Definition:

Creating a hole in the zona pellucida of an oocyte and embryo by using acidic tyrode’s solution.

Acidic Tyrode’s assisted hatching:
The fine micropipette containing acidic tyroide’s solution is brought very close to the zona pellucida and the acidic solution expelled gently over a small area (~20-30mm) until the zona is dissolved through to the inside. After the procedure the embryos are thoroughly washed in fresh medium and cultured until the time of transfer.
 
Principle of Tyrode’s solution:
Acidic tyrode’s solution of pronase is used for drilling holes in zona pellucida.