Lost orange tabby cat with blue collar

I lost Milo yesterday around 3pm near the Riverfront Market on Market Street in Wilmington, Delaware. He’s a short-haired orange tabby, about 12 pounds, with a white chest and white paws. He wears a bright blue collar with a small silver bell, and there’s a tiny crescent-shaped white patch on his chest. He has green eyes and a small notch in his right ear. This cat belongs to my grandmother, and we’re really worried—he means a lot to our family and has sentimental value. If anyone spots him, I’d really appreciate any help getting him home.