Validate text using RegEx

'Email address:
Regex.IsMatch(Me.txtEmail.Text, "\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*")

'Alpha-numeric (no space):
Regex.IsMatch(Me.txtUsername.Text, "^[0-9a-zA-Z]+$")

'Alpha-numeric with space, at least 5 chars:
Regex.IsMatch(Me.txtUsername.Text, "[0-9a-zA-Z' ']{5,} )