Node-Pore-Sensing: A Versatile Method to Phenotype Cells

We have developed an electronic method to screen cells for their phenotypic profile, which we call Node-Pore Sensing (NPS). NPS involves using a four-terminal measurement to measure the modulated current pulse caused by a cell transiting a microfluidic channel that has been segmented by a series of inserted nodes. By simply inserting between two nodes a straight “contraction” channel through which cells can squeeze, we can simultaneously measure a cell’s size, resistance to deformation, transverse deformation, and ability to recover from deformation. I will describe how we have used “mechano-NPS” to distinguish sublineages of primary human mammary epithelial cells and the chronological age groups (i.e. “young” vs. “old”) of women from which these cells were derived—all based on the mechanical properties of the cells measured. In addition to mechanophenotyping cells, I will show how we have performed label-free, immunophenotyping of cells using NPS. In this case, cell transit an NPS device in which different segments are functionalized with antibodies corresponding to different cell-surface epitopes. When a cell has a specific surface epitope that can interact specifically with the functionalized antibodies, the cell will transit slower in that segment vs. in a segment functionalized with a control. I will show how we have successfully immunophenotyped blasts found within the bone marrow of acute myeloid leukemia patients with NPS, and how we are now using a method called highthroughput DNA-directed patterning to functionalize our devices in a straightforward and efficient manner. Finally, I will also describe the development of the next-generation NPS platform which utilizes advanced signal processing algorithms—Barker and Gold codes—directly encoded in the NPS channels to thus achieve multiplexing and higher throughput.

Learning Objectives:

1. Explain how to utilize microfluidics to perform mechanophenotyping.

2. Discuss how to utilize mechanophenotyping to differentiate malignant vs. non-malignant cells and to assess the chronological age of women who’s cells are mechanophenotyped.

3. Discuss a new method of functionalizing antibodies on a substrate and how to perform label-free immunophenotyping.