The development of an alternative to natural blood has evolved from the initial goal of replicating blood properties to the current objective of formulating a fluid that can be used to replace blood while preserving microvascular function and delivering oxygen. The properties of this fluid are counterintuitive and different from blood because it has high viscosity, oxygen affinity, and a low oxygen carrier concentration when compared with blood. The optimal oxygen carrier devised presently is poly-ethylene-conjugated human hemoglobin, a material demonstrated to be vasoinactive and void of the toxicities present in previous hemoglobin formulations. A feature of this material is that it is effective in small quantities, and therefore amplifies the equivalent supply of blood derived from blood donations.

中文翻译：

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携带氧气和不携带氧气的血液代用品的微血管观点。

天然血液替代品的开发已从复制血液特性的最初目标演变为当前的目标，即配制一种可用来替代血液同时保留微血管功能和输送氧气的流体。这种流体的性质与直觉相反，与血液不同，因为与血液相比，它具有高粘度，氧亲和力和低的氧载体浓度。目前设计的最佳氧气载体是聚乙烯缀合的人血红蛋白，该材料被证明具有血管活性，并且没有以前血红蛋白配方中存在的毒性。这种材料的一个特点是少量有效，因此可以放大来自献血的血液的等效供应。