Ultrahigh-throughput magnetic sorting of large blood volumes for epitope-agnostic isolation of circulating tumor cells

Abstract

<jats:p>Circulating tumor cell (CTC)-based liquid biopsies provide unique opportunities for cancer diagnostics, treatment selection, and response monitoring, but even with advanced microfluidic technologies for rare cell detection the very low number of CTCs in standard 10-mL peripheral blood samples limits their clinical utility. Clinical leukapheresis can concentrate mononuclear cells from almost the entire blood volume, but such large numbers and concentrations of cells are incompatible with current rare cell enrichment technologies. Here, we describe an ultrahigh-throughput microfluidic chip, <jats:sup>LP</jats:sup>CTC-iChip, that rapidly sorts through an entire leukapheresis product of over 6 billion nucleated cells, increasing CTC isolation capacity by two orders of magnitude (86% recovery with 10<jats:sup>5</jats:sup> enrichment). Using soft iron-filled channels to act as magnetic microlenses, we intensify the field gradient within sorting channels. Increasing magnetic fields applied to inertially focused streams of cells effectively deplete massive numbers of magnetically labeled leukocytes within microfluidic channels. The negative depletion of antibody-tagged leukocytes enables isolation of potentially viable CTCs without bias for expression of specific tumor epitopes, making this platform applicable to all solid tumors. Thus, the initial enrichment by routine leukapheresis of mononuclear cells from very large blood volumes, followed by rapid flow, high-gradient magnetic sorting of untagged CTCs, provides a technology for noninvasive isolation of cancer cells in sufficient numbers for multiple clinical and experimental applications.</jats:p>

A Review of Circulating Tumour Cell Enrichment Technologies

“…Most recently, the fourth generation MGH microfluidic chip has been published; the ultrahigh-throughput microfluidic LP CTC-iChip which combines leukapheresis with high precision microfluidic negative enrichment to allow for the sorting of unlabelled, viable CTCs [ 50 ].…”

“…Leukepheresis concentrates on average 7 × 10 9 PBMCs (including CTCs) from ∼5 L blood into a leukopak of ∼65 mL during an hour long procedure which is estimated to contain between 100 and 20,000 CTCs depending on the type and stage of disease [ 50 , 136 ]. The LP CTC-iChip is able to process the entire 65 mL leukopak and allows for the depletion of between 50- and 100-fold more WBCs than other magnetic enrichment technologies.…”

“…The CTC-Chip was the first of four generations of chips developed by MGH; superseded by the herringbone (HB)-chip, CTC-iChip and most recently the LP CTC-iChip [ 20 , 49 , 50 ]. The CTC-iChip and LP CTC-iChip employ combinatorial approaches for CTC enrichment and will be discussed later.…”

What Is Known about Theragnostic Strategies in Colorectal Cancer

“…Recently, for the selection of CTC, a “negative depletion” microfluidic chip has been developed [ 140 ]. In this system, named leukapheresis, the leukocyte depletion strategy can enrich for untagged CTCs in a “tumor-independent” manner applicable to all tumor types, as demonstrated in several tumor types [ 141 , 142 , 143 , 144 ].…”

Current strategies and opportunities to manufacture cells for modeling human lungs

“…The challenge of assembling lung cells into reproducible arrays of “lung tissues” is starting to be addressed by emerging high-throughput techniques that seek to purify specific cell populations [ [254] , [255] , [256] ] that could be later mixed in controlled ratios to generate precise tissue compositions. Bioprinting [ [257] , [258] , [259] ] and cellular assembly efforts, including organoid fabrication through DNA programming [ 260 ], could also potentially prove useful to enabling complex tissue assembly in a manner that is adequately scalable and reproducible for screening.…”