National Research Centre for Environmental Toxicology (Entox), The University of Queensland, 39 Kessels Road, Coopers Plains, QLD 4108, Australia.
Environ Sci Technol. 2013 Jul 16;47(14):7982-8. doi: 10.1021/es401014b. Epub 2013 Jun 27.
Quantification of bioaccumulative contaminants in biota is time and cost-intensive and the required extensive cleanup steps make it selective toward targeted chemical groups. Therefore tissue extracts prepared for chemical analysis are not amenable to assess the combined effects of unresolved complex mixtures. Passive equilibrium sampling with polydimethylsiloxane (PDMS) has the potential for unbiased sampling of mixtures, and the PDMS extracts can be directly dosed into cell-based bioassays. The passive sampling approach was tested by exposing PDMS to lipid-rich tissue (dugong blubber; 85% lipid) spiked with a known mixture of hydrophobic contaminants (five congeners of tetra- to octachloro-dibenzo-p-dioxins). The equilibrium was attained within 24 h. Lipid-PDMS partition coefficients (Klip-PDMS) ranged from 20 to 38, were independent of hydrophobicity, and within the range of those previously measured for organochlorine compounds. To test if passive sampling can be combined with bioanalysis without the need for chemical cleanup, spiked blubber-PDMS extracts were dosed into the CAFLUX bioassay, which specifically targets dioxin-like chemicals. Small quantities of lipids coextracted by the PDMS were found to affect the kinetics in the regularly applied 24-h bioassay; however, this effect was eliminated by a longer exposure period (72 h). The validated method was applied to 11 unspiked dugong blubber samples with known (native) dioxin concentrations. These results provide the first proof of concept for linking passive sampling of lipid-rich tissue with cell-based bioassays, and could be further extended to other lipid rich species and a wider range of bioanalytical end points.
生物体内生物蓄积污染物的定量分析既费时又费钱，而且所需的广泛清理步骤使其对目标化学物质具有选择性。因此，为化学分析而制备的组织提取物不适合评估未解析复杂混合物的综合效应。聚二甲基硅氧烷（PDMS）的被动平衡采样具有对混合物进行无偏采样的潜力，并且 PDMS 提取物可以直接用于基于细胞的生物测定。通过将 PDMS 暴露于富含脂质的组织（儒艮鲸脂；85%的脂质）中来测试被动采样方法，该组织中添加了已知的疏水性污染物混合物（五种四氯至八氯二苯并对二恶英同系物）。在 24 小时内达到平衡。脂质-PDMS 分配系数（Klip-PDMS）范围为 20 至 38，与疏水性无关，并且在先前测量的有机氯化合物的范围内。为了测试如果不需要化学清理就可以将被动采样与生物分析结合使用，向添加有疏水性污染物混合物的鲸脂-PDMS 提取物中添加了剂量，该混合物专门针对类二恶英化学物质。由 PDMS 共提取的少量脂质被发现会影响常规应用的 24 小时生物测定中的动力学；然而，通过延长暴露时间（72 小时）可以消除这种影响。该验证方法应用于 11 个已知（天然）二恶英浓度的未添加儒艮鲸脂样本。这些结果首次证明了将富含脂质的组织的被动采样与基于细胞的生物测定相结合的概念验证，并且可以进一步扩展到其他富含脂质的物种和更广泛的生物分析终点。
