Compared with the conventional DNA probe immobilization on the planar surface, nanoparticles-based DNA probes enable more RNA molecules to be anchored to the sensor surface, thereby improving the detection sensitivity. In this work, we report phosphorodiamidate morpholino oligomers (PMO)-graphene quantum dots (GQDs)-functionalized reduced graphene oxide (RGO) field effect transistor (FET) biosensors for ultrasensitive detection of exosomal microRNAs. After the RGO FET sensor was fabricated, polylysine (PLL) film was deposited onto the RGO surface. GQDs-PMO hybrid was prepared and covalently bound to PLL surface, enabling detection of exosomal microRNAs (miRNAs). The method achieved a detection limit as low as 85 aM and high specificity. Furthermore, the FET sensor was able to detect exosomal miRNAs in plasma samples and distinguish breast cancer samples from healthy samples. Compared with other methods, we use GQDs to further improve the sensitivity of FET, making it a potential tool for early diagnosis of breast cancer.

与传统的DNA探针固定在平面上相比，基于纳米颗粒的DNA探针可以使更多的RNA分子锚定在传感器表面，从而提高检测灵敏度。在这项工作中，我们报告了用于超灵敏检测外泌体 microRNA 的磷酰二胺吗啉寡聚物 (PMO)-石墨烯量子点 (GQD)-功能化还原氧化石墨烯 (RGO) 场效应晶体管 (FET) 生物传感器。在制造 RGO FET 传感器后，将聚赖氨酸 (PLL) 薄膜沉积在 RGO 表面上。制备了 GQDs-PMO 杂合体并与 PLL 表面共价结合，从而能够检测外泌体 microRNA (miRNA)。该方法实现了低至 85 aM 的检测限和高特异性。此外，FET 传感器能够检测血浆样本中的外泌体 miRNA，并将乳腺癌样本与健康样本区分开来。与其他方法相比，我们使用 GQD 进一步提高了 FET 的灵敏度，使其成为乳腺癌早期诊断的潜在工具。