Because the broadly consumed pain killer diclofenac (DCF) is a recognized pollutant, monitoring of its concentration is routinely performed in surface waters. As a valuable alternative to chromatographic and immunochemical assays, we developed a piezoelectric immunosensor to quantify DCF, first in buffer (PBS) and then in river water samples. A sensing layer comprising DCF was built up on the surface of silica-coated quartz sensors using a robust coupling chemistry. Binding of a highly affine monoclonal anti-DCF antibody was monitored in real time by quartz crystal microbalance with dissipation (QCM-D) measurements from which were determined a dissociation constant K_D of 0.24 nM and an acoustic antibody surface coverage of 1120 ng/cm² at saturation. On the other hand, an optical antibody surface coverage of 260 ng/cm² was determined by combined nanoplasmonic sensing measurement, giving a hydration percentage of 75% for the antibody monolayer. DCF assay was further set up following a competitive format for which binding of antibody to the sensing layer is inhibited by DCF in solution. The piezoelectric sensor response expressed as frequency shift ΔF was inversely related to the concentration of DCF with a dynamic range of 15–46 nM and a limit of detection (LoD) of 9.5 nM (2.8 μg/L) in PBS. This piezoelectric immunosensor was eventually applied to the assay of DCF in surface water samples taken at three different locations in the Seine and Marne rivers. The calculated concentration of DCF in these samples was in good agreement with official data published by the French center of water analysis eaufrance.

中文翻译：

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用于水资源监测的双氯芬酸生物传感器的设计和分析性能

由于广泛消耗的止痛药双氯芬酸 (DCF) 是公认的污染物，因此通常在地表水中对其浓度进行监测。作为色谱和免疫化学分析的一种有价值的替代方法，我们开发了一种压电免疫传感器来量化 DCF，首先在缓冲液 (PBS) 中，然后在河水样本中。使用强大的耦合化学在二氧化硅涂层的石英传感器表面上构建了包含 DCF 的传感层。高度亲和的单克隆抗 DCF 抗体的结合通过石英晶体微天平与耗散 (QCM-D) 测量实时监测，从中确定了0.24 nM的解离常数K _D和 1120 ng/cm 的声学抗体表面覆盖率²处于饱和状态。另一方面，通过组合纳米等离子体传感测量确定了260 ng/cm ²的光学抗体表面覆盖率，抗体单层的水合百分比为 75%。DCF 测定是按照竞争形式进一步建立的，其中抗体与传感层的结合被溶液中的 DCF 抑制。压电传感器响应表示为频移 Δ F与 DCF 的浓度呈负相关，在 PBS 中的动态范围为 15-46 nM，检测限 (LoD) 为 9.5 nM (2.8 μg/L)。这种压电免疫传感器最终被应用于在塞纳河和马恩河三个不同地点采集的地表水样品中的 DCF 分析。这些样品中 DCF 的计算浓度与法国水分析中心公布的官方数据非常吻合。