循环肿瘤DNA (ctDNA) 是从肿瘤细胞脱落到外周血液循环中的裸露DNA 分子。它们包含肿瘤特异性基因突变和其他有价值的信息。 ctDNA 被认为是液体活检中最重要的分析物之一。在过去的几十年中，许多研究人员开发了各种检测策略来进行定量或定性 ctDNA 分析，包括基于 PCR 的检测和基于测序的检测。越来越多的研究表明ctDNA作为生物标志物在肿瘤的诊断、预后和异质性方面的巨大价值。在这篇综述中，我们首先概述了基于数字 PCR (dPCR) 和基于下一代测序 (NGS) 的 ctDNA 检测系统的发展。此外，我们还介绍了基于各种生物传感器的新兴ctDNA分析策略，如电化学生物传感器、荧光生物传感器、表面等离子体共振和拉曼光谱，以及它们在生物医学领域的应用。最后，我们总结了前面讨论的要点，还涉及到现有的挑战和未来的前景。© 2023 作者。 Wiley‐VCH GmbH 代表中国科学院大学温州研究院出版的《智慧医疗》。

Circulating tumor DNA (ctDNA) is naked DNA molecules shed from the tumor cells into the peripheral blood circulation. They contain tumor-specific gene mutations and other valuable information. ctDNA is considered to be one of the most significant analytes in liquid biopsies. Over the past decades, numerous researchers have developed various detection strategies to perform quantitative or qualitative ctDNA analysis, including PCR-based detection and sequencing-based detection. More and more studies have illustrated the great value of ctDNA as a biomarker in the diagnosis, prognosis and heterogeneity of tumor. In this review, we first outlined the development of digital PCR (dPCR)-based and next generation sequencing (NGS)-based ctDNA detection systems. Besides, we presented the introduction of the emerging ctDNA analysis strategies based on various biosensors, such as electrochemical biosensors, fluorescent biosensors, surface plasmon resonance and Raman spectroscopy, as well as their applications in the field of biomedicine. Finally, we summarized the essentials of the preceding discussions, and the existing challenges and prospects for the future are also involved.© 2023 The Authors. Smart Medicine published by Wiley‐VCH GmbH on behalf of Wenzhou Institute, University of Chinese Academy of Sciences.