Yap Sue Lyn, Dekiwadia Chaitali, Della Gaspera Enrico, Drummond Calum J, Conn Charlotte E, Tran Nhiem
School of Science, STEM College, RMIT University, 124 La Trobe St, Melbourne, VIC, 3000, Australia.
RMIT Microscopy & Microanalysis Facility (RMMF), STEM College, RMIT University, 124 La Trobe St, Melbourne, VIC, 3000, Australia.
Small. 2025 Nov;21(44):e2502231. doi: 10.1002/smll.202502231. Epub 2025 Jul 25.
Lipid nanoparticles (LNPs) are versatile platforms for drug delivery, offering solutions for targeted therapeutics, gene therapy, and vaccines. Cubosomes - cubic phase lipid nanoparticles - exhibit unique structural properties that may allow direct cytosolic delivery, bypassing endocytic pathways that often limit intracellular drug delivery. Despite their potential, the mechanisms of cubosome interactions with mammalian cells, particularly their membrane fusion behavior, remain unclear. This study employs a multimodal microscopy-based approach to investigate cubosome interactions with cells, focusing on membrane fusion, lipid exchange, and endosomal escape. Advanced imaging techniques, including transmission, scanning, and cryogenic scanning electron microscopy, and live-cell fluorescence imaging, are used alongside tailored cubosome variants to examine interactions at micro- and nanoscale dimensions. Cubosome behaviors are compared to other nanoparticleslike liposomes and gold nanoparticles. For the first time, membrane fusion with mammalian plasma and endosomal membranes is visualized at the nanoscale, revealing how cubosomes bypass conventional endocytic pathways to deliver cargo directly into the cytosol. This work provides critical insights into LNP-cell interactions, establishing cubosomes as promising candidates for overcoming endosomal escape limitations in drug delivery. These findings will aid in developing next-generation lipid-based nanocarriers, particularly for RNA therapeutics, where efficient cytosolic delivery is essential for therapeutic efficacy.
脂质纳米颗粒（LNPs）是用于药物递送的多功能平台，为靶向治疗、基因治疗和疫苗提供了解决方案。立方液晶纳米粒——立方相脂质纳米颗粒——具有独特的结构特性，可能允许直接进行胞质递送，绕过通常会限制细胞内药物递送的内吞途径。尽管它们具有潜力，但立方液晶纳米粒与哺乳动物细胞相互作用的机制，尤其是它们的膜融合行为，仍不清楚。本研究采用基于多模态显微镜的方法来研究立方液晶纳米粒与细胞的相互作用，重点关注膜融合、脂质交换和内体逃逸。先进的成像技术，包括透射电子显微镜、扫描电子显微镜和低温扫描电子显微镜以及活细胞荧光成像，与定制的立方液晶纳米粒变体一起使用，以在微米和纳米尺度上检查相互作用。将立方液晶纳米粒的行为与其他纳米颗粒（如脂质体和金纳米颗粒）进行比较。首次在纳米尺度上观察到与哺乳动物质膜和内体膜的膜融合，揭示了立方液晶纳米粒如何绕过传统的内吞途径将货物直接递送至胞质溶胶中。这项工作为LNP-细胞相互作用提供了关键见解，确立了立方液晶纳米粒作为克服药物递送中内体逃逸限制的有前途的候选者。这些发现将有助于开发下一代基于脂质的纳米载体，特别是对于RNA治疗，其中有效的胞质递送对于治疗效果至关重要。
