Medical devices having antimicrobial coatings thereon

A method for producing a contact lens having an antimicrobial coating, comprising the steps of:

• (a) forming a mold for making the contact lens, wherein the mold comprises a first mold portion defining a first optical surface and a second mold portion defining a second optical surface, wherein said first mold portion and said second mold portion are configured to receive each other such that a contact lens-forming cavity is formed between said first optical surface and said second optical surface;
• (b) applying a transferable antimicrobial coating, using a layer-by-layer polyelectrolyte deposition technique, onto at least one of said optical surface, wherein the transferable antimicrobial coating comprises at least one layer of polyquat of formula (I) or (II)
• 5
• wherein R1, R2, R3 and R4, independently of one another, are C1-C10 hydrocarbon radicals, preferably C1 to C6 alkyl radicals or C1 to C6 alkyl radicals having one or more hydroxyl groups, more preferably methyl, ethyl, or benzyl radicals, even more preferably methyl radicals, wherein A and B, independently of one another, are n-alkylene groups having 3 to 15 carbon atoms or n-alkylene groups having 3 to 15 carbon atoms and one or more hydroxyl groups, wherein the index y is a number from about 10 to 500, preferably a number from 25 to 400, and more preferably a number from 50 to 300, wherein X is chlorine, bromine, or iodine, wherein the index n is a number from about 100 to 5000, preferably a number from 500 to 4000, and more preferably a number from 500 to 3000, wherein R5 and R6, independently of one another, are n-alkyl groups having 1 to 10 carbon atoms or n-alkyl groups having 1 to 10 carbon atoms and one or more hydroxyl groups;
• (c) positioning said first mold portion and said second mold portion such that said mold portions receive each other and said optical surfaces define said contact lens forming cavity;
• (d) dispensing a polymerizable composition into said contact lens-forming cavity;
• (e) curing said polymerizable composition within said contact lens-forming cavity such that the contact lens is formed, whereby at least a portion of said transferable coating detaches from said at least one optical surface of said mold portion and reattaches to said formed contact lens such that said contact lens becomes coated with the antimicrobial coating.

A method for characterizing coefficient of friction of a contact lens, comprising the steps of:

• (a) sliding said contact lens, at a prescribed speed, against a biologically relevant substrate under a load of weight;
• (b) measuring simultaneously the normal (N) and frictional (FT) forces that are produced from the interaction between said contact lens and the biologically relevant substrate lubricated with a lubricant under said load of weight;
• and
• (c) calculating the coefficient of friction (μ) of the contact lens based on the equation of
• μ=FT/N

An apparatus for characterizing coefficient of friction of a contact lens, comprising:

• (a) a horizontally movable platform that is capable of moving uniaxially at various speeds and accelerations;
• (b) a biologically relevant substrate which is mounted onto said horizontally movable table platform;
• (c) a stationary lens holder assembly for holding said contact lens and for placing said contact lens in contact with said biologically relevant substrate;
• and
• (d) a plurality of force measuring means for simultaneously measuring normal force and tangential force when said contact lens slides against said biologically relevant substrate, wherein the normal and tangential forces are produced from the interaction between said contact lens and said biologically relevant substrate lubricated with a lubricant under a load of weight, wherein the load of weight is applied to said contact lens in normal direction to said contact lens.