Needs for artificial blood:
-Worldwide blood shortage
-Some donors ineligible to donate due to diseases
-Have to be cross matched, receiving wrong blood type can be fatal
-Difficulty of storing fresh blood
-blood can obtain infectious pathogens, testing blood is costly
-Short shelf life, red blood cells only survive 3 months
Now I'm not going to write up a full thing because that's just doing all your work for a dot point for you, but I did outline above for what ideas to think up when you look up alternative replacements. Contrast those to real blood (how does it compare to real blood, can it do everything?), and the alternatives between each other. (Pst, PFCs and HBOCs are best to look up). But I gave you the things above to help get your brain switched on for them okay?
Make sure to note your sources down as you do your self-research yay. Maybe do a little pro and con table for two alternatives to real blood. Doing a pro/con table for normal blood can help orientate you to contrast/compare in your research.