Liquid biopsies allow non-invasive tumor detection by analyzing circulating tumor DNA (ctDNA) in a blood sample. However, ctDNA in blood is usually sparse, limiting the sensitivity of liquid biopsies. Writing in Science, Martin-Alonso and colleagues overcome this challenge by developing two injectable priming agents that temporarily boost the concentration of ctDNA in vivo.

To increase the levels of ctDNA in circulation, the authors developed a nanoparticle that acts on macrophages in the liver responsible for clearing ctDNA from the blood. The liposomal nanoparticles are efficiently phagocytosed by the liver-resident cells, which are then temporarily unable to take up ctDNA. Injecting the nanoparticle primer in mice increased ctDNA recovery from blood samples over tenfold.

液体活检通过分析血液样本中的循环肿瘤 DNA (ctDNA) 来实现非侵入性肿瘤检测。然而，血液中的 ctDNA 通常很稀疏，限制了液体活检的灵敏度。 Martin-Alonso 及其同事在《科学》杂志上撰文，克服了这一挑战，开发了两种可注射的启动剂，可暂时提高体内 ctDNA 的浓度。

为了提高循环中 ctDNA 的水平，作者开发了一种纳米颗粒，作用于肝脏中负责清除血液中 ctDNA 的巨噬细胞。脂质体纳米粒子被肝脏驻留细胞有效吞噬，然后暂时无法吸收 ctDNA。在小鼠体内注射纳米颗粒引物可使血液样本中 ctDNA 的回收率提高十倍以上。