What is the ruling on using artificial blood, composed of pig red blood cells, which replaces natural blood in all its functions and provides all blood types?

The default ruling is that it is impermissible to seek medical treatment using something unlawful, such as blood transfusions and organ transplants, unless it is a matter of necessity. This is based on Allah's saying: (And He has already detailed for you what He has forbidden you, excepting that to which you are compelled) [Al-An'am: 119], and the jurisprudential maxim: "Necessities permit the forbidden."