Collider on Z axis

Hi,

I'm trying to get a collider from this line render
(

if (Input.GetMouseButton(0))
{
lineX.positionCount = i + 1;
Vector3 mPosition = new Vector3(Input.mousePosition.x, Input.mousePosition.y, 100);
lineX.SetPosition(i, Camera.main.ScreenToWorldPoint(mPosition));
i++;
/* Add Collider */
BoxCollider bc = lineGO.AddComponent<BoxCollider>();
bc.transform.position = lineX.transform.position;
bc.size = new Vector3(0.1f, 0.1f, 0.1f);
}
else
{
lineX.positionCount = 0;
i = 0;
BoxCollider[] lineColliders = lineGO.GetComponents<BoxCollider>();
foreach (BoxCollider b in lineColliders)
{
Destroy(b);
}
}
)
to hit 2d sprites with 3D Colliders (varying 3D colliders) on the Z axis, is there anyway of working around this as I can't use 2D colliders as i want the sprite game objects to be moving towards the camera.

void OnCollisionEnter(Collision other)
{
if (other.gameObject.name == "Line")
{
Camera.main.GetComponent<AudioSource>().Play();
Destroy(gameObject);
scoreReference.text = (int.Parse(scoreReference.text) + 1).ToString();
}
}
Above is the collision code.

Please help!

 

public class LineRender : MonoBehaviour {
public Color c1 = Color.black;
public Color c2 = Color.red;
private GameObject lineGO;
private LineRenderer lineX;
private int i = 0;
// Use this for initialization
void Start ()
{
lineGO = new GameObject("Line");
lineGO.AddComponent<LineRenderer>();
lineX = lineGO.GetComponent<LineRenderer>();
lineX.material = new Material(Shader.Find("Mobile/Particles/Additive"));
lineX.startColor = c1;
lineX.endColor = c2;
lineX.startWidth = 0.3F;
lineX.endWidth = 0;
lineX.positionCount = 0 ;
}
}

Should have put this in with the original but here is the void start for the line render.