Size-Specific Capture of Circulating DNA Onto a Nanotip Using Dielectrophoretic and Capillary Forces

One of the critical challenges in the fields of disease diagnostics and environmental molecular biology is detection of circulating DNA from a sample mixture. Circulating DNA is free DNA in biological solution, which can provide critical information about pathogens and toxins. Current DNA detection methods, however, are not able to directly capture circulating DNA. This paper presents a novel, size-specific concentration mechanism that captures DNA onto a nanotip using dielectrophoresis and capillary action in a size-specific way. To investigate the size-specific mechanism, the dielectrophoretic force and the capillary forces are compared. The experiment using nanospheres are performed to validate the size-specific mechanism. The size-specific concentration is also demonstrated for capturing DNA from sample mixtures. The experimental and analytical work will provide the ground work formulating the basic principles for a nanoscale concentrator in a size-specific way.