Hydrogel lens, an innovation that utilises tears to monitor patient’s health.
Fluids and secretions of the body are a mirror of one’s health. The biomarkers in these secretions such as tears, sweat, saliva, etc. can provide a great deal of information regarding an individual’s health. To utilise this source of information, researchers at the Terasaki Institute in Los Angeles developed a prototype of a hydrogel contact lens. It can assist with tear sampling for diagnostic purposes. Moreover, this hydrogel lens can improve the tear flow to prevent/treat dryness of the eyes.
Tears are an excellent source of biomarkers. Tears are sterile and readily available. Additionally, they are less susceptible to temperature change, evaporation, and the rate of secretion. They contain measurable biomarkers such as sodium ions, glucose molecules, and pH of the tears. The latter third can aid in checking cell viability, drug effectiveness, and disease signs. Whereas, the former two are useful indicators of dry eyes and early stage of diabetes, respectively.
The hydrogel in the prototype of the contact lens has microchannels and testing chambers. Through the former, the tears can travel. Whereas, in the latter, electrochemical and colorimetric tests can assess sodium levels and pH, respectively.
Testing of the prototype:
After the researchers developed the prototype, they tested it for its performance in channelling and collecting fluids. They also measured the flow rates of artificial tears in the channels at different levels of hydration. Observation revealed full spontaneous flow at full hydration and zero flow at complete dehydration. They also tested sodium levels and pH levels of the artificial tears flowing through the microchannels.
Thus, after these tests, the prototype seemed to be effective in detecting sodium levels, pH levels, etc. for diagnostic purposes.
Ali Khademhosseini, Ph.D., director, and CEO of the Terasaki Institute, said:
“The production of the successful prototype described here, and the continuing efforts to perfect its capabilities mark a significant advance in contact lens biosensing. Such innovative work fits in well with our institute’s mission to create solutions that restore or enhance the health of individuals.”
Up until now, it was challenge for researchers to design microchannels in hydrogel lenses which can be suitable for such fine features. The Terasaki researchers remained successful in achieving this by optimizing the gel. The hydrogel had elastic and had a smooth surface, and then used a 3D-printed mold to introduce the microchannels.
Shiming Zhang, a researcher involved in the study said:
“In addition to our successful fabrication of microchannels in commercial contact lens hydrogels, we also found that eye-blinking pressure may facilitate tear exchange in the lens through these microchannels. This is an exciting finding because it opens the possibility for the lenses to be a means of preventing dry eye disease, a condition commonly found in contact lens wearers. We aim to develop a patented contact lens that actively treats this condition by enhancing tear flow in the eye.”