Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
Nanotoxicology. 2012 Aug;6(5):514-25. doi: 10.3109/17435390.2011.587904. Epub 2011 Jun 3.
The objective of this study was to investigate whether nanoparticle-exposure affects enzyme function and to determine the mechanisms responsible. Silicon, Au, and CdSe nanoparticles were synthesized in house and their physicochemical properties were characterized. The activity of purified lactate dehydrogenase (LDH) was inhibited or abolished by all nanoparticles tested. Inhibition was dependent upon particle core and surface-functional group composition. Inhibition of LDH was absent in crude tissue homogenates, in the presence of albumin, and at the isoelectric point of the protein, indicating that nanoparticles bind non-specifically to abundant proteins via a charge interaction. Circular dichroism spectroscopy suggests that the structure of LDH may be altered by nanoparticles in a manner different from that of bulk controls. We present new data on the specific physicochemical properties of nanoparticles that may lead to bioactivity and highlight a number of potentially serious problems with common nanotoxicity testing methods.
本研究旨在探讨纳米颗粒暴露是否会影响酶的功能，并确定其相关机制。我们在实验室中合成了硅、金和 CdSe 纳米颗粒，并对其物理化学性质进行了表征。所有测试的纳米颗粒均能抑制或完全破坏纯化的乳酸脱氢酶（LDH）的活性。这种抑制作用取决于颗粒的核心和表面官能团组成。在粗组织匀浆中、白蛋白存在的情况下以及在蛋白质等电点时，LDH 的抑制作用均不存在，这表明纳米颗粒通过电荷相互作用非特异性地与丰富的蛋白质结合。圆二色性光谱分析表明，纳米颗粒可能以不同于块状对照的方式改变 LDH 的结构。我们提出了有关纳米颗粒特定物理化学性质的新数据，这些性质可能导致其具有生物活性，并强调了常见的纳米毒性测试方法存在的一些潜在严重问题。
