# Controlled Electrokinetic Particle Manipulation using Paper-and-Pencil Microfluidics

## TL;DR

This paper presents a simple paper-and-pencil device that uses dielectrophoresis for controlled manipulation of particles, enabling low-cost, portable, and tunable particle trapping suitable for point-of-care diagnostics.

## Contribution

It introduces a novel, accessible paper-based dielectrophoretic device that does not require complex lab equipment for particle manipulation.

## Key findings

- Successfully trapped 1 μm polystyrene particles using low-voltage fields.
- Achieved switching between positive and negative dielectrophoresis by adjusting media conductivity.
- Identified optimal pH range for effective particle trapping.

## Abstract

Dielectrophoresis is a very promising technique for particle manipulation on a chip. In this study, we demonstrate a controlled mannuvering of polystryrene particles on a simple paper-and-pencil based device by exploiting the underlying electrokinetics with primary contribution from dielectrophoretic (DEP) forces. On contrary to other reported DEP devices, the present configuration does not demand a shophitcated laboratory module for creating a non-uniform electric field, which is essential requirement in DEP settings. We demonstrate positive dielectrophoresis (pDEP) to trap 1 um size polystyrene particle for low-conductivity suspending medium, at an applied field strength of 100 V/cm. In addition, the switching of the trapping direction (positive to negative dielectrophoresis) can be simply achieved by manipulating the conductivity of the media. We further bring out an optimum range of pH for effective particle trapping. These results have significant implications towards designing cell-on-a-chip based point of care diagnostic devices for resource limited settings.

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Source: https://tomesphere.com/paper/1901.07325