Bind_param不能正确保存特殊字符

我需要使用bind_param来摆脱数据注入。当我使用bind_param时，特殊字符如€或http://在mysql中被保存为صذÙ，。

1-我确定mysql表设置正确

2-我已将文字处理器的编码更改为UTF8。

3-我已经包含了许多utf8字符集。

有什么想法如何解决这个问题?或者我应该开始使用其他方法，如mysqli_real_escape_string?

($_POST["post_word"]在另一个页面生成)

$connect = mysqli_connect("r"," r","r","r");  //not real data here
$connect->set_charset('utf8');
$connect->query("SET NAMES utf8");
$querye= mysql_query("SET NAMES utf8");
mysqli_query($connect,"INSERT INTO wordtable ( wdate) VALUES (CURRENT_TIMESTAMP())");
$sqlz = "SELECT wid FROM wordtable ORDER BY  wdate DESC LIMIT 1";
$resultz = mysql_query($sqlz);
$rowz = mysql_fetch_array($resultz);
$wid=$rowz['wid'];
$mysqli = new mysqli(HOSTNAME, MYSQLUSER, MYSQLPASS, MYSQLDB);
$connect->set_charset('utf8');
$unsafe_variable = $_POST["post_word"];
$stmt = $mysqli->prepare("UPDATE wordtable SET  word=(?)
                            WHERE wid='$wid' ");
 $stmt->bind_param("s", $unsafe_variable);
 $stmt->execute();
 $stmt->close();
 $mysqli->close();