Patent ID: 7927830

Claim:
A method of staining a biological sample, comprising: combining a dye solution comprising a compound having the formula: and its salts, wherein, R 2 is alkyl or sulfoalkyl; R 12 is alkyl or sulfoalkyl; R 3 is carboxyalkyl or —(CH 2 ) d (CONH(CH 2 ) e ) z′ —R x , wherein R x is a carboxylic acid, a succinimidyl ester of a carboxylic acid, a hydrazide, or a maleimide; d is 0-5; e is 1-5; and z′ is 0 or 1; R 4 is alkyl; R 13 is alkyl or sulfoalkyl; R 14 is alkyl or sulfoalkyl; R 6 is selected from hydrogen or sulfo; R 7 is selected from hydrogen or sulfo; R 8 is selected from hydrogen or sulfo; R 9 is selected from hydrogen or sulfo; R 16 is selected from hydrogen or sulfo; R 17 is selected from hydrogen or sulfo; R 18 is selected from hydrogen or sulfo; R 19 is selected from hydrogen or sulfo; wherein sulfo is sulfonic acid or sulfonate; and n is 1, 2, or 3; with a biological sample in a concentration sufficient to yield a detectable optical response under desired conditions.