Model stuck on the heating bed
Unfortunately, you may have to destroy this part, or the build surface, just to get it off the plate. It looks really on there, and if you can't get under it even with a razor that further supports my gut instinct. It's happened to me before, just part of learning how to print with a particular material on a particular printer and build surface.

One thing to try before just hacking away at the part or replacing the build surface (which you may have to do anyway) would be to heat the plate back up to maybe 60-70*C, then hit the part with some freeze spray (or the poor man's version, turning a can of air duster upside-down). The rapid expansion-contraction may pop the part free. How effective this is depends on the plastic you used. PLA doesn't stretch and shrink much, but by the same token it's also very inflexible, so the stretching and shrinking it does do can stil pop the part off. This method's really effective for plastics like ABS that stretch/shrink a lot with heat. Remember to ventilate well; the principal component of these sprays is difluoroethane, which isn't great stuff to breathe in any significant concentration, and when spraying the liquid the resulting "steam" state of boiling liquid is much more flammable (so after the bed comes up to proper heat, I'd turn off the printer just in case).

EDIT: Per the comment to this answer, an alternate method would be to heat the plate even further, to about 80-90*C, which would heat the PLA beyond its glass transition temperature, softening it and reducing its adhesion. You would destroy the part, but parts can be reprinted, that's the beauty of owning a general-purpose computer-controlled additive plastic forming machine.

Your first layer including the brim looks a little close to the plate, which is part of the problem; you really squished that first layer down onto the bed. I would relevel the bed a bit further away, or (if you're happy with how actually level the bed is) set a Z-offset to increase first layer width. There's a very fine balance to be struck here; once you find it, printing (and removing said prints) becomes a lot easier.

In future, a build adhesive like Elmer's glue stick or hairspray (or a dedicated adhesive like 3DLAC or Bed Weld) also doubles as a release agent; the adhesive grabs the extruded plastic to keep it on the plate, but also prevents direct contact between two plastics and thus avoids any chemical bonding between the part and plate. Also consider upgrading to a flexible removable surface, like a magnetic BuildTak surface. Being able to take the bed off the printer and then flex the surface to help  pull a corner free (at which point you can slip a scraper in to lift the rest of it off) is a real boon to these types of situations.