Smart quotes not encoded correctly by Twitter share pop-up in IE7

Question

I am building a Wordpress theme in which I have a twitter share link beside each post

<a class="tw-share-link" href="http://twitter.com/home?status=Currently reading <?php             the_article_title() ?>" Target="_blank">Tweet</a>

If the article title includes smart quotes, the quotes are replaced by '?'s in IE8 and below.

I tried converting the smart quotes to regular quotation marks hooking a function that uses string replace to the action of saving or updating a post. This didn't fix the issue.

?php
function convert_smart_quotes($string) {
    //converts smart quotes to normal quotes.
    $search = array(chr(145), chr(146), chr(147), chr(148), chr(151));
    $replace = array("'", "'", '"', '"', '-');
    return str_replace($search, $replace, $string);
}
?>

I need guidance troubleshooting this issue: + Do I need to add some sort of character set declaration to my code so that IE8 and below can handle smart-quotes? + Or is there a way in php to encode the twitter link so that smart quotes will be replaced by regular quotes? Thanks in advance.

Update: I found a fix. Removing the wptexturize filter fixes the issue: http://www.malcolmcoles.co.uk/blog/wordpress-smart-quotes/