Converting output into an array

The thing is, the value of $m is "Container Reference"

So I tried converting it into an array using explode function so I can display it like.... $m->0; $m->1

but got an error

it gives me an error saying "String to array conversion"

//TestController.php

     $mess = $request->message;
    $data = array(
        'name'=>"Rick Sanchez Sample",
        'm1' => "Email Sample",
        'm2' => $mess
    );

    Mail::send('emails.mail', $data, function($message) use ($data) {
      $message->to('simplerick@gmail.com', 'Rick Sanchez')->subject
          ($data['m1']);
       $message->from('xyz@gmail.com','Rick Main Machine');
    });
    echo "HTML Email Sent. Check your inbox.";

//test.blade.php

         <input class="form-check-input" type="checkbox" name="message[]" value=" ">

//mail.phpFile

  @foreach($m2 as $m)
 <p>
 {

  <br>
  "ContainerID": "$m",
  <br>
 }

 </p>
 <br>
 @endforeach

via Chebli Mohamed