This article presents a compact, low-cost, robust, and flexible test platform for determining the concentration of drugs in fluids. This device is based on a PVC foil card containing copper conductive foils in which disposable paper test strips are inserted. The paper test strips are overlaid with deposition of multiwalled carbon nanotubes (MWCNTs) acting as a sensing layer. When a paper test strip is inserted into the test card, the conductive path between two copper lines is established. A drop of test fluid on the sensing MWCNT layer changes the conductivity in a concentration-dependent manner, enabling calculation of the drug concentration after measurement of the electrical resistance at the copper terminals. An equivalent electrical circuit was also proposed to model the response of the fabricated sensor. It was shown that model parameters are dependent on the concentration of the cytostatic drug methotrexate. Additionally, the fabricated sensor demonstrated the ability to differentiate the same concentration of methotrexate and cyclophosphamide. The complete readout electronics and polynomial transfer function for calculating drug concentrations were also developed and are presented.

中文翻译：

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基于功能化纸条的平台，用于快速检测抗癌药物浓度

本文介绍了一种紧凑、低成本、稳健且灵活的测试平台，用于确定液体中的药物浓度。该设备基于包含铜导电箔的 PVC 箔卡，其中插入了一次性纸测试条。纸测试条上覆盖着多壁碳纳米管 (MWCNT) 的沉积物，作为传感层。当纸试纸插入试卡时，两条铜线之间的导电通路就建立起来了。检测 MWCNT 层上的一滴测试液会以浓度相关的方式改变电导率，从而能够在测量铜端子处的电阻后计算药物浓度。还提出了等效电路来模拟制造的传感器的响应。结果表明，模型参数取决于细胞抑制药物甲氨蝶呤的浓度。此外，制造的传感器展示了区分相同浓度的甲氨蝶呤和环磷酰胺的能力。还开发并介绍了用于计算药物浓度的完整读出电子学和多项式传递函数。