High-throughput rare cell separation from blood samples using steric hindrance and inertial microfluidics

Abstract

The presence and quantity of rare cells in the bloodstream of cancer patients provide a potentially accessible source for the early detection of invasive cancer and for monitoring the treatment of advanced diseases. The separation of rare cells from peripheral blood, as a "virtual and real-time liquid biopsy", is expected to replace conventional tissue biopsies of metastatic tumors for therapy guidance. However, technical obstacles, similar to looking for a needle in a haystack, have hindered the broad clinical utility of this method. In this study, we developed a multistage microfluidic device for continuous label-free separation and enrichment of rare cells from blood samples based on cell size and deformability. We successfully separated tumor cells (MCF-7 and HeLa cells) and leukemic (K562) cells spiked in diluted whole blood using a unique complementary combination of inertial microfluidics and steric hindrance in a microfluidic system. The processing parameters of the inertial focusing and steric hindrance regions were optimized to achieve high-throughput and high-efficiency separation, significant advantages compared with existing rare cell isolation technologies. The results from experiments with rare cells spiked in 1% hematocrit blood indicated >90% cell recovery at a throughput of 2.24 × 10(7) cells min(-1). The enrichment of rare cells was >2.02 × 10(5)-fold. Thus, this microfluidic system driven by purely hydrodynamic forces has practical potential to be applied either alone or as a sample preparation platform for fundamental studies and clinical applications.

Classification of large circulating tumor cells isolated with ultra-high throughput microfluidic Vortex technology

“…Continuous flow microfluidics has emerged as a promising technology for the reduced-contact isolation and extraction of viable CTCs by size, such as hydrodynamic filtration [ 20 , 21 ] or deterministic lateral displacement [ 22 , 23 ]. Recent advances in inertial microfluidics have offered a more rapid platform through which cells may be sorted by size, as fluidic forces generated from high flow rates scale strongly with cell size [ 24 , 25 ].…”

Skeletal stem cell isolation: A review on the state-of-the-art microfluidic label-free sorting techniques

“…However, the purity was only about 0.025% owing to the presence of large numbers of RBCs at the sample outlet . Later, Shen et al combined inertial microfluidics with steric hindrance into a single system achieving a 5.3 log-depletion of all blood cells in a sample diluted 40 times and spiked with fewer than 1,000 CTCs/mL, which was comparable to the work of Bhagat et al Recovery of 90% of the CTCs equated to a purity of 20% (Shen et al, 2014).…”

“…MACS separation of Stro-1 + cells provides a 950-fold enrichment of SSCs over bone marrow stromal cell populations , a value which can be further increased to 2,000-fold by further selection of CD146 + cells . Such enrichment factors are far above the best examples using microfluidic techniques for sorting stem cells (Vykoukal et al, 2008), but are clearly in the range of enrichment values achieved for sorting CTCs from whole blood, which can reach 10 4 -fold (Karabacak et al, 2014;Shen et al, 2014), or from relevant examples found for sorting progenitor cells, such as nucleated RBCs, in which over 10 3 -fold enrichment was achieved (Huang et al, 2008). Table 3 summarises the best examples found for each technique.…”

Microfluidic Platform for Cell Isolation and Manipulation Based on Cell Properties

“…Using only a single CEA channel, Wang et al [ 105 ] created siphoning outlets beside the entrapment chambers, shown in Figure 4 E, to continuously draw off 86% of the large cells trapped in the vortices and achieved 99% purity when separating RBCs from large polystyrene particles at a flow rate of 0.5 mL/min. Shen et al [ 106 ] also designed a multistage device by combining inertial microfluidics with a size-based pre filtering with CEA and post filtering with steric hindrances to sort blood cells and tumor cells MCF-7 and HeLa cells, shown in Figure 4 F. This combined stage provides >90% recovery rate at throughput of 2.24 × 10 7 cells/min with >92% viable cells were found.…”