Public Research Seminar by Advanced Materials Thrust, Function Hub, HKUST(GZ) - Stability of the Tear Film: Remarkable Role of Electrolytes
The tear film is generated to provide protection to the cornea against the deposition of contaminants and maintains the hydration of the cornea epithelium. This stratified, thin film is roughly 4-6 microns in thickness and consists of a layer of mucins tethered to the cells of the cornea, an electrolyte layer, and capped by insoluble phospholipids (the meibum). There are a number abnormalities that can induce instabilities in the tear film, leading to premature de-wetting and discomfort and damage to the cornea. These dysfunctions are, collectively, referred to as dry-eye phenomena. In this presentation, the role of the electrolyte composition in tear film stability is examined.
The electrolyte composition of a healthy tear film is well known with NaCl being the primary salt. We focus on the influence of trace amounts of phosphate salts and glucose. The experiments utilize an instrument developed in the Fuller laboratory, the i-DDrOP (interfacial drainage and dewetting optical platform) that allows a thin film to be created above a dome having the radius of curvature of the human eye. Above the film is an optical interferometer that captures interference patterns that are used to compute the thickness of the film as a function of time. The results reveal that, as the tear film diminishes in thickness due to evaporation, the influence of phosphate salts and glucose become more prominent, resulting in a cascade of fluid mechanical phenomena that substantially stabilize the tear film.
Gerald Fuller is the Fletcher-Jones Professor of Chemical Engineering at Stanford University. He joined Stanford in 1980 having received his Ph.D. from Caltech and his B.Sc. from University of Calgary. His research interests lie in the subjects of interfacial fluid mechanics and rheology with a particular focus on problems in biophysical phenomena, foams, and emulsions. His work has teen recognized by receipt of the Bingham Medal of the Society of Rheology, election to the National Academy of Engineering, and Fellowship in the American Academy of Arts and Science. He has been granted honarry doctorates from the Universities of Crete and Leuven. He presently serves as the General Secretary of the International Committee on Rheology.