Security app like Tigertext secure texting but for email

Hello,
 
 At the hospital I work at, they use Tigertext (all the doctors and admin) for
 text messaging, because it is HIPAA compliant.
 
 Tigertext is an app for smartphones that let's you use a secure network, to
send
 text messages which deleted themselves after a certain period of time. Because
 it prevents patient info from falling into the wrong hands, it allows doctors
to
 use their own phones without the hospital getting sued or find for a HIPAA
 violation like these guys did:
 
 http://www.hipaatext.com/100000-hipaa-fine-designed-to-send-message-to-small-physician-practices/
 
 What I am now looking for is an email system that I can use with PC and
 smartphones and tablets, where the emails are on a secure network and will
 delete themselves after a certain amount of time.
 
 I found out with Tigertext we pay about $10 a users, so I think an email system
 that cost the same and is HIPAA compliant (Sarbanes–Oxley is similar to
 HIPAA so that would also work) would be great.
 
 Anyone know of such software?