Adding attributes to button property in Actionsheet.show

1 
buttons: [
               {
                     text: '<i class="icon ion-flash"></i>'
	          }
];

I need to disable the above button in Actionsheet. So i appended a disable class like this:

buttons: [
               {
                     text: '<i class="icon ion-flash disable"></i>'
	          }
];

And the style for disable class is:

.disable{
  opacity: .4;
  cursor: default!important;
  pointer-events: none;
}

It does not work. I also tried adding ng-disable with no success. Can someone help me out? Can’t I write markup for Actionsheet as regular HTML instead of dynamically writing in JS.