“Designing Artificial Blood to Fulfill its Function of Transport, Defense, or Regulation: Challenges and Considerations”

Blood has three main functions: transport, defense, and regulation. Pick one and describe how blood accomplishes this function. Imagine you are tasked with designing artificial blood. How would you ensure that the blood would fulfill this function? What would be the challenges?
Textbook- Mader, S. S., & Windelspecht, M. (2022). Human Biology. McGraw-Hill Higher Education (U.S.). 
Chapters 5 & 6