Application of polymer-based microfluidic devices for the selection and manipulation of low-abundant biological cells

Abstract

Microfluidics are providing new opportunities for diagnostics. Innovative technologies developed in our group allow for the selection, enumeration, and molecular profiling of low-abundant (<100 cells/mL) circulating tumor cells (CTCs) directly from blood. Cancer cells overexpressing the integral membrane protein, EpCAM, were immunospecifically isolated using anti-EpCAM antibodies immobilized onto the walls of a selection bed poised on a microfluidic device. The cells were enzymatically released from the surface and hydrodynamically carried for enumeration through pair of platinum (Pt) electrodes. Following counting, CTCs were withdrawn electrophoretically from the bulk flow, and preconcentrated into an anodic reservoir. The molecular processing invoked a strategy consisting of a primary PCR for amplification of gene fragment, and an allele-specific ligation reaction to detect mutations within specific gene. The strategy developed offers the ability to profile point mutations harbored in rare CTCs in whole blood without the interferences from highly abundant leukocytes and erythrocytes. The entire CTCs enumeration and preconcentration steps can be implemented in under 40 min for 1 mL samples.