López Espinar Aida, Mulder Lianne M, Elkhashab Mohamed, Khan Zahra, Czarnocki-Cieciura Mariusz, Aburto Maria R, Vucen Sonja, Kowalski Piotr S
School of Pharmacy, University College Cork, Cork T12 K8AF, Ireland.
Laboratory of Protein Structure, International Institute of Molecular and Cell Biology, Warsaw 02-109, Poland.
ACS Appl Bio Mater. 2025 May 19;8(5):3958-3971. doi: 10.1021/acsabm.5c00116. Epub 2025 Apr 28.
Lipid nanoparticles (LNPs) containing ionizable lipids are the most clinically advanced platform for mRNA delivery, but their application beyond the liver remains challenging. Polymer-lipid hybrid nanoparticles offer a promising alternative, combining the synthetic versatility and unique properties of polymers with the biocompatibility of lipid excipients. While the significance of alkyl tail design is well-recognized for ionizable lipids, the impact of the polymer side chain composition on interactions with lipid excipients, mRNA delivery efficacy, and tissue specificity remains poorly understood. Here, we focus on a class of ionizable amino-polyesters (APEs) that exhibit features desired for potential clinical applications, including narrow molecular weight distribution and a good safety profile, and investigate the effect of polymer side chain composition on the formulation of APE lipid nanoparticles (APE-LNPs) for mRNA delivery. A library of 36 APEs was synthesized via ring-opening polymerization of chemically diverse tertiary amino-alcohols and lactone monomers with distinct alkyl side chain compositions, including variations in length and unsaturation. We show that optimal alkyl side chain length is critical for the assembly of stable mRNA nanoparticles and efficient mRNA delivery both and . Top-performing APE-LNPs display superior delivery efficacy and in extrahepatic tissues compared to benchmark LNPs, including DLin-MC3-DMA ionizable lipid. The polymer chain composition affects the tissue selectivity of APE-LNPs, with shorter side chains (4-5 carbons) effectively targeting the spleen and lungs, while longer chains (7-9 carbons) show enhanced liver delivery. We also explored the relevance of lipid excipients in APE-LNPs, demonstrating the essential role of unsaturated phospholipids in enhancing cellular uptake and mRNA delivery, and the limited relevance of cholesterol. These findings provide valuable insights into the design of polymers for use in the LNP context, which could aid the development of polymeric alternatives to ionizable lipids and expand the utility of mRNA LNP technology to nonliver tissues.
含有可电离脂质的脂质纳米颗粒（LNPs）是mRNA递送领域临床进展最为显著的平台，但它们在肝脏以外的应用仍具有挑战性。聚合物-脂质杂化纳米颗粒提供了一个有前景的替代方案，它将聚合物的合成多功能性和独特性质与脂质辅料的生物相容性结合在一起。虽然烷基尾设计对可电离脂质的重要性已得到充分认识，但聚合物侧链组成对与脂质辅料相互作用、mRNA递送效率和组织特异性的影响仍知之甚少。在这里，我们聚焦于一类具有潜在临床应用所需特性的可电离氨基聚酯（APEs），包括窄分子量分布和良好的安全性，并研究聚合物侧链组成对用于mRNA递送的APE脂质纳米颗粒（APE-LNPs）制剂的影响。通过化学性质多样的叔氨基醇和内酯单体的开环聚合反应，合成了一个包含36种APEs的文库，这些单体具有不同的烷基侧链组成，包括长度和不饱和度的变化。我们表明，最佳的烷基侧链长度对于稳定的mRNA纳米颗粒组装和有效的mRNA递送至关重要。与包括DLin-MC3-DMA可电离脂质在内的基准LNPs相比，表现最佳的APE-LNPs在肝外组织中显示出卓越的递送效率。聚合物链组成影响APE-LNPs的组织选择性，较短的侧链（4-5个碳）有效地靶向脾脏和肺，而较长的链（7-9个碳）显示出增强的肝脏递送。我们还探讨了APE-LNPs中脂质辅料的相关性，证明了不饱和磷脂在增强细胞摄取和mRNA递送中的重要作用，以及胆固醇的相关性有限。这些发现为用于LNP环境的聚合物设计提供了有价值的见解，这有助于开发可电离脂质的聚合物替代物，并将mRNA LNP技术的应用扩展到非肝脏组织。
