If your seeds haven't popped open within 72 hours, they're not going to. Here's how to properly germinate seeds using the paper towel method:
1) Take 4 paper towels and lay them on top of one another.
2) Soak them with distilled or RO water.
3) Place your seeds on the wet towels spaced a little bit apart (i.e. no seeds touching)
4) Fold the paper towels over so the seeds are sandwiched in the middle.
5) Place this in a ziplock bag and stick the bag in a drawer.
6) Every 12-14 hours or so, open up the bag and carefully unfold the towels to check the seeds.
I suspect that the electric blanket you are using is too hot and is the reason none of your seeds germinated. You do NOT need to heat the seeds - room temp is fine.
Most seeds will pop open within 24-48 hours. Once they pop open and the little root tip grows to a length of about 2cm you are ready to plant them.
Using this method, I consistently germinate 90% of the seeds I start with.