title: Pattern not surrounded by numbers or alphanumerics
body: <p>I would like to find some words not surrounded by any numerics or alphanumerics or surrounded by nothing.
  So if I'm looking for Foo123 I would like this result</p>
  
  <pre><code>="Foo123"; =&gt;TRUE
  barFoo123; =&gt;FALSE
  Foo123 =&gt;TRUE
  BarBar123Foo123Bar; =&gt;FALSE
  ;Foo123 =&gt;TRUE
  </code></pre>
  
  <p>I just built this expression:</p>
  
  <pre><code>(^[^0-9a-zA-Z]?)WORDTOFIND([^0-9a-zA-Z]?$)
  </code></pre>
  
  <p>I was pretty sure I'm in the right way but when I'm using it like this:</p>
  
  <pre><code>if (Regex.IsMatch(line, string.Format(@"(^[^0-9a-zA-Z]?){0}([^0-9a-zA-Z]?$)",snCode)) )
  {   
  }
  </code></pre>
  
  <p>It doesn't work. What am I doing wrong? </p>