Measurements of Mucin Growth and Removal in Human Corneal Epithelia

Thomas Angelini



Contact lens (CL) comfort has been correlated to lens friction coefficient. However, our understanding of the underlying mechanisms has been impeded by the difficulty of making real-time observations of eye-lens interactions at the cellular level. The purpose of this study is to establish an in vitro method to study in detail the interaction between cells and CL (or lens-like materials). Such an approach couples live-cell imaging to microtribometry and requires protocols for quantifying the rate at which corneal epithelial cells produce a protective mucin layer, enabling measurements of the living mucin-coated monolayer’s sensitivity to friction forces.


Immortalized human corneal epithelial cells (hTCEpi) were cultured on fibronectin-coated glass-bottomed petri dishes. Mucin was imaged using a fluorescent carbohydrate stain and cell bodies dyed with calcein-Red. Time-lapse imaging was performed on an inverted confocal microscope equipped with a stage-top incubator. To shear the mucin and the cells under direct contact sliding, a microtribometer system was mounted onto an inverted microscope. With this system, normal and shear forces were applied to hTCEpi monolayers by a polyethylene-glycol hydrogel hemisphere while collecting fluorescence images of the living cells.


The rate at which the cells produce the mucin monolayer was measured. Quantitative image processing of the confocal z-stacks collected in time-lapse revealed the thickness of the mucin layer increasing at a rate of 2 µm/day. Our tribological sliding tests showed that mucin is not physically removed at low contact pressures. At high contact pressures >20 kPa, the mucin layer is erased and cell damage observed.


CL lubricity in the eye is driven by lens interactions with tissue and tear film. The lens-tissue interface is very different from a lens-glass interface, which was shown using a friction probe that possesses material properties indicative of tissue.


Year: 2016

Program Number: 160119

Author Affiliation: n/a

Co-Authors: Tristan Hormel, Juan Urueña, Angela Pitenis, Kyle Schulze, W. Sawyer

Co-Author Affiliation: University of Florida, University of Florida, University of Florida, University of Florida, University of Florida

Room: 211AB