如何在php中逃避冒号？

I want add new font to array with this format

font-family: yekan,open_sans;

how i can add this and escape colon. it must be like this:

'yekan,open_sans'=>'yekan+sans'

$my_fonts = array(
'Arial' => 'Arial',
'Times New Roman' => 'Times New Roman',
'DroidArabicKufi' => 'DroidArabicKufi',
'SourceSansSemiBold' => 'SourceSansSemiBold',
'sourceSans' => 'sourceSans'
);