Simultaneous measurements of glucose, lactate, and neurotransmitters (e.g., glutamate) in cell culture over hours and days can provide a more dynamic and longitudinal perspective on ways neural cells respond to various drugs and environmental cues. Compared with conventional microfabrication techniques, direct writing of conductive ink is cheaper, faster, and customizable, which allows rapid iteration for different applications. Using a simple direct writing technique, we printed biosensor arrays onto cell culture dishes, flexible laminate, and glass to enable multianalyte monitoring. The ink was a composite of PEDOT:PSS conductive polymer, silicone, activated carbon, and Pt microparticles. We applied 0.5% Nafion to the biosensors for selectivity and functionalized them with oxidase enzymes. We characterized biosensors in phosphate-buffered saline and in cell culture medium supplemented with fetal bovine serum. The biosensor arrays measured glucose, lactate, and glutamate simultaneously and continued to function after incubation in cell culture at 37 °C for up to 2 days. We cultured primary human astrocytes on top of the biosensor arrays and placed arrays into astrocyte cultures. The biosensors simultaneously measured glucose, glutamate, and lactate from astrocyte cultures. Direct writing can be integrated with microfluidic organ-on-a-chip platforms or as part of a smart culture dish system. Because we print extrudable and flexible components, sensing elements can be printed on any 3D or flexible substrate.

中文翻译：

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使用直接写入来简单制造柔性生物传感器阵列，用于人类星形胶质细胞的多分析物测量。


在数小时和数天内同时测量细胞培养物中的葡萄糖、乳酸和神经递质（例如谷氨酸）可以为神经细胞对各种药物和环境线索的反应方式提供更动态和纵向的视角。与传统的微加工技术相比，导电墨水的直写成本更低、速度更快且可定制，从而可以针对不同的应用进行快速迭代。使用简单的直接写入技术，我们将生物传感器阵列印刷到细胞培养皿、柔性层压板和玻璃上，以实现多分析物监测。该墨水是 PEDOT:PSS 导电聚合物、有机硅、活性炭和 Pt 微粒的复合材料。我们将 0.5% Nafion 应用于生物传感器以实现选择性，并用氧化酶对其进行功能化。我们在磷酸盐缓冲盐水和补充有胎牛血清的细胞培养基中对生物传感器进行了表征。生物传感器阵列同时测量葡萄糖、乳酸和谷氨酸，并在 37°C 细胞培养物中孵育长达 2 天后继续发挥作用。我们在生物传感器阵列顶部培养原代人类星形胶质细胞，并将阵列放入星形胶质细胞培养物中。生物传感器同时测量星形胶质细胞培养物中的葡萄糖、谷氨酸和乳酸。直接写入可以与微流体芯片器官平台集成或作为智能培养皿系统的一部分。由于我们打印可挤压的柔性组件，因此传感元件可以打印在任何 3D 或柔性基材上。