It is possible to capture audience that open your email, and then follow them with a Retargeting Campaign.
To do so follow the instruction bellow:
1- Go to your audience list then click on "Get Tag", a popup will appear.
2- Mark the check-box next to 'Need e-mail audience tag'.
Now the audience tag will be updated.
3- Click over the box to copy the 'audience tag' into your clipboard.
4- Now paste the code in your email.
You should paste the audience tag before the </body> tag, while you edit the email in HTML format.