J Biomed Nanotechnol. 2014 Mar;10(3):519-28. doi: 10.1166/jbn.2014.1723.
Lipid coating is a method highly used to improve the biocompatibility of nanoparticles (NPs), even though its effect on the NP properties is still object of investigation. Herein, silica NPs containing methylene blue, which is a photosensitizer used in a variety of biomedical applications, were coated with a phospholipid bilayer. Regarding the photophysical properties, lipid-coating did not cause significant changes since bare and lipid-coated NPs presented very similar absorption spectra and generated singlet oxygen with similar efficiencies. However, NP interaction with cells and membrane mimics was totally different for bare and lipid-coated NPs. Lipid-coated NPs were distributed through the cell cytoplasm whereas bare NPs were detected only in some vacuolar regions within the cells. Since cellular uptake and cytolocalization are influenced by NP adsorption on cell membranes, the interaction of lipid-coated and bare NPs were studied on a membrane mimic, i.e., Hybrid Bilayer Membranes (HBMs) made of different compositions of negatively charged and neutral lipids. Interactions of bare and lipid-coated NPs with HBMs were analyzed by Surface Plasmon Resonance Imaging. Bare NPs presented high adsorption and aggregation on HBMs independently of the surface charge. Conversely, lipid-coated NPs presented less aggregation on the membrane surface and the adsorption was dependent on the charges of the NPs and of the HBMs. Our results indicated that NPs aggregation on the membrane surface can be modulated by lipid coating, which affects the cytosolic distribution of the NPs.
脂质涂层是一种广泛用于提高纳米粒子（NPs）生物相容性的方法，尽管其对 NP 性质的影响仍在研究之中。在此，我们使用含有亚甲蓝的二氧化硅 NPs，亚甲蓝是一种用于多种生物医学应用的光敏剂，并用磷脂双层对其进行了涂层处理。关于光物理性质，涂层并没有引起显著变化，因为裸 NPs 和脂质涂层 NPs 具有非常相似的吸收光谱，并以相似的效率产生单线态氧。然而，裸 NPs 和脂质涂层 NPs 与细胞和膜模拟物的相互作用却完全不同。脂质涂层 NPs 分布在细胞质中，而裸 NPs 仅在细胞内的一些空泡区域被检测到。由于细胞摄取和细胞内定位受 NP 在细胞膜上的吸附影响，我们在膜模拟物Hybrid Bilayer Membranes (HBMs) 上研究了脂质涂层和裸 NPs 的相互作用，HBMs 由带负电荷和中性脂质的不同组成制成。通过表面等离子体共振成像分析了裸 NPs 和脂质涂层 NPs 与 HBMs 的相互作用。裸 NPs 无论表面电荷如何，在 HBMs 上都表现出高吸附和聚集。相反，脂质涂层 NPs 在膜表面的聚集较少，吸附取决于 NPs 和 HBMs 的电荷。我们的结果表明，通过脂质涂层可以调节 NP 在膜表面的聚集，从而影响 NP 在细胞中的分布。
