Abstract
Purpose :
Human mucins which show severe inhomogeneity in a complex chemical structure are not easy to be applied to basic medical studies especially in ophthalmology because of the extremely small amount of each individual tear sample. Instead, a mucin extracted from mesoglea of jellyfish (qniumucin: Q-mucin), which were discovered in 2005 by one of the present author and co-workers, can be used as a substituting material which can be obtained in a large scale. As a test example, we analyzed the surface interaction of contact lenses with Q-mucin solutions which reproduces the interaction between a real tear film and lens surfaces.
Methods :
Q-mucin and hyaluronan (HA) was dissolved in saline for various concentrations. Solutions were dropped on various surfaces including soft and/or rigid gas permeable (RGP) contact lenses. The incidentally formed contact angle (CA) and its transient behavior were observed by a TV camera. Values and the transient lineshapes of contact angles were examined to clarify their dependence on the Q-mucin concentration.
Results :
Q-mucin solutions (0.01-1.00 wt%) dropped on a hydrophobic glass surface formed very stable droplet of which CA=46°. CA decreases on increase of mucin concentration towards better wettability. For glass plates with additional hydrophilic coatings, CAs became slightly smaller (CA=43°) showing similar dependence on mucin concentrations. On RGP contact lenses, however, CA decreased dynamically within one second, e. g. from 46° down to 8°. Similar transient lineshapes were obtained for various Q-mucin concentrations where the initial peaking values decreased on increase of mucin concentrations. CA of HA solutions increased on increase of its concentrations because the increase in viscosity affects stronger.
Conclusions :
Jellyfish mucin was used to mimic the interaction between tear films and contact lens surfaces. Reasonable concentration dependence of wettability was monitored by CA measurements. This method can be applied to estimate unknown mucin concentration of real single tear drop using Q-mucin as a standard.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.