https://www.nature.com/articles/nrd.2017.243
（这篇文章写于2017年，标志着mRNA疫苗技术已经趋于成熟完善，进入到了实际应用新阶段）
（其中提到，直接打入血行的，主要以肝细胞为靶标；而皮内、皮下、肌肉注射的，在注射位点起作用。）
Lipid nanoparticles (LNPs) have become one of the most appealing and commonly used mRNA delivery tools. LNPs often consist of four components: an ionizable cationic lipid, which promotes self-assembly into virus-sized (~100 nm) particles and allows endosomal release of mRNA to the cytoplasm; lipid-linked polyethylene glycol (PEG), which increases the half-life of formulations; cholesterol, a stabilizing agent; and naturally occurring phospholipids, which support lipid bilayer structure. Numerous studies have demonstrated efficient in vivosiRNA delivery by LNPs (reviewed in Ref. 81), but it has only recently been shown that LNPs are potent tools for in vivo delivery of self-amplifying RNA19 and conventional, non-replicating mRNA21. Systemically delivered mRNA–LNP complexes mainly target the liver owing to binding of apolipoprotein E and subsequent receptor-mediated uptake by hepatocytes82, and intradermal, intramuscular and subcutaneous administration have been shown to produce prolonged protein expression at the site of the injection21,22. The mechanisms of mRNA escape into the cytoplasm are incompletely understood, not only for artificial liposomes but also for naturally occurring exosomes83. Further research into this area will likely be of great benefit to the field of therapeutic RNA delivery.
多余的话：
前人栽树 后人乘凉。一种技术的成熟和应用，积于前人不懈的努力。
mRNA疫苗经历了三十年的发展，才有了目前的大规模应用，成了对抗疫情的利器。
对于科学问题，首先要有一个科学态度：摆事实、讲道理，言出有据。
搞笑、科幻、猜想、梦境，请标明“周末娱乐”。