You can use Var-char/text datatype to store this type of characters in sqlDB.
i think you are decoding the output when fetching from database using HtmlDecode() method.
e.g: Want to insert data like: a>b
cmd.Parameters.Add("@Message", SqlDbType.VarChar, 50).Value = Server.HtmlEncode(txtBIAttenNurse.Text.Trim().Replace("'", "''"));
your code is fine for data insertion.
but when you are fetching the data then be careful what you really want to showing.
if you want to show like a>b then use HtmlDecode() otherwise use plain text.no need to decode the output.
see here.
https://msdn.microsoft.com/en-us/library/hwzhtkke(v=vs.110).aspx[
^]
https://msdn.microsoft.com/en-us/library/ms525347(v=vs.90).aspx[
^]
http://www.dotnetperls.com/htmlencode-htmldecode[
^]