The external acid environment of cancer cells is different from that of normal cells, making a profound impact on cancer progression. Here we report a simple poly-l-lysine-modified graphene field-effect transistor (PLL@G-FET) for in situ monitoring of extracellular acidosis around cancer cells. PLL is a well-known material with good biocompatibility and is rich in amino groups that are sensitive to hydrogen ions. After a simple drop-casting of PLL on the reduced graphene oxide (RGO) FET surface, the PLL@G-FET was able to realize the real-time monitoring of the localized pH change of cancer cells after the cancer cells were grown on the device. The PLL@G-FET sensor achieved a Nernstian value of 52.9 mV/pH in phosphate buffer saline from pH 4.0 to 8.0. In addition, the sensor exhibited excellent biocompatibility as well as good anti-interference ability in the cell culture medium. Furthermore, the device was used to real-time monitor the extracellular pH changes of MCF-7 cells under the intervention of different concentrations of drugs. This developed pH-sensitive FET provides a new method to study the extracellular acid environment in situ and helps us to enhance our understanding of cancer cell metabolism.

癌细胞的外部酸性环境不同于正常细胞，对癌症进展产生深远影响。在这里，我们报告了一个简单的 poly- l-赖氨酸修饰的石墨烯场效应晶体管 (PLL@G-FET)，用于原位监测癌细胞周围的细胞外酸中毒。PLL是一种众所周知的材料，具有良好的生物相容性，富含对氢离子敏感的氨基。在还原氧化石墨烯 (RGO) FET 表面简单滴铸 PLL 后，PLL@G-FET 能够实时监测癌细胞在 RGO 上生长后的局部 pH 变化设备。PLL@G-FET 传感器在 pH 4.0 至 8.0 的磷酸盐缓冲盐水中实现了 52.9 mV/pH 的能斯特值。此外，该传感器在细胞培养基中表现出优异的生物相容性和良好的抗干扰能力。此外，该装置用于实时监测MCF-7细胞在不同浓度药物干预下的胞外pH变化。这种开发的 pH 敏感 FET 提供了一种原位研究细胞外酸环境的新方法，有助于我们增强对癌细胞代谢的理解。