Table 2.

Merits and disadvantages of different synthesis methods.

Method of synthesis	Merits	Disadvantages
coprecipitation	simple, no toxic substances introduced, high encapsulation efficiency and solubility in a polar solvent	lower stability
cross-linking	increased half-life, improved stability, and oxygen-carrying capacity, reduced protein immunogenicity	blood pressure rises, vasoconstriction
polymer	increased half-life, smaller side effects, and larger particle size	residual unreacted Hb
liposome	uniform particle size, good stability	cumbersome steps