An unexpected response from a minority of cells can have a dramatic impact on the development, prognosis, and treatment of disease. For example, in the treatment of cancer, the survival and resurgence of an aggressive, subclonal lineage of the malignant cells is not exceptional. Yet, we are only just beginning to uncover these phenomena and the underlying biological mechanisms because they are obscured at the bulk scale. Detection of a rare phenotype or cellular response can require the analysis of thousands of individual cells. To address this need, we propose to develop a dielectrophoresis (DEP)-based device with a high yield of few- or single-cell capture in an array format using inexpensive and simple components. Specifically, we propose to use ion depletion and enrichment at bipolar electrodes (BPEs) to generate an array of narrow electric field maxima and minima for array-based cell capture. This technological development is significant because 1) it addresses a need for effective and inexpensive single-cell manipulation, 2) the ion enrichment and depletion zones provide strong electric field gradients (strong DEP force) having a tunable size and location, 3) the use of BPEs allows facile arraying. DEP is a versatile and powerful technique that has grown in use recently to include commercial technology. DEP can be used to transport, sort, trap, and filter cells without cell labels or expensive components and has been extended to single-cell arrayed capture. Despite these major advantages, current DEP technologies have remaining challenges to overcome, and three of the most serious shortcomings relate to the generation of the electric field gradient required for DEP force. First, while DEP technologies can be operated in parallel, there are practical barriers to achieving an array of local electric field gradients. Second, the range over which DEP force exists around these electrodes and insulating barriers can be too short for high throughput device operation. Third and finally, the size and location of the electri field produced by each of these strategies is fixed, lacking plasticity. Here, we propose to shape the electric field using localized control of the conductivity of the DEP medium via faradaic ion enrichment and depletion at an array of BPEs. The proposed technology has the following unique advantages: 1) the ion depletion and enrichment zones will generate strong DEP force around the trapping locations owing to steep electric field gradients and a synergistic effect on the complex permittivity of the DEP medium, 2) these electric field gradients can extend further from the electrodes than those generated by traditional DEP electrode arrays, 3) the trapping location can be mobilized using fluid flow.
The proposed technology will have a broad-reaching impact on the interrogation of heterogeneity within cell populations - for example, tracking the evolution of tumor cells. This will be accomplished using a simple microdevice that will capture single cells in an array format using dielectrophoretic (DEP) force. This DEP force will be controlled through the local conductivity of the solution - a strategy that allows for strong forces and the generatio of a large array of traps.
| Thompson, Alison M; Smith, Jordan L; Monroe, Luke D et al. (2018) Self-digitization chip for single-cell genotyping of cancer-related mutations. PLoS One 13:e0196801 |
| Wu, Li; Wu, I-Che; DuFort, Christopher C et al. (2017) Photostable Ratiometric Pdot Probe for in Vitro and in Vivo Imaging of Hypochlorous Acid. J Am Chem Soc 139:6911-6918 |
