While the preparations produced today combine various substances that are intended to replace the individual properties of eye film, the scientists from the Faculty of Mechanical Engineering at BUT together with the Contipro company want to develop a raw material for eye drops from a single polymer, i.e. hyaluronic acid.

Eye irritation, redness, fatigue, pain, blurred vision. These are typical symptoms of the so-called dry eye syndrome, when the patient has a reduction in tear production or a faster evaporation of the tear film. A number of risk factors, such as an population ageing, diabetes, some other illnesses and medications (including hormonal contraception) and being in a dusty or air-conditioned environment, may be responsible for the increasing number of patients with these problems. There is also a risk of long-term watching of a monitor or television, when the physiological frequency of blinking decreases significantly.

"The tear film consists of three parts. The first mucin layer is on the cornea, followed by a thicker layer of aqueous film and the third is a lipid layer, which is mainly intended to reduce the evaporation of the tear film. Together with Contipro, we are now looking for a new and better raw material for artificial tears that could comprehensively restore the physiology of all layers of an eye film. Unlike the current preparations, which combine various polymers to replace the individual properties of the eye film, we develop one polymer based on a hyaluronic acid derivative," Martin Vrbka from the Institute of Machine and Industrial Design, Faculty of Mechanical Engineering, BUT explained.

The research will be carried out by the experts in the field of biotribology, which deals with friction, lubrication and wear studies in living organisms. "So far, we have examined, for example, the tribological properties of joint replacements. However, these are much harder and stronger materials with higher contact pressures than in the human eye. Therefore, this year we want to develop an experimental model of the eye, where we will be able to analyse the contact between the eyeball and the eyelid. First, it will be a simple model consisting of a silicone layer replacing the eyelid and a flexible ball with a contact lens replacing the eyeball. We want to gradually improve the model and at the end of the project we would like to work with biological material, for example with a part of a pig's eye," Vrbka said.

The samples of hyaluronic acid derivatives will be supplied to scientists by the domestic company Contipro, which is one of the largest producers of this biopolymer in the world. "Hyaluronic acid itself, with its properties and ability to bind water, contributes to the hydration and lubrication of the eye film. In addition, the developed hyaluronic acid derivative will be able to better bind mucin, which is a protein that prevents the surface of the eye from drying out. By interacting with mucin and other proteins on the surface of the eye, the adhesion of the eye drop solution will be better and longer, thus prolonging their effectiveness. All this is thanks to the only substance that is also specific to the body," the Contipro researcher Gloria Huerta-Angeles explained.

Biotribologists are now looking for young scientists who would be interested in getting involved in the project. "In the next phases of the project, we will also examine the formation of a lubricating film. Using the fluorescence microscopy, we will see whether the film is sufficiently stable, continuous and whether it will not tear, in other words, if it will withstand a certain number of winks," Vrbka added. Researchers have the approved research funding for four years. The result should be a suitable pharmaceutical raw material that Contipro will offer to manufacturers of artificial tears.