How to preserve the Checkbox value after closing the notebook

I am trying to create a to-do list style for the stylesheet. The goal is to have a CellDingbat that is a check box. And after pressing enter, a new cell with a checkbox CellDingbat should be created, just like the style Item.

Initially, I posted the question in another thread, and with the help from @kglr I was able to create a to-do list style that has the desired behavior. Now, to make this to-do list style more practically useful, I would like the state of the Checkbox to be preserved after closing and re-opening the notebook. Can anyone suggest how to achieve this?