Soman Nr, Marsh Jn, Lanza Gm, Wickline Sa
Washington University School of Medicine, Consortium for Translational Research in Advanced Imaging and Nanomedicine, CTRAIN, Campus Box 8215, St Louis, MO 63110, USA.
Nanotechnology. 2008 May 7;19(18). doi: 10.1088/0957-4484/19/18/185102.
The cell membrane constitutes a major barrier for non-endocytotic intracellular delivery of therapeutic molecules from drug delivery vehicles. Existing approaches to breaching the cell membrane include cavitational ultrasound (with microbubbles), electroporation and cell-penetrating peptides. We report the use of diagnostic ultrasound for intracellular delivery of therapeutic bulky cargo with the use of molecularly targeted liquid perfluorocarbon (PFC) nanoparticles. To demonstrate the concept, we used a lipid with a surrogate polar head group, nanogold-DPPE, incorporated into the nanoparticle lipid monolayer. Melanoma cells were incubated with nanogold particles and this was followed by insonication with continuous wave ultrasound (2.25 MHz, 5 min, 0.6 MPa). Cells not exposed to ultrasound showed gold particles partitioned only in the outer bilayer of the cell membrane with no evidence of the intracellular transit of nanogold. However, the cells exposed to ultrasound exhibited numerous nanogold-DPPE components inside the cell that appeared polarized inside intracellular vesicles demonstrating cellular uptake and trafficking. Further, ultrasound-exposed cells manifested no incorporation of calcein or the release of lactate dehydrogenase. These observations are consistent with a mechanism that suggests that ultrasound is capable of stimulating the intracellular delivery of therapeutic molecules via non-porative mechanisms. Therefore, non-cavitational adjunctive ultrasound offers a novel paradigm in intracellular cargo delivery from PFC nanoparticles.
细胞膜是治疗性分子从药物递送载体进行非内吞性细胞内递送的主要障碍。现有的突破细胞膜的方法包括空化超声（结合微泡）、电穿孔和细胞穿透肽。我们报道了利用诊断超声，通过分子靶向液态全氟碳（PFC）纳米颗粒实现治疗性大分子货物的细胞内递送。为了验证这一概念，我们使用了一种带有替代极性头部基团的脂质，即纳米金 - 二棕榈酰磷脂酰乙醇胺（nanogold-DPPE），将其掺入纳米颗粒脂质单层中。将黑色素瘤细胞与纳米金颗粒一起孵育，随后用连续波超声（2.25 MHz，5分钟，0.6 MPa）进行超声处理。未接受超声处理的细胞显示金颗粒仅分布在细胞膜的外双层中，没有纳米金进入细胞内的迹象。然而，接受超声处理的细胞在细胞内显示出大量纳米金 - DPPE成分，这些成分在细胞内囊泡中呈极化分布，表明细胞发生了摄取和运输。此外，接受超声处理的细胞未显示钙黄绿素的掺入或乳酸脱氢酶的释放。这些观察结果与一种机制相符，该机制表明超声能够通过非孔化机制刺激治疗性分子的细胞内递送。因此，非空化辅助超声为从PFC纳米颗粒进行细胞内货物递送提供了一种新的模式。
