How do I use 'N' in my prepared SELECT statement
You should bind them using the (relatively new) PDO_PARAM_STR_NATL constant. This constant is available in PHP 7.2 and up. It will cause the desired N prefix to be added.

$query-&gt;bindParam(':term1', $text, PDO::PDO_PARAM_STR_NATL);


In case you're interested, some history can be found here:
https://bugs.php.net/bug.php?id=60818

The Github commit that is linked there shows how N is added (lines 178-184):
https://github.com/php/php-src/commit/4afce8ec8c6660ebd9f9eb174d2614361d1c6129