$re = '/(?:[\s\S]*)(\{.*)/m';
$str = '{Hello}, [123:456] (Test). This is stample data used to answer a
question {Hello2} [Ch.8 p. 87';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php