Enhanced isotachophoresis with serial zones

Researchers in Prof. Juan Santiago's laboratory have developed a modular on-chip isotachophoresis (ITP) system to extend ITP capabilities to include sensitive and selective extraction of nucleic acids. This microfludic technique establishes several initial zones of leading electrolyte (LE) arranged in series along the separation channel. As an ITP-focused sample transitions between zones, its mobility and reactivity are modified. The modifications may include sieving nucleic acids, denaturing structures, lysing cells, or hybridizing with charged species. These zones can be used to preconcentrate, select, change local denaturing conditions, and detect various analytes.

Stage of Research
The inventors have used this ITP method to quantify global microRNA (miRNA) abundance in total RNA.

Schematic showing three-zone ITP process for extraction of microRNA from total RNA. In the first zone (LE 1), we use low sieving matrix concentration to quickly but indiscriminately focus short RNA. In a second zone, we increase sieving matrix concentration to purify microRNA (straight, green bars) and reject longer RNA (curved orange segments). In a third zone, we decrease matrix concentraiton and denaturant concentration for optimal detection conditions. See Persat et al., 82, 23, Anal. Chem., 2010.