Temperature induced tunable particle separation

TL;DR

This paper presents a temperature-controlled method for separating particles of different sizes by exploiting a negative mobility phenomenon induced by thermal fluctuations, with potential applications in biomedical diagnostics.

Contribution

It introduces a novel size-selective separation mechanism based on thermal fluctuation-induced negative mobility in a symmetric periodic potential.

Findings

Particles of specific sizes can be made to move opposite to the bias by adjusting temperature.

The method enables size-based separation without changing the physical setup.

Potential application in point-of-care lab-on-a-chip devices.

Abstract

An effective approach to isolation of sub-micro sized particles is desired to separate cancer and healthy cells or in therapy of Parkinson's and Alzheimer's disease. However, since bioparticles span a large size range comprising several orders of magnitude, development of an adequate separation method is a challenging task. We consider a collection of non-interacting Brownian particles of various sizes moving in a symmetric periodic potential and subjected to an external unbiased harmonic driving as well as a constant bias. We reveal a nonintuitive, yet efficient, separation mechanism based on thermal fluctuations induced negative mobility phenomenon in which particles of a given size move in a direction opposite to the applied bias. By changing solely temperature of the system one can separate particles of various strictly defined sizes. This novel approach may be important step towards development of point-of-care lab-on-a-chip devices.