“…Subsequently, the synthesized three-antenna GalNAc can combine with the 3′ end of the antisense chain of siRNA to form a GalNAc-siRNA conjugate (Shchegravina et al, 2021). siRNA can be synthesized directly by a chemical approach or by breaking long double-stranded RNA obtained by enzyme transcription into 21-23 nt siRNA under the action of the GalNAc-siRNA LNPs loaded siRNA (Aldosari et al, 2021;Zhang et al, 2021a;Lokugamage et al, 2021) Benefits & Challenges -can be injected subcutaneously, with only small chances of plasma siRNA degradation, rapid absorption, high uptake, and long half-life, (Springer and Dowdy, 2018)-endosomal escape, hepatotoxicity from off-target effects, acidic subcellular compartments, and extensive clearance, affect GalNAc efficiency and sequence barriers (Ayyar et al, 2021;Fairman et al, 2021;Fattal and Fay, 2021;Fumoto et al, 2021;Liu et al, 2021;Nanavati et al, 2021;Schlich et al, 2021) -avoid siRNA degradation of and the stimulation of the immune system by siRNA-lack efficient nuclear penetration and sustainable transgene expression (limitations such as poor biodistribution and possible toxic discharge), immunogenic and pose safety concerns of liposome molecules and limited efficacy and biosafety since unconjugated liposomes cannot achieve targeted delivery (Ickenstein and Garidel, 2019;Hu et al, 2020;Blakney et al, 2021;Hassett et al, 2021;Maestro et al, 2021) Composition Specific arrangement of nucleoside, pO/PS linkage and monovalent GalNAc (Matsuda et al, 2015) polyethylene glycol-lipid conjugates (PEG-DMG), ionizable amino lipids (DLin-MC3-DMA), distearyl phosphatidylcholine (DSPC) and cholesterol…”