Banerji Shayla K, Hayes Mark A
Arizona State University, Department of Chemistry and Biochemistry, Tempe, AZ 85287, USA.
Langmuir. 2007 Mar 13;23(6):3305-13. doi: 10.1021/la0622875. Epub 2007 Jan 30.
Nonendocytotic transport is believed to play a role in the transmigration of particles less than 100 nm within biological systems. Determining the fundamental mechanism of this transport across cell membranes is essential if nanotechnology is to be utilized in general medical practice and may lead to methods of treating the deleterious internalization of ambient, possibly pollutant, nanoparticles. In order to gain a broader understanding of nonendocytotic transmembrane transport, it becomes essential to devise a method which allows the isolation of fundamental modes of transport such as passive Brownian diffusion through a membrane, as opposed to effusion-like transport of particles through transmembrane channels. The passive Brownian diffusion contribution was investigated using gold nanoparticles and mimetic biomembranes. Specifically, gold nanoparticle dispersions consisting of 7, 10, and 15 nm diameter particles were captured in giant unilamelar vesicles composed of phosphatidylcholine, phosphatidic acid, and cholesterol. Nonendocytotic transmembrane transport was modeled as the time derivative of the appearance of nanoparticles in the phosphate buffer outside the vesicles at 37 degrees C. The results show the transport rate to be zero; hence, a simple diffusive process of transmembrane transport is not supported.
非内吞性运输被认为在生物系统中小于100纳米的颗粒转运中发挥作用。如果要在一般医学实践中利用纳米技术，确定这种跨细胞膜运输的基本机制至关重要，并且可能会带来治疗环境中可能存在的污染物纳米颗粒有害内化的方法。为了更广泛地理解非内吞性跨膜运输，设计一种方法变得至关重要，该方法能够分离基本的运输模式，如通过膜的被动布朗扩散，这与颗粒通过跨膜通道的类似渗出的运输相反。使用金纳米颗粒和模拟生物膜研究了被动布朗扩散的贡献。具体而言，由直径为7、10和15纳米的颗粒组成的金纳米颗粒分散体被捕获在由磷脂酰胆碱、磷脂酸和胆固醇组成的巨型单层囊泡中。非内吞性跨膜运输被模拟为在37摄氏度下囊泡外部磷酸盐缓冲液中纳米颗粒出现的时间导数。结果表明运输速率为零；因此，不支持跨膜运输的简单扩散过程。
