College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
Environ Sci Technol. 2011 Jul 15;45(14):6018-24. doi: 10.1021/es200790x. Epub 2011 Jun 23.
Adsorption of phenanthrene on carbon nanotubes (CNTs) and bioaccessibility of adsorbed phenanthrene were studied in simulated gastrointestinal fluids. Adsorption of phenanthrene on CNTs was suppressed in pepsin (800 mg/L) solution (gastric) and bile salt (500 and 5000 mg/L) fluids (intestinal). In addition to competitive sorption, pepsin and high-concentration bile salt (5000 mg/L, above critical micelle concentration) solubilized phenanthrene (3 and 30 times of the water solubility, respectively), thus substantially reduced phenanthrene adsorption on CNTs. Pepsin and bile salts also increased the rapidly desorbing phenanthrene fraction from CNTs. The rapidly desorbing phase lasted less than 1 h for all CNTs. Further, 43-69% of phenanthrene was released from CNTs after desorption in the simulated gastric and intestinal fluid at low bile salt concentration while 53-86% was released in the gastric and intestinal fluid at high bile salt concentration. These findings suggest that the release of residual hydrophobic organic compounds from CNTs could be enhanced by biomolecules such as pepsin and bile salts in the digestive tract, thus increasing the bioaccessibility of adsorbed phenanthrene and possibly the overall toxicity of phenanthrene associated CNTs.
在模拟胃肠道液体中研究了多环芳烃菲在碳纳米管（CNT）上的吸附和被吸附菲的生物可及性。在胃蛋白酶（800mg/L）溶液（胃）和胆汁盐（500 和 5000mg/L）（肠）中，菲在 CNT 上的吸附受到抑制。除了竞争吸附之外，胃蛋白酶和高浓度胆汁盐（5000mg/L，高于临界胶束浓度）还溶解了菲（分别是水溶解度的 3 和 30 倍），从而大大降低了 CNT 上菲的吸附。胃蛋白酶和胆汁盐还增加了 CNTs 上快速解吸的菲部分。对于所有 CNTs，快速解吸阶段持续不到 1 小时。此外，在低胆汁盐浓度下，在模拟胃和肠液中解吸后，有 43-69%的菲从 CNTs 中释放出来，而在高胆汁盐浓度下，有 53-86%的菲从 CNTs 中释放出来。这些发现表明，在消化道中的生物分子（如胃蛋白酶和胆汁盐）的作用下，CNTs 中残留的疏水性有机化合物的释放可能会增强，从而提高被吸附菲的生物可及性，并可能增加与菲相关的 CNTs 的整体毒性。
