# Gel Shrinkage in Discontinuous Electrophoresis: How to Stabilize the Electrolyte Boundary in Epitachophoresis – Part 2 – Nongel Solid Support

## TL;DR

This study explores alternative solid materials to stabilize electrolyte boundaries in DNA concentration processes using discontinuous electrophoresis.

## Contribution

The paper evaluates nongel solid supports for epitachophoresis, identifying optimal materials for DNA concentration.

## Key findings

- Mechanically supported agarose gels and filtration membranes provided sharp zones and high DNA recovery.
- Plasma-treated ultrahigh molecular weight polyethylene foamed polymers showed the best overall performance.
- Rigid open structures like silica columns or nylon nets show potential for large analytes but need optimization.

## Abstract

In the first part
of this study, we have examined the shrinkage
of hydrophilic gels during epitachophoresis, an isotachophoresis-like
discontinuous electrophoretic technique, applied to concentrate DNA
samples. In the present work, we evaluated selected solid porous media
(sponges, nanofibers, foamed polymers, membranes, and structured inserts)
as alternative anticonvective media. All materials were assessed based
on zone shape, ease of creating the boundary between the leading and
trailing electrolytes, and the DNA recovery. While nanofibers and
most sponges resulted in poor separation or high analyte adsorption,
mechanically supported agarose gels and filtration membranes provided
sharp dye zones and high DNA recovery. Foamed polymers, especially
plasma-treated ultrahigh molecular weight polyethylene, showed the
best overall performance. Some rigid open structures (e.g., silica
columns or nylon nets) demonstrated potential for large analytes but
require further optimization. These results highlight key design considerations
for robust, scalable epitachophoresis devices for preparative DNA
concentration using solid-state stabilization media.