Unsupervised capture and profiling of rare immune cells using multi-directional magnetic ratcheting

Abstract

Immunotherapies (IT) require induction, expansion, and maintenance of specific changes to a patient's immune cell repertoire which yield a therapeutic benefit. Recently, mechanistic understanding of these changes at the cellular level has revealed that IT results in complex phenotypic transitions in target cells, and that therapeutic effectiveness may be predicted by monitoring these transitions during therapy. However, monitoring will require unique tools that enable capture, manipulation, and profiling of rare immune cell populations. In this study, we introduce a method of automated and unsupervised separation and processing of rare immune cells, using high-force and multidimensional magnetic ratcheting (MR). We demonstrate capture of target immune cells using samples with up to 1 : 10 000 target cell to background cell ratios from input volumes as small as 25 microliters (i.e. a low volume and low cell frequency sample sparing assay interface). Cell capture is shown to achieve up to 90% capture efficiency and purity, and captured cell analysis is shown using both on-chip culture/activity assays and off-chip ejection and nucleic acid analysis. These results demonstrate that multi-directional magnetic ratcheting offers a unique separation system for dealing with blood cell samples that contain either rare cells or significantly small volumes, and the "sample sparing" capability leads to an expanded spectrum of parameters that can be measured. These tools will be paramount to advancing techniques for immune monitoring under conditions in which both the sample volume and number of antigen-specific target cells are often exceedingly small, including during IT and treatment of allergy, asthma, autoimmunity, immunodeficiency, cell based therapy, transplantation, and infection.

Microfluidic Passive Valve with Ultra-Low Threshold Pressure for High-Throughput Liquid Delivery

“…The conceptual design of microfluidics or lab-on-a-chip associated with point-of-care test (POCT) applications, such as biological cell separation [1,2], nucleic acid diagnostic [3,4], bacteria detection, etc. [5,6] usually require high-throughput processing, autonomous actuation, and portability.…”

Cell Separations and Sorting

“…(d) The 1 μm particles moved across the ratchet and achieved a “critical pitch” at 40 μm pillar pitch. Reproduced from Murray, C.; Miwa, H.; Dhar, M.; Park, D. E.; Pao, E.; Martinez, J.; Kaanumale, S.; Loghin, E.; Graf, J.; Rhaddassi, K.; Kwok, W. W.; Hafler, D.; Puleo, C.; Di Carlo, D. Lab Chip 2018 , 18 , 2396–2409 (ref ), with permission of The Royal Society of Chemistry. (B) Microfluidic device for MATE-seq.…”

“…Even though CTCs hold a strong presence with respect to isolation and enrichment platforms, there are other type of cells for which novel platforms were demonstrated. For example, technologies were presented for the screening and analysis of bacterial cells, − yeast cells, , immune cells, , or characterization of red blood cells. , This review will cover methods for cell separation and sorting based on numerous phenomena, such as acoustophoresis, affinity, dielectrophoresis and inertial forces, size and elasticity, deterministic lateral displacement, flow fractionation, and density gradient centrifugation. We cover in this review magnetic, impedance, and fluorescence-activated cell sorters as well as droplet-based methods.…”

Antiresonant driven systems for particle manipulation

“…Such a scenario can be realized by means of optical, electric or magnetic fields [17][18][19] or by forces resulting from the geometrical confinement of the particles. This is the case of the ondulatory motion of worm-like organisms [20,21], peristaltic pumping [22][23][24][25], fluctuating ion channels and pores [26][27][28][29][30][31][32][33][34][35][36][37] as well as synthetic soft micro-nanofluidic devices [38][39][40]. Knowing what the impact of higher order harmonics is on the response of the system is a question of great current interest.…”