Tan Hsih Yin, Loke Weng Keong, Tan Yong Teng, Nguyen Nam-Trung
DSO National Laboratories, 20 Science Park Drive, Singapore118230.
Lab Chip. 2008 Jun;8(6):885-91. doi: 10.1039/b800438b. Epub 2008 Apr 16.
Sarin (C(4)H(10)FO(2)P,O-isopropyl methylphosphonofluoridate) is a colourless, odourless and highly toxic phosphonate that acts as a cholinesterase inhibitor and disrupts neuromuscular transmission. Sarin and related phosphonates are chemical warfare agents, and there is a possibility of their application in a military or terrorist attack. This paper reports a lab-on-a-chip device for detecting a trace amount of sarin in a small volume of blood. The device should allow early detection of sarin exposure during medical triage to differentiate between those requiring medical treatment from mass psychogenic illness cases. The device is based on continuous-flow microfluidics with sequential stages for lysis of whole blood, regeneration of free nerve agent from its complex with blood cholinesterase, protein precipitation, filtration, enzyme-assisted reaction and optical detection. Whole blood was first mixed with a nerve gas regeneration agent, followed by a protein precipitation step. Subsequently, the lysed product was filtered on the chip in two steps to remove particulates and fluoride ions. The filtered blood sample was then tested for trace levels of regenerated sarin using immobilised cholinesterase on the chip. Activity of immobilised cholinesterase was monitored by the enzyme-assisted reaction of a substrate and reaction of the end-product with a chromophore. Resultant changes in chromophore-induced absorbance were recorded on the chip using a Z-shaped optical window. Loss of enzyme activity obtained prior and after passage of the treated blood sample, as shown by a decrease in recorded absorbance values, indicates the presence of either free or regenerated sarin in the blood sample. The device was fabricated in PMMA (polymethylmethacrylate) using CO(2)-laser micromachining. This paper reports the testing results of the different stages, as well as the whole device with all stages in the required assay sequence. The results demonstrate the potential use of a field-deployable hand-held device for point-of-care triage of suspected nerve agent casualties.
沙林（C₄H₁₀FO₂P，O - 异丙基甲基膦酰氟）是一种无色、无味且剧毒的膦酸酯，它作为胆碱酯酶抑制剂，会破坏神经肌肉传递。沙林及相关膦酸酯是化学战剂，有可能被用于军事或恐怖袭击。本文报道了一种用于检测少量血液中痕量沙林的芯片实验室装置。该装置应能在医疗分诊期间早期检测出沙林暴露情况，以便区分需要医疗救治的人员与群体性心因性疾病患者。该装置基于连续流微流体技术，具有全血裂解、从与血液胆碱酯酶的复合物中再生游离神经毒剂、蛋白质沉淀、过滤、酶促反应和光学检测等连续步骤。首先将全血与神经毒气再生剂混合，接着进行蛋白质沉淀步骤。随后，裂解产物在芯片上分两步过滤以去除颗粒和氟离子。然后使用芯片上固定的胆碱酯酶检测过滤后的血液样本中再生沙林的痕量水平。通过底物的酶促反应以及终产物与发色团的反应来监测固定胆碱酯酶的活性。使用Z形光学窗口在芯片上记录发色团诱导吸光度的变化。处理后的血液样本通过前后固定酶活性的损失，如记录的吸光度值降低所示，表明血液样本中存在游离或再生的沙林。该装置采用CO₂激光微加工技术在聚甲基丙烯酸甲酯（PMMA）中制造。本文报道了不同阶段以及按所需检测顺序包含所有阶段的整个装置的测试结果。结果证明了一种可现场部署的手持式装置在疑似神经毒剂伤亡人员床边分诊中的潜在用途。
