The immediate processing of whole blood specimen is required in circulating tumor cell-based liquid biopsy. Reliable blood specimen stabilization towards preserving circulating tumor cells can enable more extensive geographic sharing for precise rare-cell technology, but remains challenging due to the fragility and rarity of circulating tumor cells. Herein, we establish a zwitterionic magnetic microgel platform to stabilize whole blood specimen for long-term hypothermic preservation of model circulating tumor cells. We show in a cohort study of 20 cancer patients that blood samples can be preserved for up to 7 days without compromising circulating tumor cell viability and RNA integrity, thereby doubling the viable preservation duration. We demonstrate that the 7-day microgel-preserved blood specimen is able to reliably detect cancer-specific transcripts, similar to fresh blood specimens, while there are up/down expression regulation of 1243 genes in model circulating tumor cells that are preserved by commercial protectant. Mechanistically, we find that the zwitterionic microgel assembly counters the cold-induced excessive reactive oxygen species and platelet activation, as well as extracellular matrix loss-induced cell anoikis, to prevent circulating tumor cell loss in the whole blood sample. The present work could prove useful for the development of blood-based noninvasive diagnostics.

基于循环肿瘤细胞的液体活检需要立即处理全血标本。可靠的血液样本稳定以保存循环肿瘤细胞可以为精确的稀有细胞技术实现更广泛的地理共享，但由于循环肿瘤细胞的脆弱性和稀有性，仍然具有挑战性。在此，我们建立了两性离子磁性微凝胶平台来稳定全血样本，用于模型循环肿瘤细胞的长期低温保存。我们在 20 名癌症患者的队列研究中表明，血液样本可以保存长达 7 天，而不会影响循环肿瘤细胞的活力和 RNA 完整性，从而使可行的保存期限加倍。我们证明，与新鲜血液样本类似，经过 7 天的微凝胶保存的血液样本能够可靠地检测癌症特异性转录本，同时在商业保护剂保存的模型循环肿瘤细胞中存在 1243 个基因的表达上调/下调。从机制上讲，我们发现两性离子微凝胶组件可以抵抗寒冷诱导的过量活性氧和血小板活化，以及细胞外基质损失诱导的细胞失巢凋亡，从而防止全血样本中循环肿瘤细胞的损失。目前的工作可能对基于血液的无创诊断的发展有用。