Extremely rare circulating tumor cell (CTC) clusters are both increasingly appreciated as highly metastatic precursors and virtually unexplored. Technologies are primarily designed to detect single CTCs and often fail to account for the fragility of clusters or to leverage cluster-specific markers for higher sensitivity. Meanwhile, the few technologies targeting CTC clusters lack scalability. Here, we introduce the Cluster-Wells, which combines the speed and practicality of membrane filtration with the sensitive and deterministic screening afforded by microfluidic chips. The >100,000 microwells in the Cluster-Wells physically arrest CTC clusters in unprocessed whole blood, gently isolating virtually all clusters at a throughput of >25 mL/h, and allow viable clusters to be retrieved from the device. Using the Cluster-Wells, we isolated CTC clusters ranging from 2 to 100+ cells from prostate and ovarian cancer patients and analyzed a subset using RNA sequencing. Routine isolation of CTC clusters will democratize research on their utility in managing cancer.
Many regulated epigenetic elements and base lesions found in genomic DNA can both directly impact gene expression and play a role in disease processes. However, due to their non-canonical nature, they are challenging to assess with conventional technologies. Here, we present a new approach for the targeted detection of diverse modified bases in DNA. We first use enzymatic components of the DNA base excision repair pathway to install an individual affinity label at each location of a selected modified base with high yield. We then probe the resulting material with a solid-state nanopore assay capable of discriminating labeled DNA from unlabeled. The technique features exceptional modularity via selection of targeting enzymes, which we establish through the detection of four DNA base elements: uracil, 8-oxoguanine, T:G mismatch, and the methyladenine analog 1,N6-ethenoadenine. Our results demonstrate the potential for quantitative nanopore assessment of a broad range of base modifications.
A monolithic 3D-printed microfluidic device integrated with stacked layers of functionalized leukodepletion channels and microfiltration for the negative enrichment of circulating tumor cells directly from clinically relevant volumes of whole blood.
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