Lysis-on-Chip of Single Target Cells following Forced Interaction with CTLs or NK Cells on a Dielectrophoresis-Based Array

Abstract

Guiding the interaction of single cells acting as partners in heterotypic interactions (e.g., effectors and targets of immune lysis) and monitoring the outcome of these interactions are regarded as crucial biomedical achievements. In this study, taking advantage of a dielectrophoresis (DEP)-based Laboratory-on-a-chip platform (the DEPArray), we show that it is possible to generate closed DEP cages entrapping CTLs and NK cells as either single cells or clusters; reversibly immobilize a single virus-presenting or tumor cell within the chip at a selected position; move cages and their content to predetermined spatial coordinates by software-guided routing; force a cytotoxic effector to physically interact with a putative target within a secluded area by merging their respective cages; generate cages containing effector and target cells at predetermined E:T ratios; accurately assess cytotoxicity by real-time quantitation of the release kinetics of the fluorescent dye calcein from target cells (>50 lytic events may be tested simultaneously); estimate end points of calcein release within 16 min of initial E:T cell contact; simultaneously deliver Ab-based phenotyping and on-chip lysis assessment; and identify lytic and nonlytic E:T combinations and discriminate nonlytic effector phenotypes from target refractoriness to immune lysis. The proof of principle is provided that DEPArray technology, previously used to levitate and move single cells, can be used to identify highly lytic antiviral CTLs and tumor cells that are particularly refractory to NK cell lysis. These findings are of primary interest in targeted immunotherapy.

Transferrin Decorated Thermoresponsive Nanogels as Magnetic Trap Devices for Circulating Tumor Cells

“…Currently, there are several approaches both on the market and under trial that improve the isolation and enrichment as well as the detection of CTCs out of blood samples and in vivo . Between them, most isolation and detection techniques used are based on Velcro‐like devices, microfluidic devices, such as CTC‐chips, DEPArray system, and chaotic micromixers, or CTC enrichment methods such as electrokinetic enrichment devices, and CellCollector . Also immunochemistry‐based nanoparticles are used in systems such as CellSearch, and MagSweeper can identify and trap CTCs from whole blood .…”

Optimizing Circulating Tumor Cells’ Capture Efficiency of Magnetic Nanogels by Transferrin Decoration

“…The 1:1 ratio did not guarantee effective CTC capturing, giving values of about 30%. With a ratio of 1:3, about 60% of the CTCs were captured with PEG 4 and PEG 12 and, even more interestingly, an 81% capturing efficiency was achieved with PEG 8 . Above a ratio of 1:3, the increase of linker per Tf decreased the capturing efficiency of the system.…”

“…Different strategies have emerged in recent decades for using materials that match the requirements for capturing CTCs in blood with efficiencies ranging from 50% to 99% [3][4][5][6]. Among them, methodologies based on Velcro-like devices [7,8], biomimetic nano-platforms [9], microfluidic devices such as CTC-chips [1,10,11], DEPArray systems [12] or CTC enrichment [13,14] have been developed.…”

Spatially and temporally controlled immune cell interactions using microscale tools

“…Throughput scalability (>10 4 cell pairs), however, is nontrivial due to increasing fluidic resistances and potential for clogging. Other microfluidic systems accomplish contact formation through contactless manipulation of cells exploiting physical phenomena [33][34][35], with electrical Microscale tools for profiling immune cell interactions Dura and Voldman 25 approaches being most common [36][37][38][39] (Figure 1e). These electrical systems typically control individual cell positions, enabling creation of specific interactions on a cell-by-cell basis with precise control over number of interacting partners and initiation of interactions (within few seconds after the activation of final electrode pixel on the routing path, after moving cells to neighboring grid position).…”