Dielectrophoretic Traps for Efficient Bead and Cell Trapping and Formation of Aggregates of Controlled Size and Composition

Abstract

We present a microfluidic dielectrophoretic-actuated system designed to trap chosen single-cell and form controlled cell aggregates. A novel method is proposed to characterize the efficiency of the dielectrophoretic trapping, considering the flow speed but also the heat generated by the traps as limiting criteria in cell-safe manipulation. Two original designs with different manufacturing processes are experimentally compared. The most efficient design is selected and the cell membrane integrity is monitored by fluorescence imaging to guarantee a safe-cell trapping. Design rules are suggested to adapt the traps to multiple-cells trapping and are experimentally validated as we formed aggregates of controlled size and composition with two different types of cells. We provide hereby a simple manufactured tool allowing the controlled manipulation of particles for the composition of multicellular assemblies.

Microfluidic device combining hydrodynamic and dielectrophoretic trapping for the controlled contact between single micro-sized objects and application to adhesion assays

“…The photoresist residues remaining in the buried channels were then cleaned using oxygen plasma (GIGAbatch, PVA TePla). The top PDMS channels were then molded, aligned and permanently bonded to the electrodes and glass channels as described by Lipp et al 19 The full fabrication process is shown in Fig. S1, † and pictures of the fabricated combined traps and the whole final chip in Fig.…”

“…The effects are thus orthogonal for an independent manipulation of the two micro-sized particles. The method relies on the combination of two trapping methods based on planar hydrodynamic trapping of cells 18 and dielectrophoretic (DEP) trapping, 19 both physical principles being widely used to precisely manipulate and trap single cells. 20,21 The fabrication processes were successfully implemented sequentially to provide a novel device with both capabilities.…”

Microfluidic device combining hydrodynamic and dielectrophoretic trapping for the controlled contact between single micro-sized objects and application to adhesion assays

“…The remaining photoresist residues remaining in the buried channels are then cleaned using an oxygen plasma (GIGAbatch, PVA TePla). The top PDMS channels are then molded, aligned and permanently bonded to the electrodes and glass channels as described in (19). The full fabrication process is illustrated in Figure S4 in supplementary material, and pictures of the fabricated combined traps and the whole final chip respectively in Figures S5 and S2A.…”

“…This latter is composed of an upstream DEP actuated deviation system capable of steering the incoming particles to specific streamlines (22), followed by an expansion of the channel and two lines of DEP traps. Each line is made of coplanar electrodes and comprises four distinct trapping units capable of focusing the particles to one point in three dimensions (19) as well as a bypass zone to which unwanted particles can be deviated to leave the chamber. The upstream line is named the synchronization line because its role is to synchronize the arrival of particles to the second line once the amount of particles per trap is reached.…”

“…The effects are thus orthogonal for an independent manipulation of the two micro-sized particles. The method relies on the combination of two previously published trapping methods based on planar hydrodynamic trapping of cells (18) and dielectrophoretic (DEP) trapping (19), both physical principles being widely used to precisely manipulate and trap single cells (20,21). We first present the working principle of the microfluidic device and its capabilities (Section).…”